Sustainable Remediation and Rehabilitation of Biodiversity and Habitats of Oil Spill Sites in the Niger Delta

Annex Ie: Oguta Biophysical Fieldwork Report

A report by the independent IUCN - Niger Delta Panel (IUCN-NDP) to the Shell Petroleum Development Company Ltd of Nigeria (SPDC)

April 2013

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Citation: IUCN Niger – Delta Panel, 2013. Sustainable Remediation and Rehabilitation of Biodiversity and Habitats of Oil Spill Sites in the Niger Delta. Main Report including recommendations for the future. A report by the independent IUCN - Niger Delta Panel (IUCN-NDP) to the Shell Petroleum Development Company of Nigeria (SPDC). January 2013. Gland, Switzerland: IUCN.

ISBN: 978-2-8317-1617-6

Cover photos: Image of the Niger Delta from space, (courtesy of NASA), with community (first line (all by Alex Chindah) and main habitats overlain (second line from top left to right: lowland forest (Alex Chindah); freshwater (Alex Chindah); barrier islands (Friday Idogiye Amain); and mangroves (nigerdeltarising.org).

Layout by: Nigerian Environmental Study /Action Team

Produced by: IUCN – Niger Delta Panel

Printed by: IUCN

Available from: IUCN (International Union for Conservation of Nature) Business and Biodiversity Programme (BBP) Rue Mauverney 28 1196 Gland Switzerland Tel +41 22 999 0000 Fax +41 22 999 0002 [email protected] www.iucn.org/publications

TABLE OF CONTENTS

List of Tables...... 6 List of Figures and Plates...... 7 List of Abbreviations and acronyms ...... 8

List of Panel members………………………………………………………………………………………………………………………………. 11

Preface……………………………………………………………………………………………………………………………………………………… 12

Executive Summary ...... 13

1. Introduction ...... 17 1.1 Background information ...... 17 1.2 Post Impact Assessment ...... 18 1.3 Study objectives and scope ...... 19 1.4 The choice of Oguta field for Impact Assessment Study ...... 19 1.5 Legal and administrative framework for EA in Nigeria ...... 19 1.5.1 National environmental policy ...... 20 1.5.2 National Effluent Limitation Regulation ...... 21 1.5.3 Pollution Abatement in Industries and Facilities Generating Wastes ...... 21 1.5.4 Management of Hazardous and Solid Wastes Regulation ...... 21 1.5.5 Land Use Act ...... 21 1.5.6 Forestry Act ...... 21 1.5.7 Criminal Code...... 21 1.5.8 Constitution of the Federal Republic of Nigeria ...... 22 1.5.9 Nuclear Safety and Radiation Protection Act ...... 22 1.5.10 Imo State Environmental Protection Act of 1994 ...... 22 1.5.11 International Convention and Guidelines ...... 22 1.5.12 National Regulatory Bodies ...... 23 1.5.12.1 Federal Ministry of Environment (FMEnv) ...... 23 1.5.12.2 National Inland Waterways Authority (NWA) ...... 25

2. Oil spill history ...... 25

3. Methodology ...... 28 3.1 Sampling strategy ………………………………………………………………………...... 28 3.2 Water quality ……………………………………………………………………………………… 32 3.2.1 Field methodology ………………………………………………………………… 32 3.2.2 Quality Assurance/Quality Control ………………………………………………………...31 3.2.3 Laboratory analysis ……….……………………………………………………….. 33 3.2.4 Quality Assurance/Quality Control ……………………………………………………….. 35 3.3 Hydrobiological …………………………………………………………………………………...... 35 3.3.1 Zooplankton/phytoplankton studies …………………………………………………...... 35 3.3.2 Field methodology ……………………………………………………………………….... 36 3.3.2.1 Phytoplankton …………………………………………………………………………...... 36 3.3.2.2 Zooplankton ……………………………………………………………………………….. 36 3.3.2.3 Benthic macrofauna ……………………………………………………………………….. 37 3.3.2.4 Pelagic microalgae ………………………………………………………………………… 37 3.4 Wildlife status ...... ………………………………………………………………………….... 39 3.4.1 Introduction ...... 38 3.4.2 Methods ...... 38

4. Results and discussion…………………………………………………………………………….. 39 4.1 Surface and groundwater quality ………………………………………………………………..... 39 4.1.1 PH ………………………………………………………………………………………..... 39 4.1.2 Temperature ……………………………………………………………………………...... 39 4.1.3 Electrical Conductivity (EC) …………………………………………………………….... 40

4.1.4 Dissolved Oxygen (DO) …………………………………………………………………... 40 4.1.5 Total Dissolved Solids (TDS) …………………………………………………………...... 40 4.1.6 Biochemical Oxygen Demand (BOD) …………………………………………………..... 40 4.1.7 Nutrient ……………………………………………………………………………………. 41 4.1.8 Chloride/oil/grease ………………………………………………………………...... 41 4.1.9 Heavy metals …………………………………………………………………………….... 41 4.2 Hydrobiology ...... …………………………………………………………………………….... 41 4.2.1 Phytoplankton community ………………………………………………………...... 41 4.2.2 Periphyton community ...... 44 4.2.3 Macrophytes and vegetation ...... …………………………………………………….... 45 4.2.4 Zooplankton ……………………………………………………………………………...... 46 4.2.5 Macrofauna ... ………………………………………………………………………...... 47 4.3 Wildlife ……………………………………………………………………………...... 50 4.3.1 Mammals ……………………………………………………………………………...... 50 4.3.2 Avifauna …………………………………………………………………………...... 52 4.3.3 Reptiles ………………………………………………………………………………...... 54 4.3.4 Amphibians ………………………………………………………………………………... 55 4.4 Fish and fisheries …………………………………………………………………………...... 56 4.4.1 Fish species composition ………………………………………………………...... 56 4.4.2 Fishing gear types …………………………………...... 56 4.4.3 Fishing cycles and seasonality ...... …………………………………………………..... 57

5. Conclusions………………………………………………………………………………...... 58

References ………………………………………………………………………………………...... 59

Annex 1. Standard Operating Procedure for Analysis in Rofnel Laboratory ...... 65

LIST OF TABLES TABLE PAGE

3.1 Physicochemical parameters (in situ) for Oguta field surface 30 water 4.1 Results for physicochemical parameters of water samples 37 from Oguta Field, October 2012. 4.2 Petroleum and heavy metal levels in water samples from 39 Oguta Field, October 2012 4.3 Phytoplankton density and distribution for Oguta Field, Imo 41 State, October 2012 4.4 Periphyton density and distribution for Oguta Field, 43 October 2012 4.5 Zooplankton density and distribution for Oguta Field, 45 October 2012 4.6 Composition, distribution and abundance of macro fauna in 46 the sampled stations 4.7 Mammalian wildlife occurring in Oguta Field area 50 4.8 Avian wildlife species occurring in Oguta Field area 52 4.9 Common reptiles of the Oguta Field area 54 4.10 Diversity of Amphibian known in Oguta Field and environs 58 4.11 Common fish species found in Oguta Field Area 59

LIST OF FIGURES AND PLATES

FIGURE PAGE

1.1 Map of the Niger Delta region showing member states and 11 the study area in red block 3.1 Map of Oguta Area showing the Sampling Stations 29

4.1 Relative abundance of phytoplankton taxa from Oguta Field 42 area, October 2012 4.2 Relative abundance of Periphyton taxa from Oguta Field 43 area, October 2012 4.3 Relative abundance of zooplankton taxa from Oguta Field 46 area, October 2012 4.4 The relative proportion of benthic fauna in the study area 48 4.5 Relative proportion major taxonomic group along the 49 stations

PLATE PAGE

2.1 Flooded area in Oguta town 24 2.2 Flooded area along Oguta Creek area 24 2.3a & b Flooded area close to the Flowstation 25 2.4 Oil spillage from the pipeline 25 2.5 Oil spillage along the bridge to the flowstation 25

3.1 Consultation at the Palace of the Oguta Monarch 27 3.2 Panel members and Council of chiefs 27 3.3 Panel members and the Monarch 27

LIST OF ABBREVIATIONS AND ACRONYMS

AAS Atomic Absorption Spectrophotometer AG Associated Gas ALARP As Low as Reasonably Practicable APHA American Public Health Association ASTM American Society for Testing and Materials B Barium

BaCl2 Barium Chloride

BaSO4 Barium Sulphate BOD Biochemical Oxygen Demand

CaCO3 Calcium Carbonate Cd Cadmium CDC Community Development Committees CO Carbon monoxide

CO2 Carbon dioxide COD Chemical Oxygen Demand Cr Chromium Cu Copper DPR Department of Petroleum Resources DS Direct Sighting DO Dissolved Oxygen EC Electrical Conductivity EGASPIN Environmental Guidelines, standards for Petroleum Industries in Nigeria EIA Environmental Impact Assessment Fe Iron FEPA Federal Environmental Protection Agency FMENV Federal Ministry of Environment GPS Global Positioning System HCl Hydrogen Chloride

HNO3 Hydrogen Nitrate

H2S Hydrogen Sulphide

H2SO4 Hydrogen Sulphate HSE Health, Safety & Environment IUCN International Union for Conservation of Nature K Potassium KWW Kentucky Water Watch LGAs Local Government Areas MG/L Milligram per Litre ML Millilitre MM Millimetre N Nitrogen NA Not Applicable NDP Niger Delta Panel NDDC Niger Delta Development Commission NESREA National Environmental Standards and Regulations Enforcement Agency

NH3 Ammonia Ni Nickel NIWA National Inland Water Authority NLNG Nigeria Liquefied Natural Gas Plant NNPC Nigerian National Petroleum Company

NO2 Nitrogen dioxide

NO3 Nitrates NM Nanometre NTU Nerphelometric Turbidity Unit NW Northwest 0C Degree Celsius PAH Polyaromatic Hydrocarbon pH Hydrogen Ion Concentration PIA Post Impact Assessment PPE Personal Protective Equipment

QA/QC Quality Assurance/Quality Control QHSE Quality Health Safety and Environment RPI Research Planning Institute SPDC Shell Petroleum Development Company S-R Sedgewick Rafter SS Sample Station T Temperature TDS Total Dissolved Solids THC Total Hydrocarbon Content TN Total Nitrogen TPH Total Petroleum Hydrocarbon TOR Terms of References TSS Total Suspended Solids UNDP United Nations Development Programme UNESCO United Nations Education Scientific and Cultural Organisation WHO World Health Organization

LIST OF PANEL MEMBERS

The Panel leverages the scientific and technical expertise within the IUCN constituency (including relevant Nigerian based NGOs), IUCN Programmes, and the Regional Office for Central and West Africa (PACO). The Panel consists of seven members selected for their technical expertise in the field of oil spill management and oil site remediation and rehabilitation.

The Panel members are:

Dr Uzoamaka Egbuche – Panel Chair - Expert in Oil Spill Remediation – CERASE – IUCN member, Abuja, Nigeria;

Prof Dan Laffoley - Expert on Biodiversity Conservation (Marine) – Marine Vice Chair of IUCN World Commission on Protected Areas, Peterborough, UK;

Prof Ikem Ekweozor - Expert in environmental pollution studies and marine and estuarine ecology - Department of Applied & Environmental Biology, Rivers State University of Science & Technology, Port Harcourt, Nigeria;

Dr Muhtari Aminu-Kano - Expert on Biodiversity Conservation (Terrestrial) – IUCN Species Survival Commission, ex Birdlife International, Nigerian currently based in Cambridge, UK;

Dr James Kairo - Expert in Restoration Ecology – Head Mangrove Silviculture and Management Unit, Kenya Marine and Fisheries Research Institute, Mombasa, Kenya;

Prof Olof Linden – Expert in environmental impacts of petroleum hydrocarbons and oil spill dispersants - Director of Research and Doctoral Program, World Maritime University (WMU), International Maritime Organization, Malmo, Sweden; and

Dr Victor Obinna - Expert in Environmental Sociology – Urban & Regional Planning, Rivers State University of Science and Technology, Port Harcourt, Nigeria.

Preface

This document is one of several annexes produced as a result of the work of the IUCN- Niger Delta Panel (IUCN-NDP). This Panel was established in January 2012, at the request of the Shell Petroleum Development Company of Nigeria Limited (SPDC), as an initiative to help improve the company’s environmental management. IUCN created the Panel with the involvement of IUCN Members in Nigeria, as well as IUCN Commissions and the IUCN Secretariat. The Panel arose out of a concern among key stakeholders to improve upon remediation activities and to find a sustainable and peaceful approach towards rehabilitation of biodiversity in habitats affected by oil spills. The main report containing the formal recommendations from the Panel is listed below and can be downloaded here.

This and the other annexes present more detailed information and findings, which the Panel used to develop the recommendations that are set out in the main report, and which the Panel continues to draw from in its ongoing work. In making these supporting annexes available it should be noted that where any perception of difference occurs between what is in the annex and the main report, it is the main report and the recommendations therein that should be taken as the formal view of the Panel. It is also possible that information or situations may have changed since individual annexes were compiled. The annexes were accurate to the best of the knowledge of the Panel at the time they were produced. Some also contain records of perceptions from various stakeholders. These perceptions are very valuable to inform the work of the Panel and are recorded for information purposes, but they should not be taken as representing the views of the Panel. Finally, the information and data in the annexes should be considered “works in progress” as in many cases they are the first attempts at data gathering in a complex and challenging natural and social environment.

Uzoamaka Egbuche Chair, IUCN-NDP

Reference: IUCN Niger–Delta Panel (2013). Sustainable remediation and rehabilitation of biodiversity and habitats of oil spill sites in the Niger Delta: Main report including recommendations for the future. A report by the independent IUCN–Niger Delta Panel (IUCN–NDP) to the Shell Petroleum Development Company of Nigeria (SPDC). July 2013. Gland, Switzerland: IUCN. 73 pp.

EXECUTIVE SUMMARY

Background information

Oguta town is an urban community, comprised of 27 villages, located in Oguta Local Government area of Imo State, one of the states in the east of the Niger Delta. The national population census of 2006 put Oguta town’s population at 32,596; the 2012 projected population is 38,890. The people of the community are predominantly of the Igbo ethnic nationality, with a rich cultural heritage.

A number of petroleum industry-related facilities have been established in the area, including two flow stations (one belonging to the Shell Petroleum Development Company (SPDC) and one to the Nigerian Agip Oil Company (NAOC)) and 34 oil wells, of which 19 belong to SPDC and 15 to NAOC. Information indicates that SPDC’s average production has stood at 11,041 barrels per day from their 19 wells since 1960, while NAOC’s average production since the same year has been 12,203 barrels per day from 15 wells.

Choice of Oguta field for the study

Oguta oil field was chosen by the IUCN-NDP for the field study mainly because of its location in the Rain Forest Zone, which is one of the 4 major ecological zones of the Niger Delta. Other reasons included its accessibility by road from Owerri, the Imo State capital, which is only about 25 km away. In addition the security situation was favourable and the area has a history of oil spills from the oil field.

Legal and administrative framework for the study

The post-impact assessment (PIA) study was carried out within the framework of both national and international environmental guidelines and regulations. International guidelines include those of the World Bank and International Treaties and Conventions (to which Nigeria is signatory), while the national guidelines include those of national legislation and guidelines such as the Federal Ministry of Environment (FMEnv) and Imo State Ministry of Environment.

Oil spill records in and around Oguta oil field

Since production activities started in Oguta field in 1960, there have been reports of over 500 oil spills. The three most recent spill reports indicate that one occurred in Umuezedi Farmland and the other two in Oguma Land. These three spills, according to community people were attributed to ruptured pipes as a result of aged pipelines. However NAOC claim the cause of the spills was sabotage.1

1 Over the past decades and particularly in recent years a number of major causes have been attributed to the oil spills in the Niger delta. A review of literature and media reports on spills consistently identify three main sources - equipment failures, crude oil theft and illegal refining. It is not the purpose of IUCN-NDP to attribute cause or apportion blame, but rather under the specific TOR for the Panel to focus on independent advice on improvements in remediation and rehabilitation when spills have occurred, working with all parties involved.

Field methodologies

To establish the impact of the oil spills on the environment, the qualitative and quantitative effects of the oil were studied using a number of different methods. The information was gathered through extensive multi-disciplinary studies that comprised surface water quality assessment, investigations of the status of vegetation and biodiversity and a baseline survey of the socio-economic situation and the general health of the communities. The baseline data acquisition exercise involved a multi- disciplinary approach and was executed within the framework of a QHSE management system approach. This approach ensured that the required data and samples were collected in accordance with agreed requirements (scientific and regulatory) using the best available equipment, materials and personnel.

Due to the extensive flooding of the area at the time of the field visit, soil and sediment sampling was not carried out.

To complement information obtained from a review of existing data on the project area and fill identified information gaps, the first season field sampling and measurement exercise was conducted between 20th and 23rd October 2012.

To ensure effective quality assurance and control on the laboratory analysis, two separate laboratories were used and data obtained identified.

Results and discussion

Surface water physico-chemistry Results indicate a DO range of 0.94–1.93mg/l; pH (7.34–7.86); EC (50.1–52.7 µS/cm); TDS (34.3-37.0); BOD (0.8–2.4mg/l), nitrate level (0.36–0.52mg/l); phosphate levels (<0.05mg/l) and sulphate levels (<1.0–1.8mg/l). These levels were all within the regulatory limit, whilst the oil and grease concentrations of 0.85–2.91mg/l recorded at the sampled stations were quite high and are indicative of hydrocarbon contamination.

Hydrobiological status

Phytoplankton The abundance and distribution of phytoplankton community within the sampled stations at Oguta field area was found to include 23 species representing 5 families respectively, with an overall density of 795 cells/ml.

The results indicate that within the study site the Chlorophyceae (green microalgae) have the highest abundance and distribution (42.29%), followed by Bacillarophyceae (25.96%), Cyanophyceae (24.39%), Xanthophyceae (4.61%) and Euglenophyceae (2.77%).

Periphyton The abundance and distribution of Periphyton community within the study stations at Oguta field was found to include a total of 15 species representing 4 families, namely

Chlorophyceae (40.49%), Bacillarophyceae (30.73%), Cyanophyceae (26.74%) and Euglenophyceae (1.08%); with an overall density of 576 cells/ml.

Macrophytes A total of eight aquatic macrophytes were recorded within the area. These macrophytes include: Pterocarpus spp., Vitex grandifolia, Upaca senegalensis, Alchornea cordifolia, Omphalocarpus precerum, Napoleona talbotii, Pteris marginata, Myriantus cirratus and Ficus asperifolia.

Zooplankton The zooplankton species obtained in this study were represented by Copepoda (80.23%), Cladocera (6.84%), Protozoa (6.46%), Rotifera (5.32%), and Insecta (1.14%). The percentage composition of each of these major zooplankton groups in the study area show that the Calanoid Copepods were the most dominant zooplankton followed by the Cladocerans, Protozoan species, the Rotiferan species and then the Insecta taxa.

Benthic macrofauna A total of only 38 macrofaunal organisms were harvested from the study area, including various classes of insecta, gastropoda, amphibian and pisces.

Wildlife The study area shows a fairly high taxonomic diversity of wildlife species which are described under the indicated major groups.

Mammals The study revealed the presence of thirty Five (35) species of mammals. Of these, the chimpanzee (Pan troglodytes) is becoming extinct. Some foraging parties are still in some areas outside the study area according to information gathered from hunters. It is endangered in both IUCN Red List and under Decree No 11 of 1985 of the Federal Republic of Nigeria. The sitatunga and dwarf antelope (Neotragus batesi) are listed in decree No 11 as Endangered. Three rodents found in the area are the most common animals in the study area. They include the cane rat (Thryonomys swinderianus), brush- tailed porcupine (Atherurus africanus) and Emin’s giant rat (Cricetomyy emini). None of the three is endangered in IUCN Red List but the brush-tailed porcupine is listed in Decree No 11 of Nigeria as Endangered.

Avifauna Sixty three (63) avifauna species were sighted and recorded in the field. Great white egret (Egretta alba), grey heron (Ardea cinerama), little egret (Egretta garzetta), squacco heron (Areolas ralloides), green backed heron (Butorides striatus), white face whistling duck (Dendrocygna viduata) and Hartlaub’s duck (Pteronetta hartlaubi) and others were sighted. Hartlaub’s duck is listed in the IUCN Red List as Vulnerable, as is the grey parrot (Psittacus erithacus).

Reptiles Thirteen (13) species of reptiles representing ten (10) families were recorded in the Oguta field study area. The most important species are the dwarf crocodile (Osteolaemus tetraspis), monitor lizard (Varanus niloticus), Nile crocodile (Crocodylus niloticus) and West African blade forest turtle (Pelusios niger). They are hunted for food more than any other species in the area. The West African blade forest turtle is listed in the IUCN Red List as Endangered. They are also listed as endangered species in the Nigerian Endangered Species Act of (1985). Also listed as endangered in Nigerian Endangered Species Act of 1985 are dwarf crocodile, monitor lizard and the African rock python.

Fish and fisheries

The composition of fish species commonly found in the study area includes sardines, mullets, tilapia, catfish, moonfish, gobies and prawns. The seasonality of exploitation of the different fish species in the area is described. The peak period for clupeids including sardines, shad and bonga is between October and about February/March, corresponding to the dry season period. The peak period of estuarine white shrimp Nematopalaemon sp. is from December to May.

Conclusions

The Total Hydrocarbon (THC) concentrations recorded for the surface waters of 0.85– 2.91mg/l were indicative of hydrocarbon contamination, which may have been aggravated by the extensive flooding experienced during the period of sampling.

The recorded phytoplankton total abundance were 795 cells/ml, species richness of 23 and only 5 taxonomic groups; periphyton only 4 major taxa, 15 species and overall abundance of 576 and zooplankton only 5 major taxa, 263 individuals and near absence of fish and molluscan larvae were indicative of stressed environment. These observations showed low faunal abundance and diversity.

1. Introduction

1.1 Background information

Oguta town is an urban community, comprised of 27 villages, located in Oguta Local Government area of Imo State, one of the states within the east of the Niger Delta (see Figure 1.1). The national population census of 2006 put Oguta town’s population at 32,596; the 2012 projected population is 38,890. The people of the community are predominantly of the Igbo ethnic nationality, with a rich cultural heritage.

Ecologically, Oguta town is part of the lowland rainforest ecozone of the Niger Delta inland water ways, within the freshwater forest of the Oguta–Sombreiro River axis. The forest is complex and complicated with variable vegetative structures and compositions that existed due to zoogenic and anthropogenic activities as well as the nature of physio-geographic features in the entire area.

The water bodies are similar to that of freshwater, very flooded at the period of sampling and often prone to one directional flow. They are the source of drinking, cooking, bathing, washing, farming, transportation, fishing and varied agricultural uses/practices. The water bodies in the area are mostly rivers, streams, with some lakes and ponds too.

Oguta community currently hosts two major oil companies operating within the area, namely the Shell Petroleum Development Company (SDPC) and the Nigerian Agip Oil Company (NAOC). Oil production by both companies started in 1960. There are a number of petroleum industry-related facilities in the area, including two flow stations (1 SPDC, 1 NAOC) and 34 oil wells, of which 19 wells belong to SPDC and 15 to NAOC. Information indicates that SPDC’s average production has stood at 11,041 barrels per day from their 19 wells since 1960, while NAOC’s average production since the same year has been 12,203 barrels per day from 15 wells.

With the expansion of oil exploration and production, the incidence of oil spills has increased considerably within the region. Available records show that a total of 6,817 oil spills occurred between 1976 and 2001, with a loss of approximately three million barrels of oil. More than 70 per cent of this oil was not recovered. 2

Approximately six per cent of the oil spills happened on land, 25 per cent in swamps and 69 per cent in offshore environments. In recent times, oil spills appear to be caused more by criminal damage to facilities than by accidents.

2 Over the past decades and particularly in recent years a number of major causes have been attributed to the oil spills in the Niger delta. A review of literature and media reports on spills consistently identify three main sources - equipment failures, crude oil theft and illegal refining. It is not the purpose of IUCN-NDP to attribute cause or apportion blame, but rather under the specific TOR for the Panel to focus on independent advice on improvements in remediation and rehabilitation when spills have occurred, working with all parties involved.

OGUTA

Figure 1.1: Map of the Niger Delta region showing member states and the study area in red block

The environmental effects of oil pollution are well known. They include the degradation of vegetation, depletion of aquatic fauna and destruction of biodiversity. Long-term impacts are also possible, as in cases where mangrove and freshwater swamps and groundwater resources are impacted.

The field study and assessments carried out are in compliance with relevant regulatory environmental requirements (DPR’s EGASPIN, 2002 and FMEnv EA S.15), as well as SPDC’s HSE Policy.

It is hoped that the results of this study will enable the company to establish the extent of damage on the environment and effectiveness of its remediation activities following oil spillages and pollution within the environment, and hence take adequate steps where necessary to ensure the rehabilitation and recovery of the ecosystem. The study was carried out to enable the company to develop an effective environmental management and remediation plan for the impacted area as well as perform their other activities within the area in compliance with regulatory requirements (EA, and DPR EGASPIN, 2002). 1.2 Post Impact Assessment Post Impact Assessment (PIA) study is one of the environmental management and control tools employed in assessing the environmental impacts of spillage due to an existing facility, project or operation. It reviews the immediate and long-term impacts of accidental discharges and spillages of hazardous substances (industrial wastes/effluents, raw materials, chemicals, crude oil and refined petroleum products). These are usually done using established scientific methods in baseline ecological and

18 socio-economic studies, environmental audits and environmental evaluation reports. The studies are carried out in accordance with the standards and guidelines laid out by the Federal Ministry of Environment (FMEnv) and the Department of Petroleum Resources (DPR). The PIA study also enables the industry, the operator and the government to understand the state of the polluted or impacted areas and develop strategies for protection and restoration of the affected areas. 1.3 Study objectives and scope As earlier indicated, the general objectives of this assessment study are to:

 determine the existing ecological and socio-economic conditions of the project area;  determine the effect of oil spills on sensitive areas;  determine the effect of oil spills on biodiversity  assess the effects of remediation activities on soil quality;  assess the effects of remediation activities on water quality;  establish the sensitivity of the various environmental components of the area;  identify and evaluate the impact of the oil spillage and remediation activities on the socio-ecological environment; and  develop control and rehabilitation strategies with a view to mitigating and ameliorating significant adverse impacts, which the spillage and its remediation activities had on the biophysical and socio-environmental characteristics.

To achieve these objectives, detailed fieldwork was carried between 20th and 24th October 2012, during which water samples were collected, and vegetation, wildlife/biodiversity and socioeconomic/health studies were carried out. The results of these studies helped in the evaluation of ecological and socioeconomic/health impacts.

1.4 The choice of Oguta field for impact assessment study Oguta oil field was chosen by the IUCN-NDP for the field study mainly because of its location in the Rain Forest Zone, which is considered as one of the 4 ecological zones of the Niger Delta. Other reasons included its accessibility as the field is easily accessible by road from Owerri, the Imo State capital, which is only about 25 km away; a favourable security report; and a history of oil spillage within the field.

Oguta was therefore a suitable alternative to the earlier chosen site in Akwa Ibom State, which at the time had legal and administrative issues and therefore was not possible for study.

The area had been degraded considerably due to infrastructural (industrial and municipal) development, cultivation and extraction of timber produces. The biodiversity group visited the area from 20th October, 2012 on field sampling, the sampling period coincided with the highest peak of the flood season which made the sampling almost impossible due to very high flood and swift movement of water current.

1.5 Legal and administrative framework for EA in Nigeria The PIA study was carried out within the framework of both national and state environmental guidelines and regulations. The national guidelines include legislation and guidelines from the Federal Ministry of Environment (FMEnv) and Imo State Ministry of Environment.

Reviews of Nigerian legislation, guidelines and international conventions that are relevant to the project have been provided below. These legislation and guidelines are derived from Nigerian government laws and regulations, and international conventions/agreements/requirements.

The requirements for compliance with Environmental Audit in all parts of Nigeria derive from the following general laws and enactments that stipulate and mandate project proponents to abide by the standard requirements for sustainable development:

- National Environmental (Sanitation and Wastes Control) Regulations, S.I. No.28 of 2009 - National Environmental (Noise Standards and Control) Regulations, S.I. No.35 of 2009 - National Environmental (Permitting and Licensing System) Regulations, S.I. No.29 of 2009 - National Policy on Environment (1989) - Environmental Audit (EA) Act - The Oil in Water Act,1986 - National Environmental Protection (Effluent Limitation) regulation S.I.8 of 1991. Pollution Abatement for Industries and Facilities Generating Wastes Regulations) FMENV, 1991 - The Harmful Wastes ( Criminal Provisions) Act No.42,1988 - National guidelines and standard for Environmental Pollution Control in Nigeria 1991 (The Green Book) - National Environmental Protection (Pollution Abatement in industries and facilities generating wastes) Regulation S.I. 9 of 1991 - Pollution Abatement in Industries and Facilities Generating Wastes, Regulation, S.1.9 of 1991 - National Environmental Protection (Management of Solid and Hazardous wastes) Regulation S.I.15 of 1991 - Waste Management Regulations S.1.15 of 1991 - Act No 101 of 23 August 1993: Water Resources Act - Environmental Guidelines and Standards for the Petroleum Industry 2002 - NOSDRA Act of 2006 - SPDC’s Policy on Safety Health and Environment - Imo State Ministry of Environment Act

1.5.1 National environmental policy The National Policy on Environment, 1991, defines guidelines and strategies for achieving the policy goal of sustainable development by:

 securing for all Nigerians a quality of environment adequate for their health and well-being;  conserving and using the natural resources for the benefit of present and future generations;  restoring, maintaining and enhancing the ecosystem and ecological processes essential for the preservation of biological diversity; and  raising public awareness and promoting understanding of the essential linkages between the environment, resources and development.

1.5.2 National Effluent Limitation Regulation The National Effluent Limitation Regulation, S.1.8 of 1991 (No. 42, Vol. 78, August, 1991) makes it mandatory for industries as waste-generating facilities to install anti- pollution and pollution abatement equipment on site.

1.5.3 Pollution Abatement in Industries and Facilities Generating Wastes Regulation The Pollution Abatement Regulation, S.1.9 of 1991 (No.42, Vol. 78, August, 1991) imposes restrictions on the release of toxic substances and stipulates requirements for pollution monitoring units, machinery for combating pollution and contingency plan by industries, protection of workers and safety requirements; environmental audit (or environmental impact assessment for new industries) and penalty for contravention.

1.5.4 Management of Hazardous and Solid Wastes Regulation The Management of Hazardous and Solid Waste Regulation, S.1.15 of 1991 (No.102, Vol. 78, August, 1991) defines the requirements for groundwater protection, surface impoundment, land treatment, waste piles, landfills, incinerators etc. It states procedures for inspection, enforcement and penalty.

1.5.5 Land use Act The Land use Act of 1978 protects the rights of all Nigerians to use and enjoy land in Nigeria which must be protected and preserved. Land acquisition must follow all the due process of law.

1.5.6 Forestry Act This Act of 1958 provides for the preservation of forests and the setting up of forest reserves. It is an offence, punishable by up to 6 months imprisonment, to cut down trees over 2ft in height or to set fire to the forest except under special circumstances.

1.5.7 Criminal Code The Nigerian Criminal Code makes it an offence punishable by up to 6 months imprisonment for any person who violates the atmosphere in any place so as to make it noxious to the health of persons in general dwelling or carrying on business in the neighbourhood, or passing along a public way.

1.5.8 Constitution of the Federal Republic of Nigeria The Constitution of the Federal Republic of Nigeria expressly provides for a number of rights, which are recognized as inalienable to every citizen of the country. Deriving from this, the Consumer Affairs Bureau of the Nigerian Communication Commission (NCC) has listed some rights (Consumer Bill of Rights) which every consumer is entitled to. One of these is: the right to be heard. This provides ample opportunities and channels of expressing grievances and opinions, lodging complaints, and suggesting ways and means of improving services delivery to customers.

1.5.9 Nuclear Safety and Radiation Protection Act The Nuclear Safety and Radiation Protection Act No. 19 of 1995 established the Nigerian Nuclear Regulatory Authority is charged with the following responsibilities, among others:  regulate the possession and application of radioactive substances and devices emitting ionizing radiation;  ensure protection of life, health, property and the environment from the harmful effects of ionizing radiation while allowing beneficial practices involving exposure to ionizing radiation; and  regulate the introduction of radioactive sources, equipment or practices and of existing sources, equipment and practices involving exposure of workers and the general public to ionizing radiation.

1.5.10 Imo State Environmental Protection Act of 1994

This covers forestry management, environmental sanitation and waste management. The Act establishes such environmental criteria, guidelines/specifications or standards for the protection of the state’s air, lands and waters as may be necessary to protect the health and welfare of the people.

1.5.11 International Conventions and Guidelines United Nations Guiding Principles on the Human Environment in 1972, and the Rio Declaration on Environment and Development 1992 are key. Nigeria is signatory to these guiding principles and declarations.

United Nations Convention on Climate Change The convention on climate change was signed in 1992 during the Rio Earth Summit and came into force in 1994 to limit Green House Gas (GHG) emissions, which cause global warming.

Convention on Conservation of Migratory Species of Wild Animals This convention also known as the Bonn Convention of 1979 stipulates actions for the conservation and management of migratory species including habitat conservation.

Vienna Convention for the Protection of the Ozone Layer The convention was instituted in 1985 and places general obligations on countries to make appropriate measures to protect human health and the environment against adverse effects resulting from human activities which tend to modify the ozone layer.

Montreal Protocol on Substances that Deplete the Ozone Layer The protocol was adopted in 1987 as an international treaty to eliminate the production and use of ozone-depleting chemicals.

1.5.12 National regulatory bodies

Federal Ministry of Environment (FMEnv) The Federal Environmental Protection Agency (FEPA), which is now under the Federal Ministry of Environment with the enactment of democratic rule in May 1999, was set up by Act 58 of 1988. FMEnv is responsible for the protection and conservation of Nigerian environment.

The FMEnv is the major authority that has the statutory responsibility for ensuring environmental compliance by development projects in Nigeria. FMEnv has put in place statutory documents to aid the control and abatement of industrial wastes and indiscriminate pollution of the environment. Statutory documents prepared towards this end include:

 S.1.9 - National Environmental Protection (Pollution Abatement in Industries and Facilities Generating Wastes).  S.1.15 - National Environmental Protection Management of Solid and Hazardous Wastes Regulations of 1991.  EIA Act No 86 of 1992.  The Harmful Wastes (Criminal Provisions) Act 42 of 1988.  The 1989 National Policy on the Environment.  The 1992 National Guidelines and Standards for Waste Management in the Oil and Gas Industry.

These documents spell out clearly the restrictions imposed on the release of toxic substances into the environment and the responsibilities of all industries whose operations are likely to pollute the environment. Such responsibilities include provision of anti-pollution equipment, adequate treatment of effluent before discharge into the environment, etc. (S.I.9). For example, paragraph 15(2) of S.I.9 states that “no oil in any form shall be discharged into public drain, rivers, lakes, seas, atmosphere or underground injection without permit being issued by FMEnv or any organisation designated by the Ministry.” Also paragraph 17 states that an industry or a facility which is likely to release gaseous, particulate, liquid or solid untreated discharges

23 shall install into its system, appropriate abatement equipment in such a manner as may be determined by the Ministry.

Specifically, S.I.15 provides a comprehensive list of wastes that are classified as being dangerous to the environment. It also gives detail on the contingency planning and emergency procedure to be followed in case of sudden release of any of these hazardous wastes into the environment.

National Inland Waterways Authority (NIWA) The National Inland Waterways Agency (NIWA) was established by the National Inland Waterways Act No. 31 of 1997 with the statutory mandate to oversee the improvement and development of the inland waterways for navigation. The agency is also responsible for the provision of alternative mode of transportation for the evacuation of economic goods and persons as well as to execute the objectives of the national transport policy as they concern inland waterways. The specific functions of NIWA relevant to this study are to:

 provide regulations for inland navigation;  ensure the development of infrastructural facilities for a national inland waterways network connecting the creeks and the rivers with the economic centres using the river-ports as nodal points for intermodal exchange;  ensure the development of indigenous technical and managerial skill to meet the challenges of modern inland waterways transportation;  undertake capital and maintenance dredging;  undertake hydrological and hydrographic survey;  design ferry routes;  survey, remove, and receive derelicts, wrecks and other obstructions from inland waterways;  operate ferry services within the inland waterways system;  undertake installation and maintenance of lights, buoys and all navigational aids along water channels and banks;  issue and control licences for inland navigation, piers, jellies, dockyards; grant permit and licences for sand dredging, pipeline construction, dredging of slots; and crossing of waterways by utility lines, water intake, rock blasting and removal;  approve and control all jetties, dockyards, piers within the inland waterways;  reclaim land within the right-of-way;  provide hydraulic structures for river and dams, bed and bank stabilisation, barrages, groynes;  subject to the provisions of the Environmental Impact Assessment Act, carry out environmental impact assessment of navigation and other dredging activities within the inland water and its right-of-ways;  undertake erection and maintenance of gauges, kilometre boards, horizontal and vertical control marks;  advise government on all border mailers that relate to the inland waters;  undertake acquisition, leasing and hiring of properties; and  clear water hyacinth and other aquatic weeds.

2. Oil spill history of the area

Since production activities started in Oguta field in 1960, there have been reports of over 500 oil spills. The three most recent reports of spills include one in Umuezedi Farmland and two in Oguma Land, the latter of which involved about 1,460 barrels and affected about three hectares of land.

At the time of the present field work, the Oguta area was affected by massive flooding which affected most of the Oguta oil field and parts of the Oguta community (Plates 2.1–2.3). The flood was so massive that even the Oguta flow station and most of the oil field with wells and road network were affected. Much of the communication in the area had to be done using boats.

It was reported that an oil spill occurred in the SPDC area in February 2012. This spill had since been cleaned up and remediated. As the task force completed the fieldwork, another spillage occurred along an on-the-ground pipeline in the area. Because of the nature and number of pipelines in the area, the immediate source of this spill could not be immediately determined as it had spread extensively in the aquatic environment.

Plate 2.1: Flooded area in Oguta town Plate 2.2: Flooded area along Oguta Creek area October 2012 October 2012

Plate 2.3a & b: Flooded area close to the flow station (17 October 2012)

Plates 2.4 & 2.5: Oil spillage from the NAOC pipeline (21st October 2012)

Available records of oil spillages in the area as adapted from SPDC oil spill maps (2010) show that quite a number of spillages have occurred within the study area as indicated in Table 2.1. However the quantities of oil involved were not available in most cases; where the quantities were provided, the magnitudes of the spills were minor.

Table 2.1: Oil spill records in Oguta field from 1985 to 2008

S/N YEAR OF SPIL QUANTITY/ S/N YEAR OF SPIL QUANTITY/ SPILLAGE CODE AMOUNT SPILLAGE CODE AMOUNT (bbl) (bbl) 1 1985 0078 15 1998 00226 10 2 1986 0079 16 2003 00167 2 3 1986 0089 17 2004 00095 0.5 4 1987 0096 18 2005 00234 2 5 1987 00105 19 2006 00067 70 6 1987 00130 20 2006 00154 0.133 7 1988 0071 21 2006 00184 1 8 1989 00142 22 2007 00122 1 9 1990 00172 23 2007 00124 1 10 1993 00240 24 2007 00176 10 11 1994 00277 25 2008 00240 - 12 1996 00090 26 13 1998 00133 1 27 14 1998 00207 5 28

3. Methodology

Qualitative and quantitative information was gathered on the impacts of oil spills within the study area, through extensive multi-disciplinary studies that comprised surface, groundwater and soil quality assessments, investigations of the state of vegetation and biodiversity, and the collection of basic socio-economic conditions and community health characteristics.

Baseline data acquisition involved a multi-disciplinary approach and was executed within the framework of a QHSE management system approach. This approach ensured that the required data and samples were collected in accordance with agreed requirements (scientific and regulatory) using the best available equipment, materials and personnel.

Elements of this approach included:  a review of existing reports on the environment of the project area;  designing and development of a field sampling strategy to meet work scope and regulatory requirements;  review/confirmation of the work scope and sampling design and locations by IUCN-NDP;  pre-mobilization activities (assembling of field team, sampling equipment/materials, calibrations/checks, review of work plan and schedule with team, and job hazard analysis);  mobilization to the field and fieldwork implementation: sample collection (including positioning and field observations), handling, documentation and storage protocols and procedures; and  demobilization from the field and transfer of sample custody to the laboratory for analysis.

3.1 Sampling strategy The study covered the following main sampling measurements:  physico-chemicals – soil, water and sediment analysis which will help to analyse the standards/level of contamination after remediation;  public/ecosystem health issues – sampling of groundwater, surface water and aquatic resources (particularly totemic species) to ascertain level of contamination and possible transfer through food chain; and  biodiversity – sampling of flora and fauna to establish impact and possible recolonization/regeneration following remediation; data on density and relative abundance will help to establish species richness and hence biodiversity in each ecosystem.

In order to complement information obtained from a review of existing data on the project area and fill identified information gaps, the first season field sampling and measurement exercise was conducted between 20th and 24th October 2012.

Community consultations were held with the Monarch/Traditional Ruler and Council of Chiefs of Oguta Kingdom by the NDP members on the 19th October 2012 (Plates 3.1 – 3.3). Following these interactions, community guides were appointed to assist the Biophysical Task Force Team. These guides briefed the NDP members on the terrain of the area and based on this information a sampling strategy was adopted.

Plate 3.1a & b: Consultation at the Palace of the Oguta Monarch

Plate 3.2: Panel members and Council of chiefs Plate 3.3: Panel members and the Monarch

The specific objectives of the field sampling were to complement information on the:  ambient air quality and noise levels in the study area;  physico-chemical and microbiological characteristics of the surface and subsurface soil within the study area;  contemporary wildlife abundance and diversity in the study area and environs;

 contemporary vegetation characteristics of the area; and  socio-economic and health status of the stakeholder communities.

Sampling design Four sampling stations were established by the team, to cover different parts of the study area. These included:

 Station 1 (OGU.01): very close to Oguta Well 1;  Station 2 (OGU.02): outside the submerged perimeter fence of SPDC facility;  Station3 (OGU.03): further off the SPDC facility, an area with dense stands of Indian bamboo vegetation; and  Station 4 (0GU.04): at a distance of about 1km from the flow station, this site was selected as control.

Due to the impact of the flood, only water samples at top/surface and bottom levels were collected at each station. In situ measurements were made for temperature, pH, electrical conductivity (EC), dissolved oxygen (DO) and total dissolved substances (TDS).

Water samples were taken for physico-chemical and microbiological analysis. Biological specimens including fish, macrofauna, benthos, phytoplankton, zooplankton and macrophytes were collected for laboratory analysis.

The samples/measurements taken were as follows:  A vegetation/wildlife survey was carried out at 12 different locations in the study area  Water and sediment samples were taken at the four sampling stations  Hydrobiological samples including phytoplankton, zooplankton and periphyton and macrophytes were collected.

Positioning During fieldwork activities, positioning at each sampling station was carried out with the aid of Global Positioning Systems (GPS) which were hand-carried by the different groups of the study team. At each station, coordinates at which sampling actually took place were marked with the GPS and subsequently transferred into a field notebook.

Fig 3.1: Map of Oguta area showing the sampling stations

3.2 Water quality

3.2.1 Field methodology After a detailed reconnaissance visit the aquatic studies were undertaken to determine the effect of remediation activities on water quality. To be able to predict the affects of the remediation exercises on the environmental quality, sampling stations were established in such a manner as to adequately represent the area of operations. Sampling stations were chosen, marked and geo-located using Geographical Positioning System (Germin-12GPS). Stations for surface water sampling were located both upstream and downstream to the Oguta oil field.

Sampling techniques The water samples were collected on the 20th of October 2012; those for physico- chemical analyses were placed in a 2-litre plastic container which was previously rinsed three times with the water sample to be analysed and sealed appropriately. Surface water samples were collected with the aid of sampling bottles at about 10– 15cm beneath the surface layers. The bottom samples were collected by lowering the sampling bottle to lower depths of the water body and the water sample was then taken up. Those for total hydrocarbon (THC) measurements were placed in 1 litre glass containers, to which concentrated hydrochloric acid (HCl) was added, and sealed with aluminium foil; while the samples for the heavy metal analyses were placed in a 150ml plastic container to which concentrated nitric acid (HNO3) was added to adjust the pH to 2. Biochemical oxygen demand (BOD) samples were collected in 250ml brown reagent bottles, sealed to exclude air bubbles while the dissolved oxygen (DO) samples were fixed immediately with Winkler’s I and II reagents. All samples were preserved in a cool box and transported to the laboratory for analyses.

Table 3.1: Physico-chemical parameters (in situ) for Oguta surface water S/ Sample Location Co ordinates Depth pH oC µµS/cm mg/l Remarks N Code µS/cm N E Temp EC TDS DO 0 0 1. OGU.01 Oguta 05 39’32.3” 006 42’48.7” Top 7.33 28.8 52.3 35.4 1.60 Oil sheen observed Well 1 on surface water, oil 2. Bottom 7.36 29.0 51.8 35.6 1.04 spill occurred Feb; 2012 remediated immediately 0 0 3. OGU.02 Oguta 05 39’25.0” 006 42’45.2” Top 7.34 29.0 51.3 36.1 1.93 4. Bottom 7.86 29.3 50.1 34.3 0.94 0 0 5. OGU.03 Oguta 05 39’13.5” 006 42’44.7” Top 7.54 29.2 51.9 34.5 1.84 Dominated by Indian Well 2 bamboo, 6. Bottom 7.38 29.4 51.2 35.7 0.98 macrophytes, sampling sediment impossible 0 0 7. OGU.04 1km away 05 39’18.3” 006 43’28.2” Top 7.38 30.3 52.5 37.0 1.93 Freshwater swamp Control) from site forest, flooded 8. Bottom 7.34 29.6 52.7 36.0 1.40 FMEnv 6-9 <40 N/A 2000 N/A Limits DPR Limits 6.5- <40 N/A 2000 N/A 9.5 WHO Limits 6.5- N/A N/A 1000 5.0 8.5 Source: IUCN Taskforce Field Study, 2012

3.2.2 Quality Assurance/Quality Control Standard field methods were used in the sample collection at the site as recommended by DPR (EGASPIN, 2002). To ensure the integrity of some unstable physic-chemical parameters, in-situ measurements of temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), turbidity, salinity and total dissolved solids (TDS) were carried out in the field using water quality checker Horiba U-10. All the samples were then preserved in an ice-packed cool box and taken to the laboratory for analysis.

3.2.3 Laboratory analysis Laboratory analyses of the physico-chemical parameters were carried out in keeping with standard practice specified in DPR Environmental Guidelines and Standards (EGASPIN, 2002). Except where otherwise stated, the laboratory methodologies for wastewater are from Standard Methods for the Examination of Water and Wastewater 19th Edition, 1998. Investigations involving heavy metals concentrations were carried out using atomic spectrophotometer (AAS Unicam 969). Exchangeable cations and anions were measured using flame photometer and UV/Visible spectrometer (Unicam Helios Gamma, UVG 073201; Spectronic 21D). Briefly, the methods employed are as follows: pH, electrical conductivity, turbidity, dissolved solids, temperature and salinity Measured using Horiba Water Checker (Model U-10) after calibrating the instrument with the standard Horiba solution. The units of measurement are µS/cm, NTU, mg/l, 0C and ‰; respectively for conductivity, turbidity, temperature and salinity.

Dissolved Oxygen (APHA-4500 C) The dissolved oxygen (DO) was determined by the Modified Azide or Winkler’s method (APHA 1998). To a 70ml BOD bottle filled with sample, 0.5ml manganous sulphate (Winkler I) solution and 0.5ml alkali-iodide-azide reagent (Winkler II) were added, and the bottle then stoppered (to exclude air bubbles) and mixed by several inversions. After about 10 minutes, 0.5ml conc. H2SO4 was added, and the bottle re- stoppered and mixed for complete dissolution of the precipitate. The fixed sample was taken to the laboratory for further analysis.

Bio-chemical Oxygen Demand (APHA-5210-B) A known portion of the water sample collected was incubated at 20oC for five days. At the end of the incubation period the samples were treated in the same manner as the DO samples stated above. Detection limits 2.0mg/l.

Total Alkalinity (API-RP 45) Bicarbonate determination was by titration with 0.02N H2SO4 using methyl orange indicator. The detection limit is 1.0mg/l as CaCO3 (APHA, 1985).

Chloride (APHA 4500 – Cl- B) Chloride was titrimetrically determined by the Argentometric method in the presence of potassium chromate as indicator. Limit of detection is 1.0mg/l

Sulphate (APHA 4500-SO42- E/AST MID 516)

Sulphate determination was by the turbidimetric method (APHA 1998). To a 50ml sample or portion diluted to 50ml contained in a conical flask, 2.5-ml of conditioning reagent (i.e. a mixture of 50ml glycerol with a solution of 30ml concentrated hydrochloric acid, 300ml distilled water, 100ml 95% ethanol and 75g sodium chloride) and a quarter spatula full barium chloride (BaCl2) were added. The mixture was swirled for a minute and the barium sulphate (BaSO4) turbidity read at fifth minute on Spectronic 21D at 420nm against water. Sulphate level was read from a calibration curve prepared for known sulphate standards treated the same way as the samples. The detection limit is 1.0mg/l.

Phosphate (APHA 4500-P E/ASTM D 515) Phosphate was determined using the stannous chloride method (APHA, 1998). To a 50ml sample, the following were added with mixing: 2.0ml ammonium molybdate reagent and 0.2ml stannous chloride reagent. After 10 minutes but before 12 minutes from addition of the stannous chloride, the absorption of the treated sample was read on Spectronic 21D at 690nm. The phosphate level was obtained by reading off the absorption level from standard curve of known standards treated as the samples. The detection limit is 0.05mg/l.

Nitrate Nitrate measurement was by Ultraviolet Spectrophotometric screening method. To a 50ml clear sample, 1ml HCl solution was added and mixed thoroughly. Absorbance measurements made at the wavelength of 220nm and the nitrate concentration obtained from the standard curve. Limit of detection is 0.05mg/l.

Total Hydrocarbon Content (THC) ASTM D3921 (Extraction/Spectrophotometry) A known volume of the sample was well agitated and poured into a separatory funnel. A known quantity of sodium chloride was added to prevent emulsification.

Fifty millilitres (50ml) of xylene were added to the sample container and then shaken properly to rinse the container before transferring into the separatory funnel. The funnel was corked and shaken vigorously for about one minute. The mixture was allowed to stand for separation. The sample portion was run off by opening the tap and then the extract transferred into a 100ml centrifuge tube by passing it through a filter paper containing 1g of sodium sulphate. The extraction process was repeated with another 50ml of xylene. The xylene layer was then collected into the same centrifuge tube containing the first extract.

The separatory funnel was rinsed with 10ml xylene before transferring into the centrifuge tube. The extract was centrifuged for 15mins at 1500 rpm and placed in a standard cuvette with a light path of 10mm. The spectrophotometer was standardized and sample readings taken. THC concentration was calculated with reference to the standard curve and multiplication by the appropriate dilution factor. Detection limit is 0.01mg/l.

Heavy metals (Cr, Cu, Pb, Fe, Cd) APHA 3111-B (AAS) Heavy metals were determined using an Atomic Absorption Spectrophotometer (AAS) as described in APHA 3111B and ASTM D3651. This involved direct aspiration of the sample into an air/acetylene or nitrous oxide/acetylene flame generated by a hollow cathode lamp at a specific wavelength peculiar only to the metal programmed for analysis. For every metal investigated, standards and blanks were prepared and used for calibration before samples were aspirated. Concentrations at specific absorbance displayed on the data system monitor for printing. Limit of detection is <0.001mg/l.

3.2.4 Quality Assurance/Quality Control Quality measures adopted for the laboratory analyses were in accordance with the recommendation of DPR Guidelines and Standards for Petroleum Industry in Nigeria (EGASPIN, 2002). To maintain analytical accuracy, duplicate and blank samples were included in the analyses. Distilled water used for analysis conforms to ASTM D 1193 Type 1. Only qualified and trained personnel were employed in the laboratory work.

Analysis for hydrocarbons and heavy metals were carried out in two laboratories to ensure that dependable results were obtained.

3.3 Hydrobiological

3.3.1 Zooplankton/ phytoplankton studies The distribution, composition and abundance of the biotic components of any aquatic system are correlated to environmental parameters such as temperature, dissolved oxygen, alkalinity and salinity.

The aim of this part of the study was to identify and enumerate the plankton communities in the study area, with a view to describing their taxonomic composition and spatial distribution. It was also intended to monitor any likely changes due to environmental stress.

The plankton of mangrove creeks, fresh water creeks and swamps includes permanent forms and several temporary components including newly-hatched invertebrate larvae about to leave the creeks and returning post-larvae juveniles of the same species. In addition, mobile benthic forms may occur in the water column from time to time for various reasons. The composition and abundance varies considerably with the season and according to diurnal, tidal and semi-lunar cycles.

3.3.2 Field methodology

Phytoplankton Samples were collected in sub-surface (20cm) water. One litre of water was collected and preserved in 30ml of 4%formalin and stored in the dark at room temperature. In the laboratory samples were concentrated to about 50m1 by sedimentation over a

35 period of 48 hours. Further concentration was done using a centrifuge at a speed of 100 rev/mm. From the concentration, 1ml of the sample was taken and transferred to a Sedgwick rafter cell and a preliminary scan was made under a microscope. In all samples 1ml of the concentrate was diluted; because of the large number of cells in the concentration 1ml of the concentrate was diluted with 9m1 of the diluted water. The sample was thoroughly mixed and five sub-samples of 1ml each were placed in Sedgwick rafter cell and viewed under a binocular microscope (x200). The cells viewed under the microscope were identified with the aid of keys to plankton identification, the cells were enumerated and the total number of the cells per litre of sample was estimated from the relationship:

N/L =C (1000mm3) ------(1) LDWS

Where C= mean number of organisms or cells in the sample viewed L= Length of Sedgwick rafter cell D= Depth of Sedgwick rafter cell W = Width of strip viewed S = Number of strips

Zooplankton A plankton net with a mesh size of 30–50 µm was towed for a minimum of three minutes at a maximum speed of 5km/h. The zooplankton on the sides of the net was washed down into the collection bottle (Plate 3.3). Samples were then put in a 250 ml labelled container and preserved with 5% ethanol and kept in the dark. In the laboratory the samples were concentrated immediately and preserved with 70% ethanol (5% glycerin was also added) and the volume made up to 100ml. The size of the sub-sample was 1/100.

In the laboratory analysis, the plankton population was enumerated using a counting chamber (Sedgwick–Rafter (S-R) counting cell) which limits the volume and area for the ready calculation of population densities. The tally system was also adopted in this method: after counting, the number of cells per mL was then multiplied by a correction factor so as to adjust for dilution of the sample. The organisms were identified using standard bench references (Pourriot, 1980) and reported as number of individuals per ml. The individual organisms were identified with the aid of a Zeiss binocular microscope at x40/100x, a standard bench references and CD–ROM from the Intergovernmental Oceanographic Commission of UNESCO.

Pelagic microalgae A plankton net (with a mesh aperture of 30–70 µm) was used for the quantitative (10l) tow-sampling of the microalgae. The microalgae on the sides of the net were washed down into the collection bottle with the water from the outside. Samples were put in a 250 ml labelled container and preserved with 5% neutral formalin and kept in the dark. On arrival at the laboratory, the samples were filtered through a 0.45μm

36 membrane filter paper (with a vacuum of less than 0.5 atm.) and preserved with 70% ethanol. The volume was made up to 100 ml. The size of the sub-sample was 1/100.

The microalgae population was enumerated using a counting chamber (Sedgwick– Rafter (S-R) counting cell). The tally system was adopted in this method: after counting, the number of cells per ml was then multiplied by a correction factor so as to adjust for dilution of the sample. The individual organisms were identified with the aid of a Zeiss binocular microscope at x40/x100, standard bench references (see reference section) and a CD–ROM from UNESCO, while an Olympus CX3, Hypercrystal LCD binocular microscope was deployed for the photo-microscopy of the samples from this study.

For the aquatic macrophytic studies, the vegetation samples were as much as possible identified in the field to the species level with the aid of Akobundu and Agyakwa (1998), “A handbook of West African weeds and the life form spectrum”, and the floristic structure and composition of the various plant community samples were worked out using the Raunkaerium (1934) life form classification scheme.

Benthic macrofauna The methodology of sampling was by taking a 1m2 quadrat and studying all the observable macrofauna within it and recording their distribution and density. Unfortunately due to the difficulty of the terrain occasioned by the heavy flooding of the area, only sampling stations within the fringes of the rivers were sampled.

3.4 Wildlife studies

Wildlife study in Oguta and its environs was investigated between 7am and 6pm local time. This involved various conventional techniques, both direct and indirect methods (Moshby 1974; Dasmann 1964; Sutherland 2000; Davies 2002, Akani et al 1999, 2008), as the major objectives were to produce a comprehensive checklist of the fauna, determine their distribution and conservation status. Several wildlife ecologists of the Niger Delta region have successfully adopted these methods (Anadu and Oates 1982; Happold, 1987; Anadu and Green 1990; AA.VV 1997, 1998; Powell 1998; Angelici 1998; Angelici et al 1999, Akani 1999, 2008). Considering the wildlife dependence on vegetation for shelter, foods, nesting site, etc., sampling stations were the same as those for the vegetation transects.

Within each transect and nearby footpaths, farmlands and streams, wildlife physical presence and evidence of occupation (footprints, trails, burrows, faecal droppings, sloughed skin, carcass, food remains, playground, etc.) were searched for, while walking at a rate of 1km/hr. Stopovers were made at intervals to listen for animal vocalizations or calls, and high power binoculars (Fujiyama Model) were used to view/screen trees for arboreal forms such as squirrels, snakes, birds, etc.

Critical habitats and microhabitats such as logs, litter, forest undergrowth, crevices and burrows were ransacked with the aid of 1m long stick to dislodge any hiding herpetofauna and mammals. All dislodged and sighted animal were identified to possible taxonomic levels, using the field guides and keys of Happold (1987), Kingdom (1997), and Powell (1995) for mammals; Peterson (1980) and Borrow and Demey (2001) for birds; Branch (1995) for reptiles; Schiotz (1963, 1969) and Rodel (2000) for amphibians.

Further information concerning the wildlife of the area was collected from literature data from tertiary institutions and interviews with a group of hunters within Oguta who assisted the Task Force team as field guides. Only the information for which there was > 50% consensus of opinion was taken as correct (Akani, 2008). Interviewing of locals as adopted in this study has been acknowledged by several ecologists as a reliable source of information for the habitat history and land use of any place (Gadgil 1992, Akani, et al., 1999; Akani, 2008).

4. Results and discussion

4.1 Surface and groundwater quality

The results of the physico-chemical parameters of the water samples from the Oguta area are shown in Table 4.1. They indicate a BOD range of 0.8–2.4mg/l, which is very much within the regulatory limit and indicative of low biological activity. The nitrate levels at all the sampling stations were in the range of 0.36 to 0.52mg/l, phosphate levels (<0.05mg/l) and sulphate levels (<1.0 – 1.3mg/l) were all within the regulatory limit, whilst the oil and grease concentrations of 0.85–2.91mg/l were high and comparable to those recorded in contaminated sites.

Table 4.1: RESULTS FOR PHYSICO-CHEMICAL PARAMETERS OF WATER SAMPLES FROM OGUTA FIELD, OCTOBER 2012.

S/N SAMP LOCAT CO-ORDINATES DEPTH pH TEMP EC TDS mg/l LE ION oC µS/cm mg/l N E DO BOD NO3 PO43- SO42 Cl THC CODE 0 0 1. OGU. Oguta 05 39’32.3” 006 42’48.7 Top 7.33 28.8 52.3 35.4 1.60 2.4 0.36 <0.05 <1.0 1.0 2.91 01 (Oguta ” Well 1) 2. Bottom 7.36 29.0 51.8 35.6 1.04 - 0.52 <0.05 <1.0 1.0 1.62 0 0 3. OGU. Oguta 05 39’25.0” 006 42’45.2 Top 7.34 29.0 51.3 36.1 1.93 0.8 0.46 <0.05 <1.0 1.0 1.74 02 ” 4. Bottom 7.86 29.3 50.1 34.3 0.94 - 0.48 <0.05 <1.0 1.0 2.50 0 0 5. OGU. Well 2 05 39’13.5” 006 42’44.7 Top 7.54 29.2 51.9 34.5 1.84 0.8 0.52 <0.05 <1.0 1.0 1.68 03 ” 6. Bottom 7.38 29.4 51.2 35.7 0.98 - 0.39 <0.05 1.3 1.0 1.21 0 0 7. OGU. 1km 05 39’18.3” 006 43’28.2 Top 7.38 30.3 52.5 37.0 1.93 0.8 0.45 <0.05 <1.0 1.0 0.85 04 away ” (Contr from ol) site 8. Bottom 7.34 29.6 52.7 36.0 1.40 - 0.47 <0.05 <1.0 1.0 1.26 Source: IUCN Taskforce Field Study, 2012

4.1.1 pH The pH of a solution measures the hydrogen ion concentration in that solution. A small change in pH represents a large change in hydrogen ion concentration. KWW, (2001) observed pH between the range of 6.0 to 9.0 as favourable for freshwater fishes and bottom-dwelling invertebrates. This study recorded pH values for Oguta field between the range of 7.33 and 7.86 which indicate slight alkaline to neutral water bodies. The values are within the DPR regulatory limits of 6-9/6.5-9.5 respectively.

4.1.2 Temperature Temperature influences the distribution of many aquatic organisms; many cannot survive very high or low temperatures. Surface water temperature in the study area ranged from 28.8OC to 30.3 OC. This signifies the most favorable condition for the survival of aquatic life (RPI, 1985; Osibanjo and Ajayi, 1981).

4.1.3 Electrical Conductivity (EC) Electrical Conductivity (EC) is related to the concentration of ionized substances in water or the measure of ionic richness in a river course. In the study area EC varied from 50.1 S/cm to 52.7S/cm. The recorded values compared well with EC level recorded earlier within the Niger Delta Region (RPI, 1985).

4.1.4 Dissolved Oxygen (DO) Dissolved oxygen (DO) is the measure of the amount of gaseous oxygen dissolved in an aqueous solution. It is one of the most important parameters in aquatic life as it is an absolute requirement for the metabolism of aerobic organisms and also influences inorganic chemical reactions.

The concentration of DO varies daily and seasonally and depends on the species and volume of plants present, light penetration, nutrient availability, temperature, salinity, water movement, partial pressure of atmospheric oxygen in contact with the water, thickness of the surface film and the bio-depletion rates.

The DO levels of the surface waters in the area ranged from 0.94 mg/l to 1.93mg/l which is below WHO regulatory limits of 5 mg/l. Odiete, (1999) confirms levels above those recorded to be favourable for the survival of aquatic organisms within the Niger Delta. The dissolved oxygen concentrations, consumption and demand vary between aquatic organisms, especially fish species. Ophiocephalus obscura, the snakehead, Clarias gariepinus and other catfish species among others can survive with DO values within the range 0.5 to 4mg/l while higher concentrations of DO (7 to 11mg/l) is required to keep species such as Palaemonetes africana, Paeneus kerathurus (shrimps) healthy.

4.1.5 Total Dissolved Solids (TDS) Excess TDS discharge in water bodies are of concern due to its potential for causing unfavourable physiological reactions in aquatic organisms (EBM, 1994). However, in the study area the total dissolved solids varied from 34.3 mg/l to 37.0mg/l. These values are lower than the DPR limit of 2000mg/l for surface water and 1000 mg/l WHO limits for drinking water. Any noticeable increase in this value may be associated with increasing runoff (occasioned by regular rainfall) and vigorous anthropogenic activities as well as disturbances of the waterways by boats and fishing activities.

4.1.6 Biochemical Oxygen Demand (BOD) Biochemical oxygen demand (BOD) is an indirect measure of the amount of biologically degradable organic materials in water, and is an indicator of the amount of dissolved oxygen that will be used during natural biological degradation of organic matter including biologically degradable pollutants. High BOD in water could adversely affect the survival of aquatic organisms due to the risk of inadequate oxygen concentrations. The BOD recorded in this study ranged from 0.8–2.40 mg/l and are all below the FMEnv limits of 30mg/1.

4.1.7 Nutrients While nitrogen and phosphorus occur in nature and are critical to plant life in the aquatic environment, too much of these nutrients cause an excessive growth of phytoplankton and other organisms, which deprive aquatic life including fish and plants of oxygen.

The concentration of nitrates (NO3-) ranged from 0.36 mg/l to 0.52mg/l as against the FMENV limits of 20mg/l while sulphates (SO42-) recorded values were between <1.0mg/l and 1.30mg/l, very much lower and highly insignificant compared to the

FMEnv regulatory limits of 500mg/l. Phosphate values were lower than 0.05mg/l. The values were consistent with Niger Delta swamp water environment (RPI, 1985).

4.1.8 Chloride/ oil/grease The chloride levels of the water bodies in the study area were below 1.0 mg/l. The values were lower than the FMEnv/DPR regulatory limits of 600mg/l. Oil and grease varied from 0.85 mg/l to 2.91mg/l indicating presence of hydrocarbon contamination.

4.1.9 Heavy metals Some of these heavy metals were investigated in Oguta field surface water and the results obtained are summarized in Table 4.2. A comparison between the values obtained and DPR limits indicates that all the heavy metal concentrations were within the background levels recorded for freshwater environments within the Niger Delta and were below the DPR regulatory limits.

TABLE 4.2: PETROLEUM AND HEAVY METAL LEVELS IN WATER SAMPLES FROM OGUTA FIELD, OCTOBER 2012

S/N PARAMETERS SURFACE WATER SAMPLE IDENTIFICATION AND RESULTS DPR LIMITS OGU SW 1 OGU SW 2 OGU SW 3 OGU SW 4 TARGET INTERV. TOP BOTTOM TOP BOTTOM TOP BOTTOM TOP BOTTOM PETROLEUM HYDROCARBONS (mg/l) 1 TPH <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 2 PAH <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 3 THC 2.91 1.62 1.74 2.30 1.68 1.21 0.85 1.26

HEAVY METALS (mg/l) 5 Chromium (Cr) <0.01 0.271 0.210 0.252 <0.01 0.246 0.251 <0.01 100 380 6 Cadmium (Cd) <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.80 12 7 Nickel (Ni) <0.01 0.550 0.891 1.021 0.510 0.456 0.501 1.021 35 210 8 Lead (Pb) 0.168 <0.01 0.096 0.117 <0.01 <0.01 <0.01 <0.01 85 530 9 Vanadium (V) <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 NA NA 10 Zinc (Zn) 0.017 0.161 0.032 0.040 0.031 0.046 0.011 0.032 140 720 11 Copper (Cu) <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 36 190 12 Manganese (Mn) 0.056 0.061 0.068 0.091 0.170 0.082 0.172 0.033 NA NA 13 Iron (Fe) 1.491 2.001 3.012 2.510 5.101 1.891 2.102 2.101 NA NA Source: IUCN Taskforce Field Study, 2012

4.2 Hydrobiology

4.2.1 Phytoplankton community The relative abundance and distribution of phytoplankton community within the study sites at Oguta field (a total phytoplankton checklist of 23 species representing 5 families, with an overall density of 759 cells/ml) is shown in Table 4.3.

The results indicate that within the study stations the Chlorophyceae (green microalgae) have the highest abundance and distribution (42.9%), followed by Bacillarophyceae (25.96%), then Cyanophyceae (24.39%), Xanthophyceae (4.61%) and Euglenophyceae (2.77).

The pie chart in Figure 4.1 shows the contribution of each of the major families of phytoplankton in the sampled Oguta field environment. Five major families of phytoplankton were recorded, namely Chlorophyceae, Bacillarophyceae,

Cyanophyceae, Xanthophyceae and Euglenophyceae and this composition is in conformity with observations made in other studies (Ekeh and Sikoki 2004, Chowdhury 2007).

Chlorophyceae were the dominant family and constituted 42.9% of the total number of phytoplankton in sampled surface waters in Oguta field and its environs. The Chlorophyceae were represented by seven species with the most numerous species being Spirogyra sp., followed by Volvox aureus, Volvox globistor and Microspora sp.

The second dominant group of phytoplankton was the Bacillarophyceae, which contributed 25.96%, of the total number of phytoplankton count. They were represented by seven species. The most dominant of the Bacillarophyceae species were Gyrosigma accuminatum, Melosira virans, Syadra rupens and Navicula pusilcan. The third dominant group of the phytoplankton was the Cyanophyceae and they contributed 23.49% of the total number of phytoplankton. Members in this family include Raphidopsis curvata, Oscillatoria tenus and Oscillatoria lacustris. The other family, which is one of the least in terms of dominance is the Xanthophyceae, which contributed just 4.61% of the total phytoplankton population. Members of the family include Tribonema species. This is followed by the least dominant group, the Euglenophyceae that had Phacus sp. as the sole member of this family represented in Oguta field.

TABLE 4.3: PHYTOPLANKTON DENSITY AND DISTRIBUTION FOR OGUTA FIELD, OCTOBER 2012 S/N TAXANOMIC GROUP STATIONS TOTAL RELATIVE CYANOPHYTA 1 2 3 4 OCCURRENCE ABUNDANCE PER GROUP PER GROUP 1 Raphidopsis curvata 14 18 11 7 2 Oscillatori lacustris 18 10 11 6 3 Rivularia planctonica 7 4 3 2 4 Spirulina subtilissima 11 6 6 5 5 Oscillatoria tenuis 19 11 8 8 Total 69 49 39 28 185 24.39 CHLOROPHYTA 1 Volvox aureus 23 18 15 12 2 Volvox globator 18 13 11 9 3 Spirogyra sp. 29 21 19 15 4 Coelostrum reticulatum 8 5 5 3 5 Ulothrix sp. 8 6 4 4 6 Microspora sp. 16 12 11 8 7 Crucigenia tetrapedia 11 6 7 4 Total 133 81 72 55 321 42.29 XANTHOPHYTA 1 Tribonema minus 6 3 1 0 2 Tribonema vulgare 11 6 5 3 Total 17 9 6 3 35 4.61 EUGLENOPHYTA 1 Phacus sp. 5 6 3 3

2 Euglena acus 3 0 1 0 Total 8 6 4 3 21 2.77 BACILLARIOPHYTA 1 Melosira varians 13 8 6 4 2 Syadra runpens 20 11 9 5 3 Tabellaria fenestrate 8 4 3 0 4 Pinnularia amphibola 3 2 1 1 5 Navicula pusilca 14 10 6 6 6 Gyrosigma accuminatum 21 18 11 8 7 Amphora ovalis 3 2 0 0 Total 82 55 36 24 197 25.96 759 100.0 Source: IUCN Taskforce Field Study, 2012

Overall, the dominance pattern of the various families of phytoplankton in the aquatic systems around Oguta Field is in the order of: Chlorophyceae > Bacillarophyceae > Cyanophyceae > Xanthophyceae > Euglenophyceae. A total of twenty three (23) species of phytoplankton were recorded in the area during the study. Phytoplankton species composition and diversity are known to change with environmental conditions such as nutrient levels, temperature, light, predator pressure etc. The relative importance of these factors varies considerably among the different taxa and ecosystems (Akin-Oriola, 2003; Raybaud et. al.; 2008). Under conditions of nutrient enrichment or eutrophication, the Baccilariophyceae are known to proliferate (Reynolds 1984).

24.39%

42.29%

2.77% 4.61%

25.96%

FIGURE 4.1: PHYTOPLANKTON RELATIVE DENSITY AND DISTRIBUTION FOR SAMPLED WATERS IN OGUTA FIELD, OCTOBER 2012

4.2.2 Periphyton community The relative abundance and distribution of periphyton community within the study stations in Oguta field showed a total of 15 species representing 4 families, namely Bacillarophyceae, Chlorophyceae, Cyanophyceae and Euglenophyceae with an overall density of 576 cells/ml as shown in Table 4.4. The contribution of each of the major families of the sampled periphyton community is shown in Figure 4.2.

Chlorophyceae were the dominant family and constituted 40.49% of the total number of periphyton sampled in Oguta field and its environs. The Chlorophyceae were represented by five species with the most numerous species within the family being Spirogyra sp., followed by Volvox globator, Ulothrix sp. and Volvox aureus.

Bacillarophyceae were the second-most dominant family with a total of 30.73% and represented by five species, the most dominant of which include Navicula pusilla, Synedrarunpus and Gyrosigma accuminatum.

The other dominant group of periphyton was the Cyanophyceae, which contributed 26.74%, of the total number of periphyton count. They were represented by five species. The most numerous of this group include Spirulina subtilissima, Rivullaria pluctonia and Raphidiopsis curvata. The smallest group in terms of abundance is the Euglenophyceae with only 1.08% and Phacus species as the dominant species.

TABLE 4.4: PERIPHYTON RELATIVE DENSITY AND DISTRIBUTION FOR OGUTA FIELD, OCTOBER 2012 S/N TAXANOMIC GROUP STATIONS TOTAL RELATIVE CYANOPHYTA 1 2 3 4 OCCURRENCE ABUNDANCE PER GROUP PER GROUP 1 Osiculatoria lacustris 8 4 4 3 2 Rivullaria planctonia 11 8 7 5 3 Spirulina subtilissima 23 18 12 10 4 Lyngbya major 5 6 3 2 5 Raphidiopsis curvata 8 3 5 6 Total 55 39 31 26 154 26.74 CHLOROPHYTA 1 Volvox globator 21 18 11 9 2 Volvox aureus 13 9 6 4 3 Spirogyra sp. 28 23 18 14 4 Ulothrix sp. 15 11 8 8 5 Coelostrum reticulate 10 5 5 3 Total 87 66 48 38 239 41.49 EUGLENOPHYTA 1 Phacus sp 4 2 0 0 Total 4 2 0 0 6 1.04 BACILLARIOPHYTA 1 Gyrosigma accuminatum 16 11 8 5 2 Navicula pusilla 20 12 10 7 3 Pinnularia amphibola 8 11 7 4 4 Synedra runpens 18 10 18 9

Total 62 44 43 28 177 30.73 576 100.0 Source: IUCN Taskforce Field Study, 2012

26.74% 30.73%

1.08%

41.49%

FIGURE 4.2: PERIPHYTON RELATIVE DENSITY AND DISTRIBUTION FOR SAMPLED WATERS FROM OGUTA FIELD, OCTOBER 2012

4.2.3 Macrophytes and vegetation For the aquatic macrophytic studies, the vegetation samples were as much as possible identified in the field to the species level with the aid of Akobundu and Agyakwa (1998), “A handbook of West African weeds and the life form spectrum, the floristic structure” whilst the composition of the various plant communities sampled was determined using the Raunkaerium (1934) life form classification scheme.

The vegetation type consisted mostly of species of endemic freshwater species. The sampling sites are located along the Oguta Lake – Sombreiro River route which served as the transect for all the collection of samples. The vegetation description and floristic composition appeared the same and consequently one vegetation description is given for all four sampling sites.

The vegetation which fringes the bank of Oguta Lake include: 1. Pterocarpus spp. 2. Vitex grandifolia 3. Upaca senegalensis 4. Alchornea cordifolia 5. Omphalocarpus precerum 6. Napoleona talbotii 7. Pteris marginata 8. Myriantus cirratus 9. Ficus asperifolia

The following macrophytes were also observed: 1. Pistia stratiotes 2. Ceratophilum demersum 3. Utricularia inflexa

4. Azolla africana

4.2.4 Zooplankton The zooplankton fauna in any aquatic environment is usually categorized into Rotifers, Cladocera, Calanoid, Harpaticoid and Cyclopoid Copepods, Shrimps, Decapod crustaceans, and larval forms of bivalve molluscs and various fishes. The zooplankton species obtained in the surface waters of Oguta Field and environs were represented by Copepoda (80.23%), Cladocera 6.84%), Protozoa (6.46%), Rotifera (5.32%), and Insecta (1.14%) (see Table 4.5). The percentage composition of each of these major zooplankton groups in the study area is presented in Fig. 4.3. Calanoid Copepods were the most dominant zooplankton and the dominant species included Macrocyclops distinctus, Euclyclops serullatus, Paracyclops affinis and Acanthacyclops bicuspidatus. The dominant species within the Cladocera taxa included Monia dubia and Daphnia cavinata. Among dominant Protozoan species were Arecella mitrata, and Eglypha acanthoptera. The dominant Rotiferan species included Branchionus angularis and Diurella stylata. The insect group is represented by the Anopheline larvae.

Zooplankton communities encountered during this study are similar to those recorded for other waters in southern Nigeria (Ogbeibu et al., 1996; Imoobe and Ogbeibu, 1996). The observed percentage zooplankton density, with crustaceans accounting for the highest quota, agrees with the report of Ockiya and Otobo (1990) who reported that crustaceans contributed 79% of the total zooplankton fauna.

TABLE 4.5: ZOOPLANKTON RELATIVE DENSITY AND DISTRIBUTION FOR OGUTA FIELD, OCTOBER 2012 S/N TAXANOMIC GROUP STATIONS TOTAL RELATIVE COPEPODA 1 2 3 4 OCCURRENCE ABUNDANCE PER GROUP PER GROUP 1 Macrocyclops distinctus 4 5 7 11 2 Euclyclops serrulatus 8 11 18 23 3 Paracyclops affini 5 3 11 16 4 Acanthacyclops bicuspidatus 4 3 7 12 5 Nitocra lacustris 6 6 11 14 6 Onchocalamus mohammed 0 2 5 7 7 Heliodiaptmus serrate 1 0 4 7 Total 28 30 63 90 211 80.23 CLADOCERA 1 Alona affinis 0 0 1 2 2 Bosmina longirostris 1 0 0 2 3 Monia dubia 1 1 0 3 4 Daphnia carinata 0 1 2 4 Total 2 2 3 11 18 6.85 ROTIFERA 1 Colurella ucinata 0 0 1 1 2 Branchionus angularis 0 2 1 3 3 Diurella stylata 2 0 1 3 Total 2 2 3 7 14 5.32

PROTOZOA 1 Eglypha acanthophora 0 0 2 1 2 Arecella mitrata 0 1 0 2 3 Frontonia leucas 1 0 3 3 4 Pseudodileptus sp. 0 0 2 2 Total 1 1 7 8 17 6.46 INSECTA 1 Anopheline (larva) 0 0 1 2 Total 0 0 1 2 3 1.14 263 100 Source: IUCN Taskforce Field Study, 2012

1.14% 6.46%

5.32%

6.84%

80.23%

FIGURE 4.3: ZOOPLANKTON RELATIVE DENSITY AND DISTRIBUTION FOR SAMPLED WATERS FROM OGUTA FIELD, OCTOBER 2012

4.2.5 Macrofauna The macro fauna identified from the four sampling stations consisted of different assemblages of aquatic organisms. These organisms are classified into four broad taxonomic groups such as Insecta, Gastropoda, Amphibia, and Pisces (fish). The distribution of the organisms found varied with the stations as would be expected in view of the differences in abiotic characteristics of the stations. The biological characteristics of the benthic macrofauna recorded is presented in Table 4.6.

Table 4.6: Composition, distribution and abundance of Benthic Macrofauna in the sampled stations

S/N TAXONOMIC SAMPLE STATIONS TOTAL RELATIVE GROUP OCCURRE ABUNDAN OGUTA 1 OGUTA 2 OGUTA 3 OGUTA 4 NCE PER CE PER OGB OGF OGB OGF OGB OGF OGB OGF GROUP GROUP

A Insecta Naididae Naucoridae 1 Ilyocaris rousseau - 2 - - - 3 3 1 9 Nepidae 2 Nepa cinerea - 1 1 1 1 - 2 1 7 Chrysometridae 3 Gelurucella sp - 1 - - 1 - - - 2 Hydrophilidae 4 Loccobius minutes - - 1 1 - - 1 4 7 Epheroptera 5 Hydroflabia fusca - 1 - - 1 - 2 - 4 Agridae 6 Agrion sp - - 1 - - - 2 1 4 Lestidae 7 Lestes sp ------1 3 4 Aeshnidae 8 Aeshna cyanea - - - - 1 - - 1 2 Chironomidae 9 Chironomus ablabiesmia 1 - - 1 - 1 - - 3 10 Corynoneura sp 3 ------3 Total 4 5 3 3 4 4 11 11 45 75.0 B GASTROPODA Lymnaeidae 11 Lymnaea palustris - - - - - 1 - - 1 Bulinidae 12 Bulinus forskali - - - - - 2 - - 2 13 Bulinus globusus ------1 1 Bulinidae 12 Bulinus forskali - - - - - 2 - - 2 13 Bulinus globusus ------1 1 Total 5 - 2 7 11.67 C Amphibia Ranidae 14 Rana sp - 2 ------2 Total - 2 ------2 3.33 D Fish (Pieces) Claridae 15 Clarias gariepinus - - - - - 2 - - 2 Nandidae 16 Polycentropsis - - - - - 2 - - 2 abbreviate Cichlidae 17 Henichromis binaculatus - - - - - 1 - - 1 Nandidae Protopteridae 18 Protopterus annectens - - - - - 1 - - 1 Total 6 - 6 10 Total no of species 3 5 3 3 4 9 6 8 44 Total of individuals 4 7 3 3 4 15 11 13 60 100 (No/m2) Source: IUCN Taskforce Field Study, 2012

The Insecta class had the highest representative taxon of 11 species from 9 families. Total relative abundance of insects in the study area amounted to 45 individuals (75.0%) of all the organisms recorded during the study. Gastropoda with seven individuals scored 11.67% and ranked second. Fish came third with six individuals scoring 10.0%, and amphibians, with two individuals, were the least abundant with 3.33% occurring in decreasing order of individual forms (see Figure 4.4).

A total of 18 taxonomic groups of organisms comprising 39 individuals/m2 were recorded during the study period. This is an indication of low distribution and poor species diversity.

3.33% 10.0%

11.67%

75.0%

Figure 4.4: The relative proportion of benthic macrofauna in the study area

The pattern of distribution and relative abundance in the sampled stations is presented in Figure 4.5. All the species identified within the class Insecta were observed to occur in some stations, but were absent in others. For example, Ilyocaris rousseau occurred in Stations 1, 3 and 4 and Nepa cinerea was encountered in Stations 1, 2 and 4. Other species such as Loccobius minutes were recorded in two stations (Stations 2 and 4). Chironomus ablabiesmia had consistent occurrence in Stations 1, 2 and 3 but was absent in Station 4. The class Gastropoda had three species that were present in Stations 3 and 4 respectively. The Amphibia class (with one species present) occurred only in Station 1. The fish class were Clarias gariepinus, Polycentropsis obbreviata, Hemichromis bimaculatus, and Protopterus annectens, all of which were sampled in Station 4.

Generally, Station 3 had the highest number of individuals with a maximum density of 13 individuals, accounting for 33.3% of the total taxa recorded in the study area. The lowest number of organisms was recorded in Station 2 (three individuals: 7.7%). The relative proportions of the major taxonomic groups recorded in the different stations are shown in Figure 4.5.

The benthic fauna community is dominated by Insecta and fish. Among the Insecta, chironomid larvae were the most prevalent group as in the case of the tropical waters (Bishop, 1973, Bylmakers and Sobalvarro, 1988, Victor and Ogbeibu, 1991). The absence of oligochaeta in the samples is attributed to substrate factor. The area was newly flooded substrate, making it almost difficult for oligochaetes to establish.

The distribution of fauna in the study area was not uniform. Some taxa showed biotope restriction, appearing in some stations and absent in others. (Ogbeibu and

Egborge, 1985). The factors that influence the abundance and distribution of fauna in an environment include the physical and chemical qualities of water, habitat area, immediate substrate of occupation, trophic conditions, resource partitioning and predation (Bishop, 1973; Dance and Hyne, 1980; Hart, 1994; Bronmark et al., 1984, Oscarson, 1987; Ogbeibu and Victor, 1980).

33.3 30.8

28.2

OGUTA 1 0GUTA 2 OGUTA 3

7.7 OGUTA 4 % oftotal % taxa recorded

Sampling stations

Figure 4.5: Relative proportions of major taxonomic groups found in the sampling stations

4.3 Wildlife

4.3.1 Mammals Six primate species were reported in the study area: 1. Dwarf galago (Galagoides demidovii) 2. Bosman’s potto (Perodicticus potto) 3. Mona monkey (Cercopithecus mona) 4. Tantalus monkey (Cercopithecus tantalus) 5. Sclater’s monkey (Cercopithecus sclateri) 6. Chimpanzee (Pan troglodyles)

One of the primates, the chimpanzee (Pan troglodytes), is becoming extinct in the area. Some foraging parties are still occurring in some areas outside the study area, according to information gathered from hunters. The chimpanzee is listed as Endangered in both the IUCN Red List and Decree No 11 of 1985 of the Federal Republic of Nigeria. Cercopithecus sclatei is listed in the IUCN Red List as Vulnerable, and as Endangered in Decree No 11 of 1985 of the Federal Republic of Nigeria. It is endemic to south-east Nigeria.

Tantalus monkey (Cercopithecus tantalus) is another monkey found in the area. It is a savannah species found in some parts of the Niger Delta (Powell, 1998). This monkey is an enemy to farmers because it feed mostly on cultivated plants, roots, fruits, buds

50 and bark. Tantalus monkeys are spreading fast to other parts of the area because it lives in open forest only and degradation of the forest is increasing daily, thus making the area conducive for its habitation.

Mona monkey is also recorded in the area. It is widely distributed in the Niger Delta area, unlike other monkeys that are not so widely distributed.

Three rodents found in the area are the most common animals in the study area. They include the cane rat (Thryonomys swinderianus), brush-tailed porcupine (Atherurus africanus) and Emin’s giant rat (Cricetomyy emini). None of the three is endangered in IUCN Red List; the brush-tailed porcupine is listed in Decree No 11 of Nigeria as Endangered but the killing of the animal is carried every day unabated throughout the entire nation. Maxwell’s duiker (Cephalophus maxwelli) is another animal that is seriously hunted in the area. The sitatunga and dwarf antelope (Neotragus batesi) are listed in decree No 11 as Endangered. These and the other mammals found in the area are listed in Table 4.7.

TABLE 4.7: MAMMALS OF THE OGUTA FIELD AREA, OCTOBER 2012

COMMON NAMES SCIENTIFIC NAMES IUCN Act 11 1985 ORDER PRIMATES Family Cercopithecidae  Mona Monkey Cercopithecus mona - -  Tantalus monkey Cercopithecus tantalus - -  Sclater’s monkey Cercopithecus sclateri - -  Chimpanzee Pan troglodytes EN E Family Galagonidae  Dwarf galago Galagoides demidovii - -  Bosman’s potto Perodicticus potto - -  Calabar Angwantibo Arctocebus calabarensis - E

ORDER HOLIDOTA Family Manidae  Black bellied pangolin Uromanis tetradactyla - -  Tree pangolin Phataginus tricuspis - E

ORDER CARNIVORE Family Herpestidae  Marsh mongoose Atilax paludinosus - -  Egyptian mongoose Herpestes ichneumon - -  Cusimanse mongoose Corossarchus obscurus - -

Family Canidae  Cape’s clawless otter Anoyx capensis - E  Spot necked otter Lutra maculicollis - E Family Viverridae  African civet Viverra civetta - -  Two-spot palm civet Nandinia binotata - -

ORDER RODENTIA Family Sciuridae  Red legged sun – squirrel Heliosciurus rufbrachium - -  Fire-footed Tree-squirrel Funisciurus pyrrhopus - -

 Giant forest squirrel Protexerus stangeri - -  Geoffroy’s Ground squirrel Xerus erythropus - -

Family Anomaluridae  Derby’s Flying squirrel Anomalurus derbianus - -  Beecroft’s flying squirrel Anomalurus beecrofti - -

Family Thryonomidae  Cane rat Thryonomys swinderianus - -

Family Hystricidae  Brush-tailed porcupine Atherurus africanus - E

Family Muridae  Spotted Grass mouse Lemniscomys striatus - -  Black House rat Rattus rattus - -  House mouse Mus musculus - - Family Cricetidae  Emin’s Giant rat Cricetomys emini - -  Dwarf antelope Neotragus batesi - -

ORDER SIRENIA Family Procaviidae  Tree hyrax Dendrohyrax dorsalis - -

ORDER ARTIONDACTYLA Family Bovidae  Bush buck Tragelaphus scriptus - -  Maxwell’s duiker Cephalophus maxwelli  Sitatunga Trogelaphus spekei - -

Family Suidae  Red River hog Potamochoerus porcus - -

KEY IUCN 2012 Red List  EN = Endangered  VU = Vulnerable

Nigerian 1985 Decree II  E = Endangered Source: IUCN Taskforce Field Study, 2012

4.3.2 Avifauna (Birds) The birds of the study area are typical of those found in lowland forest throughout the Niger Delta area. Birds were found in the open swamp water bodies and the creeks. The avifauna of the study area is listed in Table 4.8.

Great white egret (Egretta alba), grey heron (Ardea cinerama), little egret (Egretta garzetta), squacco heron (Areolas ralloides), green-backed heron (Butriodes striatus), white face whistling duck (Dendrocygna viduata) and Hartlaub’s duck (Pteronetta hartlaubi) were among the species sighted. Hartlaub’s duck which is listed in IUCN Red List as Vulnerable and also the grey parrot (Psittacus erithacus), and three hornbills were recorded in the study area. The African pied hornbill (Tockus fasciatus), piping

52 hornbill (Bycanistes fisterlator) and white crested hornbill (Tropicranus albocristatus) were also listed but none of the big hornbills were recorded. This is an indication that, that most of the forests in the study area have been degraded. In the open grass areas the seed and insect eaters were commonly seen, such as the village-weaver bird (Ploceus cucullatus), magpie manikin (Lonshura fringilloides), bronze manikin (Lonchura cucullata), orange-cheeked waxbill (Estrilae melpoda) and others.

TABLE 4.8: AVIFAUNA OF THE OGUTA FIELD AREA, OCTOBER 2012

COMMON NAMES SCIENTIFIC NAMES IUCN Act 11 1985 Family Cuculidae  Yellow bill Ceuthmochares aereus - -  Senegal Coucal Centropus senegalensis - -  Didric Cuckoo Chrysococcyx caprius - - Family Pycnonotidae  Western Nicator Nicator chloris - -  Common Garden Bulbul Pycnonotus barbatus - -  Little Green bulbul Andropadus virens - -  Leaf love Pyrrhurus scandens - - Family Psittacidae  Grey parrot Psittacus erithacus VU E Family Columbidae  Red-eyed Dove Streptoplia semitorguata - -  Laughing Dove Streptoplia senegalansis - -  Blue-spotted wood dove Turtur afer - -  Tambourine dove Turtur tympanistria - -  Green fruit pigeon Treron calva - - Family Buceratidae  Piping Hornbill Bycanistes fistulator - -  Pied Hornbill Tockus fasciatus - -  White-crested hornbill Tropicranus albocristatus - - Family Accipitridae  Lizard Buzzard Kaupifalco monogrammicus - -  African Goshawk Accipiter tachiro - E  Black kite Milvus migrans - E  Palm Nut-vulture Gypohierax angolensis - E  Hooded vulture Necrosyrtes monachus - E  Long-tailed Hawk Urotriorchis macrourus - - Family Sturnidae  Splendid Glossy starling Lamprotornis splendius - - Family Dicruiridae  Fork tailed Drongo Dicrurus adsimilis - - Family Charadriidae Common sandpiper Actitis hypoleucos - - Family Capitonidae  Yellow-rumped Tinker-bird Pogoniulus bilineatus - - Family Hirundinidae  Rufous chested swallow Hirundo semirufa - -  Lesser striped swallow Hirundo abyssinica - -  House martin Delichon urbica - - Family Ardeidae  Little egret Egretta garzetta - -  Great White Egret Egretta alba - -  Cattle Egret Bubulcus ibis - -  Green-backed heron Butorides striatus - -

 Grey Heron Ardea cinerea - -  Squacco Heron Ardeoda ralloides - - Family Estrildidae  Orange-checked waxbill Estrilda melpoda - -  Magpie Mannikin Lonchura fringilloides - -  Bronze mannikin Lonchura cucullata - -  Black and White mannikin Lonchura bicolor - -  Grey-crowed Negro-finch Nigrita canicapilla - - Family Ploceidae  Village weaver Ploceus cucullatus - -  Vieillot’s Back weaver Ploceus nigerrimus - -  Black-Headed weaver Ploceus melanocephalus - -  Grey-Headed sparrow Passer grisenus - - Family Viduidae  Pin-tailed whydah Vidua macroura - - Family Nectariniidae  Green Headed sunbird Cyanomitra verticalis - -  Superb Sunbird Cinnyris superbus - -  Yellow bellied sunbird Nectarinia venusta - - Family Alcedinidae  Giant Kingfisher Megaceryle maxima - -  Blue-breasted king fisher Halcyon malimbica - -  Malachite Kingfisher Alcedo cristata - -  Senegal king fisher Halcyon senegalensis - - Family Platysteiridae  Common Wattle eye Platysteira cyanea - - Family Jacanidae  African Jacana Actophilornis africana - - Family Phasianidae  Scaly Francolin Franicolinus squamatus - - Family Musophagidae  Great Blue Turaco Corythaeola cristata - -  Green Turaco Tauraco persa - - Family Numididae  Helmeted Guineafowl Numida meleagris - - Family Picidae  Grey wood pecker Dendropicos goertae - - Family Anatidae  White-faced Whistling Duck Dendrocygna viduata - -  Hartlaub’s duck Pteronetta hartlaubi - -

KEY IUCN 2012 Red List  EN = Endangered  VU = Vulnerable

Nigerian 1985 Decree II  E = Endangered Source: IUCN Taskforce Field Study, 2012

4.3.3 REPTILES Thirteen (13) species of reptiles representing ten (10) families were recorded in the Oguta field study area, as shown in Table 4.9.

The most important species are the dwarf crocodile (Osteolaemus tetraspis), Monitor lizard (Varanus niloticus), Nile crocodile (Crocodylus niloticus) and West African blade forest turtle (Pelusios niger). They are more important species in the area as they are hunted for food more than any other species.

The West African blade forest turtle is listed in IUCN Red List as Endangered. It is also an endangered species in the Nigerian Endangered Species Act of (1985). Also listed as endangered in the Nigerian Act are dwarf crocodile, monitor lizard and the rock python.

The dominant species in the study site are grey skink, Trachylepis (=Mabuya) blandingi and agama lizard (Agama agama).

TABLE 4.9: REPTILES OF THE OGUTA FIELD, OCTOBER 2012

COMMON NAMES SCIENTIFIC NAMES IUCN Act 11 1985 Family Python Biodae  Rock Python Python sebae - -  Calabar Ground Python Calabaria reinhardtii - - Family Colubridae  Emerald snake Gastropyxis smaragdina - - Family Elapidae  Green mambas Dendroaspis jamesoni - -  Forest cobra Naja melanoleuca - - Family Viperidae  Gaboon Viper Bitis gabonica - -  Night Adder Causus maculatus - - Family Crocodylidae  Dwarf crocodile Osteolaemus tetraspis - E Family Varanidae  Nile monitor lizard Varanus niloticus - E Family Scincidae  Grey skink Trachylepis(=Mabuya) blandingi - - Family Agamidae  Agama lizard Agama agama - - Family Pelomedusidae  West African Black Forest Turtle Pelusios niger - E Family Testudiniae  Serrated Hinge Back Tortoise Kinixys erosa E -

KEY IUCN 2012 Red List

 EN = Endangered  VU = Vulnerable

Nigerian 1985 Decree II  E = Endangered Source: IUCN Taskforce Field Study, 2012

4.3.4 Amphibians Oguta field is located in the seasonally flooded freshwater environment and will thus provide lots of breeding grounds for amphibians. These amphibians usually breed among the flooded grass and in ditches, swamp forest, ponds, gutters, borrow pits, culverts, etc. Based on earlier studies carried out in some seasonally flooded

55 freshwater environments in the Niger Delta region, the common amphibian species recorded in these will represent the amphibian fauna of the Niger Delta area (Romer, 1953, Schiotz 1963, 1999; Akani and Luiselli, 2002 and Akani et al, 2004) as shown in Table 4.10.

Table 4.10: Diversity of amphibians known in Oguta field and environs

Family Species Abundance index Bufonidae Amietophrynus maculates +++ A. regularis ++ Nectophryne sp. + Dicroglossidae Holobatrachus occipitalis ++ Ptychadenidae Ptychadena mascariensis +++ P. aequiplicata ++ P. oxyrhychus ++ P. pumilio + Phrynobatrachidae Phrynobatrachus sp + Pipidae Silurana (Xenopus) tropicalis +++ Hyperolidae Hyperolius concolor + H. guttalutus + H. fusciventris + Afrixalus dorsalis ++ Arthroleptidae Leptopelis viridis ++ Arthroleptis sp + Key: +++ = Abundant; ++ = Few, + = Very few

The amphibian population in the area may be declining as the habitat is progressively becoming degraded by various anthropogenic activities such as infrastructural development, reclamation and sand filling project, shore protection project, oil spillage, motor bike and car washings around and in freshwater bodies (Akani and Luiselli, 2002 and Akani et al., 2004). Thus, amphibians in Oguta field can serve as good bio indicators of polluted freshwaters (Akani et al., 2004), given that their skin is permeable and very sensitive to chemical changes in water and air. 4.4 Fish and fisheries

Fishing is one of the major occupations of the inhabitants within the study area. It is carried out at both commercial and subsistence levels.

4.4.1 Fish species composition The composition of fish species from the general study area is listed in Table 4.11 which indicates their common and scientific names, preferred fishing location and peak periods of exploitation in the area. The fishery is generally a multi-species stock largely exploited by artisanal fishers operating dug-out wooden canoes of various sizes.

Table 4.11: Common fish species in Oguta Lake area

S/N Common Scientific Name Status Fishing Fishing Fishing gear Name areas period

1 Sardines Pellonula sp Common Rivers & February Cast and seine Lakes to July Net 2 Shad Ilisha sp Common Rivers & August to Cast Net Lakes March 3 Mullet Mugil sp Common Rivers November Cast net to July 4 Tilapia Tilapia guinensis, Common Rivers & May to Cast net Sarotherodon sp Lakes November 5 Flat fish Chaetodipterus Common Rivers & - Cast net goreensis Lakes 6 Cat Fish Chrysichthys Common Rivers & November Gill net & Hook nigrodigitatus Lakes to July 7 Cat fish Arius heudoloti Common October to Hook May 8 Juvenile Cat Chrysichthys Common Rivers & May to Small hook fish nigrodigitatus Lakes November 9 Hepsetus Hepsetus odoe Less Rivers & November Hook common Lakes to July 10 Gobies Bostrychus Common Rivers & All the Hook/ Titi (Sleeper africanus Lakes time gobies) 11 Prawns Macrobrachium Common Inland June to Imbigbo Net macrobrachium Fresh November (Drag net) water Source: IUCN Taskforce Field Study, 2012

4.4.2 Fishing gear types Artisanal fishing is based on traditional methods of fishing that employ mainly canoe and different fishing nets which depend on the season and target fish species. Canoes could be motorized or hand-paddled. Common fishing gear types include shrimp traps, drift gill nets, set gill nets, cast nets, seine nets, hook and lines. Lift nets may be used by women who target small shrimp species in the creeks and creeklets. Other fishing methods include hand-picking for different types of molluscs by the women and children.

Fishing gears are largely made of long setlines, circling nets and seine nets of different mesh sizes varying between ½”, 1”, 1½”, 2”, 2½ and 3” (1.0mm to 5.0mm). Gears measure 6-12m in length and 2-4 meters in width. Nets are manually operated. They are set and allowed to stay for up to one hour before they are removed with the catch.

4.4.3 Fishing seasons Seasonality of exploitation of the different fish species in the area is indicated in Table 4.10. The peak period for clupeids including sardines, shad and bonga is between October and February/March, corresponding to the dry season period. During this time, considerable catches of the clupeids contribute significantly to income of fisher- folk. Freshwater prawns, Macrobrachium, are the predominant harvest during the rainy season between June and November. Palaemon, Penaeus and Atya spp. are also exploited during this period. The peak period of estuarine white shrimp Nematopalaemon sp. is between December and May.

5. Conclusions

The results of observations on water quality based on the in situ measurements indicate that the pH values and temperature values were within the permissible limits for freshwater, while the dissolved oxygen (DO) were quite low.

The Total Hydrocarbon (THC) concentration recorded for the sampled stations were significantly higher for the subsurface samples compared to bottom samples, indicating contamination.

The recorded phytoplankton total abundance was 759 cells/ml, with a species richness of 23 and only 5 taxonomic groups; periphyton – only 4 major taxa, 15 species and overall abundance of 576 and zooplankton – only 5 major taxa, 19 species, overall abundance of 263 individuals/ml and near absence of fish and molluscan larvae, mainly due to the impact of oil spills.

The environmental problems as a result of oil spills and a number of other anthropogenic activities in the area have resulted in degradation of the ecosystem and wildlife in the area. The impacts are particularly severe in the area of Oguta Flow Station and in the nearby areas. Pipelines and roads have opened up different parts of the forest, making these areas more accessible to farmers and hunters. This has affected the wildlife of the area. Also logging is now a major activity in the area. Indiscriminate logging constitutes a major threat to wildlife in the area.

A more comprehensive sampling of soil and sediments could not be carried out due to the extensive flooding of the area at the time of the field work for this investigation.

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Annex 1.

STANDARD OPERATING PROCEDURE FOR ANALYSIS IN ROFNEL LABORATORY

DETERMINATION OF HYDROCARBON IN SOIL AND EFFLUENT WATER.OIL AND GREASE and TOTAL PETROLIUM HYDROCARBON. ASTM D3921-09

SCOPE OF THE TEST Hydrocarbon in the context of this test is all substance extractible by TETRE CHLORO ETHYLENE in water sample of interest as an estimate of combined OIL and GREASE and the PETROLIUM HYDROCARBON.

INTERFERENCES Organic solvents and certain other organic compounds not considered as oil and grease on the basis of chemical structure may be extracted and measured as oil and grease. Using a pure and appropriate solvent will minimize additional hydrocarbon. Also zeroing the solvent in the instrument before reading samples will eliminate additional hydrocarbon.

APPARATUS REQUIRED - -Infrared Spectrophotometer. HC 404 - -Weighing Balance - -100ml Volumetric Flask - -1ml Pipette - -Cells made of quartz, 10mm path length. At least 2 required - -Filter Paper, IPS (Interphase Separator) - -Glass bottle - -Measuring Cylinder, 1litre - -Separating Funnel - Glass Funnel

REAGENTS - -Dehydrated crude oil, or Calibration Standard - -Tetrachloroethylene solvent - Silica gel - Hydrochloric acid, mixed 1:1 with distilled water - -Sodium Sulphate anhydrous and granular

PROCEDURE Before Measurement - -Ensure that all that materials required in terms of reagents and apparatus are available – - -Put on the infrared spectrophotometer, HC 404 and allow to warm up for 30 minutes.

- The extraction process - Weigh 10g of soil - Add 200ml of distilled water and shake properly - Decant into a 500ml bottle - -Put 20ml of solvent into the 500ml bottle (glass sampling bottle) - -Add a few quantity of HCl to adjust the pH to 2. - -Close the sampling bottle and shake vigorously for 2minutes - -Allow the bottle to stand until the contents settle and the bubble disappear. - -Open it with care to release any pressure build-up. - -Transfer the content of the bottle to a clean separatory funnel, using a glass funnel and recap the empty bottle - -Wash down the transfer funnel with clean solvent - -Allow the contents of the separatory funnel to settle. - -Transfer the bottom layer into a clean 50ml volumetric flask, through an IPS filter paper containing 1g of sodium sulphate. - -Add another 25ml of solvent to the original empty sample bottle, recap and shake the container to obtain good contact between the liquid and all inner surfaces. - -Transfer this new wash into the separatory funnel, replace the stopper and shake the mixture vigorously for 2minutes - -Allow the content to settle, remove the stopper to release any pressure - -Transfer the bottom layer through the same IPS / sodium sulphate filter into the same 50ml volumetric flask. - -Wash down the filter assembly with fresh solvent and bring the liquid level to the mark in the flask. - (This is the volume of extraction solvent V1)

Taking the water volume Drain the remaining contents of the separatory funnel into a 1000ml graduated cylinder and record the volume. For water calculation (This is the volume used, V2)

Measurement of Oil and Grease Take some of the extract in V1 above and measure the absorbance in the infrared spectrophotometer. (This is A1) If the gross absorbance exceeds 0.6, dilute one part of the extract to ten parts total volume with solvent and take the absorbance reading. Remember to multiply with this dilution factor later in the calculation (X.10)

Measurement of petroleum hydrocarbon Take about 25ml (V3) of the extract Put about 5 grams of FLORISIL in the glass column of florisil by passing pure solvent through it. Pass the 25ml extract through the FLORISIL column, into a 50ml volumetric flask Pass fresh solvent through the FLORISIL column (to wash down) until the solvent gets to the 50ml mark on the flask. (This is V4)

Take a portion of the 50ml obtained above and measure the absorbance (This I A2)

CALIBRATION PROCEDURE Weigh 0.1g of Calibration standard in a 100ml volumetric flask make up to mark with tetrachloroethylene.

STANDARDS - -Take 10ml, 8ml, 5ml, 4ml, & 2ml from the stock into another 5 of 100ml volumetric flask and make up to mark with the solvent. - -Introduce each of these standards into the cuvette and measure the respective absorption values. - -Plot a calibration graph of concentration versus absorbance, to get an R2 value as close as possible to 1. (0.999xx) and note the equation of the line

NOTE: The coefficient of X in the line equation will be used in the calculation as ‘B’

CALCULATION Oil and Grease mg/l = A1 x V1 x B V2 Petroleum Hydrocarbon = A2 x V1 x V4 x B V2 x V3 Where A1 = Absorbance value of oil and grease Extract A2 = Absorbance value petroleum Hydrocarbon B = Coefficient of X in the line equation relating absorbance to concentration V1 = Volume of solvent sample used for extraction 50ml V2 = Volume of water sample used for extraction as measured in the cylinder for chromatography, 25ml V4 = Final diluted volume of petroleum hydrocarbon, 50ml

QA/QC - Analyze at least four working standards containing concentration of hydrocarbon in solvent within the expected sample concentration prior to the analysis of the sample to calibrate the equipment. - Verify instrument calibration after standardization by analyzing the standard at the concentration of one the calibration standards. - If the calibration cannot be verified, recalibrate the instrument. - A laboratory control sample should be analyzed with each batch of sample at a minimum frequency of 10%. - Wear correct PPE - Shake vigorously for clear separation - Adhere to equipment instrument instruction manual before & during use - Turn on the instrument and allow to stabilize.

DETERMINATION OF TPH AND PAH IN SOIL BY GAS CHROMATOGRAPHY (FID) TEST METHOD USEPA 8015

SCOPE OF THE TEST This method describes the procedure for analysis of extractable total petroleum hydrocarbon (ETPH) and polycyclic aromatic hydrocarbon (PAH) in sediment and soil samples. The purpose of this document is to ensure that determination of TPH in soil/sediment/sludge using Agilent 6890N is carried out in a manner that will not alter the validity of results obtained.

INTERFERENCES Contamination by carryover can occur whenever high and low concentrations are analysed in sequence, to reduce the potential for carry over the sample syringe must be rinsed out between samples with an appropriate solvent.

During analysis major contaminant sources are volatile materials in the laboratory or impurities in the inert purging gas in the sorbent trap. Avoid the use of plastic tubing or thread sealants order than PTFE. Whenever an unusually concentrated sample is encountered, it should be followed by injection of a solvent blank to check for cross contamination.

TEST METHOD Gas Chromatography - USEPA 8015

Compilation of EPA’s Sampling and Analysis Methods, Edited by Lawrence H. Keith, 2nd edition, 1996

EQUIPMENT / APPARATUS

. Agilent 6890N Gas Chromatographs/ Flame Ionization Detector . Capillary column (DB – 5 or HP – 5) . Shaking Water bath . 100ml extraction bottles . Measuring cylinder . Glass funnel . Glass wool . Microsyringes . Soxhlet Extraction Unit . Rotary Evaporator

Note: Clean all glass wares by detergent washing in hot water, and rinse with tap water, distilled water and the acetone. Then oven dry glassware at 150oC to 200oC for a minimum of 30min.

REAGENTS / MATERIALS

. #2 Diesel Fuel (AccuStandard), 20mg/ml in Dichloromethane, storage: ambient, refrigerate after opening) . Methylene chloride . Sodium sulphate . Silica gel (100-200 mesh) . Surrogate Standard (AccuStandard): 1-Chlorooctadecane 1000µg/ml in hexane, storage: 0-5oC at all times or o-Terphenyl 2mg/ml in Acetone, storage: Ambient

SOLVENT QA/QC Test every batch with GC-FID to make sure that there are no contaminants like an extra peak that can contribute to the measurement.

PROCEDURE

Sample Preservation a] Store samples below 0oC in ice if to be analysed within 7 days otherwise store at -18 oC until analysed. b] Soil/Sediment/Sludge samples should be extracted within 7 days after sampling and extracts analysed within 40 days of extraction.

Sample Preparation a] Decant and discard any water layer on sample surface b] Mix sample thoroughly c] Discard foreign objects such as, leaves, sticks, and rocks

Soxhlet Extraction Method a] Blend 10.0 ± 0.1g of sample with 5 - 10g of anhydrous sodium sulphate. b] Add 1ml of 100µg/ml 1 – Chlorooctadecane or 1ml of 50µg/ml o-Terphenyl surrogate standard. c] Place in an extraction thimble made of filter papers. The extraction thimble must drain freely for the duration of the extraction period. d] Place 100 - 200ml methylene chloride/Acetone 1:1 mixture (extraction solvent) into a 250ml round bottom flask containing one or two boiling chips. Attach the flask to the extractor and extract sample for 5 hours e] Allow the extract to cool after the extraction is complete.

Sonication Water Bath Method a] Weigh 10.0 ± 0.1g of sample into a clean extraction bottle. b] Dry with anhydrous sodium sulphate until it is free flowing. c] Add 1ml of 100µg/ml 1-Chlorooctadecane or 1ml of 50µg/ml o-Terphenyl

surrogate standard d] Add 20 - 40ml of methylene chloride into the bottle. e] Shake in shaking water bath for 1 hour. f] Allow extract to settle at least 20mins. g] Carefully filter sample through glass funnel fitted with glass wool and sodium sulphate into a clean beaker or amber coloured extraction bottles washed with methylene chloride. h] Wash residue with 20ml of extracting solvent and filter through the funnel. i] Carry along a procedural blank (solvent alone) through the entire process.

Sample Clean-Up and Sample Concentration a) Pre-activate silica gel, by heating overnight at 130oC, after washing with methylene chloride. b) If sample extract is relatively dark dilute 5ml to 10ml with methylene chloride. If thickly concentrated, dilute 2ml sample extract to 10ml with methylene chloride. If sample extract is clear, proceed to (c) below c) Add about 2g of preactivated silica gel to the filtered sample extract and let stand for about 10minutes d) Decant the supernatant into a clean beaker e) Concentrate sample extract by evaporating to 1ml at room temperature in a fume cupboard otherwise concentrate using a rotary evaporator. f) Transfer concentrated extract to GC vial ready for analysis Note: Do not evaporate to dryness

Preparation of #2 Diesel fuel Standard  Add 10, 20, 30, 40 and 50L of 20mg/ml #2 Diesel fuel standard into separate 1ml vials.  Add 20, 40, 60, 80 and 100L of 1000g/ml 1 – Chlorooctadecane or 10, 20, 300, 40 and 50L of 2mg/ml o-Terphenyl into each vial and make up the final volume to 1ml with dichloromethane.

Note: The concentrations of the #2 Diesel fuel standard is 200, 400, 600, 800 and 1000mg/L respectively and the concentrations of the surrogate standards is 20, 40, 60, 80, and 100mg/L each.

Surrogate Standards Preparation Prepare the 1-Chlorooctadecane standard from a stock of 1000g/ml by measuring 100L of the stock and make up to 1ml in a sample vial or prepare the o-terphenyl from a stock of 2mg/ml by measuring 50L of it and make up to 1ml in a sample vial. This will give a concentration of 100mg/L.

The expected absolute recovery of the surrogate using 10.0 ± 0.1g of sample will be 10mg/kg.

Preparation of QC. Sample Prepare a QC standard (1 – Chlorooctadecane) from a stock solution of 1000g/ml by measuring 60L of the stock and make up to 1ml in a sample vial or o-Terphenyl from a stock solution of 2mg/ml by measuring 30L of the stock and make up to 1ml in a sample vial. This will give a concentration of 60mg/l.

AGILENT 6890N GC Conditions Assess and define the GC controls by clicking on METHOD, Entire method. Check that the following conditions are in order, if not adjust.

Injector (Auto Sampler): Use Front Injector and both for dual channel GC Injection volume 3L Washes Pre injection Post injection Sample 2 0 Solvent A 3 3 Solvent B 0 0 Pumps 2 0 Inlet: Mode: Split Heater 275 oC Pressure Kpa 30.3 Total flow ml/min 11.8 Split ratio 10:1 Split flow 8.0ml/min

Column: Column 1 and both for dual channel GC Mode Ramp flow Inlet Front for front channel and Back for back channel Detector Front for front channel and Back for back channel

He Flow: Pressure 11.8 Flow 0.8 Average velocity 37 Initial flow 0.8ml/min hold for 11min 0.8ml/min to 0.7ml/min @ 0.1min/min2 Oven: Oven ON Set point 50oC Initial Temperature 50oC hold for 2mins 50oC to 310oC @ 24oC/min hold for 15mins.

FID Detector: Heater ON 340oC H2 Flow, ml/min 45 Air flow, ml/min 450 Make-up flow 35 Flame On Electrometer On

Signal 1: Data Rate 20Hz Minimum peak width 0.01min

Integration Access and input the integration events by clicking on Integration menu. Check that the following conditions are the same, if not adjust

Slope sensitivity 3.7936 Peak width 0.4248 Area reject 3.1407 Height reject 0.4037 Shoulders Off

CALIBRATION OF THE SYSTEM

Agilent 6890N GC . Prior to calibration, select sequence table from sequence menu. . Create a sequence table by filling the sample name, sample type etc. For sample type click calibration click sample when running sample. . Click External Standard Mode for Calibration mode in sequence parameters through Edit/sequence parameters. . Acquire the sample by injecting 3L of the #2 Diesel fuel standards of 200, 400, 600, 800 and 1000mg/L in CH2Cl2 for a five level calibration. . Manually integrate the chromatograms of each standard and call it TPH, then manually integrate (remove) the surrogate standard from the chromatogram and call it 1-chlorooctadecane or o-Terphenyl as the case may be. . Subsequently add the other levels of the calibration through the calibration/add level menu. . Insert the concentration of each calibration level in the calibration table or through the “add level” dialog box. . Check the correlation factor of the calibration. The minimum acceptable correlation factor is 0.99 . Finally save this calibration as a method through the path File/Save/Method

Table 1.0: List of Standard Components TPH Surrogate:

1-Chlorooctadecane or o-Terphenyl

ANALYSES OF SAMPLE EXTRACTS ON THE AGILENT 6890N a] Inject 3l of methylene chloride as a blank sample b] Inject 3l of extract after concentration into the injection port c] If peaks generated are above scale, dilute extract with methylene chloride and re- analyse.

Quality Control a) Prior to sample analysis each day run a solvent blank of methylene chloride. b) Carry a procedural blank through the entire process as the sample and subtract its value from sample if any. c) Run the surrogate QC standard after every 20 samples or a batch whichever is less. Recovery should be 80–120%, if not, check the system. d) After every 20 samples or a batch whichever is less, run one sample in duplicate Determine the Relative Percent Difference (RPD %). %RPD = [2(D1 – D2)/ (D1+D2)] x 100

Where D1 = Concentration of the analyte in the first duplicate sample. D2 = Concentration of the analyte in second duplicate sample.

If recovery is not within 70 - 130%, check to be sure that there are no errors in calculation. Otherwise re-analyse. Enter the result of first duplicate analysis into the Q.C. notebook. e) Prepare and run a midpoint calibration standard after every 20 samples or a batch whichever is less. If recovery is not within 80 - 120%, check to be sure that there are no errors in calculation. Otherwise re-analyse. f) For each sample analysed, calculate the percentage recovery of the surrogate. If recovery is not within 40-120%, check to be sure that there are no errors in calculation and preparation of the surrogate solutions. Otherwise re-extract and re-analyse the sample. f. Enter the surrogate QC standard result into the Q.C. notebook and use this value to plot the control chart. g. If one measurement of QC solution exceeds the control limit in quality chart repeat the analysis immediately. If the repeat is within the control limit continue analysis. If it exceeds the control limit discontinue analysis and correct the problem. h. If two out of three successive points exceed the warning limit, analyse the fourth time, if the next point exceeds warning limit, discontinue analysis and correct the problem, if not continue analysis. i. If six successive point of the control chart either above or below the central line, then seventh point should not be on the same side. If the seventh point is on the same side, the analyst should discontinue analysis and rectify the problem. j. If four out of five successive points exceed the standard deviation or are in decreasing or increasing order, analyse another sample. If the next point is less than the standard deviation or changes the order, continue analysis, otherwise discontinue analysis and correct the problem. k. Pre-treat glass wool by washing with methylene chloride before use.

DATA PROCESSING NOTE: Integration is done manually to achieve the integration of both resolved and unresolved hydrocarbon peaks. Below are the steps to follow: . Integrate the gas chromatogram between C8 and C40. Start the integration just after the C8 peak at the signal level in front of the solvent peak. . End the integration just before the beginning of the C40 peak on the same signal level. . Draw a straight line from C8 to C40. . Mark the beginning and end of the integration on the chromatogram. . Check all chromatograms visually to ensure correct integration.

. Calculate the concentration of the analyte from the data generated by the Agilent GC equipment as follows

Concentration in mg/Kg = A x B / C

Where: A = Data generated by equipment in mg/L B = volume of concentrated extract in ml. C = Weight of sample extracted in g

Note: The equipment will turn out the concentration of the analyte if the reciprocal of the weight of sample is entered as the multiplier in the sequence table.

Use this formula to determine the % recovery for the QC or Surrogate standard: % Recovery (R) = 100 x (Absolute) / (Theoretical)

Where: Absolute = measured concentration Theoretical = Concentration of standard added to sample matrix.

Reporting Results are reported in mg/kg To two significant figures if result is less than 100mg/kg To three significant figures if result is less than 10mg/kg.

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