What are Persistent Organic Pollutants and what does the POPT research group do?

Transcription

1 What are Persistent Organic Pollutants and what does the POPT research group do? Persistent Organic Pollutants and Toxicants Research Group (POPT) Persistent Organic Pollutants (POPs) are chemical substances that are resistant to degradation and may therefore remain in the environment for long periods. These substances are also capable of long range transport, and therefore widely distributed geographically, even in places where it has never been used or produced. POPs bio accumulate in the fatty tissues of organisms, and can biomagnify in food chains. POPs also cause adverse health effects in humans and animals. Health effects caused by POPs may include chloracne, hyperpigmentation, endocrine disruption, immune, nervous and reproductive system defects, and even cancer. These pollutants arouse global concern, and to curb the spreading of POPs, the United Nations Environment Programme (UNEP) initiated the Stockholm Convention on Persistent Organic Pollutants in May This Convention is an international treaty aimed at the reduction and elimination of the twelve most harmful POPs, known as the dirty dozen. These twelve groups of chemicals include the chlorinated pesticides: aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex and toxaphene, two groups of industrial chemicals: hexachlorobenzene and polychlorinated biphenyls (PCBs), and unintentional combustion by products generally known as dioxins and furans. Since its inception more chemicals have been added to the convention, such as PFOS, PBDEs and lindane. As a party to the Convention, South Africa is legally obligated to abide by the objectives of the Stockholm Convention. In undertaking our research, the POPT research group are contributing towards our responsibility to the Convention, in providing a better understanding of POPs, since very little is known about these substances in our country. Our research group is well established in the biological analysis for the unintentionally produced dioxin like substances, which include dioxins, furans and dioxin like PCBs. More recently, we have added other persistent organic toxicants, to the list, which includes chlorinated pesticides such as endosulphan, dicofol, methoxychlor, DDT and lindane, as well as industrial related pollutants which include polycyclic aromatic hydrocarbons (PAHs), polychlorinated naphthalenes, PCBs, octachlorostyrene, short and medium chained chlorinated paraffins, hexachlorobutadiene and 1

2 tetrachlorobenzene. In doing so, we use the acronym of our research group that stands for Persistent Organic Pollutants and Toxicants. We analyse soils, sediments, and fish tissue for the presence of some of the above mentioned substances, and will be including chicken eggs, wild bird s eggs and human breast milk soon. Knowing the concentration of these compounds bio accumulation in food chains can be determined, and possible health risks associated with the consumption of contaminated food, may be calculated. In addition to the biological and chemical analysis of biotic and abiotic materials, morphological structures of snails, frogs and small mammals are also examined, to act as indicators of possible endocrine disruption. The POPT group is a very diverse and dynamic group of people, who aims at contributing towards a better understanding regarding POPs in South Africa. Techniques The group has expertise on a variety of research techniques. These techniques range from the physical fieldwork to the analytical determination of pollutant concentrations in the different matrices that are currently been tested. Fieldwork Arguably, the most exciting portion of our work is the collection of our different sample matrices. These fieldtrips offer the opportunity to see diverse areas of our country that one would normally overlook. In the last few years, fieldtrips have extended from areas as beautiful as Magoebaskloof to desolate regions of the Karoo. These trips include a lot of preparation, lending researchers experience in project design, problem management, as well as thorough training in reassessing routes after becoming lost. Matrices that have been collected include sediment, fish samples, soil, bird's eggs and human breast milk. For this diversity, researchers need to be able to climb not only trees, but often fences and bridge posts as well. It is also a prerequisite that the drivers in the team are familiar with the different techniques in getting cars out of sticky situations, such as mud and sand. This physically and mentally challenging portion of our work also leads to the accumulation of interesting experiences, not only with the physical world, but also with people. Residents often find our exploits, in blue nitrile gloves, intriguing. 2

3 Chemical laboratory After the fieldwork has been completed, the samples are transported to our chemical laboratory in which a number of standards procedures are followed, as summarised in the following figure. Our laboratories are equipped with of the latest extraction equipment, including an Accelerated Solvent Extractor (ASE) and Gel Permeation Chromatography (GPC). Then there are also facilities for the old and trusted: wet chemistry techniques such as acid digestion, determination of total organic carbon (TOC), gravimetric fat content determination and Soxhlet extraction. After the preparation of the extracts, they are analysed locally with cell bio assays or at outside institutions with Gas Chromatography High Resolution Mass Spectrometry (GC HRMS). Cell culture laboratory Cell culture bio assays are becoming increasingly important as cost effective screening techniques for POPs. These techniques are still relatively new in South Africa and are prominent avenues for new and expanding research. Currently, our group has established the H4IIE reporter gene bioassay. This assay is used to determine the level of compounds which method of action is through the Aryl Hydrocarbon Receptor. Compounds that can be analysed through this assay include the dioxinlike chemical group: dioxin like PCBs and the polychlorinated furans and dioxins as well as the PAHs. We have also added other cell lines to detect endocrine disruption in various matrices. Our vision for the future Currently, we have two excellently equipped chemical extraction laboratories and an outstanding tissue culture laboratory. The H4IIE luc bio assay is well established and used to determine the presence of dioxin like substances in biotic and abiotic samples. We have successfully cultured the MDA kb2 and the MVLN cell lines, and are in the process of establishing these bio assays to test androgen and estrogen activity in samples. An additional cell line, also used to indicate the presence of endocrine disruptive chemicals in samples, is the H295R cell line. The intricacies of this cell line are still undiscovered for us. We are however striving towards the establishment of this bio assay. To comprehend the effects of certain substances on the wellbeing of organisms, health risk assessments are very useful, and commonly performed. Risk assessment is a science used to calculate the possible carcinogenic or non carcinogenic risks associated with the direct or indirect exposure to toxic substances. Members of the POPT research group have been trained in performing human health risk assessments, and we intend on expanding our knowledge on risk assessment, and 3

4 applying the science to generated data. In doing so, we aim at raising awareness of the dangers of POPs exposure. Many of the members of the POPT group have some experience on statistical software, but in this field one can never know enough! We would like to increase our knowledge on current and relevant statistical programs, and to apply it to our data, concentrating on multivariate statistics. We strive towards keeping up to date with the most relevant methods and issues concerning POPs. The POPT research group aspires towards understanding and integrating various aspects of ecotoxicological research, to gain a better perspective of the bigger picture of global environmental pollution. Projects and Collaborations Levels and implications of persistent organic pollutants and other contaminants in South Africa ( ). In collaboration with: Norwegian School of Veterinary Science and Norwegian institute for Air Research. Water Research Commission (WRC) project on the use of sentinel species to determine the endocrine disruptive activity in an urban nature reserve. In collaboration with University of Pretoria, University of Johannesburg and the Council for Scientific and Industrial Research. Water Research Commission (WRC) project on characterising the scale and significance of persistent organic pollutants (POPs) in South African sediments. Presence, levels and implications of pollutants in bird eggs from South Africa and Mauritius. In collaboration with various institutions Endocrine disruptive effects of pollutants on indicators such as frogs, snails and birds. Background monitoring of POPs in air. Part of a Stockholm Convention project on effectiveness evaluation. Levels of DDT, pyrethroids and other insecticides in breast milk from Limpopo and KwaZulu Natal. Contact patterns of birds on cyanide containing tailings from gold mines. Effects of airborne pollutants on the Blue Swallow. Cause and effects of crocodile mortalities in the Kruger National Park. 4

5 Publications Bouwman, H. & Reinecke, A.J Effects of carbofuran on the earthworm Eisenia fetida using a defined medium. Bulletin of Environmental Contamination and Toxicology 38: Bouwman, H., Cooppan, R.M. & Reinecke, A.J Extraction and clean up procedure to determine DDT and metabolites in human breast milk. Chemosphere 19: Bouwman, H., Sydenham, E.W. & Schutte, C.H.J Single step extraction and cleanup procedure for determining serum levels of DDT, DDE and DDD. Chemosphere 18: Bouwman, H., Coetzee, A. & Schutte, C.H.J Environmental and health implications of DDTcontaminated fish from the Pongolo Flood Plain. African Journal of Zoology 104: Bouwman, H., Cooppan, R.M., Reinecke, A.J. & Becker, P.J Levels of DDT and metabolites in breast milk from KwaZulu mothers after DDT application for malaria control. Bulletin of the World Health Organization 68: Bouwman, H., Reinecke, A.J., Cooppan, R.M. & Becker, P.J Factors affecting levels of DDT and metabolites in human breast milk from KwaZulu. Journal of Toxicology and Environmental Health 31(2) : Bouwman, H., Cooppan, R.M., Botha, M.J. & Becker, P.J Serum levels of DDT and liver function of malaria control personnel. South African Medical Journal 79: Bouwman, H., Cooppan, R.M., Becker, P.J. & Ngxongo, S Malaria control and levels of DDT in serum of two populations in KwaZulu. Journal of Toxicology and Environmental Health 33 (2): Bouwman, H. & Reinecke, A.J A defined medium to study growth and reproduction of the earthworm Eisenia fetida (Oligochaeta). Biology and Fertility of Soils 10: Bouwman, H., Becker, P.J., Cooppan, R.M. & Reinecke, A.J Transfer of DDT used in malaria control to infants via breast milk. Bulletin of the World Health Organization 70: Smit, H.E., Bouwman, H. & Le Sueur, D DDT and community health. Journal of Comprehensive Health 3: Bouwman, H. & Schutte, C.H.J Effect of sibship on DDT residue levels in human serum from a malaria endemic area in northern KwaZulu. Bulletin of Environmental Toxicology and Chemistry 50: Evans, S.W. & Bouwman, H Levels of DDT in the liver tissue of two duck species from the Pongolo Floodplain. Ostrich 64: Evans, S.W. & Bouwman, H DDT levels in the blood of Pied Kingfishers Ceryle rudis from KwaZulu, South Africa. (In Wilson, R.T. ed. Birds and the African environment: Proceedings of the 5

6 Eighth Pan African Ornithological Congress. Annales Museé Royal de l'afrique Centrale (Zoologie) 268: ). Van Wyk, E., Van der Bank, F.H., Verdoorn, G.H. & Bouwman, H Chlorinated hydrocarbon insecticide residues in the cape griffon vulture (Gyps coprotheres). Comparative Biochemistry and Physiology C 104: Bouwman, H., Becker, P.J. &.Schutte, C.H.J Malaria control and longitudinal changes in levels of DDT and metabolites in human serum from KwaZulu. Bulletin of the World Health Organization 72: Evans, S.W., Lötter, L. & Bouwman, H A technique for obtaining small volumes of blood from birds. Ostrich 66: Lötter, L. & Bouwman, H DDT levels in the blood of waders from the North West Province (South Africa). African Journal of Zoology 111: Bouwman, H Evaluation of a technique to obtain development stage synchronised earthworms (Eisenia fetida). Biology and Fertility of Soils 27: Mineau, P. & Bouwman, H Avian conservation and current pesticide use. (In Adams, N.J. & Slotow, R.H. eds Proceedings of the 22nd International Ornithology Congress, Durban: Johannesburg, BirdLife South Africa). Evans, S.W. & Bouwman, H The geographic variation and potential risk of DDT in the blood of Pied Kingfishers from the Northern KwaZulu Natal, South Africa. Ostrich 71: Evans, S.W. & Bouwman, H The influence of mist and rain on the reproductive success of the Blue Swallow Hirundo atrocaerulea. Ostrich 71: Rijke, A.M., Jesser, W.A., Evans, S.W. & Bouwman, H Water repellency and feather structure of the Blue Swallow, Hirundo atrocaerulea. Ostrich 71: Smith, R.I. & Bouwman, H Levels of organochlorine pesticides in raptors from the Northwest Province, South Africa. Ostrich 71: Lötter, L. & Bouwman, H Organochlorine pesticide residues in Helmeted Guineafowl (Numida meleagris), South Africa. Bulletin of Environmental Contamination and Toxicology 66: Van Wyk, E., Bouwman, H., Van der Bank, F.H., Verdoorn, G.H. & Hofmann, D Persistent organochlorine pesticides detected in blood and tissue samples of vultures from different localities in South Africa. Comparative Biochemistry and Physiology 129: Bouwman, H POPs in Southern Africa. The handbook of environmental chemistry. Persistent Organic Pollutants 3 (0): Elfvendahl, S., Mihale, M., Kishimba, M.A., Kylin, H. & Bouwman, H Severe pesticide pollution despite cleanup of obsolete pesticides at Vikuge, Tanzania. Organohalogen Compounds 62:

7 Bouwman, H South Africa and the Stockholm Convention on Persistent Organic Pollutants. South African Journal of Science 100: Bouwman, H Die Stockholmkonvensie: wisselwerking tussen wetenskap en beleid. The Journal for Transdisciplinary Research in Southern Africa 1: Vosloo, R. & Bouwman, H Survey of certain persistent organic pollutants in major South African waters. Water Research Commission, Pretoria. WRC Report No. 1213/1/05 Bouwman, H., Sereda, B. & Meinhardt, H.M Simultaneous presence of DDT and pyrethroid residues in human breast milk from a malaria endemic area in South Africa. Environmental Pollution 144: Bouwman, H., Sereda, B., Meinhardt, H.M. & Kylin, H DDT and pyrethroid residues in human breast milk from KwaZulu Natal, South Africa. Organohalogen Compounds 68: Bornman, M.S., Van Vuren, J.H., Bouwman, H., De Jager, C., Genthe, B. & Barnhoorn, E.J The use of sentinal species to determine the endocrine disruptive activity in an urban nature reserve. Water Research Commission, Pretoria. WRC Report No. 1505/1/0. Bouwman, H Evaluation of modifications to a defined medium for the study of the biology and ecotoxicology of the earthworm Eisenia fetida (Oligochaeta). Applied Soil Ecology 35: Jordaan, I., Pieters, R., Quinn, L.P., Giesy, J.P., Jones, P.D., Murphy, M.B. & Bouwman, H Platinum mining and processing as a possible source of dioxin like compounds. Minerals and Engineering 20: Quinn, L.P., Jordaan, I., Bouwman, H. & Pieters, R Inventory of chlorinated dioxin and furan sources and releases in Potchefstroom, a small city in South Africa. South African Journal of Science 103: Bouwman, H., Polder, A., Venter, B. & Skaare, J.U.S Organochlorine contaminants in cormorant, darter, egret, and ibis eggs from South Africa. Chemosphere, 71: Polder, A., Venter, B., Skaare, J.U., Bouwman, H Polybrominated diphenyl ethers in bird eggs from South Africa. Chemosphere. 73: Sereda, B., Bouwman, H., Kylin, H. (2009) Comparing water, bovine milk, and indoor residual spraying as possible sources of DDT and pyrethroid residues in breast milk. Journal of toxicology and environmental health. Journal of toxicology and environmental health, Part A. 72: Eskenazi, B., Chevrier, J., Goldman Rosas, L., Anderson, H.A., Bornman M.S., Bouwman, H., Chen, A., Cohn, B.A., de Jager, C., Henshel, D.S., Leipzig, F., Leipzig, J.S., Lorenz, E.C., Snedeker, S.M., Stapleton, D. (2009) The Pine River Statement: Human health consequences of DDT use. Environmental health perspectives, 117:

8 Kylin, H., Bouwman H., Evans, S.W. (2009) Using proxies to elucidate environmental threats to endangered species. Invited Learned Discourse. Integrated environmental assessment and management. 5: Bouwman, H., Kylin, H. (2009) Malaria control insecticide residues in breastmilk: The need to consider infant health risks. Environmental health perspectives. 117: (Supplementary review online) Nieuwhoudt, C., Quinn, L.P., Pieters, R., Jordaan, I., Visser, M., Kylin, H., Borgen, A.P., Giesy, J.P., Bouwman, H. (2009) Dioxin like chemicals in soil and sediment from residential and industrial areas in central South Africa. Chemosphere. 76: Quinn, L., Pieters, R., Nieuwhoudt, C., Borgen, A.R., Kylin, H., Bouwman, H. (2009) Distribution profiles of selected organic pollutants in soils and sediments of industrial, residential and agricultural areas of South Africa. Journal of environmental monitoring. 11: Pieters, R., Bouwman, H., Ellis, S. (2009) Comparison of PCDD/F sources between northern and southern hemispheres. Organohalogen compounds. 70: Evans, S.W., Bouwman, H. Habitat selection by blue swallows Hirundo atrocaerulea breeding in South Africa and its implications for conservation. Accepted 2009 African Journal of Ecology. Evans, S.W., Bouwman, H. Historical and current distribution, population size, and possible migration routes of the Blue Swallow in Africa. Accepted 2009, Bird conservation international. Barnhoorn, I.E.J., Bornman, M.S., Jansen van Rensburg, C., Bouwman, H DDT residues in water, sediment, domestic and indigenous biota from a currently DDT sprayed area. Chemosphere. 77: Osthoff, G., Hugo, A., Bouwman, H., Buss, P., Govender, D., Joubert, C.C., Swarts, J.C Comparison of the lipid properties of captive, healthy wild, and pansteatitis affected wild Nile crocodiles (Crocodylus niloticus). Comparative biochemistry and physiology, Part A. 155: Van Dyk, JC, Bouwman, H., Barnhoorn, I.E.J., Bornman, M.S. IRS applied DDT contamination in the domestic environment of malaria controlled dwellings. Accepted Science of the total environment. 8