Mustafa A.M. Department of Pharmacology, Faculty of Medicine, University of Malaya

For a long time now, awareness has been growing about the threats posed to human health and the global environment by the ever-increasing release of synthesized chemicals. Mounting evidence of damage to human health and the environment has focused the attention of many developed and underdeveloped countries on several classes of compounds, which include a group of compounds classed as endocrine disruptors or EDCs. Most pesticides, PCB, dioxins, phytoestrogens, phthalates and alkylphenols are endocrine-disrupting chemicals (EDCs), causing biological effects, with modes of action mimicking that of the female hormone, estrogen.

In Malaysia, monitoring of EDCs has been actively going on for many years, especially for the agricultural chemicals or pesticides group. Recently, more specific monitoring of EDCs is becoming increasingly important and has been given special attention. The new approach by the Ministry of Health in conducting surveys and monitoring of EDC chemicals leaching from domestic materials and utensils has opened avenues for researchers and other government agencies to embark on similar activities. Some of the chemicals recently incorporated into these activities are phthalates, bisphenol A , nonylphenols,dioxins, pesticides and phytoestrogens.

Some of the matrix or materials used for these monitoring activities include population blood samples, drinking water, bottled drinks, babies feeding bottles, food containers, fatty food, rice, plastic containers and packing materials, sweets and candies and various others.

In this presentation, discussions will be based on some of these screening and monitoring results. Seven pesticides and eight alkylphenols were monitored in human plasma using the GCMS method. The pesticides are lindane, diazinon, a-endosulfan, b-endosulfan, endosulfan sulfate, chlorpyrifos and endrin; while the alkylphenols are 4-n-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol, nonylphenol, 4-n-octylphenol and bisphenol A. 130 babies' bottles, including both new and old bottles, were collected to test for the leaching of bisphenol A in water at 30°C and 80°C. Bisphenol A was extracted using a liquid-liquid extraction and analyzed with a GCMS. This study revealed that more bisphenol A leached from used or old babies' bottles compared to the new babies' bottles. EDCs found in the cord blood ranged from trace levels to 15.17ng/ml.

A nationwide assessment of phytoestrogens levels in cord blood was also started. A total of 250 samples of cord blood were sampled to assay for phytoestrogens, diadzein and genistein, in the population. As Malaysia is not a soya consuming country, in contrast to Japan, the baseline level of phytoestrogens were not expected to be high.

577 schoolchildren in 60 schools throughout Peninsular Malaysia were investigated for pesticide residues levels in a cross-sectional study. The results of this monitoring survey revealed the following range of concentrations of pesticide residues in blood (ng per gram): aldrin, nd-47.6; dieldrin, nd; endrin, nd; alpha-endosulfan, nd-0.6; beta-endosulfan, nd; endosulfan sulfate, nd; heptachlor, nd-3.8; lindane, nd-5.7; p,p'-DDT, nd-3.4; o,p'-DDE, nd-1.4; p,p'-DDE, nd; chlorpyrifos, nd-10.3; diazinon, nd-103.0. There was a statistically significant relationship between the contaminated children and ethnic as well as site distribution. The results of this study underline the importance for government and public health authorities to evaluate the magnitude of exposure to environmental contaminants in humans in the future. There is also a need to evaluate the possible means of contamination and sources as some of the detected pesticides were banned or not legally available in Malaysia. This study also has managed to initiate a preliminary baseline establishment in the levels of these chemicals in the population.

Acknowledgement: SUCXeS (Shimadzu-UMMC Centre for Xenobiotic Studies) University of Malaya, Japan Chemical Industry Association, Ministry of Health Malaysia, Government of Malaysia (for IRPA grant granted to HeRDU), University of Malaya Endocrine disruptors research group.

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