• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.228-236
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• 2001

Objectives : To propose a feasible, valid and appropriate study designs and epidemiologic methods for evaluating the adverse health effects of Agent Orange-chemical defoliants used in Vietnam- in Korea. Methods : A literature study was peformed on Agent Orange, herbicides, pesticides and dioxins. The study subjects, study design, exposure assessment and health outcomes assessment were examined in each study. The potential data sources for the study subjects, study design, exposure assessment and health outcomes assessment in Korea were investigated. Results and Conclusion : In earlier Korean studies, research subjects for studying the effects of Agent Orange were identified from the patients or persons who claimed to have Agent Orange-related diseases due to the difficulties in identifying the entire population of Vietnam veterans in Korea. In this study, an attempt was made to identify the total number of Vietnam veterans in Korea. As a result, the addresses of 20,000 Vietnam veterans were obtained. It is proposed that a retrospective cohort design on a sample of the total number of Vietnam veterans is a feasible and appropriate study design. Self report questionnaires and military records were proposed to assess the exposure level. It is believed that measuring the plasma or tissue TCDD should be used only for a validation study assessing the level of exposure. For the health outcomes assessment, it is possible to obtain the mortality, cancer frequency, physical examination, screening and medical insurance record data.

• Toxicological Research
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• v.17
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• pp.323-327
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• 2001

March 19, 1999, the renovation qf the runway of the Bo-Fai ai1field in Hua Hin, Prachubk-erikhan, Thailand, unearthed chemicals which were left over from the project "anch Hand Operation" held during the Vietnam war era. The chemical mixtures were analyzed by the US EPA, the Department oj Medical Sciences (DMSc), Ministry oj Public Health (MoPH) and the Pollution Control Department (PCD), the Ministry oj Science Technology and Environment (MOSTE) of Thailand, The samples were found to contain several defoliants used in the operation. They were 2,4-D, 2,4,5-T, Dicamba, Cocydelic acid, and Dioxins. Due to the complexity of the issue, the multiplicity of possible health effects, and the socio-economic implications for imports and exports, the Thai Society of Toxicology submitted a proposal to request World Health Organization (WHO), Geneva. The assistance is for the area of chemical safety and called for immediate action to explore the magnitude qf risk involved with Dioxins. In this paper we present our approach to health risk assessment which takes into an account the epidemiological studies of high-risk group exposed to the Ranch Hand operation. Dioxins are endocrine disruption chemicals which public concerns are developed due to presumption that a hazard exists (www.eva.gov/dioxins/html) for which current methodologies are deemed insufficient. The recent concepts of how oxidative stress toxicants may affect health end points and biomarkers of exposure of exposed individuals are discussed. While research activities are undergoing, The Thai Society of Toxicology do not anticipate significant risk to local residents and the environment due to our concurrence with opinion from the international experts invited by the World Health Organization proposed to the local experts at a workshop in Bangkok.n Bangkok.

• Korean Journal of Plant Resources
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• v.32 no.6
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• pp.677-682
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• 2019

Hand leaf thinning for improvement of fruit coloration and quality is one of the most labor-consuming works in Korean apple cultivation. The study was aimed at investigating whether foliar application of two chelate compounds (Cu-EDTA, Fe-EDTA) could defoliate effectively 'Hongro'/M.9 apple leaves and enhance fruit coloration and quality. At 30 days before harvest, foliar spray with two chelate compounds defoliated significantly the apple leaves. Chelate treatments did not affect the leaf chlorophyll content. High concentration of chelates decreased drastically photosynthetic rate of true leaves, and then it stayed in low levels, whereas low levels of chelates reduced sharply the photosynthetic rate but it was gradually restored over time. Cu-EDTA regardless of its concentration triggered higher defoliation compared to Fe-EDTA. Consequently, higher defoliation improved light interception of fruits and accumulated more anthocyanin. Particularly, Cu-EDTA could target mainly fruit cluster leaves which affect directly light interception of the fruits, i.e. more selective defoliants compared to Fe-EDTA. However, 3% Cu-EDTA rather defoliated excessively, accompanying with reduction of fruit weight and soluble solids. Therefore, our results suggest that 1% Cu-EDTA which defoliates properly the fruit cluster leaves could improve coloration and quality of 'Hongro'/M.9 apple fruits.