| 研究実績の概要 |
Insecticides such as DDT are useful in many ways; one important way is by spraying homes to help control diseases transmitted by insects. To better understand the levels of organochlorine pesticides (OCPs, of which DDT is one) contaminating foods, I performed a literature review. This focused on reports in peer-reviewed periods over a 15 year period, analysing pesticide levels in both different foods and in people in African countries. This showed many foods are contaminated by OCPs. I have submitted this review for peer-reviewed publication.
My main aim in the research project this year was to collect and analyse chemical concentrations from field samples. In the study area in South Africa, DDT and other insecticides are regularly applied to homes (as “indoor residual spraying”). These chemicals are highly persistence in the environment and have been shown to be taken up and accumulate in animals, including livestock. My analysis showed high levels of DDT and its metabolites in free-ranging chicken and eggs from the area.
Questionnaires with local people enabled me to estimate daily consumption of chicken meat and eggs. By knowing the concentrations of DDT and its metabolites in the products, and considering their daily consumption, I was able to calculate the potential health risk from eating these foods. For both meat and eggs, free-ranging foodstuffs were shown to contain levels of DDTs that are a potential carcinogenic health risk to people eating them. However, commercially produced chicken products do not have this increased risk.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
Completion of a substantial literature review has highlighted both problem areas and gaps in our knowledge. This review has also given me a good understanding of the topic, and should also be useful to policy makers who need to consider the benefits of using chemicals and the risks associated with food contamination.
Initial analysis of field samples from an area in South Africa using DDT routinely to control malaria shows a potential health risk to local people from eating free-ranging chicken products. From this information, we can suggest that policy makers advise people to reduce consumption of these and ideally substituting with commercial products.
Gene expression analysis of field samples is underway. Microarray analysis of two samples (considered from chemical analysis results to have “low” and “high” contamination levels of DDT) has been performed. Meanwhile, I have also conducted an in vivo exposure study and administering p,p’-DDT to chicks and collecting samples at various time points.
|
| 今後の研究の推進方策 |
I will continue analysis of data obtained from field sample microarrays. This will be complemented by similar data from the in vivo study, along with PCR validation of results in other samples from both the field and laboratory studies. Analysis of samples collected during the laboratory exposure study will be performed in the next year of my research.
I will next prepare a manuscript on the contamination of chicken products in my study area in South Africa. This will include a health risk assessment for people consuming the products.
During this year, I will also perform collaborative research with a laboratory at the Okinawa Institute of Science and Technology, at Professor Yamamoto’s “cell signalling” laboratory. A link between DDT and cancer has been proposed but the mechanism has not been elucidated. My research will focus on the biological effects of DDT and close analogue, β-estradiol, on cancer cells in culture.
|
