Comprehensive site mapping and analytical assessment report Detailed Design, Technical Definition of Works, and Supporting
Assessments/Studies required for the Removal of POPs Pesticides and Recovery of Associated Contaminated Soil along with Site Cleanup, Stabilization, Containment, and Monitoring applied to the Nubarashen Burial Site (Yerevan, Armenia) December 2017
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
Contractor: DEKONTA, a.s. Seat: Dretovice 109, 273 42 Stehelceves, Czech Republic Address: Volutova 2523, 158 00 Praha 5 Phone: + 420 235 522 252-3 Fax: + 420 235 522 254 E-mail: [email protected] Internet: www.dekonta.cz
Contact Mr. Vojtech Musil persons: Phone: + 420 724 047 927 E-mail: [email protected]
Client: United Nations Development Programme Address: 14 Petros Adamyan str. Yerevan 0010, Armenia
Contact person: Ms. Gayane Gharagebakyan, [email protected], +37491 490 243
UNDP Project Coordinator
Project: Comprehensive Site Mapping and Analytical Assessment Report
Project title: Detailed Design, Technical Definition of Works, and Supporting Assessments/Studies required for the Removal of POPs Pesticides and Recovery of Associated Contaminated Soil along with Site Cleanup, Stabilization, Containment, and Monitoring applied to the Nubarashen Burial Site (Yerevan, Armenia)
Report: FINAL
Completed by: Mr. Prokop Barson Mr. Michal Černý Mr. Petr Lacina Mr. Otakar Pazdírek Mr. Marek Polák Mr. Boris Urbánek Mr. Adam Zapletal
Reviewed and Mr. Jan Vaněk approved by: Head of Remediation and Environmental Projects Division Member of the Board of Directors
Date: December 24, 2017
Copy No. : 1 2 3
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
CONTENTS
Executive Summary ...... 1 1. Introduction ...... 10 2. Data on the Area ...... 10 2.1 Geographic Delineation of the Area ...... 10 2.2 Existing and Planned Land Use ...... 11 2.3 Basic Characterization of the Area Inhabitation ...... 13 2.4 Relations of Property Rights ...... 14 2.5 Geomorphological and Climatic Conditions ...... 14 2.6 Geological Conditions ...... 17 2.6.1 Pre-Quaternary Development ...... 17 2.6.2 Quaternary Development ...... 17 2.6.3 Tectonics ...... 18 2.6.4 Seismic Activity in the Area ...... 18 2.7 Hydrogeological Conditions ...... 20 2.8 Hydrological Conditions ...... 20 3. The Present State of Exploration of the Area ...... 21 Assessing the Discharge of Contaminants from the Nubarashen Toxic Chemicals Repository Site (2010) ...... 21 Site Assessment and Feasibility study of the Nubarashen Burial Site of Obsolete Banned Pesticides in Nubarashen, Armenia, Contract No. ARM/01/2013, OSCE, TAUW (2013) ...... 22 Strengthening National Capacities on Comprehensive Chemicals (Persistent Organic Pollutants) Contaminated Site Assessment in Armenia, Analytical Report on Sampling on Nubarashen Site, Tranfer of Czech Knowledge, GEOtest (2013) ... 24 3.1 Overview of Contamination Sources...... 25 4. Current Survey Work ...... 26 4.1 The Methodology and Scope of Survey and Analytical Work...... 26 4.1.1 RTG Spectrometry ...... 26 4.1.2 Drilling and Excavatory Works ...... 28 4.1.3 Sampling and Analytics of Soil Samples ...... 29 4.1.4 Engineering Geology ...... 32 4.1.5 Geophysical Measurements ...... 33 4.1.6 Geodesy ...... 37 4.2 Results of Survey Work...... 39 4.2.1 Geological Conditions of the Assessed Area ...... 39 4.2.2 Hydrogeological Conditions of the Assessed Area ...... 42 4.2.3 RTG Spectrometry - Evaluation of Surface Contamination ...... 42 4.2.4 RTG Spectrometry – Pure Pesticides ...... 43 4.2.5 Evaluation of Chemical Analyses of Soil Samples ...... 45 Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
4.2.6 Correlation of RTG Spectrometry and Chemical Analyses ...... 48 4.2.7 Evaluation of Soil Mechanics Analyses of Soil Samples ...... 49 4.2.8 Geotechnical Calculations ...... 50 4.2.9 Evaluation of Geophysical Measurements ...... 53 4.2.10 Techological samples ...... 55 4.3 Summary of the Extent and Degree of Contamination ...... 56 4.3.1 Category 1 – Pure Pesticides ...... 58 4.3.2 Category 2 – High Contamination ...... 58 4.3.3 Category 3 – Low Contamination ...... 58 4.3.4 Category 4 – Contaminated Construction Material ...... 59 4.4 The Balance of Contamination ...... 59 4.4.1 Methodology of calculation ...... 60 4.5 Approximate Distribution of the Main Types of POPs in the Landfill and Its Surroundings ...... 64 4.6 Migration of Contamination ...... 66 4.7 Constraints and Uncertainties ...... 67 5. Conclusions and Recommendations...... 68
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
LIST OF ANNEXES
1. Graphic Annexes Scale 1.1 General Situation of the Site 1 : 3 000 1.2 Detailed Situation of the Site 1 : 500 1.3 Geological Map 1 : 1 500 1.4 Location of Engineering-Geological Exploratory Objects 1 : 500 1.5 Location of Contamination Exploratory Objects 1 : 500 1.6 Location of Surface Contamination Exploratory Objects (X-ray Measurements) 1 : 1 000 1.7 Location of Geophysical Measurements 1 : 500 1.8 Geological Profiles of Boreholes and Pits 1 : 50 1.9 Contour map of Apparent Conductivity 1 : 500 1.10 Contour map of true Conductivity 1 : 500 1.11 Vertical sections of true Conductivity 1 : 500 1.12 Map of Surface Contamination (X-Ray Measurements) 1 : 500 1.13 Map of Subsurface Contamination - Actual Investigation 1 : 500 1.14 Photo Documentation of probes 2. Textual Annexes 2.1 Geological Documentation of Boreholes, Probes and Pits 2.2 Sampling Plan 2.3 Protocols of Chemical Laboratories Samples Collection 2.4 Laboratory Protocols of Chemical Analyses 2.5 Protocols of X-Ray Measurements 2.6 Laboratory Protocols of Soil Mechanics Analyses 2.7 Overview of Laboratory Analyses Results 2.8 Overview of Samples and Laboratory Tests 2.9 Report on Geotechnical Calculations 2.10 Report on Geodetical Survey 2.11 Documentation of Engineering-Geological Mapping Points 2.12 Permition for Site Investigation Works
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
LIST OF ABBREVIATIONS
AMA – Advanced Mercury Analyser AOX – Adsorbable Organic Halogenes BC – The Basel Convention BRL – Basic Reference Level DEMP – Dipole Electro Magnetic Profiling d.m. – Dry Matter E-G – Engineering-Geology EM – Electromagnetics EOX – Extractable Organic Halogenes GEF – Global Environment Facility GRG – Generalized Reduced Gradient LOD – Limit of Detection MES – Ministry of Emergency Situations MDL – Maximum Dose Level MG ME CR – Methodical Guidelines of the Ministry of the Czech Republic MNP – Ministry of Nature Protection NBS – Nubarashen site OCP – Organo Chlorinated Pesticides PE – Polyethylene PMB – Project Management Board POPs – Persistent Organic Polutants RoA – Republic of Armenia TCB – Tertrachlorbenzene UNDP – United Nations Development Programme
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report
Executive Summary 1. Purpose and Objective of Nubarashen Site Assessment and Characterization The site of the landfill of obsolete pesticides, founded in a landslide area of Nubarashen District of Yerevan, has been the subject of increased interest particularly since the unprofessional operations and release of buried material due the vandalism and illegal excavation of pesticides done into the landfill body before 2010. Due to the handling of the deposited pesticides, these have been spread beyond the landfill body. In compliance with the commitment of the country as a signatory party of Stockholm Convention, Armenia together with the international community has acceded to the systematic solution of the environmental load at the burial site. The extent, degree, spreading and evaluation of the risk of contamination was the subject of several previous surveys and studies co-financed largely by the international donor community including OSCE, Global Environment Facility and UNDP. The results of these surveys have directed the future activities towards the purposeful remediation of this site. Therefore, the purpose of this site assessment and characterization was chiefly a detailed delineation of areas of site contamination with particular emphasis on the identified burial cells and their immediate surroundings. Another key objective of this site assessment was to assess the stability of the area in relation to various scenarios of remedial measures. The survey was to serve for obtaining, gathering and evaluating all information relating to the site and is required for the subsequent evaluation of risks and for the design of remedial measures. 2. Brief Description of the Results/Conclusions of the Previous Survey Works The results of the previous survey works led to a general determination of the spread and quality of contamination. The following step (TAUW, 2013) was to determine the amount of contaminated material. For determining the key chemical parameters to be benchmarked and their concentration benchmark values, the values arising from the Basel and Stockholm Convention (50 mg/kg d.m. of DDT) and the limit values of CSOIL 2000 were used. Based on these benchmark values, a primary estimate of the amount of contaminated materials was carried out. Within the same commitment a risk assessment of the site was conducted and primary proposals for remediation were presented. The risk assessment concluded that at present the risks associated with the landfill site are moderate. Latent risks associated with agriculture and animal husbandry around the site, however, were present. One of the needs arising from the risk evaluation results was to carry out a supplemental survey that would specify in more detail the extent of contamination at the site. The follow-up survey (GEOtest, 2013) provided more data for the future estimation of the total amount of above-benchmark contaminated soil. The survey ascertained that a significant amount of contaminated soils occurred outside the landfill body. At the same time, a number of questions has arisen, the answers of which were the subject of the current survey. 3. Scope of Survey and Analytical Work Implemented by DEKONTA and GEOtest Based on the approved sampling plan, in total 30 probes1, 5 trenched pits, 20 surface collection points were installed and field measurements were conducted for the purpose of a contamination survey in the following scope: • 15 probes into individual cells of the landfill to the depth 2.5 – 3.5 m from the landfill surface level (geological and contamination documentation, sampling for screening
1 Probe: narrow-profile, shallow exploratory object, installed by pushing the sampler to the ground by electrical jackhammer (differs from the borehole) Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 1
analysis – 5 mixed samples and analysis, sampling for contamination spreading – 6 stratified samples and chemical analyses*); • 15 probes in the close vicinity of the landfill to the depth 1.8 – 2.0 m (geological and contamination documentation, sampling for stratification of contamination – 57 stratified samples and chemical analyses2); • 20 surface samples collected from the wider vicinity of the landfill body to the depth 0.1 m (contamination documentation and sampling for contamination spreading – 20 chemical analyses3); • 5 trenched pits (geological and contamination documentation, sampling for further technological tests); and • Field measurements using an X-ray Fluorescence (XRF) spectrometer instrument (contamination spreading and correlation of spectrometry and chemical analysis based on more than 200 measurements). Within the engineering-geological and hydrogeological surveys 13 boreholes were drilled, with a total depth of 180 m. In addition, 15 exploration trenched pits were dug. After the geological documentation of these exploratory objects, altogether 35 soil samples for soil mechanics analyses were collected. For the purpose of engineering-geological mapping of the site and its wider vicinity 43 points were documented. The geophysical survey using shallow dipole electromagnetic profiling (DEMP) was conducted to specify the location of burial cells and to identify the bedrock profile for future construction objects. In the area situated within the land surrounded by fence, in total 3,660 m of transversal and longitudinal profiles were measured. In the area outside the fence, a total of 1,773 m of profiles were measured. 4. Main Findings of Site Sampling, Analytical Characterization and Assessment Quantification of Volumes According to Categories C1, C2, C3 and C4 Based on the fusion of data from the previous surveys (TAUW, 2013 and GEOtest, 2013) and especially the current survey, the amount of the materials present was specified in the given concentration ranges: Category 1 Category 2 Category 3 Average <30% pure Depth level >30 % pure 1,500 - 50 ppm 1,500 – 0.7 ppm Thickness pesticides - pesticides d.m. d.m. 1,500 ppm d.m. [m] [m] [m2] [m3] [m2] [m3] [m2] [m3] [m2] [m3] 0.0-0.5/0.6 0.55 - - 32 18 2,034 1,119 13,423 5,105 0.5/0.6-1.0 0.45 - - 270 122 3,408 1,534 9,297 4,184 1.0-1.5 0.50 120 60 602 301 2,066 1,033 4,550 2,275 1.5-2.0 0.50 145 73 1,002 501 313 157 3,257 1,629 2.0-2.5 0.50 258 129 795 398 390 195 2,408 1,204 2.5-3.5 * 1.00 262 262 786 786 652 652 1,603 1,603 >3.5 ** 1.00 150 150 300 300 300 300 800 800 Total volume 674 2,425 4,989 16,799
2,3 Sampling for contamination – organochlorine and triazine pesticides, extractable organic halogen, chlorides, arsenic, mercury, zinc, copper and sulphur
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 2
Category 1 Category 2 Category 3 Average <30% pure Depth level >30 % pure 1,500 - 50 ppm 1,500 – 0.7 ppm Thickness pesticides - pesticides d.m. d.m. 1,500 ppm d.m. Specific gravity (t/m3) 1.5 1,7 1,7 1,7 Estimated weight (t) 1,051.5*** 4,122.5 8,481 28,558 * only in the landfill body, values calculated based on previous survey TAUW, 2013 ** only in the landfill body, values estimated based on previous survey TAUW, 2013 *** calculation made for mixture of 70% of pesticides mixture with expected specific gravity 1,5 t/m3 and 30% soil with specific gravity 1,7 t/m3. The amount of contaminated construction materials (Category 4) is estimated at 20 m3. The specific gravity for the synthetic cover of construction elements is 1,2 t/,m3, the specific gravity for construction elements (concrete, bricks, rubble) is estimated at value of 2,2 t/m3. The resulting weight of contaminated construction materials is 41 t. However, the highest permissible concentration (HPC) value(s) for contaminants will definitively be determined only by a Risk Assessment. Based on the Risk Assessment HPC value(s), the amount of contaminated material will be quantified. Quantification will be done for individual contamination categories, i.e. pure pesticides (C1 category), highly (C2 category) and lowly (C3 category) contaminated soil and contaminated construction elements (C4 category). Distribution of the Main Types of POPs in the Landfill and Its Surroundings The survey work also focused on the qualitative abundance of the individual pesticide types at the site, particularly in the individual cells (XIII-1 to XIII-5). The screening analyses revealed that a wide range of chemicals were deposited into the landfill, prevailing of which are sulphur, DDT and its metabolites (DDE, DDD) and HCH; an occurrence of Carbaryl/Sevin was sporadically detected to a larger extent (0.094 – 1,226 mg/kg). In addition, copper, phosphorus, zinc and arsenic are present in variable concentrations. The results show that only a part of the chemicals spread to the surroundings of the landfill. In the near vicinity, particularly HCH and the DDT including its decay series occur in concentrations varying from 0.06 – 1,186.46 mg/kg (mostly of Category 3 contamination with average concentration of 93 mg/kg), as well as the remnants of sulphur and zinc. Outside the fenced area, only the increased concentrations of the DDT and its decay series were found. The following figures show the data processed graphically. Cell 1 Cell 2
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 3
Cell 3 Cell 4
Cell 5 Soil associated with cells
To conclude on the real occurrence and distribution of the pesticide specimen based on the sampling of the landfill cells within the site investigation is not possible. Nevertheless, certain suggestion could be perceived from the evaluation of major pesticide specimen and chemical elements distribution and concentration shown in the table below. The cell No. 1 (the eastern most) sample contains the highest concentration of DDT (approx. 38 mass %) and sulphur (32 mass %), which indicates presence of Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green, prevailing from zinc (approx. 15 mass %) and arsenic (approx. 10 mass %) containing pesticides (Cyneb, Calcium arsenate) and DDD. The cell No. 2 sample contains predominantly sulphur-based pesticides (approx. 80 mass %), while DDT and zinc containing pesticides (Cyneb) are both present in minor concentrations lower than ca 7 mass %. Copper containing pesticides represent ca 6 mass % (Vitriol, Paris green). The cell No. 3 sample indicates major presence of DDT (65 mass %) prevailing the sulphur containing pesticides (approx. 20 mass %) and DDD (approx. 9 mass %). In the sample from the cell No. 4 sulphur containing pesticides (Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green) dominate with ca 65 mass % followed by zinc and copper containing pesticides (Cyneb, Vitriol, Paris green). Phosphorus containing pesticides
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 4
(Rezetopth, Diamin phosphate, Chlorophos, Dichol, Cynox) and HCH are both present in ca 4 wt. % concentration. The sample from the cell No. 5 represents most probably Vitriol or Paris Green pesticides assuming from the cumulative concentration of sulphur and copper at approx. 90 mass %. Zinc was present at about 7 mass % concentration. The following table presents distribution of pesticides in samples analysed. The values are calculated as a weight proportion of individual component on the bulk weight of all components detected by chemical analysis.
Cell Detected pesticides (mass %) designation according to DDT DDE DDD HCH Tetrachlorbenzene Pentachlorbenzene Carbaryl TAUW (2013) Cell 1 37,8 1,1 4,2 0,4 0,0 0,0 0,0 Cell 2 7,2 0,5 0,8 0,4 0,0 0,0 0,0 Cell 3 65,1 2,1 8,7 1,4 0,4 0,1 0,0 Cell 4 3,0 0,2 0,3 3,9 0,0 0,1 7,8 Cell 5 1,1 0,1 0,1 0,7 0,0 0,0 0,0 Cell Detected elements (mass %) Other designation detected according to As Zn Hg S P Cu pesticides TAUW (2013) Cell 1 9,6 15,1 0,0 31,5 0,0 0,1 0,1 Cell 2 0,2 4,0 0,1 81,0 0,0 5,6 0,3 Cell 3 0,0 1,8 0,0 19,8 0,0 0,1 0,5 Cell 4 0,1 7,6 0,0 64,8 4,4 7,6 0,3 Cell 5 0,0 7,4 0,1 38,9 1,1 50,5 0,1 Chemical Potentially related pesticide element As Calcium arsenate Zn Cyneb Hg Granosan S Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green P Rezetopth, Diamin phosphate, Chlorophos, Dichol, Cynox Cu Vitriol, Paris green Other detected 2,4,5-T, 2,4-D, Desmetryne, HCB, Propazine, Simetryn, DNOC, Carbedazim, Chloridazone, pesticides Propachlor, Florasulam, Monuron, Thiophanate-methyl, Simazine
Various survey works has been done on the Nubarashen burial site focused on a variable scale of pesticides and other chemical components identification. Nevertheless, the arsenic; mercury; zinc; alpha HCH; beta HCH; gama HCH; delta HCH; HCB; 2,4 DDD; 4,4 DDD; 2,4 DDE; 4,4 DDE; 2,4 DDT and 4,4 DDT were detected both by GEOtest (2013, 2017) and Tauw (2013) investigations. While Tauw in 2013 detected also presence of alpha Endosulphan, the 2017 site investigation detected the following chemical components in addition: Ametryn, Atrazin, Atrazin-desisopropyl, Atrazine-2-hydroxy, Carbedazim, Desmetryn, 2,4-D, DNOC, Florasulam, epsilon HCH, Chloridazone, Monuron, Pentachlorbenzene, Prometryn, Propachlor, Propazine, Simazine, Simetryn, Tetrachlorbenzene, 2,4,5-T, Thiophanate-methyl. This investigation have not detected alpha Endosulphan above the detection limits in any of samples analysed.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 5
Extent of Contamination The following graphic figures depict the detected findings showing the spreading of contamination exceeding the relevant benchmarks. The spreading of contamination of POPs in various concentrations at the site is significant: • In the concentration range 0.7 – 50 mg/kg d.m. of the Category 3 there is an evident presence of DDT + HCH at all studied depth levels, with the highest spreading being indicated particularly in the surface layer in which contamination occurs inside and outside the fenced area. Contamination outside the premises is spread chiefly in the western (and possibly north-eastern) direction.
• The DDT and HCH contamination surface spread is a result of previous improper site management. During an illegal intervention the landfill was opened and pesticides buried in the landfill could have been spread. These are near-surface parts and just these parts are exposed to weather effects and contaminants are spreading. The pesticides can be carried onto the surrounding land by wind or by (near-) surface runoff depending on the topographic character of the vicinity.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 6
• The occurrence of the DDT + HCH contamination concentration range 50 – 1,500 mg/kg d.m. of Category 3 is evident at all studied depth levels. The most extensive occurrence was located at a depth of 0.5 – 1.5 m. The results of the previous surveys show that the clay basement of the individual cells of the landfill is also contaminated in this concentration range. At the surface this material occurs along the northern and southern slopes of the landfill, from where it largely spreads through surface runoff towards the west. • The variable zoned distribution of the Category 2 contamination (the concentration range: > 1,500 mg/kg DDT + HCH to < 30 % pure pesticides) is evident. This concentration range was detected particularly in the landfill body and relates to the handling of the deposited waste. Contamination at the surface is present on the part adjacent to the northern edge of the landfill where in the past illegal excavation probably took place. The part adjacent to southern edge of the landfill is also affected by handling of waste and spread of contamination. • Pure pesticides or materials > 30% of pure pesticides (Category 1) were found only in the landfill cells considering the cell No. 5 being unsecured part of the landfill. • Contaminated construction materials (Category 4) were found only in the easternmost cell (XIII-1) of the landfill, where part of pesticides detected was in a liquid form. The following table presents indicative chemical parameters of the category 2 material from the landfill body, determined by the screening analyses of 5 mixed samples (each representing one pesticide-containing cell).
Ar1 Ar2 Ar3 Ar4 Ar5 Chemical Parameter /Sample +Cell Name unit Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Sum of 5 isomers of HCH 901.5 617.9 293.3 132.1 161.4 Sum of 6 isomers DDT 1,290.0 468.0 13,000.0 2,310.0 13,500.0 Sum of DDD mg/kg 167.0 43.8 1,740.0 248.8 1,988.0 Sum of DDE 84.2 27.5 420.6 157.0 391.7 Sum of DDT + HCH4 2,442.7 1,157.35 15,453.9 2,847.9 16,041.1
The geophysical method used for the purpose of the supplementary investigation use a different electrical conductivity of materials (soil with natural water content vs. high conductivity showing chemicals, substances with high content of water etc.) to indicate presence of abnormal conductivity values which indicate anthropogenic influence of the investigated area. There is no direct correlation between individual pesticide specimen and intensity of conductivity it shows. From this perspective the geophysical data confirmed and/or specified in more detail the extent or intensity of contamination discovered by contamination surveys. Intensive anomalies in electrical conductivity correspond well with the position of 5 burial cells. Moreover, the contaminated parts detected by the contamination survey in the area adjacent to the southwestern edge of the landfill were also confirmed by the geophysical survey. A place with high conductivity has been identified (approx. 1 – 4 m below ground level), situated at the entrance gate to the area. The high conductivity there more probably indicates an occurrence of natural gypsum or increased humidity rather than POPs contamination. Only the one soil sample from the surface of terrain to the depth of 0,5 m was analysed from this area. Analytical results (GEOtest, 2013) proved very low contamination by pesticides (0,3 mg/kg DDT+HCH). The presence of natural gypsum (high
4 Sum of DDT + HCH = 4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'-DDE+2,4'-DDE+αHCH+βHCH+γHCH+δHCH+εHCH 5 With respect to the accuracy of analytical method ± 40% the sample is included into the category 2 Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 7
conductivity material) was documented in the trenched pit P-5 adjacent to entrance gate where its occurrence is most likely the reason of increased values of conductivity. The presence of gypsum implies that especially in the deeper soil profile on the site (more than 1,5 – 2 m below the surface) the soil is stiff and compact, with natural gypsum filling natural vertical fractures. This indicates undisturbed natural profile not affected by excavation - construction works. Also the fact that these fractures are filled with the gypsum diminish the probability of pesticides spreading. Thus, presence of contamination deeper in the soil is highly unprobable, though not verified by chemical analyses. Main Findings, Results and Conclusions of Geotechnical and Hydrogeological Surveys and Geophysical Measurements The engineering-geological (EG) and hydrogeological (HG) conditions which control the slope stability of the site are considerably complex. The landfill of pesticides is located inside the body of a relatively large landslide. This landslide is considered as an active one, based on both observable marks (fissures) and the calculated slope stability degree at groundwater level (FS = 1,260), which indicates that the landslide slope is unstable from the medium-term perspective. Moreover, completed detailed geological mapping of the site revealed that the site is probably located in a tectonically pre-disposed valley, where a downslip fall of the northern part of the original terrain probably occurred. The region of the site is seismically active and belongs to a zone of the second highest category of hazard with gravity acceleration agR ˂ 0.4 g. Thus a possibility of earthquake of up to M 7 can be expected. The activation of a part of the landslide may occur at water saturation, during an earthquake, or in a combination of these causes. The slope inclining to the landfill site from the south (southern slope) stability calculations done for the period of spring snow melting revealed a critical situation; in such conditions the slope is just on the edge of its stability. The slope movements on this side may be activated both by the infiltration of water through the weakened geological layers and by construction activity at the slope base. With regard to the fact that the site is located on the landslide which is multiplied by real possibility of the landslide activation by groundwater infiltration, high seismic activity in the Garni fault zone and the position of the landfill on the geological fault, its permanent location is extremely hazardous. Therefore removal of sources of contamination from the site is highly recommendable. Doing excavation work in the landfill body during the future potential clean- up is possible only during the dry period. During remedial operations and building the temporary infrastructure, it is necessary to allow for risks connected with unstable slopes and clay soil changing properties subject to water saturation. Construction of temporary infrastructure buildings on the foreland area is possible. However, it is recommendable that the foundation joints be aligned and reinforced with gravel or other suitable material in such a thickness as depending on the future loading. Local engineering- geological conditions also enable to construct suitable access road or to reconstruct the existing one. The elevation and direction of the route must be designed in accordance with applicable local standards and regulations. 5. Constraints and Uncertainties Even though the amount and quality of contamination present on site was the subject of several surveys conducted, there are still minor uncertainties there. From the nature of survey works the exact extent of contamination as well as the distribution of pesticide specimen on site can never be estimated before the remedial action is completed. Nevertheless, this survey
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 8
made the latest estimates on the extent and quality of contamination significantly more valid and more exact, compiling results of the current and previous investigation results.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 9
1. Introduction
This report was compiled in order to summarise results of the site investigation conducted within the Task 2: Comprehensive Site Mapping and Analytical Assessment Report, which is a part of a Project: Detailed Design, Technical Definition of Works, and Supporting Assessments/Studies required for the Removal of POPs Pesticides and Recovery of Associated Contaminated Soil along with Site Cleanup, Stabilization, Containment, and Monitoring applied to the Nubarashen Burial Site (Yerevan, Armenia). This Project is a part of a complex programme entitled: “Elimination of obsolete pesticide stockpiles and addressing POPs contaminated sites within a sound chemicals management framework in Armenia”. It is a Global Environment Facility (GEF) project with UNDP as the GEF Implementing Agency that was first approved for preparation in February 2012 and received approval for grant funding of US$4.7 million with a co‐financing commitment of US$19.3 million in December 2014.
2. Data on the Area
2.1 Geographic Delineation of the Area
Nubarashen persistent organic pollutants (POPs) burial site (hereinafter – NBS) is situated on the south-eastern edge of the Yerevan city at the altitude of ca 1380 m above the sea level. The aerial distance between the site and the Yerevan center is ca10 km. Administratively, NBS is located in Erebuni district of Yerevan, on a relatively remote elevated slope used as a communal grazing area within a natural drainage course and it is an occupied area of approx. 0.8 ha. The "Erebuni" State Reserve (with 89 ha total area) is located in close vicinity of NBS, at the distance of 90 – 100 m to the north. Its goal is to protect the wild species of wheat and other cereals growing in their natural (original) environment. The nearest settlement is so called "Sovetashen" summer residence/cottages area that is located at the western and south-western side of NBS and the closest cottage is placed at the distance of approx. 300 m. There are 5 residential settlements, situated in more or less the same distance (3 – 4 km) from the site. The distance between the NBS and the settlements as well as their locations and directions are presented below:
3000 m Voghjaberd Kotayk region to the north-east 3200 m Geghadir Kotayk region to the north-east Nubarashen 3600 m Hatsavan Kotayk region to the east burial site 3800 m Mushavan Yerevan to the west 3800 m Verin Jrashen Yerevan to the west
Physiographically, NBS is located in drainage area and flood plain, which downhill from there turns into a seasonal stream valley. Geotechnically, it is located in an unstable area, which is situated at the eastern edge of the massive slide block called – Voghjaberd landslide field that covers a big area about 40 km2. The recent landslide reactivation started in late 1980 s, mostly due to uncontrolled irrigation in rural community of Voghjaberd. The general view of NBS with surroundings and Voghjaberd Landslide Field is presented in Figure 2.1-1.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 10
The general view of NBS and surroundings Figure 2.1-1
From Yerevan city the NBS can be reached on a predominantly tarred road by car up to the Mushavan settlement. From there the road turns into a gravel road being very bumpy in some parts. Especially during the rainy weather the road can be unpassable. View from the top of the hill near the western border of NBS to the Mushavan and Verin Jrashen settlements is shown in Figure 2.1-2.
View from the eastern border of NBS to the Mushavan and Verin Jrashen Figure 2.1-2
Verin Jrashen Mushavan
NBS
2.2 Existing and Planned Land Use
It was a widespread program initiated by Government of former Armenian Soviet Union to allocate 600m2 land-spot to each family for the construction of summer cottages and horticultural activities. The land-spot allocation and further coordination of the summer
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 11
residence blocks were conducted by the so called "Horticultural cooperatives", created by summer cottage land users. In 1980s the land-plots located on the western part of Voghjaberd Landslide Field near the Mushavan was allocated among a number of families as a new area for summer cottages and leisure. Several blocks of cottages were constructed in 1980s. Initially the area was prone to erosions, but the process was activated in late 1980s, mostly due to uncontrolled irrigation in village of Voghjaberd. Currently, part of the cottages was demolished, while some of them are still in use.As a result of this activities Voghjaberd community became another settlement that suffers from landslide phenomenon (see Figure 2.2-1). Currently, all houses and public buildings of Voghjaberd community are in emergency conditions. Construction activities are prohibited there and the population should be resettled. The area within landslide field (including the NBS) is geotechnically unstable and useless for the construction of facilities, buildings and other structures. Therefore, urbanistic developments in and around the project area are not expected. However, the attractiveness of this area can be raised with the existence of "Erebuni" State Reserve as well as gravestones of different age, ranging probably from the late medieval age until the beginning of the 21st century (located southwest to the "Erebuni" Reserve). Demolished houses and roads in Voghjaberd community Figure 2.2-1
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 12
2.3 Basic Characterization of the Area Inhabitation
The population of the Voghjaberd, Geghadir and Hatsavan rural communities, located 3 – 3.6 km south-southeast from the NBS as of January 2016 is 23206, from which 51.4% are female and 48.6% are male. The total number of households of all 3 communities is 726. The population and households number for each community is given below in Table 2.3-1. The households are mainly engaged in horticulture activities (apricot, cherry, apple, nuts, etc.) and cattle-farming.
Population of Voghjaberd, Geghadir and Hatsavan communities of Kotayk region Table 2.3-1 № Community Population Households 1 Voghjaberd 1011 317 2 Geghadir 719 240 3 Hatsavan 590 169
The 98% of population in Kotayk region are Armenians. The rest 2% are ethnic minorities, represented by Russians, Yazidis and Assyrians. The minority people are generally well integrated with Armenian people and they are not classified as indigenous. Basically, the minority people do not have difficulty of communication by Armenian language. They have all the rights and obligations of Armenians.
View from the West to the blocks of summer residence/cottages Figure 2.3-1
There are approximately 400 households based in Mushavan and Verin Jrashen settlements (situated 3.8 km west from the NBS), the outskirts of Yerevan, which are administratively
6 Marzes and Yerevan city of the RoA in figures, 2016 (www.armstat.am) Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 13
located in Erebuni district. Part of the residents works in Yerevan, while another part is engaged in agriculture. Blocks of summer residence/cottages are located at the western and south-western side of NBS in distance of ca 300 m and more. They were built during former Soviet Union time, but currently most of them are in a state of deterioration, however, some of the cottages are still in use (see Figure 2.3-1). The area is used for leisure purposes, especially in summer times, but the quantity of cottagers is gradually decreasing.
2.4 Relations of Property Rights
The NBS is situated within the administrative boundary of Yerevan, in the Erebuni district. The site was constructed in 1976 based on the Government Decree of former Armenian Soviet Union and operated by the "ArmAgroChemistry" Unit under the Ministry of agriculture of Armenian Soviet Union. Until 1989, the site was regularly monitored and maintained, but this was then discontinued. In 1991, the operation of "ArmAgroChemistry" Unit was ceased and till now the NBS has no ownership and management body. In the period 2003 – 2004, the site became generally recognized as presenting a major potential environmental risk due to its location on an unstable slope and drainage course. In 2004, a Government Decree of RoA officially designated the situation as a priority issue, and mandated and funded the Ministry of Emergency Situations (MES) to take action. As a consequence, a number of national and international initiatives have been undertaken in relation to the NBS. In the summer of 2010, the Government through Ministry of Nature Protection (MNP) and MES made a more substantial investment in stabilization of the site. The Executive Agency of this project is the Ministry of Nature Protection (MNP) based on its role as GEF Focal point. In terms of implementation, the Ministry of Emergency Situations (MES) acts as the primary counterpart and functional Executive agency for separate components acting in its statutory regulatory capacity. Overall, institutional supervision of the project is provided by a Project Management Board (PMB) co-chaired by MNP and MES. A broader stakeholder advisory committee including representation of civil society is also anticipated to be involved.
2.5 Geomorphological and Climatic Conditions
The area is characterized by wavy, open tertiary landscape. The relief is waved with some ravines dividing the area into several plots. The prevalent exposition is towards the north. There is no permanent surface water in the reserve, the ravines only flooding after good rains, mainly in spring. According to its location at the borderline between semi-desert and the dry mountainous steppe area, the climate is typically continental with dry summers and cold and snowy winters. This is attributed to Yerevan being on a plain surrounded by mountains and to its distance from the sea and its effects. Monitoring the data of the "Yerevan-Erebuni" station, presented in the RoA Construction Norms II-7.01-2011 "Construction Climatology" (HHShN) approved by the Minister of Urban Development on 26.09.2011, was used to describe the baseline meteorological conditions in the project region. The summary of meteorological data is presented w in Tables 2.5-1 to 2.5-3.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 14
Average air temperatures by months Table 2.5-1
Average temperature by months,°C
Settlement /
meteorological °C ture,
July
May June
station April
March
August
January
October
February
December
November
September
Average annual Average
tempera °C temperature, °C temperature.
Absolute lowest lowest Absolute
Absolute highest highest Absolute Elevation, MASL Elevation, Yerevan / Erebuni 888 -3.6 -1.0 5.3 12.5 17.4 21.8 25.8 25.2 20.5 13.3 6.3 -0.2 11.9 -28 42
Relative humidity data by months Table 2.5-2
Relative humidity, %
Average monthly By months at 15:00
Settlement /
meteorological
station
July
May June
April
March
the coldest coldest the
August
January
October
February
month % month
month, % month,
December
November
September
Average annual,% Average
For For For the warmest warmest the For Yerevan / Erebuni 79 75 62 56 57 49 45 46 49 62 73 79 61 67 28
Precipitation data Table 2.5-3
Snow cover
Precipitation Average monthly , mm
Maximum daily
days days
Settlement / By months -
meteorological
m ten m
station
level, mm level,
cover days cover
Annual
July
May June
April
March
Number of snow Number
August
January
October
water in snow, mm in snow, water
February
Maximu
December
November
September Maximum quantity of of quantity Maximum 24 23 32 35 45 23 11 8 12 29 28 21 291 Yerevan / Erebuni 58 47 - 24 23 34 29 42 34 29 37 51 35 36 28 51
The average annual temperature is 11.9°C (summer 25.5°C; winter 3.9°C). The coldest month is usually January (average air temperature is -3.6oC) and the warmest is July (average air temperature is 25.8oC). Absolute lowest temperature is -28oC, while the absolute highest is 42oC. The average annual relative humidity is 61%, the average monthly relative humidity for the coldest month (January) is 67% and for the warmest months (July – August) is 28%. The average annual precipitation is 291 mm. The majority of precipitation occurs between March and May (112 mm), while July, August and September are the driest months. The maximum daily precipitation occurs in September (51 mm). The snow cover maximum height for ten-day period is 58 cm; snow pressure is 70 kg/m2. The soil frost line is 60 cm. The average number of days with lying snow is 48. The solar radiation balance exceeds 60 kcal/cm2.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 15
Distribution of wind average velocities Figure 2.5-1
The wind blowing direction varies and there is no prevailing direction. North easterly and south easterly winds dominate in April, south westerly winds - in June, north easterly winds – in July and north easterly, south and south easterly winds – in October.
Wind predominant directions Figure 2.5-2
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 16
2.6 Geological Conditions
Geologically the broader surrounding of the locality belongs to the Near Yerevan Geologic Province. Here prevail paleogene to neogene sediments of both marine and lacustrine and terrigene origin. On these sediments there are quarternary magma flows and tuffaceous formations originating from the igneous chain of mountains Gegham, located approximately 30 km to the ENE and aluvial or lacustrine terraces containing aggregates and conglomerates. The general stratigraphic overview is stated below (Mkrtchian 2017):
2.6.1 Pre-Quaternary Development
Upper Cretaceous – 1,200 m thick carbonate, clay and sandstone formations. These formations are below 2,500 m depth at the vicinity of the NBS. Paleocene – Middle Eocene carbonate formations, with beds of clays, shales and sandstones. The cumulative thickness of the formations of this age group is about 1,500 m. Upper Eocene age rocks cover older formations with azimuthal unconformity. These rocks are represented by clays, sandstones and different tuffaceous beds, having 500 m thickness. Lower – Middle Oligocene is represented by Shoraghbyur flyshoid formation, comprised from clays (60 – 70%), sands and fewer carbonate beds (10 – 40%) and having thickness up to 1,000 m. Upper Oligocene – Lower Miocene age rocks comprise Hatsavan formation, represented by clays and continental terrigenous deposits, mostly conglomerates, having thickness of 430 m and unconformably overlaying the older formations. The conglomerates are at the base of the formation. Conglomerates and sandstones make up about 35 – 40% of the formation. Clays are around 60% of the Hatsavan Formation and are outcropping neat the NBS. Middle Miocene age is represented with gypsum-salt bearing formations having thickness in excess of 1,200 m. There are minor beds of carbonates and sandstones within it. The clays and salt form the lower half of the formation and gypsum with clays form the upper half. The salt bearing formation consists of the following rocks – clays (60%); salt (30%); anhydrites (10%). The gypsum bearing portion of the formation consists of the following rocks – sandstones at the base (5%); clays (70%); gypsum (25%) Upper Miocene age rocks form Hrazdan formation and are represented with clays and sandstones, having thickness of 1,000 m. Lower – Middle Pliocene is represented with Voghjaberd Volcanic formation, formed with various volcanic tuffs, breccias and lava flows, with lesser amounts of alluvial and lacustrine deposits, having thickness 300 to 1,000 m.
2.6.2 Quaternary Development
Upper Pliocene and Quaternary lava flows cover different horizons of Voghjaberd formation and older rocks. The lava flows have originated in Gegham Volcanic Mountain range northeast off NBS. Quaternary terrace deposits and alluvial accumulations are widespread in the area.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 17
Geological map of the area to the east from Yerevan. The blue circle approximately marks the area of interest. (Geological Map of Armenia, Kharazyan 2005) Picture 2.6.2-1
Explanations: 6 – Terrace block-pebbles formations, upper Nubarashen terrace; 8 – Covers of volcanogenic fragmentary materials, ignimbrituffs; 13 – Alluvial, flood block-pebbles formations, pebbles of lower Nubarashen and Yegnegnadzor terraces; 33 – Terigenous molasic sediments. Clays, sandstones, aleurites, conglomerates (upper Oligocene, lower Miocene); 37 – Marine sediments, Shoragbyur suite, sandstones, aleurolites, clays, marles, reef sandstones (Oligocene); 39 – Marine sediments, Zovashen suite, clays sandstones marles, aleurolites, limestones.
2.6.3 Tectonics
Nearest fault zone is Azat reverse fault, trending in North-easterly direction along the valley of river Azat and dipping to south-east. The NBS is located at the distance of 6.7 km from the fault. Another significant fault in the vicinity of the site is the Garni fault, that runs in the direction NW-SE, approximately 10 km easterly from the site and is known for its high activity with possible strong earthquakes.
2.6.4 Seismic Activity in the Area
The entire territory of Armenia is known for its high seismic activity. This is caused by the collision of the Arabic and Eurasian plates, their contact passes through the Black sea and the Caspian Sea. The Arabic plate is being moved towards north or north-east and its pressure
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 18
causes formation of active deep fault, along which intensive movements accompanied by lots of earth shocks occur. In Armenia the most active is Pambak-Sevan-Sunik fault, that passes in WNW-ESE direction through the whole northern part of the country of the north-west promontory through the lake Sevan up to the border with Azerbaijan.
Map of seismic zoning of Armenia showing acceleration gravity (a) (Taken from the Armenian National Survey for Seismic Protection portal) Picture 2.6.4-1
Another prominent seismic zone is the Garni fault that passes practically parallel with the Pambak-Sevan-Sunik area to the east of Yerevan. At that fault an extensive earthquake of M 7,0 took place in 1679. The historically most significant registered earthquakes are shown in the Table No. 2.6.4-1.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 19
The historically registered earthquakes Table No. 2.6.4-1 Year Region Magnitude Fatalities 7. 12. 1988 Spitak, Leninakan 6.8 25,000 + 27. 4. 1931 Zangezur 6,4 300 – 2,890 1679 Harni, Yerevan, Kanaker 7,0 7,600 + 1268 Lhanate, Antioch 7,0 60,000 + 27. 12. 893 Dvin, Artashat 5.3 – 7.0 30,000 During the last year (October 2016 – September 2017) there were 13 earth shocks of M ≥ 1, 5 registered over the territory of Armenia. The strongest one of M5 had its epicenter in north- west Iran. The NBS lies close to the fault Garni and is included in the zone of the second highest category of danger with gravity acceleration agR ˂ 0,4 g (Picture 2.6.4-1). A possibility of earthquake of M7 and higher can be expected.
2.7 Hydrogeological Conditions
The following description of hydrogeological conditions of the NBS wider area is a result of research of only limited literary and archival materials. At the depth of 300 m and more of the area geological section, rocks are presented with clay – loamy sediments of the upper Pliocene lake-marine origin. Below is a massive, impermeable volcanogenic stratum, followed by not thick and low water gravel-cobble sediments. In clay-loamy sediment at different depths (5 – 60 m) one can meet locally spread, not thick, lenticular sandy gravel-cobble formations. In the case of the mentioned lithological section, atmospheric precipitations are mainly spent on surface flow formation, whereas the earth infiltrated water is extremely limited. They mostly accumulate into lenticular formations. Groundwater originated in them has mainly seasonal character, while the flow of water in lenticular formations located deeper does not exceed 1 – 2 l/sec during the discharge through the boreholes, and this is only for a certain period of time. Therefore, they cannot participate in the formation of groundwater body which is located very deep (500 – 600 m) and with limited strike; the connection between them is not possible. They cannot promote to existing or bring to future landslide phenomena either, as the cracks and hollows resulting from the landslides are not deep. The formation and feeding of aquifers in the study area is possible to a certain extent only at the expense of deep water originated from atmospheric and condense waters on southern, south-eastern slopes of the Geghama Ridge and flowing to the Ararat valley. Here, the water bearing stratum, which is at the depth of 500 m and more, has a small thickness, is represented mainly with sandy gravel-cobble sediments and is a transit route/zone for accumulation of groundwaters of Ararat valley artesian basin.
2.8 Hydrological Conditions
Around the NBS the network of drainage channels is very limited. Through the territory to the east from Yerevan there is no larger river flowing and the aqueousness of the few permanent rivers is significantly changing during the year, depending on precipitations and summer high temperatures. The closest river is Azat, flowing approximately 6.5 km SE and Hrazdan, flowing through Yerevan 8 km NW. On the river Azat there is a small reservoir. In the close vicinity of the NBS there are some minor, often seasonal, rivers. The whole territory belongs Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 20
to the basin of the river Araks, that forms the Armenia-Turkey border (app. 20 km SW from the locality) and after junction with the river Kura it empties into the Caspian sea. Most rivers in the vicinity have their direction in accord with the tectonic predisposition in direction NE- SW, or E-W.
3. The Present State of Exploration of the Area
Until now there were 3 essential surveys carried out in the NBS. • Assessing the discharge of contaminants from the Nubarashen toxic chemicals repository site, Center of Ecological-Noosphere Studies NAS RA (2010) • Site Assessment and Feasibility study of the Nubarashen Burial Site of Obsolete Banned Pesticides in Nubarashen, Armenia, Contract No. ARM/01/2013, OSCE, TAUW (2013) • Strengthening National Capacities on Comprehensive Chemicals (Persistent Organic Pollutants) contaminated site assessment in Armenia, Analytical Report on Sampling on Nubarashen Site, Transfer of Czech Knowledge, GEOtest (2013) The following text state principal results of those assignments.
Assessing the Discharge of Contaminants from the Nubarashen Toxic Chemicals Repository Site (2010)
In 2010 the Center of Ecological-Noosphere Studies NAS RA implemented episodic investigations of contaminants discharge from the NBS. Their investigations were divided into two stages: 1. Pilot survey aiming at the confirmation of the assumption, that POPs do migrate from the site and 2. More detailed survey aiming at evaluation of the spread of the contamination. Pilot survey – small radius In the frame of the project concentrations of As and Hg and three DDT metabolites (p,p'- DDT, DDE, DDD) and lindane (γ-HCCH) were studied in the: 1. waters of a brook forming under the NBS, 2. bottom sediments of the brook and 3. the river the brook empties in. The results of the pilot stepwise sampling of the territory adjoining the NBS allowed concluding that: • The presence of the p,p´/-DDT isomer in the waters of the brook and the river evidences the active discharge of the contaminant from the NBS in water medium, • In summer low-water period the pesticide concentration increase in river waters due to a decrease of the amount of precipitation and the concentrating of river solution, • DDT in form of a DDE isomer accumulates in clayey bottom sediments and soils of neighboring wetlands.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 21
The pilot investigations proved that toxic chemicals discharge from the NBS. More detailed survey – wide radius With a goal to indicate the distance of contaminants migration and their possible accumulation in depositing media, more detailed investigation was implemented. To reach the stated goal, the waters and bottom sediments of the Rivers Voghchaberd, Getar and Hrazdan as well as waters and bottom sediments of the Yerevanyan Lich were sampled. Water and bottom sediment samples were analyzed for DDT isomers (p,p/-DDT, DDE, DDD) concentrations in the accredited laboratory of the Center for Ecological-Noosphere Studies NAS RA. The obtained research results support the following conclusions: • Established was a p,p/-DDT isomer discharge from the NBS in water medium, • DDT in form of a DDE isomer accumulates in clayey bottom sediments of the rivers and soils of wetlands adjacent to the river, • DDT isomers in transitive and depositing media were established within a 4 km distance from the NBS; downstream the rivers of Voghchaberd, Getar, Hrazdan and in the waters and bottom sediments of the Yerevanyan Lich the concentrations of pesticides were lower than maximum dose level (MDL).
Site Assessment and Feasibility study of the Nubarashen Burial Site of Obsolete Banned Pesticides in Nubarashen, Armenia, Contract No. ARM/01/2013, OSCE, TAUW (2013)
Conclusions of the complex site investigation are summarized below. The fenced landfill site at Nubarashen: • Is 0.8 hectares large • Comprises of a landfill body (0.2 hectare) and surrounding land (0.6 hectare) • The landfill body is a hillock of 1.5 m high and is enclosed at three sides by concrete runoff drains • The clay cover (0.4 – 0.7 m) of the 0.2 hectare landfill body is slightly contaminated with pesticides • The estimated in situ volume of the contaminated landfill cover is at around 890 m3 • The topsoil of the surrounding 0.6 hectare is heavily contaminated up to of 0.5 m • The estimated in situ volume of the fenced contaminated top soil is at around 3,000 m3 The landfill body itself contains/has: • A 2 mm ruberoid foil on a 5 cm thick sandy layer under the clay cover of 0.4 – 0.7 m • Five isolated cells with 506 m3 of pure pesticides and contaminated clay (29 m3) at the bottom of the cells • Contaminated clay layers (1,127 m3) with traces of pure pesticides The groundwater and the surface water downstream the NBS is not impacted.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 22
The balance of contaminated material identified by the Tauw is included in the chapter 4.4. Uphill from the landfill site: • Are a pond with standing run off water and a road with a leaking water main • The run-off water drainage blocked by water main and a culvert filled with sediments • The standing water in the pond and the water from the leaking water main infiltrate in the soil and percolates laterally in the catchment area of the landfill • The perched groundwater table upstream is influencing the stability of the landslide • Slope movement upstream of the landfill site is the mechanism behind the observed mass movement at the landfill site • Lowering the perched groundwater table reduces the influx of water into the slope and will improve the stability of the landslide The risk assessment: • The Tier 2 risk assessment concluded that only the people entering/working at the landfill site and in a buffer zone of 100 m around the landfill site have direct contact risk with the contaminated soil • Direct contact can be avoided when proper personal protective equipment is used when entering the buffer zone and site and be restricting entrance of the landfill site and buffer zone Based on the results of the study it is concluded that the contamination in the landfill site is present in the following landfill components: • Category 1: Pure pesticides or associated material > 30 % pure pesticides: a) Pesticides in cells and between them 605 m3 b) Contaminated clay at the bottom of cells and between them 69 m3 Total 674 m3 • Category 2: High contaminated soil, soil with DDT concentration higher than 1,500 mg/kg dry matter according to CSOIL 2000 for workers on the site (above the human health risk threshold for direct exposure): a) Contaminated top soil with traces of pure pesticides in landfill body 1,127 m3 b) Contaminated top soil with traces of pure pesticides in fenced area 3,000 m3 Total 4,127 m3 • Category 3: Low contaminated soil, soil with DDT concentration lower than 1,500 mg/kg dry matter and higher than 0.7 mg/kg dry matter according to Canadian Soil Quality for Environment and Human Health for agricultural soils (where animals products are produced): a) Contaminated top soil without pure traces of pesticides in landfill body 2,387 m3 b) Slightly contaminated top cover landfill body 890 m3 c) Low contaminated soil outside the landfill site 4,000 m3
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 23
d) Nominally clean white/purple coarse sandy liner support / drainage layer 100 m3 Total 7,377 m3 • Category 4: Contaminated construction materials: a) Synthetic cover (2 mm) 4 m3 b) Contaminated bricks/concrete/rubble 16 m3 Total 20 m3
Strengthening National Capacities on Comprehensive Chemicals (Persistent Organic Pollutants) Contaminated Site Assessment in Armenia, Analytical Report on Sampling on Nubarashen Site, Tranfer of Czech Knowledge, GEOtest (2013)
The task of the study was to precise the existing results (TAUW 2013), that provided basic information on area and depth extent of contamination. The basic reference level (BRL) of 50 mg/kg d.m. for estimation of amount of material contaminated was determined. The BRL originates from the The Basel Convention (BC) which has developed Technical guidelines on the Environmentally Sound Management of POPs wastes. The BRL was determined for the sum of 2,4'-DDD+2,4'-DDE+2,4'-DDT+4,4'-DDD+4,4'-DDE+4,4'-DDT+αHCH+β HCH+γ HCH+δ HCH. The approximate areal delineation of above-limit contaminated material was interpolated and, where data were insufficient, the boundary was extrapolated. The 50 mg of pesticides/kg d.m. was determined as the reference concentration for the sum of 4,4'-DDT+2,4'-DDT+4,4'- DDD+2,4'-DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH. 15 samples were taken from the depth interval 0–0.5 (measured from the ground surface). Above-limit concentrations were detected in two areas: area III and on the body of the landfill in its western part. In this depth interval, the areal extent of contamination was estimated at 300 m2 × 0.5 m = 150 m3. At the depth interval 0.5–1 m above-limit contamination was identified in the landfill body (clay partitions) and in the adjacent areas III, IV, V, VI and VII. An isolated occurrence was detected between trenches (IX-1). The areal extent of above-limit contaminated material in the depth interval 0.5–1 m was determined at 3,000 m2 × 0.5 m = 1,500 m3. In the depth interval 1–1.5, above-limit contamination was identified on an area of 2,800 m2 × 0.5 = 1,400 m3. This material occurred particularly in the landfill body and in its close vicinity in the areas IV to VII. In holes C and V-6, occurrence of more than 95% of pure pesticides was detected. Samples from the depth interval 1.5-2 were collected only in the probes made into the landfill body (cells A, B, C, D and E) – into the places in which soil partitions separating individual cells with pesticides were assumed. Above-limit concentrations were identified in holes A, B and C. In hole C, the concentration exceeded 1,500 mg/kg – the Human Health Risk limit (Tauw, 2013). In hole B, the occurrence of more than 95% of pure pesticides was encountered. The depth interval 2–2.5 m is represented by one sample from hole B, in which the concentration of pesticides has exceeded the limit value.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 24
The analyses of soil samples taken outside the fenced area have shown that pesticides occur in the upper near-surface layer at low concentrations; increased concentrations have been detected at the gate to the premises. It is probable that the contamination can be spread due to the increased movement in the area around the gate rather than due to the wind. The results of soil analyses have proved the occurrence of As mostly at increased concentrations as compared with the indicators of contamination (Methodical Guideline of the Ministry of Environment of the CR, 2011) for “the other areas” apart from industrially utilized area”. The highest concentration was determined in sample V-5 1-1.5 collected at the base of the landfill and it is certain that it comes from an anthropogenic source. The occurrence of As in soils relates to the pesticides deposited at the site. The concentrations of Hg were identified in soils mostly below the detection limit of the applied method of determination (< 0.2 mg/kg d.m.). The highest concentration was detected in sample V-5 0.5–1. As in the case of As, the high concentrations of Hg relate to the pesticides deposited at the site.
Approximate location of holes Fig 3.-1
3.1 Overview of Contamination Sources The contamination source is represented by pesticides deposited in partly secured landfill. The pesticides occur in two source areas within the site. The first one is the landfill itself, pesticides were deposited in 4 landfill cells. One cell is expected to had been used for pesticides burning, no pure pesticides were found there. The landfill in its upper part is secured with the ruberoid foil. In bottom part of the landfill a natural insulation is created by impermeable clay-silty bedrock. The second source form pesticides occurring out of the landfill body - for depositing of dozens up to hundreds kg of pesticides at SW edge of the landfill body in the past there was additionally built the sixth cell that has no technical protection. Further pesticides occurring out of the landfill body were probably spread out of it
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 25
during construction of the landfill or during subsequent uncontrolled exploatation. Today these materials constitute the main source of contamination spreading. The available historical file reports state an overview of approximately 512 t of pesticides allegedly deposited in the NBS.
Overview of pesticides presumably deposited in the NBS Table No. 3.1-1 Weigh Weigh Weigh Weigh Agent Agent (t) (%) (t) (%) Trochlor sodium 1 DDT 192.5 38.24 18 4.98 0.99 acetate 2 Hexachlorcyclohexane 48.396 9.61 19 Cosan 2.693 0.53 3 Calcium arsenate 42.640 8.47 20 Lissapol 1.878 0.37 4 Endobacterin 33.121 6.58 21 Sevin 1.846 0.37 Other pesticides containing 5 arsenic, sulphur, phosphor, App. 30 5.96 22 Thovit 1.810 0.36 cyanides and mercury 6 Simazine 18.117 3.60 23 Chlorophos 1.695 0.34 7 Colloid Sulphur 17.950 3.57 24 Cosan 1.498 0.30 8 Rezetopth 17.1 3.40 25 TUR 1.280 0.25 9 Dalapon 17.0 3.38 26 Hexachlor benzene 1.265 0.25 10 Cyneb 16.374 3.25 27 Dendrobacilin 0.890 0.18 11 Pentachlor phenol 8.715 1.73 28 DNOC 0.890 0.18 12 Granosan 8.402 1.67 29 Liquid soap 0.289 0.06 13 Vitriol 7.318 1.45 30 Paris Green 0.239 0.05 14 TMTD * 7.205 1.43 31 Dichol 0.168 0.03 15 Fenthiuram 6.765 1.34 32 Metaldehyde 0.1 0.02 BIP (biological insecticide 16 5.160 1.03 33 Cynox 0.096 0.02 preparation) 5,494 17 Diamine phosphate 5.0 0.99 34 Fumigating box ? boxes * tetramethylthiuramdisulphide, known also as Aatiram, Tiram, etc.) However, this overview probably does not include pesticides deposited in a not secured segment outside the SW landfill edge.
4. Current Survey Work
4.1 The Methodology and Scope of Survey and Analytical Work
4.1.1 RTG Spectrometry
The RTG spectrometry was used during the survey aimed at the extent of surface contamination. The survey consisted of measurement of elements´ content in the surface soil by means of a portable element analyzer based on X-ray fluorescence (XRF) DELTA Professional (Innov-X, Canada) (Picture 4.1.1-1). Each measurement contained the range of the following elements: P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sn, Sb, W, Hg, Pb, Bi. Out of these elements the attention was paid especially to Cl, S, Hg, As, that can evidence the presence of pesticides and heavy metals Cr, Co, Ni, Cu, Zn, Cd, Sn, Sb and Pb, that often accompany the pesticide contamination and also evidence the anthropogenic origin of contamination.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 26
Based on the detected elements and the rage of their abundance there were subsequently evaluated places with potential surface contamination. For this purpose the area of interest was divided into 4 sectors A – D (see Pict. 4.1.1-2) and subsequently there was created a network of measured points that contained not only the fenced area of the NBS but also its close vicinity (see Annex No. 1.6). The sectors A – C were situated in the fenced area, the sector D outside that area. The sector A formed the landfill body as such. The sector B formed the surface between the landfill body and the drainage trench. The sector C formed the area between the sector B and the site fence. The sector D formed a broad zone in the vicinity of the fenced area. In total there were realized 178 measurements out of which 10 were done in the sector A, 35 in the sector B, 56 in the sector C and 77 in the sector D. All the results, including GPS coordinates of the single points, are stated in the attached report (Annex No. 2.5) from the field measurements. The description of each measured point consists of a letter depending on in which sector the latter was found and a figure stating the the order of the measurement. The letter „S“ in brackets at some measured points mean blank (background) places. These are places that often distinctively misalign outside the area of interest and in which the contamination was eliminated or not assumed. These points serve only for comparison with values measured in the area of interest.
Surface contamination measurement by the X-ray fluorescence DELTA Professional analyzer Picture No. 4.1.1-1
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 27
Sector division of the site during the surface contamination survey Pict. 4.1.1-2
In addition to the surface measurements the RTG Spectromentry was used for guick field screening of either materials which were collected for later chemical analyses or served as a quick instrument for geological or contamination documentation. All measurements (in total 140) were recorded and are presented in annex 2.5: Analytical report – survey monitoring. These data were further utilized during the processs of contamination extend evaluation (chapter 4.3) and correlation of RTG spectrometry and chemical analyses (chapter 4.2.6).
4.1.2 Drilling and Excavatory Works
For the engineering-geological (E-G) survey there were machine core wells and trenched pits used. The wells were installed to verify the geological conditions close to the landfill and at its northern and southern fore-land. In total there were 13 wells done (180 m altogether). The original disposition of the drilling operations (Sampling plan) was to a certain extent changed during the works. The reason was the impermeability of some places, presence of pesticides in the south neighborhood of the landfill and the necessity to check the northern fore-land of the area and the NE slope of the latter because of future building infrastructure. The wells were done by three units UGB-50 on chassis of the vehicles GAZ 66 4x4. Originally only one unit was used and was operating the whole time from 14. 8 till 4. 9. 2017. Because of problems with the drilling a slow progress of the works from 21. 8. there was the second unit taken in operation, shortly another - third one was running. The works were carried out from 14. 8 – 4. 9. 2017. In total there were 13 wells drilled to depths of 7,5 – 17,5 m with overall metrage of 180 m. The trenched pits (altogether 15 pcs.) were planned with regard to particular needs of the survey. Their number and location was left to the consideration of the present geologist. Some of them replaced the originally planned wells in the southern fore-land of the landfill, other were excavated close to the wells with the aim to try and take an undisturbed soil sample for analyses that could not be taken from the wells. Further trenches were excavated in the slope in which the access road was planned.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 28
The excavations were done by the excavator K428. The total number of the wells was 15 to depths of 1,8 – 3,3 m. The works were carried out between 22. and 24. 8. 2017. The works were carried out by the Armenian company HGSN LLC.
4.1.3 Sampling and Analytics of Soil Samples
The designation of the landfill cells in the interpretative parts of this report follows the terminology established by the Tauw (2013), where the cell no. 1 is the eastern-most one and the cell no. 4 is located on the western-most sector of the landfill, cells no. 2 and 3 are located in-between, while the cell no. 5 was constructed out of the landfill body by its western-most edge. Nevertheless, the primary documentation and designation of the samples differes. Probes designated as XIII-1 were located into the cell no. 5, probes XIII-2 into the cell no. 4, probes XIII-3 into the cell 3, probes XIII-4 into the cell no. 2 and probes designated XIII-5 into the cell no. 1.
4.1.3.1 Sampling for Contamination Survey
The sampling was primarily focused on determination of rate and type of soil contamination. For the purpose there were realized in total: 1. 15 probes in individual cells of the landfill by means of portable manual sampling set, 2. 15 probes in close vicinity of the landfill by means of portable manual sampling set, 3. 20 surface samples collected from wider vicinity of the landfill body, 4. 5 trenched pits Ad 1. The probes in the individual cells of the landfill were realized with the purpose of checking the structure of the landfill body and volume of the contaminated material identified by previous survey works (in particular TAUW, 2013). Another reason was the collection of partial samples for creation of one mixed sample for each cell each time, for screening analyses. Thus in total there were 5 mixed samples of highly contaminated samples of soil or pure pesticides subject to screening analysis to determine types of pesticides deposited in the landfill body. There were 3 probes realized in each cell. Apart from the above mentioned there were 6 samples of highly contaminated soil taken in total determined mainly for the purposes of inter-laboratory comparison (see below). Ad 2. The probes were situated so that the missing information on the extent and quality of contamination could be completed. Thus the survey was oriented to places where the sampling operations in 2013 (GEOtest) failed to completely delimitate the area and namely the depth extent of the contamination so that it would be possible to specify the volume of contaminated soil in the vicinity of the landfill body. The depth of the sample taking from these probes was determined on site according to the sensory evaluation of the contamination presence. Based on the carried out screening analyses these samples underwent laboratory analyses aimed at determination of chlorinated pesticides, triazine pesticides, sulfur, extractable organic halogen, inorganic chlorine, mercury, zinc and arsenic. Ad 3. The samples from the landfill vicinity (behind the fence) were taken from the terrain surface. These samples were taken for the purpose of determination of surface contamination spread. In total there were 20 samples taken from the depth of up to 0.1 m. The taking of samples was localized in places with atypical concentrations of monitored elements determined by means of an X-ray analyzer. Based on the carried out screening analyses within the framework of Ad 1 these samples underwent laboratory analyses aimed at determination
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 29
of chlorinated pesticides, triazine pesticides, sulfur, extractable organic halogen, inorganic chlorine, mercury, zinc and arsenic. All the samples were taken according to the sampling plan, that forms a part of the Annex No.: 2.2. As against the sampling plan there were only minor changes done depending on the situation in the locality. All the samples (or their parts) were taken by means of a stainless scoop and placed on a stainless tray. Each sample was quartered and homogenized. After taking the sample into a PE bag and marking the latter the sample was placed into a PE bag and within the shortest possible time placed in a refrigerator where it was stored at the temperature of 4 - 8 °C. After their receipt in Czech Republic all the samples were placed in quarantine and until laboratory analyses were done they stayed frozen. Apart from the above mentioned samples there were also duplicate samples for local laboratories taken. These samples should serve for inter-laboratory comparison. The list of samples and types of laboratory analyses form a part of the Annex No. 2.8. The location of all sampling places can be seen in the Attachment 1.5. The reports on collection of all the samples are given in the Attachment No. 2.3. During the works there was a geological documentation kept that forms a part of the evaluation works (see below).
4.1.3.2 Analytical Methods of Contamination Survey
Extractable Organic Halogene (EOX) Organic bonded halogens are extracted from a fixed matrix by hexane and burned in oxygen stream under generation of halogen hydrides that subsequently coulometric titrate in combustible products in automatic microtitrate cell. 10 g of prepared sample is weighed in a dark glass bottle with screwing cap of 45 ml volume and 1 g of dried water-free sodium sulphate is added. 15 ml of hexane are then added to the sample and the glass bottle is tightly closed. The sample is inserted into a ultra sound bath and extracted for 30 min. After settling 10 ml of the extract are withdrawn and filtered by means of vacuum filtration apparatus (glass SPE column with quartz frit and filter paper made if glass micro fibers) into a graduated tube. The extract is then concentrated to a volume of 500 μl by means of nitrogen. 100 μl of the sample are injected into the AOX/EOX analyzer. The combustion chamber must be heated at least to 950°C, the gas absorber with sulfuric acid will connect with the titration cell. By means of a microsyringe 100 µl of sample will be taken for assessment, the module septum is perforated, the microsyringe is laid on the support and the sample is automatically dosed into the heated zone of the combustion device fitted with an argentometric titrate apparatus. Organochlorinated Pesticides (GC-MS Analysis) The most common method for sample treatment is based on extraction of target compounds into a mixture of hexane and acetone followed by a group of cleaning steps. A small amount of soil sample is dried on a glass mat at room temperature for at least 48 hours. After this time, 1 g of dry soil sample is placed into 40mL glass test-tube and 30 mL of a mixture of n-hexane and acetone (2:1) is added. The extraction is done in an ultrasound water bath for 60 min. Then the extract is left in the same test-tube for next 8-12 hours. After this time, the decantation of the extract into a separating funnel is done. Then the test-tube with the soil is rinsed again by 30 mL of n-hexane and it is also decanted into the same separating funnel. Approximately 20 mL of H2SO4 is added into the separating funnel and the mixture is shaken for approximately 5 seconds intensively. Then the layer of the acid is let out and the extract in
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 30
the separating funnel is shaken with 3 × 500 mL of distilled water subsequently - 3rd water shaking is carried out with an addition of a small amount of CaCO3 (one teaspoon) in order to neutralize the residual acid. The layer of the water is separated from the organic layer (extract) in the separating funnel in all three cases. Finally the organic layer is let out into a beaker and the small amounts of anhydrous Na2SO4 (approximately one teaspoon) is added into the extract in order to eliminate residual water. Then the extract is evaporated, concentrated to 0.5 mL and finally analysed by GC-MS. GC-MS analysis is carried out with the Thermo Trace GC Ultra system equipped with a DB- 5MS capillary column (dimensions: 60 m × 0.25 mm × 0.25 μm). The sample (1 μL) is injected in the splitless mode at 280 °C. The carrier gas is ultrapure helium (99.99990%) set at a constant flow mode (1 mL/min). The temperature programme is as follows: 5 min at 50 °C, then heat at 7 °C/min to 300 °C and hold for 10 min. The transfer line temperature is set to 300 °C. The mass spectrometer with an ion trap (Thermo ITQ 900) is operated in the electron-impact mode at 70 eV. The ion trap is operated in the MS/MS mode. The temperature of the ion source is set at 200 °C. As, S, Zn (Analysis by ICP-OES) A small amount of soil sample is dried on a glass mat at temperature 105 °C for at least 24 hours. The dried sample is crushed in an Alsing-cylinder and is ready for weighing. After this procedure, 0.25 g of dry soil sample is placed into a Teflon mineralization cartridge. 5 mL of HNO3 + 3 mL of 30% H2O2 is added into the cartridge and left to stand for 15–120 min, until the reaction stops. Then the microwave decomposition is done using a microwave mineralization device (speedwave MWS-2) using a default program for soil decomposition. After the microwave decomposition process is finished, the whole contents of the cartridge including soil is placed into a 50 mL flask and filled with distilled water to the volume. Then, the contents of flask is filtered by filter paper to a test-tube and analysed. The analysis of As, S and Zn is carried out with a Thermo Scientific iCAP 6000 series ICP- OES instrument under the operating conditions listed in the following table.
Thermo Scientific iCAP 6000 series operating conditions Table 4.1.3.2-1 Analysis preferences Repeats 3 Sample options Delay Time 0.0 sec Sample Flush Time 30 sec Sample Introduction Nebuliser Source Plasma View Line Selection Analysis maximum Low WL Range Axial 15; Radial 15 Integration Times (sec) High WL Range Axial 5; Radial 5 Calibration Mode Concentration Intelli-Frame Yes Max Integration Time 30 sec Trailing Full Frame Options WL Range Low View Radial Source Settings Flush Pump Rate 100 rpm Analysis Pump Rate 50 rpm Pump Relaxation Time 5 sec Nebuliser Pump RF Power 1200 W Nebuliser Flow 0.65 L/min Auxiliary Gas 1.5 L/min
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 31
Hg (analysis with AMA) A small amount of soil sample is dried on a glass mat at temperature 105 °C for at least 24 hours. The dried sample is crushed in an Alsing-cylinder and is ready for weighing. After this procedure, 0.25 g of dry soil sample is placed into a Teflon mineralization cartridge. 5 mL of HNO3 + 3 mL of 30% H2O2 is added into the cartridge and left to stand for 15 – 120 min, until the reaction stops. Then the microwave decomposition is done using a microwave mineralization device (speedwave MWS-2) using a default program for soil decomposition. After the microwave decomposition process is finished, the whole contents of the cartridge including soil is placed into a 50 mL flask and filled with distilled water to the volume. Then, the contents of flask was filtered by filtration paper to a test-tube and analysed. The analysis of Hg is carried out with an Advanced Mercury Analyser (AMA 254) equipped with an autosampler for analysis of liquid samples. 100 μL of the prepared extract is applied to analysis. Time conditions is set as follows: Drying – 130 s, decomposition – 150 s, waiting – 45 s. The AMA is a very specific analytical instrument used only for analysis of Hg. For settings of the AMA it is necessary to do own optimization of the instrument in our conditions. Due to this fact, other specific settings are not listed. Chlorides After preparation of extract 1:10 w/v in distilled water an argentometric titration is carried out. Triazine pesticides The sample is extracted with methanol after addition of some water. After partition into dichloromethane the organic phase is evaporated and the residue is reconstituted with methanol. Quantification of pesticide residues is performed by liquid chromatography with tandem mass spectrometric detection, using electrospray ionisation. To achieve the required selectivity the mass spectrometer is operated in the selected reaction monitoring mode (SRM) The reports of laboratory analyses form a part of the Annex No. 2.4.
4.1.4 Engineering Geology
From wells and trenched pits samples were taken for geotechnical tests according to the sampling plan. Originally it was planned to take undisturbed samples from the wells, however it was not possible due to the present material presented by hard clays. Therefore only disturbed samples were taken from the wells. Instead, signifficant efforts to collect an undisturbed samples from the bottom of the trenceh pits had been undertaken. However, the samples were taken by a metal sampler pushed into the pit bottom. In addition there were technological samples of about 30 kg taken. In total: • 14 pcs of undisturbed samples, all from trenched pits, • 18 pcs of disturbed samples, all from wells, • 4 pcs of technological samples, out of them 3 from pits and 1 from the well. The overview of the samples is shown in Annex No. 2.8. With altogether 35 samples from wells and pits there were classification analyses realized, see the Annex No. 2.8.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 32
The task of the laboratory tests was as follows: • Undisturbed samples: classification test (see the set of tests of disrupted samples, volume density, porosity, degree of saturation, box shearing test including determination of residual shear strength • Disturbed samples: determination of water content, grain size analysis, determination of Atterberg limits (of consolidated soil), particle density Technological samples: classification test (see the classification test of disrupted samples), determination of compactibility by the Proctor Standard test. Already the field sampling (see above) indicated difficult processibility of undisturbed samples. During cutting the test specimen a destruction of the soil matrix and breakage of specimen to smaller pieces occurred. Thus it was possible to cut only 5 specimen for determination of the volume density and one set of specimen for the box shearing test. This set was complemented with 3 sets for the compressibility test in oedometer. In addition it was decided that for all four technological samples after determination of compactibility, based on the established parameters (maximum compactibility at optimum water content) there would be their compacting done and for thus prepared test specimen the box shearing test including determination of residual shear strength would be carried out. Further on the characteristics of the soil with most samples made it impossible to determine the Atterberg limits and thus determination of precise classification.
4.1.5 Geophysical Measurements
4.1.5.1 Introduction
Primary goal of the survey was a location of burial cells / clayey partition walls and determination of bedrock profile. Secondary goals of the survey were: • verification of an areal extent of contamination and/or its vertical distribution, • verification of conditions in the area of future construction project in terms of foundation conditions. Ancillary geophysical survey was conducted using electromagnetic conductivity mapping / profiling with conductivity meter. Instrument used is designed for a multi-layer survey and enables a multi-depth mapping in the depth range of 1.1 – 6.7 m. The most important advantage of electromagnetic conductivity meters is a fast contactless mapping of apparent electric conductivity and inphase (magnetic susceptibility) components. Most important properties of the device are: • short & long term stability of readings (negligible temperature drift, no need of frequent recalibration), • correct absolute calibration of apparent conductivity, • defined depth range. Stability of readings is determined by design quality of electronics and mechanical parts of the device.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 33
Inphase component can especially serve for indication of artificial metal objects like cables, pipes, reinforced concrete, tanks, barrels etc. Thus the inphase map can help to distinguish artificial structures from natural geology seen in apparent conductivity map. Assumed scope of the survey was as follows: • Within the landfill itself a network of profiles consisting of 5 longitudinal profiles (of 100 m length each) and set of 50 transverse profiles (of 20 m length each, 2 m apart), step of measurements being 1 m in both cases. Exact location of particular profiles was specified on site taking into consideration local conditions. • In the area of future construction projects measurements in a rectangular grid of profiles 2 x 2 m with step of measurement 1 m were conducted.
4.1.5.2 Methodological Considerations
In order to choose the most suitable technique / set of techniques, available findings obtained during previous stages of survey (both by GEOtest and by other contractors) were thoroughly analyzed. As key factors following circumstances were considered: • selected physical properties of soils / rocks and/or other materials occurring in near surface zone (namely electrical conductivity), • occurrence of water in near surface zone, • accessibility and passability of the field and • assessment of potential influence of parasitic interfering signals. Several geophysical techniques were considered: • GPR, DC Resistivity, shallow EM, Capacitive Coupled Resistivity. A shallow DEMP (Dipole Electro Magnetic Profiling) method was selected as the most promising one. Following assumptions and limiting factors were taken in account: • dry clays near the surface possess lower /extremely low conductivity, • clays / claystones in the lower part of the section possess lower / medium conductivities depending on the water content, • conductivity of POP´s: no data concerning bulk conductivity of big volumes of such chemicals are available, high conductivities assumed (ionic conductors), • disturbances in measured field may occur close to the drainage system (steel lining in the concrete) and the fence surrounding the NBS. CMD Explorer manufactured by GF Instruments (Czech Republic) was chosen.
4.1.5.3 Description and Characteristics of Instrument Selected
CMD Electromagnetic Conductivity Meters represent large family of contactless geophysical instruments for fast assessment of ground conductivity and of inphase (corresponding with magnetic susceptibility). Single or multi depth probes designed for 0.25 – 9 m depth range
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 34
allow single or multi layer mapping in classic or GPS positioning modes including vehicle applications. Due to high temperature stability and calibration accuracy CMD systems open correct way for electromagnetic inversion with results (sections with two- or multi-layered structures) well matched with DC resistivity imaging. This way could be especially appreciated under exacting field conditions like dry and icy soil. CMD-Explorer - effective depth range: • 2.2 / 1.1 m (for intercoil distance = 1.48 m) • 4.2 / 2.1 m (for intercoil distance = 2.82 m) • 6.7 / 3.3 m (for intercoil distance = 4.49 m)
4.1.5.4 Methodology of Field Measurements Using CMD EXPLORER
Due to rather difficult field conditions a step-mode of measurements was chosen (measurements is taken after reaching particular position at the survey line). With respect to pretty large amount of geodetical works performed at the site by a local contractor (surveying of a dense network of significant points in the field, location of points of sampling / drillings / trenches) the geophysical measurements were not performed with support of GPS. Measurements along particular survey lines were performed utilizing a geodetical tape fixed to a network of wooden sticks that was incorporated into the geodetical network. A non-magnetic tape 50 m long (with marks every meter) was used. In order to keep the same conditions for the whole set of measurements, following measures were taken: • all measurements were taken by the same operator (in order to keep the constant height of instrument above the surface – 1m), • all runs along survey lines were performed keeping the same direction (in case of transverse lines ca from the south to the north – in order to keep the mutual position of the operator and the instrument constant with respect to orientation of the magnetic field of the Earth)
4.1.5.5 Data Processing
Attachment of measurements to the topographical network Reconstruction of the course of particular survey lines / stations was the first step. Each measured station was assigned geographical coordinates (X,Y,Z in UTM WGS-84 coordinate system). Basic Processing, Quality Control of data Basic processing (display of data) enabled evaluation of quality of data and qualitative segmentation of survey lines on parts with higher and lower conductivities. Due to its just indicative nature these data are not presented in this report. Inversion of data Usually, data obtained by multi-coil DEMP survey are presented in the form of graphs and/or maps. Presentation in the form of graphs enables just qualitative (semi-quantitative) considerations concerning the conductivity changes with depth.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 35
Presentation in the form of maps for particular intercoil distances enables qualitative segmentation of studied area with respect to the areal conductivity distribution (enables to distinguish eg sand and clayey parts of the area, identify areal inhomogenities etc). Comparing maps obtained by measurements with different intercoil distances considerations concerning the conductivity changes with depth can also be made. Basis for these assumptions is as follows: measured values of apparent conductivity represent (roughly) a weighted conductivity of the half-sphere with diameter proportional to the intercoil distance. EM inversion serves for data processing at multilayer measurement. The up-to-date choice of commercially available EM inversion software for shallow depth range conductivity meters is really not wide: • 1-D inversion (2-layer model) provided by manufacturer of the instrument, • 1-D inversion (2-layer model) SW IX1D provided by Interpex (Canada) Since 1-D inversion programs (providing just a 2-layer model) did not provide. Due to unsatisfactory results obtained by commercial software, a special inversion program was developed for this task: • horizontally layered medium with fixed thickness of layers (equal to 0.5m) is assumed • isotropic medium with constant conductivity is assumed in each particular layer • generally applicable GRG algorithm for non-linear optimization is used • iterative scheme • well known formulas for EM field above a horizontally layered isotropic half-space (eg in Kaufman, Keller, 1983) were used • 1-D inversion scheme is applied, a 10 - 12m long part of profile is processed simultaneously (taking into account neighbouring stations) • resulting model reflects optimum distribution of conductivities with depths with respect to RMS error (best fit between measured and modeled data) • no additional constraints concerning geometry etc were introduced. • inversion algorithm was tested on a number of models (model response of the model = “measured” data inversion of these data comparison of input model vs. calculated model): in most cases inversion algorithm provided satisfactory results • Note: in cases where the field conditions differ from the model of horizontally layered medium (point sources, steel lining in drainage system, fence etc) the inversion algorithm didn´t provide reasonable results (non realistic values of conductivities) – these results were excluded Results of inversion of data are presented in following ways (concerns of both areas under studiy): • each survey line (ie lines nos. -24 to 130 in case of Area_1, lines nos. 200 to 300 in case of Area_2 respectively) is presented in the form of depth section, • vertical distribution of true conductivities (ie model with optimum distribution of conductivities reaching the best fit with measured data) are displayed; elevation data are introduced,
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 36
• based on particular sets of depth sections (Area_1, Area_2 respectively) depth slices are presented each slice representing a 0.5 m thick layer, • thickness of particular layers / depth slice (0.5 m) is conformable to a sampling scheme used during the survey in 2013; it enables comparison of “true” conductivities with results of chemical analyses.
4.1.6 Geodesy
4.1.6.1 Data Collection
Surveying works covered: • Measurement of absolute relief elevations, • Demarcation. Geodetic survey works together with measurement of absolute relief elevations were conducted on the area of 11 ha. Topographic survey was conducted with Trimble M3 dr5 Total Station and Trimble R8 and R10-GSM (GPS) satellite receivers. Based on the nature of the measured area a team work was selected for the survey. Two teams composed of 1 senior surveyor, 2 surveyor assistants, and 2 draftsmen worked on the site.
Overview of survey area, team and equipment used Table 4.1.6.1-1 Surveyed area Working team Survey equipment 1 senior surveyor Trimble M3 dr5 total station 11 ha 2 surveyor assistants Trimble R8 satellite receiver 2 draftsmen Trimble R10 satellite receiver In total, 5 person (2 teams) worked on the mentioned area. Tachometrical survey was carried out from the geodetic base points with the help of Total Station. Before starting the works the tachometer has been adjusted/aligned on geodetic base point using an optical plummet, then the device has been adjusted based on at least two nearby geodetic base points. After having and checking the coordinates of aligned points topographical survey was conducted. For all measurements taken a contour diagram (“abris”) was made. With the help of Satellite Receiver the relief absolute altitude was measured, as well as measurement of survey system base points being the basis for tachometrical survey. Topographical survey with satellite receiver was conducted as follows: the receiver was placed alternately on points subjected to the survey. In this case also a contour diagram was made for all the measurements conducted in the area. Surveying works were carried out in the WGS-84 coordinate system according to the requirements of the Government Decision No. 225 as of March 11, 2002 on “Establishing WGS-84 World Geodetic Coordinate System on the territory of the Republic of Armenia”.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 37
4.1.6.2 Data Processing
Surveyed data were processed using Autocad Civil3D 2012 Software, which are resulted into digital topographic maps of the scale 1:500. Topographic survey was conducted on the area of 11 ha. Topographic survey was conducted according to the norms developed for topographic surveys in a scale of 1:500. From 120 to 150 points were measured on 1 ha, and the distance between the points did not exceed 20 m.
4.1.6.3 Technological samples (Task 3)
During the site investigation activities, samples in total weight of 154 kg for decontamination/destruction technological tests had been taken within the Task 3. Collection of the technological samples focused on category 1 (pure pesticides), category 2 (highly contaminated soil) and category 3 (lowly contaminated soil) samples. • Samples of the category 1 were taken from the following probes: XIII-1, XIII-2, XIII- 3 and XIII-5. • Samples of the category 2 were taken from the following probes: XIII-1, XIII-2, XIII- 3, XIII-4, XIII-5, and trenched pits: P3, P20, P21. • Samples of the category 3 were collected from trenched pits: P4, P20. The following tables present the list of technological samples following the categorization of contamination.
List of collected technological samples of the category 1 Table No. 4.1.6.3-1 Total weight Category No Name (kg) 1 TSP XIII-1 2 TSP XIII-1 Category 1 3 TSP XIII-1 20.0 (>30 % pure pesticides) 4 TSP XIII-2 5 TSP XIII-3 6 TSP XIII-5
List of collected technological samples of the category 2 Table No. 4.1.6.3-2 Total weight Category No Name (kg) 1 TSH XIII-1 2 TSH XIII-2 3 TSH XIII-3 4 TSH XIII-4 5 TSH XIII-5 Category 2 6 TSH XIII-5 84.3 (<30% pure pesticides - 1,500 mg/kg d.m.) 7 TSH XIII-1 8 TSH XIII-1 9 TSH XIII-1 10 TSH XIII-1 11 TSH P3 12 TSH P3
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 38
Total weight Category No Name (kg) 13 TSH P3 14 TSH P21 15 TSH P21 16 TSH P21 17 TSH P21 18 TSH P21 19 TSH P3+P20
List of collected technological samples of the category 3 Table No. 4.1.6.3-3 Total weight Category No Name (kg) 1 TSL P20 2 TSL P4 + P20 3 TSL landfill Category 3 4 TSL P4 57.3 (1,500 – 50 mg/kg d.m.) 5 TSL P4 6 TSL P20 7 TSL P20 8 TSL P20 The results of the chemical analyses of the soil taken from the probes are available and discussed in the chapter “4.2.10 Technological samples” also they are available in the annex 2.4 of this report.
4.2 Results of Survey Work
4.2.1 Geological Conditions of the Assessed Area
There are dominant sediments of Shoraghbyur formation of lower Oligocene age present on NBS. There prevail stiff clays of brown, gray, up to blue-gray color with minimum portion of silt and very fine sand (see the documentation related to probes and wells). Other types of sediments, i. e. sandstone and limestone, known from that formation, were not found on the site. The clays found in the probes were hard, dry, in greater depths up to slightly wet, according to classification analyses mostly with high up to extremely high plasticity. That, of course, may vary depending on precipitations. The clays are largely splintered mainly in near-surface parts, in probes there were partly seen indications of stratification under the angle of 20°. Apart from sub-horizontal up to slightly inclined cracks indicating layering there were vertical cracks. Closer to the surface in depths of approximately 1.5 – 2.5 m (according to the trenched pits documentation) there were hard clays up to brick-shaped and crumbly. Both main systems of cracks usually show coatings or filling of white gypsum, that sometimes created flat crystals sized up to 3 mm. More scarcely there were coatings of hematite and black manganese mineral observed (detected by RTG Spectrometry). The outcrop of claystones of the Shoraghbyur formation was exposed by the landslide in the slope to the south off the landfill. The claystones form here layers with thickness of 5-20 cm.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 39
In some places variations of layers containing more sand and more clay can be seen. The decline of the layers is 17 – 20° towards SSE. The clays continuously pass into slope clay-like loams. Because it was the same material it was very difficult to distinguish the actual boarder between both locations. There was a certain change in the structure in wells and probes in depths from 1 to 2,5 m from the surface. The position above that border was without traces of stratification, a part contained more or less a portion of rock fragments and in its upper part it was less consolidated. Under the stated border the clays were already consolidated, hard with characteristic cracking and often with presence of gypstone coating. The position from the surface to the depth of 1 – 2 m was structurally different from lower positions, the character of erosion was different, longer cracks with filling and coating of gypstone were missing as well as signs of stratification. Therefore it is possible to consider this near-surface position as clay slope loams, more or less transported down the slope. The most upper position to the depth of approximately 40 cm contained less consolidated clay loams up to clays with high (although changing) content of volcanic rock fragments (tuffs of prevailing black and dark brown color) sized mainly up to 5 cm. On the surface there are abundantly present rock fragments sized usually up to 30 cm and in places boulders sized up to 1,5 m. These boulders “float” on the surface and gradually move towards the valley. To the south from the landfill it is closely abutted by recent accumulations of coarse clastic material originating from recent landslides of the southern wall of the valley (see below), Above the eastern edge of the valley there is a shallow basin filled with washed sediments. This basin is filled with water for a part of a year. Further small depressions with wash sediments spread on the southern edge of the landslide and its contact with the adjacent slope. To the south from the landfill in the position above the steep slope there are lower quarter alluvial up to lacustrine sediments containing subrounded to rounded boulders of volcanic rocks (andesites, basalts, tuffs) of various sizes, usually up to 20 cm, sporadically up to app. 50 cm. The outcrop of these sediments with thickness of 2 - 3 m can be seen in the upper part in the slope section exposed due to the landslide to the S from the NBS and in some parts of the quarry (see below). On the above mentioned gravel terrace there is the position of quarter tuffs, thickness up to approximately 4 m. These tuffs have been recently quarried for construction purposes. The quarry is located ca 600 m to the south from the NBS. The territory of exploitation takes an area of ca 1,5 ha. On the platform in immediate vicinity of the slope to the S from the locality there is the topsoil and overburden stockpile - surface stripping and waste covering the area of ca 1,7 ha. Based on the gathered facts it is possible to reconstitute geological-tectonic development of the site. The marine sedimentation of the Shoraghbyur formation of Oligocene age is dominant here, represented by relatively pure or slightly dusty up to sand clays in the site. During younger period there followed discordance, or the younger sediments were denuded off. The sedimentation continued only in quarter with lacustrine sediments and sediments of tuffs. From tectonic point of view the main influence was represented by the fault of W-E direction along which the subsidence in the northern segment occurred. Due to that fact there are no quarter sediments found in the northern part of the locality and on the surface there are tuff boulders that, on the contrary, form a continuous stratum that has been mined for dozens of years.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 40
Slope movements on the site NBS lie in the area with very frequent slope movements of minor and major extent. It is a part of the Voghjaberd landslide field, which covers the zone of irregular shape to the east from Yerevan. The region is subject to landslides that are often caused by human activities. The most affected village was Voghjaberd where massive landslides were started in the seventies of the last century after erection of the water distribution system feeding water from the river Azat. Also in other cases there are visible and active landslides depending on leakage of water from the unattended water supply and irrigation system, where seepage through upper layers of loam and clay seepage out to lower situated layers of sediments occurred and thus caused activation of sshear planes. The landfill itself is situated in the body of a quite extensive landslide. The age of the landslide is not known. This probably occurred due to seepage of water into layers from the shallow basin above the eastern edge of the valley that is being filled with water during the spring period. Shallow basin or plain with flow-off direction the south. The situation was impaired by building the road and water pipe line at SE of the basin. That raised (or directly created) the basin bank and thus enabled the formation of the periodical shallow lake. Its seepage basically influences the conditions in the clay layers and raises the risk of slope movements. The whole landslide is approximately 950 m long and is elongated in the W-E direction. The main scarp is 185 m to the E from the border of the fenced area, or 220 m from the landfill edge. The mean width is about 30 m, max. 45 m. In this area the separating zone with partial landslides can be observed as well as side mounds and flattening upper parts of transport zones. In the central part of the zone that is flat and relatively stable there was the pesticide landfill built. Further to the west the landslide continues up to the distance of 650 m and after ca 450 m it is turning to north-west. Its width is up to 140 m. Here is a large accumulation zone with several partial ridges, brows and gorges. At the actual landslide there were neither new breaks nor distinct movements observed. A series of non-regular breaks was observed above the slope, behind the edge of the separating crest. Nevertheless, the presence of wide older lateral and longitudinal breaks and gorges suggests that the landslide is still active and some minor or larger movements that may endanger the present dumping ground may occur. The water from the landslide surface is drained at its edges at the contact with neighboring slopes and several longitudinal gorges. Thus at several places fenland with vegetation of higher grass and reed emerge. But water in those small depressions stays only during the period of larger precipitations and snow melting. The stability analysis was performed in the area of the upper part of the landslide in the previous project (Fokke 2013). The authors have in this part (from the landfill to the main scarp) three slide planes. They assumed that the slide plane would be conditioned by the change of the clays strength in the depth of 2 – 4 m. This fact was proved by our survey as there were documented more disturbed clays in depths of 1 – 3 m and lower with less content of cracks and cavities. The slide planes are activated in case of water saturation of the upper horizon with. This happens during spring rains and snow melting. As a risk factor the presence of the shallow lake is considered that appears during that time behind the eastern edge of the valley, i. e. on the landslide crest. In their report they present the plan for drainage of that lake and thus decrease of risk of perched groundwater body. Further landslides of minor extent are present on the steep northern slope, bordering from the south the valley with the landfill. The largest of them allegedly occurred in the seventies of
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 41
the past century after excavation of soil from its base during the construction of the landfill. However, direct documents on that are missing. But it also can be a result of exploitation of tuffs and disposal of topsoil and overburden stockpile for mining on the platform above the slope. On both sides of the most profound landslide there are many other smaller shallow landslides. A distinctive erosion ditch on a steep slope, approximately 10 m wide and up to 3 m deep occurred during water seepage from broken pipeline that runs along the way between the quarry and its topsoil and overburden stockpile.
4.2.2 Hydrogeological Conditions of the Assessed Area
The hydrogeological conditions within the site are conditioned by the presence of little permeable up to impermeable clays of Oligocene age and slope clay loams of approximately the same composition. These clays in the investigated area are more or less homogeneous, without profound transitions. Nevertheless, it is possible to differentiate three horizons. The first one is the upper horizon of slope loams, which are loose up to the depth of 0,4 m, in lower positions consolidated but very cracked with content of rock fragments. Within the site this horizon is the most permeable with intersticial permeability. Below these there are Oligocene clays, which, however, usually are up to 3 m at least splintered with many interstratified (slightly inclined) and vertical cracks, often slightly open and filled with gypsum. Here mainly the fissure permeability is active. The lower situated consolidated hard clays are minimally splintered, even if also here there are mainly interstratified cracks and surfaces of layers present. The rain and melting water flows through the above mentioned upper layers and on the surface. It is not probable that the water-bearing horizon and accumulation of water storage would occur. The survey works have not reached the groundwater. Neither on the site nor in its close neighborhood there are permanent water flows and water reservoirs. The minor seasonal effluent flow from the landslide body runs on the northern edge of the valley with the landfill. At the time of the survey it was without water, marked only by a profuse vegetation. Further seasonal flows are found to the north from the site. Their direction is ENE – WSW and they fall into the river Hrazdan on the territory of Yerevan. Above the eastern edge of the valley there is the already mentioned small lake and on the edge of the landslide and slope there are several further small lakes with surface of approximately hundreds of m3.
4.2.3 RTG Spectrometry - Evaluation of Surface Contamination
Based on the results gained in field measurements there was a map prepared with an orientation extent of the surface contamination related to the anthropogenic activity (Annex 1.12.1). The approximate rate of contamination is shown in colors from the heavy one (red) to the middle (orange) up to the slight one (yellow). This estimation of surface contamination extent was based on values of chlorine and other relevant elements listed below. The degree of soil contamination was decided on the base of operator experiences which primarily includes comparison of values in contaminated places with values of background samples. The places with heavy contamination were observed in the eastern part of the area, especially between the landfill body and the built drainage trench. Generally those were places in the vicinity of which there were parts of bags with pesticides or pesticides as such. A middle up to slight contamination was observed further from these places. In addition a low contamination was detected also behind the fenced area, i. e. in the creek-bed, through which the water from the NBS is drained. There is an assumption that during long lasting or fierce rains the rain water
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 42
flows through heavily contaminated places and thus partly transports the contamination into farther places beyond the area borders. But this low contamination was detected only within the distance of ca 50 m from the fenced area. In places with heavy contamination there were, apart from high Cl concentrations, detected S and heavy metals as well, especially Zn and occasionally also Cu and Ni, but also Hg. In places with middle and slight contamination there was only Cl detected and also slightly increased Zn concentrations were observed. In other parts of the area that are not marked in Annex 1.12.1 and 1.12.2, there were no abnormal values of the monitored elements measured, based on which it would be possible to state a surface contamination. That can be also stated about the surface of the landfill body itself. The Annex 1.12.2 shows designation of the places, where higher contents of some monitored elements occurred. The results from these places are stated under related designation including exact GPS in the attached report (Annex No. 2.5) from the filed measurements. For contaminated places there are red highlighted values of the elements that more distinctively exceeded the values of blind (background) measurements and thus evidence the anthropogenic contamination.
4.2.4 RTG Spectrometry – Pure Pesticides
Apart from the measurement of the stated element extent in the surface soil there was also the element composition of the clear pesticides samples taken from the landfill body (Pict. 4.2.1-1 – 4.2.1-5) measured. The purpose of that measurement was to prove that apart from typical majority elements such as Cl and S there are also heavy metals Ni, Cu, Zn, Cr, Hg present in the pesticides. Their contents accompany the presence of Cl and S and thus, based on the element abundance, it is possible with much higher probability to confirm the surface contamination caused by pesticide agents. The following pictures show clear pesticide agents drawn from the landfill body that were measured by the element RTG spectrometer.
Pesticide sample designated “Sample 1 (blue)” Pict. 4.2.1-1
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 43
Pesticide sample designated „Sample 2 (white)“ and „Sample 3 (yellow)“ Pict. 4.2.1-2
Pesticide sample designated “Sample 4 (black)” Pict. 4.2.1-3
Pesticide sample designated “Sample 5 (dark blue)” Pict. 4.2.1-4
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 44
Pesticide sample designated “Sample 6 (white)” Pict. 4.2.1-5
4.2.5 Evaluation of Chemical Analyses of Soil Samples
As the historical overview of the deposited pesticides suggests (chapter 3.1.2), the range of the deposited chemicals is very wide. The screening analyses of samples collected from pure pesticides largely showed organochlorine pesticides. Of other pesticides contained there, the following ones were present: trichlorophenoxyacetic acid (2,4,5-T), dichlorophenoxyacetic acid (2,4-D), atrazine, atrazine-2-hydroxy, atrazine-desisopropyl, desmetryn, diuron, prometryn, propazin, simazine, simetryn, DNOC, carbaryl, chloridazon, chloridazon- desphenyl, propachlorine, simazine-2-hydroxy, carbendazim, florasulam, monuron and thiophanate-methyl. Based on the screening analyses performed, groups of chemical components were selected for further monitoring. • Organochlorine pesticides; • Triazine pesticides; • Metals – As, Zn and Hg; • Sulphur; • Chlorides; and • EOX (extractable organic halogens). A part of Annex No. 2.7 is an overview of all analyses of samples. The results are compared with the limits based on: • CSOIL (2000) – calculating the human health risks posed by direct contact with the soil (TAUW, 2013) (1,500 mg/kg d.m. DDT);
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 45
• The Basel Convention (BC) – technical guidelines on the environmentally sound management of POPs wastes (50 mg/kg d.m. DDT, hexachlorobenzene, heptachlorine, aldrin, dieldrin or endrin); • Canadian Soil Quality Criteria for Environment – for agricultural soils where animals products are made (0.7 mg/kg d.m. DDT); and • MG ME CR (2013) – several indicators determined for the other areas outside the land industrially used. The following text compares the results, among others, also with the values of the natural background detected by a RTG analyser (arsenic 5.0 – 10.0 mg/kg d.m., zinc 60 – 130 mg/kg d.m., mercury < 11 mg/kg d.m., sulphur 200 – 2,000 mg/kg d.m., chlorides < 40 mg/kg d.m.).
4.2.5.1 Metals
Arsenic occurred in most samples in natural concentrations amounting to 5 – 10 mg/kg. The anthropogenically affected soils occurred directly in the cells in samples XIII-5/3 (1.2 – 1.9) and XIII-5/1 (0.9 – 1.7), and also spread outside the landfill body into the vicinity where it was present in increased concentrations in test pits XI-6, XI-7, XI-11 and XI-13. Slightly increased values of zinc concentrations as compared to the natural occurrence were recorded directly in the cells, in all samples and in test pits XI-6, XI-7, XI-11 and XI-13. The occurrence of mercury above the limit of detection of the analytical method was detected only in several samples, with increased values being present in test pits XI-7 and XI-11 and in the cells. The highest value detected was 20 mg/kg d.m. in sample XIII-5/1 (0.9 – 1.7).
4.2.5.2 Sulphur
The presence of sulphur was very variable in all samples and depth levels. The values ranged between the first hundreds and ten thousands of mg/kg d.m. The presence of sulphur in higher thousands of mg/kg d.m. can be considered as an indicator of anthropogenic impact, even though sulphur is a common element in the Earthʼs crust.
4.2.5.3 Chlorides
The occurrence of chlorides – i.e. inorganically bound chlorine – is also very variable. Inorganically bound chlorine was present in concentrations from below the limit of the analytical method (40 mg/kg DW) up to 1.0 g/kg DW.
4.2.5.4 Organically Bound Halogens (EOX)
For EOX there are no internationally applicable values of maximum admissible concentrations. This concerns a group-based determination of substances. The analyses of EOX were made as a supportive method for determining the presence of OCP and chlorine. The results of analyses of OCP and EOX correlate very well. When the values of EOX increased, the occurrence of OCP was also recorded in increased values.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 46
4.2.5.5 Organochlorine Pesticides (OCPs)
OCPs are a majority contaminant present at the site. This is shown in all of the investigation work carried out in the past as well as in the current survey. Of the monitored range of OCPs, the following ones were present: 1.2.3.5- & 1.2.4.5- tetrachlorobenzene, 1.2.3.4-tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene (alpha, beta, gamma, delta, epsilon), DDE and DDD, but the main OCP abundant there was clearly DDT. Of all the pesticides present, DDT occurred in pits of line: • XI: 94.6 %; • XII: 91.6 %; and • XIII: 80.7 %. Although the presence of the other pesticides was detected, none of them exceeded the limit value 50 mg/kg d.m. Therefore, the following text evaluates the sum of 6 isomers of DDT. It can be stated that the survey encountered soils with a wide range of contamination: • The highest contamination is present in the landfill cells, exceeding: The limit 1,500 mg/kg d.m. for highly contaminated soils: samples XIII-1/1 (0.8- 0.9), XIII-5/1 (0.9-1.7) and XIII-5/3 (1.2-1.9); and The limit 50 mg/kg d.m for lowly contaminated soils: samples XIII-2/2 (1.0-1.5), XIII-3/1 (1.5-2.1) and XIII-4/3 (2.2-2.5). • Outside the landfill body, but inside the fenced premises, exceeding: The limit 50 mg/kg d.m. for lowly contaminated soils: XI-4 (0.0-0.5), XI-5 (0.0- 0.5), XI-6 (0.6-1.0), XI-7 (0.0-0.6), XI-9 (0.0-0.5), XI-11 (0.0-1.0), XI-12 (0.5-1.0), XI-13 (0.0-1.0), XI-14 (0.0-1.0) and XI-15 (0.0-0.5); and The limit 0.7 mg/kg d.m. for areas agriculturally used as pastures: XI-1 (0.0-2.0), XI-2 (0.0-0.5), XI-4 (0.5-2.0), XI-5 (0.5-1.0) a (1.5-2.0), XI-6 (0.0-0.6) a XI-6 (1.0- 1.8), XI-7 (1.0-1.8), XI-8 (0.0-0.5) a (1.0-1.6), XI-9 (0.5-1.5), XI-10 (0.0-0.5) a (1.0-1.5), XI-11 (1.0-1.5), XI-12 (0.0-0.5) a (1.0-1.5), XI-13 (1.0-2.0), XI-14 (1.0- 2.0) and XI-15 (0.5-2.0). • Outside the fenced area, exceeding: The limit 50 mg/kg d.m. for lowly contaminated soils: samples XII-3, XII-7 and XII-18 collected from the ground surface); and The limit 0.7 mg/kg d.m. for areas agriculturally used as pastures: samples XII-1, XII-4, XII-8, XII-14 and XII-15 collected from the ground surface.
4.2.5.6 Triazine Pesticides
Triazine pesticides were detected at the site in small quantities. None of the monitored limits was exceeded in any of the samples. Of the pesticides of this category contained there, the following were present: desmetryn, atrazine, simazine, prometryn, simetryn, atrazine-2- hydroxy and atrazine-desisopropyl.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 47
4.2.6 Correlation of RTG Spectrometry and Chemical Analyses
In order to controll removing of contaminated soil during the site remediation by portable RTG spectrometer (Delta Professional), the results measured by this device and results from accredited laboratories were compared. A correlation of obtained results was done subsequently. On basis of this correlation a tentative approach to decision making about approximate rate of soil contamination during its removing was proposed. Given that the correlation is done between the representation rate of elements measured handheld element analyzer and the organic analysis of sum of organochlorine pesticides (OCPs), only the framework approach was proposed. A definite approach with respect to the above is not possible and the evaluation depends primarily on the experiences of the operator, carrying out the measurements, and on the conditions and circumstances on the site including comparison with blank samples (background samples). However, on bases of the measurement of both heavily contaminated soils and OCPs themselves, some rules can be defined to determine, whether the soil is contaminated by these pollutants or not. Due to the fact, that pollutants are chlorinated organic compounds, the attention is primarily given to a Cl. Its presence or absence then decides on further consideration. By measurement of background sites (listed in the Annex 2.5 and indicated in protocol "Analytical_report_sector_D" by the letter "S") on the area the presence of Cl has not been proven. Based on this finding, it can therefore be declared that the repeated presence of Cl in the soil in the landfill area is most likely of organic origin and by this the soil contamination by the OCPs is thus demonstrated. However, during the measurement of pure pesticides and heavily contaminated samples was found that other elements detected together with Cl at significantly higher levels than background samples may also be evidence of the presence of OCPs in the soil. These elements are as follows: S, Zn, Ni, Cu, As, Hg a Cr (see Annex 2.5- "Analytical_report_waste"). Monitoring of these elements can therefore be taken as targeted for deciding whether and to how extent is the soil contaminated by OCPs. If CI is repeatedly measured at above-limit concentrations in the soil, it is highly probable that it is of antropogenic origin and relates to OCPs contamination. Certain contamination caused by anthropogenic activity (in this case by the presence of OCPs) can be asserted if except for chlorine also the presence of sulphur is detected as well as heavy metals (especially Zn, Ni, Cr, Cu) in amount more than 100 ppm. If Hg (more than LOD) or As (more than 50 ppm) is detected, then the presence of pesticides can also be considered. The degree of representation of Cl, or its combination with other elements mentioned above in higher amounts, then determines the degree of soil contamination. In following table the ranges of values for the individual target elements that can be used to estimate the very approximate level of contamination in the soil are listed.
Estimation of level of soil contamination by OCPs based on detected elements and their representation rates Table 4.2.6-1
Detected Values listed in ppm (mg/kg) Cl S Cr Ni Cu Zn As Hg Cl No contamination NO < LOD LOD-1,000 LOD-50 LOD-70 LOD-60 LOD-100 LOD-20 < LOD weak contamination YES < 400 LOD-1,000 LOD-100 LOD-100 LOD-100 LOD-100 LOD-30 < LOD < 50 ppm of Σ detected OCPs lowly contaminated soil – C3 50 - 1 500 ppm of Σ detected YES 400-7,000 500-10,000 LOD-200 LOD-200 LOD-200 > 100 LOD-50 LOD - 20 OCPs Highly contaminated soil and LOD- pure pesticides – C2 + C1 LOD-500 LOD-500 LOD-500 LOD - 20 YES > 7,000 > 8,000 > 100 500 and and more and more and more and more > 1 500 ppm of Σ detected more OCPs
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 48
4.2.7 Evaluation of Soil Mechanics Analyses of Soil Samples
Results of analyses shows that the soil present on site is claily with high up to very high plasticity. Some samples have higher content of sand and gravel fraction, that influences the classification. However, here are clay fragments of hard consistency, that have character of a semirock. These fragments are not decomposed further to clay particles in the prescribed way. The following table contains statistic evaluation of the executed laboratory tests of soil mechanics.
Statistical evaluation of the executed laboratory tests of soil mechanics Table No.:4.2.7-1 Soil Clay Classification acc. to the standard ČSN EN ISO Cl, siCl, grCl 14688-2 Number of minimum diameter maximum median samples
Water content - natural wn [%] 35 4,2 41,8 18,0 17,9 - near flowability wL [%] 4 59 92 79 83 - near plasticity wp [%] 4 24 28 27 27 Plasticity index Ip [-] 4 31 68 53 55 Consistency index Ic [-] 4 0,77 1,37 1,08 1,09 Permeability from grain-size k [m.s-1] 35 <3,0E-8 curve [Mg.m- Specific gravity ρ 5 1.66 2.00 1.83 1.78 3] [Mg.m- Specific gravity of dry soil ρ 5 1.31 1.91 1.52 1.42 d 3] [Mg.m- Particle density ρ 19 2.69 2.85 2.75 2.74 s 3] Porosity n [%] 3 48 51 50 51 Degree of saturation Sr [%] 3 54 91 71 67 Shear strength - effective cohesion c' [kPa] 5 30 107 66 55 - effective internal friction ' [°] 5 0 25 17 20 angle - residual cohesion c'R [kPa] 3 10 78 33 11 -residual internal friction ' [°] 3 11 18 15 17 angle R Compressibility Eoed [Mpa]
050-100 2 6.8 11.6 9.2 9.2
Oedometric module 100-200 3 3.2 11 7.7 8.9
200-400 3 4.1 6.6 4.9 4.1
for tension range Ccollapsibility coefficient imp [%] 2 0.5 3.7 2.1 2.1 swelling pressure s' [kPa] 1 100 -3 compactibility acc. to EN dmax [kg.m ] 4 1427 1524 1472 1469
13286-2 wopt [%] 4 25.5 29.7 27.7 27.8 Upon the results of the laboratory tests and knowledge from field measurement we recommend the following values of geotechnical properties to be used for geotechnical calculations.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 49
Recommend values of geotechnical properties to be used for geotechnical calculations Table No.:4.2.7-2
Soil clay Classification acc. to the standard ČSN EN ISO 14688-2 Cl, siCl, grCl Consistency solid firm up to hard disturbed soil Consistency index IC [-] <1,0 1.0 - 1.5 Permeability from grain-size cur. k [m.s-1] <3,0E-8 2,0E-6 Unit weight of soil γ [kN.m-3] 18
Oedometric module Eoed [MPa] <200 3.2 10 3.2 for tension ranges [kPa] >200 4.1 15* 4.1 Poisson number ν [-] 0.4 Coefficient β [-] 0.47 Shear strength
- residual cohesion c'R [kPa] 10
- residual internal friction angle 'R [°] 18 - effective cohesion c' [kPa] 20 80 - effective internal friction angle ' [°] 21 22.5
*note: the value was determined conservatively by qualified appraisal, it has not been proven by tests.
4.2.8 Geotechnical Calculations
The NBS stability is essentially influenced by the stability of the steep slopes to the south and east above the area. Contingent collapse of those slopes may initiate further movement of the main landslide in which the landfill is positioned. Thus the calculations are aimed mainly at assessment of those slopes. See Annex 2.9. Firstly the soil parameters were verified by reverse calculations. This procedure is suitable for steep slopes to the south from the landfill where recently some minor landslides occurred. It is obvious that degree of stability of those slopes nears the value of 1,0. When degree of stability < 1,0 the slope is unstable. When FS = 1,0 stabilizing and destabilizing forces are in equilibrium the slope is just stable but any deviation can cause landslide. When FS > 1,0 the slope is stable for the conditions under consideration but standards and regulations usually require higher value. Degree of stability > 1,5 is usually considered safe for long-term conditions, or security is provided otherwise, e.g. by reducing soil strenght according to the Eurocode 7. For checking the soil structural parameters there were two cross-sections chosen – see the picture below.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 50
The two cross-sections for checking the soil structural parameters Picture No.: 4.2.8-1
Cross-section 2
Cross-section 1
N
Calculated degree of stability is FS = 1,108 for cross-section 1 and FS = 1,052 for cross- section 2. From this we can infer that the soil structural parameters correspond to reality. The aim of another calculations was to verify how the excavations necessary for remediation of the NBS influence the stability over the site. The assessment is done in two cross-sections – see the picture below.
The two cross-sections for checking the slope stability Picture No.: 4.2.8-2
Cross-section 3 Cross-section 4
N
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 51
At first the original stability of the slope is calculated, then the slope stability at realization of the excavation and also the slope stability during the spring snow melting, when we assume groundwater level occurence. Calculated degrees of stability for the cross-section 3 is on the picture below.
Calculated degrees of stability for cross-section 3 Picture No.: 4.2.8-3
For the cross-section 3 the original stability and the slope stability at realization of excavation are practically same (FS = 1,110) while during the spring melting the slope stability is significantly lover (FS = 1,044). Calculated degrees of stability for the cross-section 4 is on the picture below.
Calculated degrees of stability for cross-section 4 Picture No.: 4.2.8-4
For the cross-section 4 the original stability and the slope stability at realization of excavation are almost the same (FS = 1,413) while during the spring melting the slope stability is significantly lover (FS = 1,260). From this we can infer that the excavation realization in the landfill body (in the extent corresponding with the model situations) is possible only during the dry period and this activity has insignificant influence upon the stability of adjacent slopes. Lastly there were possibilities of long term stabilization of the area outlined that, however, should be suggested on the basis of a separate construction research. The calculation was used to solve only the variant of ensuring the area stability by adaptation of the slope gradient to the south from NBS. However, this plan must be understood just as a reference one. See Annex 2.9 for more details.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 52
4.2.9 Evaluation of Geophysical Measurements
Measurements (raw data) are presented in the form of maps of areal distribution of apparent conductivities (in mS/m), inphase component (in ppt) and error of measurement (in %) for all three intercoil distances. Results of processing (inversion of data) are presented in the form of: • depth section of distribution of “true” conductivities (in mS/m) along particular survey lines, • maps of areal distribution of “true” conductivities (in mS/m) in the form depth slices for particular depth ranges.
4.2.9.1 Overview of Works Done
Geophysical survey using shallow dipole electromagnetic profiling (DEMP) was conducted at 2 (sub)areas. Area 1 is situated within the area surrounded by fence. Total of 78 transversal profiles (66 of them 36 m long, 12 of them 30 m long) and 6 longitudinal profiles (each of them 154 m long) was measured; total of 3,660 m (3,750 measured points respectively) was measured. A part (ca 5%) of measurements was repeated (from the reasons of quality assessment). Area 2 is situated at the flat outer part of the NBS in the (outer) surroundings of the entrance gate. Total of 51 transversal profiles (each of them 23 m long) and 6 longitudinal profiles (each of them 101 m long) was measured; total of 1,773 m (1,830 measured points respectively) was measured. A part (ca 5%) of measurements was repeated (from the reasons of quality assessment). Measured data of Area 1 and Area 2 are presented in the form of maps of (see Annex No. 1.8- 1.11): • Apparent Conductivity 1 (in mS/m) (for intercoil distance 1.48 m) • Inphase Component 1 (in ppt) (for intercoil distance 1.48 m) • Error 1 (in %) (for intercoil distance 1.48 m) • Apparent Conductivity 2 (in mS/m) (for intercoil distance 2.82 m) • Inphase Component 2 (in ppt) (for intercoil distance 2.82 m) • Error 2 (in %) (for intercoil distance 2.82 m) • Apparent Conductivity 3 (in mS/m) (for intercoil distance 4.49 m) • Inphase Component 3 (in ppt) (for intercoil distance 4.49 m) • Error 3 (in %) (for intercoil distance 4.49 m) It should be pointed out that the quality of measurements was very high: more than 98% of readings were obtained with measuring error lower than 1%, measurements with higher measuring error correspond with location of surface drainage system.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 53
4.2.9.2 Basic Characterictics of Data
In order to obtain basic idea about areal and/or depth distribution of apparent/true conductivities a basic statistical evaluation of measured data was performed. For particular intercoil distances histograms of frequency of apparent conductivities were calculated. It can be stated that: • apparent conductivity data display a log-normal distribution, • general increase of apparent conductivity with depth was observed (in parts not affected by presence of contaminants)
4.2.9.3 Characteristics of the Site Models
Area 1: Processed data (inverted values of electric conductivity of soil) presented in the form of depth slices confirmed extent of contamination discovered by previous survey. Intensive anomalies correspond well with position of 5 cells. Moreover, intensive contaminated parts were discovered at SW (towards the SW end of concrete drainage) and northern (in the wider surroundings of the entrance gate) parts ofNBS. As for depth distribution of conductivites: • in near surface layers (Depth slice 0.0 – 0.5 m and Depth slice 0.5 – 1.0 m) conductivities are extremely low: it is probably caused by the fact that the soil are extremely dry in this part of section, • in lower parts of section conductivities increase; increase of conductivities may be caused either by natural increase of conductivity due to increasing moisture content of soils (clay), or by content of contaminants, or by both factors (since POP´s are mostly hygroscopic), • in several parts of the area gypsum occurrences were found in sampling works (ie another hygroscopic material), • anyway it should by pointed out that conductivities higher than ca 150 mS/m can hardly be explained in another way than presence of contaminants (follows also from statistical evaluation of data in unaffected parts of the area), • most intensive increase of conductivity may be observed in Depth slices 1.0 – 2.5 m , in lower parts intensity decreases; contours of cells are obvious even in lower parts, • in parts deeper than 4 m the conductivity is mostly constant (ranging from 100 – 150 mS/m). Area 2: Processed data (inverted values of electric conductivity of soil) presented in the form of depth slices discovered a intensive strip of contamination along entrance road. Above mentioned findings for the Area 1 generally hold even for this area. Increase in conductivity is not so intensive (with the exception of the close vicinity of entrance gate). Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 54
Narrow strips reaching even deeper parts of the section may indicate infiltration of contaminants along deeper cracks. As for foundation conditions in the area of future construction project no other significant inhomogeneities were found. As for findings obtained from inphase components, in both areas no indications of presence of artificial metallic bodies (barrels, cables etc) were found (other than anomalies caused by reinforcement of drainage). Space between Area 1 and Area 2 Between the Area 1 (entrance gate) and Area 2 (the landfill body) there is a void space where geophysical data were not measured. Geophysical data surrounding the void area could indicate, that the area marked by the red elipse on the picture 4.2.9-1 might also show increased values of conductivity. Similarly to the area in front of the entrance gate, the occurrence of natural gypsum is most likely the reason of increased values of conductivity. The presence of gypsum implies that especially in the deeper soil profile on the site (more than 1,5-2 m below the surface) the soil is stiff and compact, with natural gypsum filling natural vertical fractures. This indicates undisturbed natural profile not affected by excavation - construction works. Also the fact that these fractures are filled with the gypsum diminish the probability of pesticides spreading. Although the presence of contamination in the surface soil in this area has been proven during the investigation, presence of contamination deeper in the soil is highly unprobable, though not verified by chemical analyses.
Distribution of conductivity in the depth level of 3,5 – 4,0 m from the terrain surface Picture No. 4.2.9-1
4.2.10 Techological samples
The following table presents results of chemical analyses of the soil samples collected from the landfill body for the purpose of the contamination spread identification. The material for the technological samples (Task 3) was taken from the same probes or even the same samples
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 55
taken. These results of the chemical analyses were benchmarked and classified as category 2 material. The following analyses do not correspond to individual technological samples taken (but they correspond to the same probes and/or places of site investigation), except for the XIII-5/1(0,9-1,7) sample. Other analyses in the following table represent part of pesticides screening analyses results (Ar1 to Ar5) and contamination survey results (XIII-1/1 (0,8-0,9), XIII-5/3(1,2-1,9), implying the potential characteristics of the technological samples.
Indicative chemical parameters of the C 2 material from the landfill body Table No. 4.2.10
XIII-1/1 XIII-5/1 XIII-5/3 Ar1 Ar2 Ar3 Ar4 Ar5 Sample Name unit (0,8-0,9) (0,9-1,7) (1,2-1,9) Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 4 Cell 1 Cell 1 EOX 1,980.0 1,980.0 2,960.0 - - - - - Chloride 470.0 420.0 540.0 - - - - - Arsenic 7.7 151.0 81.1 - - - - - Zinc 966.0 621.0 359.0 - - - - - Mercury 15 20 <11 - - - - - Sulphur 29,180.0 6,934.0 5,362.0 - - - - - mg/kg Sum of 3 isomers TCB <3.0 <3.0 <3.0 - - - - - Sum of 5 isomers HCH 1,640.0 563.0 29.8 901.5 617.9 293.3 132.1 161.4 Sum of 6 isomers DDT 3,890.0 2,130.0 1,780.0 1,290.0 468.0 13,000.0 2,310.0 13,500.0 Sum of DDD 293.7 167.6 146.0 167.0 43.8 1,740.0 248.8 1,988.0 Sum of DDE 30.05 11.14 7.07 84.2 27.5 420.6 157.0 391.7
Sum of DDT + HCH7 5,522.95 2,693.94 1,804.87 2,442.7 1,157.38 15,453.9 2,847.9 16,041.1
4.3 Summary of the Extent and Degree of Contamination
Annex No. 1.13 shows a synthetical map of contamination. Concentration ranges were determined for the purposes of data processing in compliance with the surveys carried out by GEOtest (2013) and TAUW (2013). This thus concerned: • Category 1: Pure pesticides or associated material > 30 % pure pesticides; • Category 2: Highly contaminated soil with ∑4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'- DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH concentration higher than 1,500 mg/kg dry matter according to CSOIL 2000 for workers on the site (above the human health risk threshold for direct exposure); • Category 3: Lowly contaminated soil with ∑4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'- DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH concentration lower than 1,500 mg/kg dry matter and higher than 50 mg/kg dry matter according to The Basel Convention (BC), Technical guidelines on the Environmentally Sound Management of POPs wastes; and
7 Sum of 4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH+ εHCH
8 With respect to the accuracy of analytical method ± 40% the sample is included into the category 2 Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 56
Lowly contaminated soil with DDT concentration lower than 50 mg/kg dry matter and higher than 0.7 mg/kg dry matter according to Canadian Soil Quality for Environment and Human Health for agricultural soils (where animals products are produced). • Category 4: Contaminated construction material. The increased occurrence of the metals (As, Hg, Zn), sulphur and chlorine, whether organically or inorganically bound, correlates with the increased occurrence of DDT. Therefore, DDT and its decay products together with HCH is considered as the key contaminant for further evaluation. Map of 4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH (further DDT + HCH) contamination in depth levels is shown in Figure: 4.3-1. Map of DDT, DDD, DDE and HCH contamination Figure No.:4.3-1
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 57
4.3.1 Category 1 – Pure Pesticides
The exploratory pits encountered pesticides in the individual cells of the landfill (trenched pit P22 and pits of line XIII – see the geological log in Annex No. 1.13). This occurrence corresponded with the results of the previous surveys.
4.3.2 Category 2 – High Contamination
Highly contaminated soil (> 1.500 mg/kg DW) was found in the following places: • Along the northern heel of the landfill: At a depth of 1.0 – 1.5 m in pit I-2. • Along the southern heel of the landfill: At a depth of 0.5 – 1.0 m in pit VI-5. • Another occurrence of high contaminated soil (< 30 % pure pesticides) was detected in a planar layer of about 10 cm in thickness roughly 0.7 m below the ground surface in pits P3 and P4, which were primarily dug for an E-G survey. • Around trenched pit P21, pesticides occur in a mixture with soil (10 – 30 % of pure pesticides). This occurrence is probably caused by illegal excavation of pesticides in the past because in the vicinity there were also remnants of wrapping material in which pesticides were packed (plastic sacks).
4.3.3 Category 3 – Low Contamination
Lowly contaminated soil, Category 3, with a range of 50 – 1.500 mg/kg d.m. of ∑4,4'- DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'-DDE+2,4'-DDE+αHCH+βHCH+γHCH+δ HCH, was found in the following places: 1. Continuous occurrence: • (Near-) surface runoff from the landfill outside the fenced premises: Contamination is here probably present to a depth of 10 cm in test pits XII-3 and XII-7. • In the northern part of the landfill inside the fenced premises, (between the drainage system and the entrance) : To a depth of 0.5 m in pits XI-9 and XI-15; To a depth of 1.0 m in pits III-2, III-3, IV-5, V-7 and XI-12; and To a depth of 1.5 m in pits IV-3, IV-4, V-1, V-2, V-3, V-5, I-2 and XI-11. • In the southern part of the landfill inside the fenced premises: To a depth of 0.5 m in pits XI-4, XI-5 and XI-7 (0.6 m); To a depth of 1.0 m in pits VI-3, VI-4, VII-1, VII-6 and XI-6; and To a depth of 1.5 m in pits VI-3, VI-5, VI-6, VII-2 and VII-5. 2. Isolated occurrence:
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 58
• In the north-eastern tip outside the fenced area: To a depth of 0.1 m in pit XII-18. • In the area of trenches: To a depth of 0.5 m in pit IX-1. • In the south-eastern and western parts inside the fenced area: In the depth level 0.5-1.0 m in pit VII-3. Lowly contaminated soil, Category 3, in the concentration range 0.7 – 50 mg/kg d.m. of the Category 3 there is an evident presence of DDT + HCH at all studied depth levels, with the highest spreading being indicated particularly in the surface layer in which contamination occurs inside and outside the fenced area. Contamination outside the premises is spread chiefly in the western (and possibly north-eastern) direction
4.3.4 Category 4 – Contaminated Construction Material
Contaminated construction material was detected only in one cell in accordance with the survey made by TAUW (2013). It is the easternmost cell (test pits XIII-5/1 and XIII-5/2). Based on a geophysical measurement, an area with high values of conductivity was identified in the place of the entry into the premises of the NBS at depths of about 1.5 – 3.0 m. This can theoretically indicate the presence of contamination. It is an area in front of the entry into the premises where in the past pesticides could have been handled and thus might have spilled. This possibility, however, was not proved by sampling work which here had focused on surface contamination. The survey work in this area recorded an increased occurrence of gypsum that could give a similar response as pesticides give to the geophysical measurement.
4.4 The Balance of Contamination
The survey carried out by the company TAUW (2013) dealt in detail with the amount of material in contamination ranges, deposited in the landfill body. Contamination in the vicinity of the landfill body was verified by several composite samples collected from the near-surface parts of the geological environment; nevertheless, the final amount of contaminated soil was only estimated. The survey carried out by the company GEOtest (2013) detected that the large amount of contamination in the vicinity of the landfill is present not only in the near-surface parts, but also at greater depths. To verify the previous work, 15 probes were drilled into the individual landfill cells. The depth boundaries of the individual contamination ranges (Categories 1 to 4) correspond with the previous survey made by TAUW (2013) and it is possible to agree with its results. Another subject of this survey was to summarise the amount of contaminated soil in the following four categories around the landfill. • Category 1: Pure pesticides or associated material > 30 % pure pesticides; • Category 2: Highly contaminated soil with ∑4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'- DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH concentration higher than 1,500 mg/kg dry matter;
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 59
• Category 3: Lowly contaminated soil with ∑4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'- DDD+4,4'-DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH concentration lower than 1,500 mg/kg dry matter and higher than 50 mg/kg dry; and Lowly contaminated soil with ∑4,4'-DDT+2,4'-DDT+4,4'-DDD+2,4'-DDD+4,4'- DDE+2,4'-DDE+α HCH+β HCH+γ HCH+δ HCH concentration lower than 50 mg/kg dry matter and higher than 0.7 mg/kg dry matter according to Canadian Soil Quality for Environment and Human Health for agricultural soils (where animal products are produced). • Category 4: Contaminated construction material (higher than 50 mg/kg dry matter).
4.4.1 Methodology of calculation
For calculation of the volume of the individual layers of the landfill surroundings, the “area × thickness” method (total area of contaminated soil in one depth level multiplied by the thickness of the layer) was applied. The thickness of each layer followed the depth interval of sampling – typical sampling vertical range was 0.5 m for one sample. Samples were taken using gouge auger with diameter of 45 mm (GEOtest 2013, DEKONTA-GEOtest 2017). As a result of this sampling approach the depth intervals were following: 0-0,5; 0,5-1,0; 1,0-1,5; 1,5-2,0; 2,0-2,5 m below ground level. In addition, 20 samples were collected from the surface of terrain (DEKONTA- GEOtest 2017) representing a thin layer from the surface to the depth of 0.1 m. For each depth layer the delineation of the area with a different intensity of contamination by pesticides (category C1 to C3) was done, assuming that the contamination intensity is homogeneously spread within the whole depth interval. In order to generate a realistic map of contamination spread (contaminated area) within individual depth layers chemical analyses of samples taken from probes and pits done in 2013 and 2017 by Tauw, GEOtest and DEKONTA were the driving input to the volume estimation. In places with sufficient density of analytical data on contamination, the linear method of interpolation was applied. In order to present the relevancy of volume estimation, it is important to present the level of accuracy of chemical analyses done. In case of GEOtest, 2013 results the accuracy of chemical analyses is ±35%, in 2017 it is ±40%. When estimating the extent of contamination in individual contamination categories, chemical data on each sampling point in each depth level was interpolated with the existing analytical data in usually 4 directions (approx. to N, S, W, E). In places with lack of data for interpolation (namely to one direction - on the edge of the contamination cloud) the missing data were extrapolated based on averaging the distance of the contamination contour line between the other 2 or 3 (depending on data availability) most adjacent sampling points. In addition, various supportive methods had been applied for extrapolation including both survey supplementary results and a judgement method in places with lack of data for interpolation (both vertical and horizontal).The following list presents the supportive tools: • Geomorphological patterns • Geological patterns • Electrical conductivity measurements results • X ray Delta measurements results • Other field observations
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 60
• Knowledge of the recent site operations These tools had been used either as a self-contained instrument or in combination with the other tool(s). As a result of this approach, contour lines for C1 to C3 contamination were drawn for each depth level. Geomorphological patterns - typically, in steep slopes between the northern fence and the landfill body, it is presumed that no subsurface contamination (no deeper than ca 0.5 m below ground level) could be present (as a result of wind migration) because: • no fractures and fissures were documented on the slope (i.e. spreading of contamination by infiltration of surface water is limited because of the quality of soil, also considering a very limited solubility of pesticides in water), • no subsurface contamination was detected on the above-laying plateaus and • steep slopes are inaccessible for heavy machinery. Another place where the geomorphological patterns were used is the area between the southern edge of the landfill body and trench running along the foot of the unstable slope. In this area it is assumed (judgement) that the > 50 ppm contamination is not spread behind the surface water drainage trench in depth deeper than 0,1 m. The depth of the trench differs in its length varying from one meter to ca 2,5 m. This presents geomorphological barrier for potential spreading of contamination either natural or anthropological. In case of surface water creek beds in the N-W edge of the site that are periodically run through during rain and snow-melting seasons the horizontal spread of contamination is assumed to be limited to the width of the creek bed. In the following picture areas where the above mentioned assumptions were applied are presented in green-hatched fields. The map is also presented in graphic annex 1.14.
Map of supportive methods used for delineation of contamination Picture No.: 4.4.1-1
Geomorphological patterns discussed above and shown in the picture were applied as a supportive instrument for contamination delineation for contamination layers ranging from the depth of 0,5 to 2,5 m bgl. Geological patterns – the original geological material on site is formed by marine sediments of oligocene age with abundant presence of natural gypsum. Clays in its natural state are hard
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 61
with typical brownish coatings of Fe oxides and gypsum crystals (up to 3 mm). When doing the primary documentation of all survey probes, boreholes and trenched pits, the presence of these indicators were tracked in order to identify the original geological environment. This knowledge was later used for delineation of contamination on places with lack of analytical data implying that the presence of original undisturbed geological profile excludes the possibility of contamination presence. Another geological aspect is a presence of vertical fractures formed from the surface to the variable depth levels (2 - 4 m), where closed cracks prevent further potential spreading. In deeper horizons migration of contamination in natural environment is not expectable because of low solubility of pesticides. Therefore, where the analytical data on contamination were missing and the presence of natural geological profile without vertical cracks was documented, the presence of any contamination is not expected. Areas where the above mentioned assumptions on geological patterns were applied are presented in the picture 4.4.1-1 as the red-hatched fields. Electrical conductivity is a geophysical method revealing materials with a different electrical conductivity than the one of a natural soil. In a natural environment, the increased conductivity can be represented by materials with high content of water with dissolved ions, for instance. Clean water does not increase electrical conductivity substantially. This method enables to distinguish between the natural geological background (original soil in situ) and anthropogenically affected geological environment (typically fill material). However, this method is an indirect method not capable of specific detection of pesticides location. Based on on-site measurement of the electrical conductivity natural background, it can be identified which material differs from natural state. While electrical conductivity of 100 - 150 mS/m can be assessed as natural, the values higher than 150 mS/m indicate anomalous situation. Values of electrical conductivity (DEKONTA-GEOtest, 2017) were generated as an average value of conductivity in the given depth layer. Therefore, in places inside the fenced area where the analytical data on contamination were not available, but contamination was indicated by chemical analyses in adjacent place (in vertical or horizontal manner) or by X ray measurement in that particular place or in adjacent place, and the intensity of electrical conductivity was comparable on both places, the value of electrical conductivity detected on place with available analytical data was considered as indicating the contamination of analogical intensity. Delta X ray measurements (for results see annex 2.5) were used on site during the sampling (DEKONTA-GEOtest, 2017) for the future evaluation of correlation between X ray measurements and chemical analyses results; also the Delta equipment was used for verification of presence of contamination in trenched pits done in the area surrounding the landfill body. The results of these measurements were recorded, correlated with results of natural background measurements and later used for the operational field contamination identification. With knowledge of natural chemical composition of soil on site, trenched pits between the fenced area and the landfill body were examined with the X ray equipment. Results of these measurements were used as a supportive field tool for confirmation of natural composition of soil. Knowledge of recent operations on site - most of the out-of-landfill secondary contamination spread is a result of unauthorised manipulation with pesticides in 2009. As a result of the activity, the out-of-the-landfill contamination is formed rather by a mixture of various types of pesticides and soil.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 62
Contour lines of contamination developed in the above described manner were then transformed into the real coordinate system WGS-UTM maps of contamination for individual depth level in the Microstation software. With use of the Microstation software an areal spread of contamination in particular depth levels were computed. To obtain the volume of contamination in the individual depth level the area was multiplied by the thickness of the layer (typically 0.5 m). The calculated volumes are shown in Table No. 4.4-1.
Volumes of material contaminated Table No.: 4.4-1
Category 1 Category 2 Category 3
Average <30% pure Depth level Thickness >30 % pure pesticides - 1,500 - 50 1,500 – 0.7 mg/kg pesticides 1,500 mg/kg mg/kg d.m. d.m. d.m. [m] [m] [m2] [m3] [m2] [m3] [m2] [m3] [m2] [m3] 0.0-0.5/0.6 0,55 - - 32 18 2,034 1,119 13,423 5,105 0.5/0.6-1.0 0,45 - - 270 122 3,408 1,534 9,297 4,184 1.0-1.5 0,50 120 60 602 301 2,066 1,033 4,550 2,275 1.5-2.0 0,50 145 73 1,002 501 313 157 3,257 1,629 2.0-2.5 0,50 258 129 795 398 390 195 2,408 1,204 2.5-3.5 * 1,00 262 262 786 786 652 652 1,603 1,603 >3.5 ** 1,00 150 150 300 300 300 300 800 800 Total volume 674 2,425 4,989 16,799 Specific gravity (t/m3) 1.5 1,7 1,7 1,7 Estimated weight (t) 1051,5*** 4,122,5 8,481 28,558 * only in the landfill body, values calculated based on previous survey TAUW, 2013 ** only in the landfill body, values estimated based on previous survey TAUW, 2013 *** calculation made for mixture of 70% of pesticides with specific gravity 1,5 t/m3 and 30% soil with specific gravity 1,7 t/m3.
Category 4 (Contaminated construction material) volume was not re-calculated because the current survey just confirmed the presence of construction material. Therefore, the volume stays as it was estimated by TAUW (2013), i. e. 20 m3. The specific gravity for the synthetic cover of construction elements is 1,2 t/,m3, the specific gravity for construction elements (concrete, bricks, rubble) is estimated at value of 2,2 t/m3. The resulting weigh of contaminated construction materials is 41 t.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 63
4.5 Approximate Distribution of the Main Types of POPs in the Landfill and Its Surroundings
The survey work also focused on the qualitative abundance of the individual pesticide types at the site, particularly in the individual cells. The designation of the landfill cells follows the terminology established by the Tauw (2013), where the cell no. 1 is the eastern-most one and the cell no. 4 is located on the western-most sector of the landfill, cells no. 2 and 3 are located in-between, while the cell no. 5 was constructed out of the landfill body by its western edge. The screening analyses revealed that a wide range of chemicals were deposited into the landfill, prevailing of which are sulphur, DDT and its metabolites (DDE, DDD) and HCH; an occurrence of Carbaryl/Sevin was sporadically detected to a larger extent (0.094 – 1,226 mg/kg). In addition, copper, phosphorus, zinc and arsenic are present in variable concentrations. The results show that only a part of the chemicals spread to the surroundings of the landfill. In the near vicinity, particularly HCH and the DDT including its decay series occur in concentrations varying from 0.06 – 1,186.46 mg/kg (mostly of Category 3 contamination with average concentration of 93 mg/kg ), as well as the remnants of sulphur and zinc. Outside the fenced area, only the increased concentrations of the DDT and its decay series were found. The following figures show the data processed graphically. Cell 1 Cell 2
Cell 3 Cell 4
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 64
Cell 5 Soil associated with cells
To conclude on the real occurrence and distribution of the pesticide specimen based on the sampling of the landfill cells within the site investigation is not possible. Nevertheless, certain suggestion could be perceived from the evaluation of major pesticide specimen and chemical elements distribution and concentration shown in the table below. The cell No. 1 (the eastern most) sample contains the highest concentration of DDT (approx. 38 mass %) and sulphur (32 mass %), which indicates presence of Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green, prevailing from zinc (approx. 15 mass %) and arsenic (approx. 10 mass %) containing pesticides (Cyneb, Calcium arsenate) and DDD. The cell No. 2 sample contains predominantly sulphur-based pesticides (approx. 80 mass %), while DDT and zinc containing pesticides (Cyneb) are both present in minor concentrations lower than ca 7 mass %. Copper containing pesticides represent ca 6 mass % (Vitriol, Paris green). The cell No. 3 sample indicates major presence of DDT (65 mass %) prevailing the sulphur containing pesticides (approx. 20 mass %) and DDD (approx. 9 mass %). In the sample from the cell No. 4 sulphur containing pesticides (Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green) dominate with ca 65 mass % followed by zinc and copper containing pesticides (Cyneb, Vitriol, Paris green). Phosphorus containing pesticides (Rezetopth, Diamin phosphate, Chlorophos, Dichol, Cynox) and HCH are both present in ca 4 wt. % concentration. The sample from the cell No. 5 represents most probably Vitriol or Paris Green pesticides assuming from the cumulative concentration of sulphur and copper at approx. 90 mass %. Zinc was present at about 7 mass % concentration. The following table presents distribution of pesticides in samples analysed. The values are calculated as a weight proportion of individual component on the bulk weigh of all components detected by chemical analysis.
Distribution of pesticides in samples from the landfill Table No. 4.3-1
Cell designation Detected pesticides (mass %) according to TAUW (2013) DDT DDE DDD HCH Tetrachlorbenzene Pentachlorbenzene Carbaryl Cell 1 37,8 1,1 4,2 0,4 0,0 0,0 0,0 Cell 2 7,2 0,5 0,8 0,4 0,0 0,0 0,0 Cell 3 65,1 2,1 8,7 1,4 0,4 0,1 0,0 Cell 4 3,0 0,2 0,3 3,9 0,0 0,1 7,8 Cell 5 1,1 0,1 0,1 0,7 0,0 0,0 0,0
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 65
Cell designation Detected elements (mass %) Other according to detected TAUW (2013) As Zn Hg S P Cu pesticides Cell 1 9,6 15,1 0,0 31,5 0,0 0,1 0,1 Cell 2 0,2 4,0 0,1 81,0 0,0 5,6 0,3 Cell 3 0,0 1,8 0,0 19,8 0,0 0,1 0,5 Cell 4 0,1 7,6 0,0 64,8 4,4 7,6 0,3 Cell 5 0,0 7,4 0,1 38,9 1,1 50,5 0,1 Chemical Potentially related pesticide element As Calcium arsenate Zn Cyneb Hg Granosan S Rezetopth, Cyneb, Vitriol, TMTD, Lissapol, Paris green P Rezetopth, Diamin phosphate, Chlorophos, Dichol, Cynox Cu Vitriol, Paris green Other detected 2,4,5-T, 2,4-D, Desmetryne, HCB, Propazine, Simetryn, DNOC, Carbedazim, Chloridazone, pesticides Propachlor, Florasulam, Monuron, Thiophanate-methyl, Simazine
Various survey works have been done at the Nubarashen burial site focused on a variable scale of pesticides and other chemical components identification. Nevertheless, the arsenic; mercury; zinc; alpha HCH; beta HCH; gama HCH; delta HCH; HCB; 2,4 DDD; 4,4 DDD; 2,4 DDE; 4,4 DDE; 2,4 DDT and 4,4 DDT were detected both by GEOtest (2013), Dekonta- GEOtest (2017) and Tauw (2013) investigations. While Tauw in 2013 detected also presence of alpha Endosulphan, the 2017 site investigation detected the following chemical components in addition: Ametryn, Atrazin, Atrazin-desisopropyl, Atrazine-2-hydroxy, Carbedazim, Desmetryn, 2,4-D, DNOC, Florasulam, epsilon HCH, Chloridazone, Monuron, Pentachlorbenzene, Prometryn, Propachlor, Propazine, Simazine, Simetryn, Tetrachlorbenzene, 2,4,5-T, Thiophanate-methyl. This investigation have not detected alpha Endosulphan above the detection limits in any of samples analysed.
4.6 Migration of Contamination
At the site the presence of the groundwater table was not detected by any of the surveys. From the geological point of view, silty clay occurs at the site, being cohesionless down to about 0.5 m and then it passes into firm consistence. This means that due to the hydrogeological parameters on the site and soils which form a geomechanical barrier, the migration of contaminants towards the deeply seated aquifer can be excluded and it is possible to consider only migration through near-surface runoff in the cohesionless material, or through runoff on its surface or air transportation. The possibilities of contamination migration were eliminated to a great extent in the past by covering the landfill body with a Ruberoid foil and claily soil. Thus the washing-out of contaminants by surface wash, and wind erosion were prevented. During an illegal intervention the landfill was opened and pesticides buried in the landfill could have been spread. Due to this improper handling, there were places now more or less contaminated that remain at the site. These are near-surface parts and just these parts are exposed to weather effects and contaminants are spreading. The pesticides can be carried onto the surrounding land by wind or by (near-) surface runoff depending on the topographic character of the vicinity.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 66
Transport by wind has not a too large impact and it concerns particularly sample XI-15 (behind the fence – the south of the central part) and possibly sample XII-8. This way accounts for spreading a small amount of contaminants to the wide vicinity. This means that trace amounts of contaminants occur around the landfill. Spreading through surface wash was detected in samples XII-3, XII-4 and XII-7, the location of which was located on the basis of RTG spectrometer measurement. In this case it is a real possibility of contamination migration outside the fenced premises in more significant quantities. Subsequently, pesticides can accumulate in a certain place predisposed by topographic parameters, or further spreading can occur during rainy seasons in the downstream direction of the runoff of surface water (see the results of the survey of 2010). This is decisive for ecological and human risks in relation to the lack of drinking water for animals or for growing agricultural raw materials. Other samples in which the increased presence of pesticides was detected are XII-14, located in the handling area in front of the entry to the landfill, and XII-18 in the north-eastern part behind the fence. In these cases contamination was probably spread by improper human handling.
4.7 Constraints and Uncertainties
This report presents not only results of the site investigation conducted by the Dekonta and GEOtest team in 2017, but for the purpose of further project development steps (quantification of contamination, its distribution, risk assessment, project design etc.) it also compiles results of previous site investigation works with current survey. In doing so, various methods and approaches with a various level of accuracy entered the process of evaluation. Also chemical and mechanical analyses done in a different laboratories, not identical sampling process and different weather conditions for investigation works during individual investigation campaigns (2013, 2017) influence level of accuracy of each quantification of site investigation results. As a consequence of before mentioned constrains a certain level of generalization is inevitably involved in this work. To demonstrate this we can consider the level of generalization on example of accuracy of chemical analyses results, which in the last three site investigation actions varied from ± 20 to 40 %. Awareness of this aspect is the best practice applied world-wide being incorporated in applicable site remediation/risk assessment methodologies/gudelines, e.g. US EPA guidelines. Therefore, although the amount of contamination on NBS was the subject of several surveys, there has still some uncertainty left. On NBS there can still be places which have not been covered by the direct investigation works yet. Such places can be loaded with contamination of rather a minor extend. It is not possible to exclude the possibility that the area in front of the entry to the site is contaminated at depths at which sampling was not carried out (deeper than 0,5 m). Nevertheless, its peresence is not expected with respect to many aspects assessed within this study.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 67
5. Conclusions and Recommendations
On the basis of the survey it is possible to deduce the following conclusions:
• The site is located in tectonically pre-disposed valley, where apparently a break of the northern segment occurred. • In the distance of approximately 6 – 10 km from the locality significant active faults Azat and Garni run. • Due to the proximity of these faults the region is seismicaly active and belongs to the zone of second highest category of jeopardy with gravity acceleration agR ˂ 0,4 g. Thus a possibility of earthquake of up to M 7 can be expected. • The site is situated in the zone of active landslides Voghjaberd Landslie Field. • The pesticides landfill is located inside the body of a relatively large landslide. • This landslide is considered as an active one, or under certain conditions, it can be easily activated. The calculated slope stability degree (FS = 1,260) at increased groundwater level shows that the slope is not stable from the long-term and medium term perspective. • The activation of a part of the landslide may occur at water saturation, during earthquake or a combination of these causes. • On a steep slope bounding the site from the south several considerable landslides and an erosion furrow recently occurred. • During the period of spring snow melting there were the values FS = 1,052 a FS = 1,044 calculated for the steep slope in the south. It means that the slope is just on the edge of its stability. • The slope movements at this side may be activated both at ingress through attenuated layers and construction activity at the slope base. • The excavation works in the landfill body (during the potential clean-up action) in the extent corresponding with the model situations – see Annex 2.9) is possible only during the dry period and this activity has insignificant influence upon the stability of adjacent slopes. • Construction of temporary infrastructure on the foreland of the entrance gate is possible. We recommend that the surface be aligned and reinforced with gravel or other suitable material. • Construction of a more suitable road is manageable. The elevation and direction of the route must be designed in accordance with applicable local standards and regulations. The stability of road cuts and embankments must be assessed. • With regard to the possibility of landslide activation, seismic risks and geological position of the Nubarashen burial site permanent location of the pesticide landfill is extremely hazardous.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 68
• During remediation operations and building the temporary infrastructure it is necessary to count on risks connected with unstable slopes and clay soil changing properties subject to water saturation. • Based on the contamination survey it can be stated that the presence of contamination within the site and its vicinity is considerable. • The carried out analyses show that the major contaminant is DDT. Therefore the DDT together with HCH concentration is the indicator of contamination on site. Increased concentration of metals, EOX, chlorides and further pesticides can be correlated with the DDT concentration. Occurrence of sulphur in concentration similar to DDT was proven in the landfill body. • In the concentration range 0.7 – 50 mg/kg d.m. of the Category 3 there is an evident presence of DDT + HCH at all studied depth levels, with the highest spreading being indicated particularly in the surface layer in which contamination occurs inside and outside the fenced area. Contamination outside the premises is spread chiefly in the western (and possibly north-eastern) direction. • The occurrence of the DDT + HCH contamination concentration range 50 – 1,500 mg/kg d.m. of Category 3 is evident at all studied depth levels. The most extensive occurrence was located at a depth of 0.5 – 1.5 m. The results of the previous surveys show that the clay basement of the individual cells of the landfill is also contaminated in this concentration range. At the surface this material occurs along the northern and southern slopes of the landfill, from where it largely spreads through surface runoff towards the west. • The variable zoned distribution of the Category 2 contamination (the concentration range: > 1,500 mg/kg DDT + HCH to < 30 % pure pesticides) is evident. This concentration range was detected particularly in the landfill body and relates to the handling of the deposited waste. Contamination at the surface is present on the part adjacent to the northern edge of the landfill where in the past illegal excavation probably took place. The part adjacent to southern edge of the landfill is also affected by handling of waste and spread of contamination. • Pure pesticides or materials > 30% of pure pesticides (Category 1) were found only in the landfill cells considering the cell No. 5 being unsecured part of the landfill. • Contaminated construction materials (Category 4) were found only in the easternmost cell 1 of the landfill, where part of pesticides detected was in a liquid form. • Based on a geophysical survey a place with high conductivity has been identified (ca 1 – 4 m bg), situated at the entrance gate to the area. This fact could indicate rather occurrence of natural gypsum (confirmed by the survey) or increased humidity rather than contamination. Hence, the chemical analyses and geological documentation of probes and trenched pits adjacent to this area do not infere presence of contamination. However, presence of contamination there was not excluded by chemical analyses. • Based on the carried out survey the amount of contaminated materials was summarized. For summarization all the available documents from historically available data, previous surveys and current survey were used. Based on this synthesis the individual amounts of contamination in relevant concentration ranges were determined. • The contaminated material can be quantified as follows:
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 69
- Category 1: Pure pesticides or associated material with > 30% pure pesticides: 674 m3/1,051.5 t - Category 2: Highly contaminated soil with DDT + HCH concentration range < 30% pure pesticides - 1,500 mg/kg dry matter: 2,425 m3/4,122.5 t - Category 3: Lowly contaminated soil with DDT + HCH concentration range 1,500 - 50 mg/kg dry matter: 4,989 m3/8,481 t Lowly contaminated soil with DDT + HCH concentration range 1,500 - 0.7 mg/kg dry matter: 16,799 m3/28,558 t - Category 4: Contaminated construction materials 20 m3/41 t The final amount of contaminated materials for remediation however, will be determined only by results of the risk assessment that will recommend corrective measures and threshold values and based on the discussion and decision of the project key stakeholders.
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 70
REFERENCES USED • Fokke et al. 2013: Site Assessment and Feasibility Study of the Nubarashen Burial Site of Obsolete and Banned Pesticides in Nubarashen, Armenia. TAUW, Reference R003-1210169BFF-los-V01. • Mkrtchian, H. 2017:Engineering geological analisis. Assessing geological conditions of the areas investigated as posible site to be set-up as temporary storage facility for POPs and obsolete chemicals to be removed frm Nubarashen burial site in Yerevan, Armenia. UNDP. • Basel Convention (1989): [online: http://www.basel.int/TheConvention/Overview/tabid/1271/Default.aspx 23. 10. 2017)].
• Canadian soil quality criteria for environment (2017): [online: http://www.ccme.ca/en/resources/canadian_environmental_quality_guidelines/ 23. 10. 2017)].
• CSOIL (2000): [online: http://www.rivm.nl/dsresource?objectid=b1300413-2fb6- 4c18-a383-32c921f6e592&type=org&disposition=inline 23. 10. 2017)].
• GEOtest (2013): Strengthening National Capacities on Comprehensive Chemicals (Persistent Organic Pollutants) contaminated site assessment in Armenia, Analytical Report on Sampling on Nubarashen Site, Transfer of Czech Knowledge.
• MG ME CR (2011): Methodological instruction of Ministry of Environment of Czech Republic [online: http://www.geology.cz/rroum/stazeni/Metodika_praci_rijen_2011.pdf 23. 10. 2017)].
• MG ME CR (2013): Methodological instruction of Ministry of Environment of Czech Republic [online: https://www.mzp.cz/C1257458002F0DC7/cz/metodiky_ekologicke_zateze/$FILE/OE S-MZP_%20Indikator-%20znecisteni-akt-2013-20140318.pdf 23. 10. 2017)].
• NAS RA (2010): Assessing a discharge of contaminants from the Nubarashen toxic chemicals repository site, Center of Ecological-Noosphere Studies.
• TAUW (2013): Site Assessment and Facibility study of the Nubarashen Burial Site of Obsolete Banned Pessticides in Nubarashen, Armenia, Contract No. ARM/01/2013, OSCE.
• Kaufmann, A.A.-Keller, G.V. (1983): Frequency and transient soundings. Elsevier, Amsterdam
• EN 1997-1:Eurocode 7: Geotechnical design - Part 1: General rules
• EN 1997-2: Eurocode 7: Geotechnical design - Part 2: Ground investigation and testing
• EN 1997-3: Eurocode 7: Geotechnical design - Part 3: Design assisted by fieldtesting
• Poulos H. G. and Davis E. H. (1974), Elastic Solutions for Soil and Rock Mechanics, John Wiley & Sons, Inc., New York, USA, Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 71
• Brinkgreve R. B. J. and Vermeer (1998), PLAXIS – Finite Element Code for Soil and Rock Analysis, A. A. Balkema, Rotterdam, The Netherlands,
• Terzaghi K., Peck R. B. and Mesri G (1996), Soil Mechanics in Engineering Practice, John Wiley & Sons, Inc., New York, USA,
• Duncan J. Michael, Wright Stephen G., Brandon Thomas L. (2014), Soil Strenght and Slope Stability, John Wiley & Sons, Inc., New York, USA,
• Plaxis bp.: Manual.GEOlogical map of Armenia
• Armenian national Survey for Seismic Protectio portal
• All the other info sources for the inception chapters
Nubarashen Burial Site Comprehensive Site Mapping and Analytical Assessment Report 72