Aquatic Water Quality Baseline Assessment Report of the Aquatic Resources in the Vicinity of the Proposed Kosmosdal Filling Station Project, Kosmosdal, Gauteng
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AQUATIC WATER QUALITY BASELINE ASSESSMENT REPORT OF THE AQUATIC RESOURCES IN THE VICINITY OF THE PROPOSED KOSMOSDAL FILLING STATION PROJECT, KOSMOSDAL, GAUTENG. Prepared for Samrand Development (Pty) Ltd JULY 2018 Prepared by: Water Use Licence Associates (Pty) Ltd Report authors: Dionne Crafford (Pr. Sci. Nat.) Report reviewer: Stephen van Staden (Pr. Sci. Nat.) Report Reference: WUL 250002 Assessment Date: 25 May 2018 Report Initiation Date: 19 July 2018 Report Submission Date: 23 July 2018 Water Use Licence Associates (Pty) Ltd CK 2016/241418/07 Vat Reg. No. 4270277074 29 Arterial Road West Oriel, Johannesburg 2007 Tel: 011 616 7893 Fax: 086 724 3132 E-mail: [email protected] WUL 250002 July 2018 EXECUTIVE SUMMARY Water Use Licence Associates (Pty) Ltd (WULA) was requested by Samrand Development (Pty) Ltd to perform a water quality baseline assessment of the aquatic resources in the vicinity of the proposed Kosmosdal Filling Station. One site, considered to be representative of the aquatic resource at the time of assessment, was assessed on 25 May 2018 downgradient of the proposed development. In the Government gazette of 18 May 1984 No 9225 the general standard to which waste water and effluent must be purified prior to discharge is stated. The value for soap, oil and grease is 2.5 mg/L. With the promulgation of the new National Water Act in 1998 the strategy for conserving aquatic resources has changed, however, no new standard for soaps, oil and grease are available. The results of the water sampling at the downgradient site were thus compared to the available general effluent standard for comparison. Of the parameters assessed, dissolved lead, extractable petroleum hydrocarbons, gasoline range organics, methyl tert-butyl ether, benzene, toluene, ethylbenzene, m/p-Xylene and o- Xylene presented with concentrations below detection, with the respective detection limits (<0.01 mg/L and lower) much lower than the recommended standard concentration (2.5 mg/L) mentioned above. These substances can thus be considered largely absent at the time of assessment. Oil and grease were also below detection (<50 mg/L), but the detection limit was much higher than the guideline recommendation. However, considering that all other hydrocarbon parameters were below detection, it can be assumed that oil and grease concentrations were also below 2.5 mg/L. Nitrate as NO3 was detected, but at a concentration of 0.3 mg/L it complies with the recommended guideline recommendation. This baseline assessment indicates that, at the time of assessment, any significant potential impact on the aquatic resource from hydrocarbon pollution is considered unlikely. Using results from this assessment as baseline data, future monitoring of potential impacts from proposed Kosmosdal Filling Station development is possible. Potential future impacts from said development may include addition of chemicals related with fossil fuels (see parameters mentioned above) to the receiving aquatic environment due to accidental spillage and seepage from underground storage tanks. It is suggested that these parameters be monitored in future at the monitoring points upstream and downstream of the proposed fuel station, should the proposed development proceed, to monitor potential impact on the receiving aquatic environment. Data can be compared to the baseline data from this study to determine spatial variation form the baseline condition ii WUL 250002 July 2018 TABLE OF CONTENTS EXECUTIVE SUMMARY ...................................................................................................... ii TABLE OF CONTENTS ...................................................................................................... iii LIST OF TABLES ................................................................................................................ iii LIST OF FIGURES .............................................................................................................. iii 1. INTRODUCTION .......................................................................................................... 1 1.1 Scope of Work .............................................................................................................. 2 1.2 Assumptions and Limitations ........................................................................................ 4 2. METHOD OF INVESTIGATION ................................................................................... 4 3. PHOTOGRAPHIC SITE DOCUMENTATION ............................................................... 5 4. WATER QUALITY RESULTS ...................................................................................... 8 5. DISCUSSION ............................................................................................................... 8 6. CONSIDERATION OF CURRENT AND POTENTIAL FUTURE IMPACTS ................. 9 7. SYNOPSIS AND CONCLUSION ................................................................................. 9 8. REFERENCES ........................................................................................................... 11 LIST OF TABLES Table 1: Co-ordinates of the water sampling points ........................................................... 2 Table 2: Water quality assessment results. ....................................................................... 8 LIST OF FIGURES Figure 1: Downgradient water sampling assessment points presented on a digital satellite image. ..................................................................................................... 3 Figure 2: a to 2e: Photographs showing conditions at the downgradient site ...................... 7 iii WUL 250002 July 2018 1. INTRODUCTION Water Use Licence Associates (Pty) Ltd (WULA) was appointed to conduct a baseline water quality assessment of the aquatic resources associated with the proposed Kosmosdal Filling Station development. The Kosmosdal Filling Station is situated immediately northeast of Samrand Avenue, and west of the M37 (Rooihuiskraal Road). The Summerfields Estate is situated immediately north of the Kosmosdal Filling Station. Furthermore, the Kosmosdal Filling Station is situated approximately 17km west of the N1 Highway, and 1.2km north of the Blue Valley Golf Estate. Automobile pollutants include substances such as oil, antifreeze, brake fluid, transmission fluid, grease and metals. Said substances that are spilled on hard surfaces may run off into stormdrains to subsequently pollute the receiving aquatic environment, or soak into groundwater (Hydro Flies Student Handout #1). These hydrocarbon substances are known to be detrimental to aquatic health (Hydro Flies Student Handout #1). Hydrocarbons have been shown to result in a decrease in the abundance of large zooplankton, protozoans, phytoplankton, microbial food benthic suspension and deposit feeding macrofauna and copepods (Fleeger et al 2003). In some marine oil spills, long-term organic enrichment resulted in organic enrichment and increased bacterial biomass of taxa that can exploit it, with resulting localised increase in benthic abundances (Fleeger et al. 2003). It must be noted that individual species can only metabolise a limited range of hydrocarbon substances, so generally a mixed population with overall broad enzymatic capacities are required to degrade complex mixtures of hydrocarbons (Leahy and Colwell 1990). Hydrocarbons may thus impact aquatic ecology either through direct negative effects, or through indirect “bottom-up effects” (via increased or decreased food supply). This is also evident when examining effects of total petroleum hydrocarbon in sediment on macro- invertebrates, with hydrocarbons at lower concentrations (860 mg/kg) increasing the abundance of some taxa but decreasing the abundance of others, whilst high concentrations (1858 to 14266 mg/kg) resulted in a reduction in the total number of taxa and their abundance (Pettigrove and Hoffmann 2005). In fish, oil exposure impairs cardio-respiratory responses and results in inability to meet the temperature-driven increase in tissues oxygen demand (Claireaux and Davoodi 2010). Direct effects of oil on forage fish also have a detrimental effect on birds and mammals that are dependent on them as food source, which is considered 1 WUL 250002 July 2018 another “bottom-up effect” (Fleeger et al. 2003). Negative effects of road traffic gases (including hydrocarbons) on plant growth have also been demonstrated (Spellerberg 1998). Hydrocarbons may also pollute sources of drinking water. It is estimated that oil from a single oil change can ruin 3.8 million litres of water, which translates to a year’s supply for 50 people (Hydro Flies Student Handout #1). It is thus imperative that the potential future impact of the proposed Kosmosdal Filling Station be considered. In order to do so, relevant baseline conditions prior to implementation of the proposed development need to be established. This document presents the results obtained during the 25 May 2018 baseline water sampling occasion. Samples were submitted for analysis on 28 May 2018, and the laboratory report was issued 05 July 2018. 1.1 Scope of Work The baseline assessment included collection of water samples at one site, considered to be representative of the aquatic resource at the time of assessment, downgradient of the proposed development. Selected water quality parameters related to hydrocarbons were assessed and compared to available guideline recommendations. This allowed evaluation of current potential