Environmental Study and Monitoring of Undesirable Chemical Substances in Fish/Seafood: a Proposal for Lake Victoria, Kenya
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P.O Box 1390, Skulagata 4, 120 Reykjavik, Iceland Final Project 2008 ENVIRONMENTAL STUDY AND MONITORING OF UNDESIRABLE CHEMICAL SUBSTANCES IN FISH/SEAFOOD: A PROPOSAL FOR LAKE VICTORIA, KENYA Mathew Ndasi Ngila Ministry of Fisheries Development P. O Box 1084 – 40100 Kisumu, Kenya [email protected] Supervisors: Helga Gunnlaugsdottir, Matis ohf [email protected] and Sasan Rabieh, [email protected] ABSTRACT Without a doubt, pollution in Lake Victoria is an issue of major concern. Various studies have shown the presence of undesirable chemical substances in the water, sediment and fish from the lake. In this paper, the current monitoring programme for the undesirable chemical substances in the lake by the Ministry of Fisheries, Kenya has been reviewed with the aim of ensuring safe fish and fish products to all fish consumers and especially local consumers who could be more vulnerable to exposure to undesirable chemical substances through consumption of fish from the lake. The objective of the on-going programme has been expanded to include monitoring of toxic trace metals, polychlorinated biphenyls (PCBs) and dioxins in addition to pesticide residues. Sampling sites have been selected while taking into consideration areas of the lake that are likely to contain higher concentrations of chemical contaminants. Lake Kanyaboli which is closely linked to Lake Victoria has been included in the monitoring programme due to the increased farming activities at the adjoining Yala swamp. The specific objectives of the programme, rationale for the programme, sampling areas, the fish species to be monitored and the chemical contaminants to be measured have all been described. Also described are the period and frequency of sampling, and sampling and sample preparation methods. While sample analysis will continue to be done at an accredited laboratory, it is proposed that limits of detection (LOD) and limits of quantification (LOQ) be agreed on since the results as currently interpreted (pass/failure) do not provide any useful information concerning trends or levels of pollution in the lake. While the estimated costs for implementation of the programme may be high as calculated in the proposal, it is humbly submitted that the need to implement this monitoring programme cannot be overemphasised. Key words: Lake Victoria, Monitoring programme, Undesirable chemical substances, Fish Ngila TABLE OF CONTENTS TABLE OF CONTENTS ........................................................................................................... 2 ABBREVIATIONS .................................................................................................................... 4 LIST OF TABLES ..................................................................................................................... 5 1. INTRODUCTION .................................................................................................................. 6 1.1 Pollution in Lake Victoria ........................................................................................... 6 1.1.1 Chemical contaminants in Lake Victoria water and sediments: .......................... 8 1.1.2 Chemical contaminants in Lake Victoria fish ..................................................... 9 1.2 Case for an improved environmental monitoring programme for Lake Victoria ...... 11 2. METHODOLOGY ............................................................................................................... 13 3. THE PROPOSED MONITORING PROGRAMME ........................................................... 14 3.1 Objectives of the monitoring programme ...................................................................... 14 3.2 Rationale for the programme .......................................................................................... 14 3.3 Sampling areas ............................................................................................................... 15 3.4 Fish species to be monitored .......................................................................................... 16 3.5 Contaminants to be measured ........................................................................................ 16 3.5.1 Pesticide residues .................................................................................................... 17 3.5.2 Polychlorinated biphenyls (PCBs) .......................................................................... 18 3.5.3 Dioxins and dioxin like PCBs .................................................................................. 18 3.5.4 Toxic metals ............................................................................................................. 19 3.6 Period and frequency of monitoring ............................................................................... 22 3.7 Methods .......................................................................................................................... 22 3.7.1 Sampling .................................................................................................................. 22 3.7.2 Sample preparation: ................................................................................................ 23 3.7.3 Sample analysis: ...................................................................................................... 24 3.8 Data analysis and results interpretation .......................................................................... 25 3.8.1 Determination of spatial variation .......................................................................... 25 3.8.2 Determination of temporal variation ...................................................................... 26 3.8.3 Determination of seasonal variation ....................................................................... 26 3.9 Proposed implementation plan ....................................................................................... 26 3.9.1 Resources and costs for the programme implementation ....................................... 27 3.9.2 Training of implementation personnel .................................................................... 28 3.9.3 Work plan for the implementation ........................................................................... 30 4. CONCLUSION .................................................................................................................... 30 ACKNOWLEDGEMENTS ..................................................................................................... 32 LIST OF REFERENCES ......................................................................................................... 33 UNU – Fisheries Training Programme 2 Ngila APPENDIX .............................................................................................................................. 39 Monitoring programme protocol .......................................................................................... 39 UNU – Fisheries Training Programme 3 Ngila ABBREVIATIONS ADI Acceptable daily intake ANOVA Analysis of variance AOAC Association of official analytical chemists BDL Below detection limit BHC Benzenehexachloride DDD Dichloro-diphenyl-dichloroethane DDE Dichloro-diphenyl-dichloroethylene DDT Dichloro-diphenyl-trichloroethane DEFRA Department of environment, food and rural affairs, United Kingdom EDTA Ethylene diamine tetra acetic acid EEC European Economic Commission ERL Extraneous residue limit EU European Union FAO Food and Agricultural Organization of the United Nations FTP Fisheries training programme GC/ECD Gas chromatography/electron capture detection GC/MS Gas chromatography/mass spectrometry HCB Hexachlorobenzene HCH Hexachlorocyclohexane IAEA International Atomic Energy Agency ICP-MS Inductively coupled plasma- mass spectrometry ILO International Labour Organization IOC Intergovernmental Oceanographic Commission IUPAC International union of pure and applied chemistry JECFA Joint FAO/WHO expert committee on food additives JMPR Joint FAO/WHO meeting on pesticide residues KEPHIS Kenya plant health inspectorate service LOD Limit of detection LOQ Limit of quantification MDL Method detection limit MRL Maximum residue limit OECD Organization for Economic Co-operation and Development PCB Polychlorinated biphenyl PCDD Polychlorinated dibenzo para-dioxin PCDF Polychlorinated dibenzofuran POP Persistent organic pollutant PWTI Provisional tolerable weekly intake SCF Scientific committee on food of the European commission TCDD Tetrachlorodibenzo-para-dioxin TDI Tolerable daily intake TEF Toxic equivalence factor TEQ Toxic equivalent quotient TWI Tolerable weekly intake UNEP United Nations Environment Programme UNIDO United Nations Industrial Development Organization UNITAR United Nations Institute for Training and Research UNU United Nations University WHO World Health Organization UNU – Fisheries Training Programme 4 Ngila LIST OF TABLES Table 1: Average discharge (m3s-1) from river basins in Lake Victoria, Kenya catchment area (Kayombo and Jorgensen 2006) ................................................................................................. 8 Table 2: Mean total dissolved metal (μgl-1) and mean sediment concentrations (μgg-1 dry weight) of heavy metals in water flowing into Winam gulf of Lake Victoria (Lalah et al. 2008). .......................................................................................................................................... 9 Table 3: Sampling areas, contaminants to be monitored in the sampling areas