Levels and patterns of persistent organic pollutants (POPs) in tilapia (Oreochromis sp.) from four different lakes in Tanzania: geographical differences and implications for human health.
In Tanzania fish is one of the most important protein sources for the rapidly increasing population. Wild fish is threatened by overfishing and pollution from agriculture, industries, mining, household effluents and vector control. To monitor possible implications for public health, the geographical differences of the occurrence and levels of persistent organic pollutants (POPs) in tilapia fish (Oreochromis sp.) from four different Tanzanian lakes were investigated in 2011. Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyls (PBDEs) and hexabromocyclododecane (HBCDD) were determined in pooled samples of tilapia muscle from Lake (L) Victoria, L. Tanganyika, L. Nyasa (also called L. Malawi) and L. Babati in Tanzania in 2011. Levels of Σ-DDTs (274 ng/g lipid weight (lw)) and sum of 7 indicator PCBs (Σ-7PCBs) (17 ng/g lw) were significantly higher in tilapia from L. Tanganyika compared to the other lakes. The highest levels of Σ-endosulfan (94 ng/g lw) were detected in tilapia from L. Victoria. Toxaphenes were detected in low levels in fish from L. Tanganyika and L. Babati. Results revealed a geographic difference in the use of DDT and endosulfan between L. Victoria and L. Tanganyika. Low ratios of DDE/DDT in tilapia from L. Tanganyika indicated an on-going use of DDT in the area. Median levels of ΣBDEs, including BDE-209, were highest in L. Victoria (19.4 ng/g lw) and BDE-209 was present in 68% of the samples from this lake. The presence of BDE-209 indicates increasing influence of imported products from heavy industrialized countries. The measured POP levels in the studied tilapia were all below MRLs of EU or were lower than recommended levels, and thus the fish is considered as safe for human consumption. They may, however, pose a risk to the fish species and threaten biodiversity.
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway. Electronic address: anuschka.polder@nmbu.no.
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Polder
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway.
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Müller
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway.
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Lyche
Sokoine University of Agriculture, Department of Veterinary Medicine and Public Health, P.O. Box 3021, Morogoro, Tanzania.
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Mdegela
Sokoine University of Agriculture, Department of Veterinary Medicine and Public Health, P.O. Box 3021, Morogoro, Tanzania.
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Nonga
Sokoine University of Agriculture, Department of Physical Sciences, P.O. Box 3038, Solomon Mahlangu Campus, Morogoro, Tanzania.
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Mabiki
Tanzania Association of Public, Occupation and Environmental Health Experts (TAPOHE), P.O. Box 732, Arusha, Tanzania.
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Mbise
The Norwegian Veterinary Institute (NVI), P.O. Box 750 Sentrum, N-0106 Oslo, Norway.
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Skaare
The Norwegian Veterinary Institute (NVI), P.O. Box 750 Sentrum, N-0106 Oslo, Norway.
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Sandvik
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway.
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Skjerve
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 5003, Campus Adamstuen, NO-1432 Ås, Norway; Norwegian Institute for Water Research (NIVA), Gaustadallèen 21, N-0349 Oslo, Norway.
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Lie
D000818:Animals; D004726:Endosulfan / Q000032:analysis; D004784:Environmental Monitoring; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000032:analysis / Q000378:metabolism; D060106:Lakes / Q000737:chemistry; D010575:Pesticides / Q000032:analysis / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D018570:Risk Assessment; D013636:Tanzania; D017210:Tilapia / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls; D004726:Endosulfan
BFRs; DDTs; PCBs; Persistent organic pollutants (POPs); Tanzania; Tilapia