Organophosphate Pesticide Exposure in School-Aged Children Living in Rice and Aquacultural Farming Regions of Thailand

Organophosphate pesticides (OPs) are widely used in agricultural sectors in Thailand. Previous studies have documented that children residing in agricultural areas have higher exposure to OPs than children living in other residential areas. The objective of this study was to quantify urinary biomarkers of OP exposure and determine the environmental conditions and activities that predict their levels among children living in Central Thailand farming regions. In October 2011, 53 6–8-year-old participants were recruited from Pathum Thani Province, Thailand. Twenty-four lived in rice farming communities at Khlong Luang District where OPs are the pesticides used frequently. Twenty-nine participants, living in aquacultural farming communities at Lum Luk Ka District where OPs are not used, were recruited to serve as controls for pathways of exposure (e.g., residential, dietary) other than occupational/paraoccupational exposures encountered in rice farming. Household environments and participants’ activities were assessed using a parental structured interview. Urine samples (first morning voids) were collected from participants for OP urinary metabolite (i.e., dialkylphosphates [DAPs] and 3,5,6-trichloro-2-pyridinol [TCPy]) measurements. The levels of most urinary OP metabolites were significantly higher in participants who lived in a rice farming community than those who lived in an aquacultural farming community (P < .05). The results from linear regression analysis revealed that the frequency of OP application on rice farms (∑DAP: P = .001; TCPy: P = .001) and living in a rice farming community (∑DAP: P = .009; TCPy: P < .001) were significant predictors of urinary DAP metabolite levels in participants. Increasing TCPy levels were significantly related to proximity to rice farm (P = .03), being with parent while working on a farm (P = .02), playing on a farm (P = .03), and the presence of observable dirt accumulated on the child’s body (P = .02). In conclusion, OP metabolite levels among children who live in rice farming communities were strongly influenced by farming activity, household environments, and child behaviors, suggesting that these are the primary pathways in which children living in these agricultural communities in Thailand were exposed to OPs.     

Agricultural Pesticide Usage and Prioritization in South Korea

This study aims to review agricultural pesticide usage and trends and to identify hazardous pesticides for regulation, in terms of public health, in South Korea. The authors collected data on usage and trends of agricultural pesticides through agriculture-related databases. Criteria from the US Environmental Protection Agency classification for carcinogenicity, World Health Organization classification for acute toxicity, and European Union prioritization list for endocrine-disrupting chemicals were used for the hazard categorization of identified individual active ingredients. Pesticides to be prioritized among all pesticides used in South Korea between 2007 and 2011 were selected by taking into account the volume of usage, toxicity, and epidemiological evidence. Annual agricultural use of pesticides has increased rapidly from the 1970s to 1990s in South Korea, but has declined since 2001. The quantity of pesticides used in 2011 was reported as 19,131 tons, and was comprised of 34.7% insecticides, 28.0% fungicides, and 27.1% herbicides. The 50 pesticides with the greatest volume of usage accounted for 82.6% of the total volume of pesticides used between 2007 and 2011, with the most-used active ingredient being machine oil, followed by mancozeb and then paraquat. Organophosphates were the most used among the top 50 pesticides. A total of 24 pesticides were selected for recommendation of intensive regulation in South Korea. In conclusion, the authors described the usage and trends of overall agricultural pesticides, which would serve as a fundamental step forward in managing pesticide in terms of public health. Intensive efforts are required for the prevention of potential health effects from the 24 identified pesticides.     

QuEChERS法结合气相色谱-串联质谱法测定贝母类中药中53种农药残留

目的建立基于QuEChERS法结合气相色谱-串联质谱法(GC-MS/MS)对贝母类中药中53种农药残留量的快速检测方法,并应用于193批样品筛查。方法根据调研选择禁限用及常用农药作为检测指标。采用QuEChERS法对样品进行前处理,在气相色谱-串联质谱多反应监测(MRM)模式下进行测定,以3个添加水平测定样品的回收率和RSD。结果 53种农药在一定含量范围内线性关系良好,r均大于0.997 8;在1倍LOD(Limit of Detection)、2倍LOD、10倍LOD 3个添加浓度水平进行回收率试验中,86.8%的农药在60%～140%,RSD均小于15%;各农药检出限均小于0.01 mg/kg。193批贝母类中药种共检出14种农药,91批样品有检出,检出率为47.2%,仅有1批超出即将执行的《中国药典》2020年版限度规定。结论该方法检测指标具有一定针对性,且操作简便快速、灵敏可靠,适用于贝母类中药中农药残留的筛查测定。对于贝母类中药的生产种植和流通监管具有一定的参考意义。     

The effects of organophosphate pesticide exposure on Hispanic children's cognitive and behavioral functioning

OBJECTIVE: This study investigates the effects of Organophosphate (OP) pesticides exposure on the cognitive and behavioral functioning of Hispanic children living in an agricultural community. METHODS: Forty-eight children were administered a battery of cognitive measures, and their parents and teachers completed behavior rating scales. Children provided a urine sample for analysis of OP pesticides metabolites. RESULTS: All children had a detectable level of at least one OP pesticide metabolite. Higher OP pesticide metabolite concentration levels were significantly correlated with poorer performance on some subtests of the Wisconsin Card Sorting Test. However, the significance of this association was dependent upon the inclusion of two samples with noticeable higher OP pesticide metabolite concentration levels. CONCLUSIONS: Short-term OP pesticide exposure seems to have deleterious effects on children's speed of attention, sequencing, mental flexibility, visual search, concept formation, and conceptual flexibility. This study is among a relatively small number of studies investigating an extremely complex problem. Limitations and suggestions for future studies are discussed.     

A retrospective analysis of the added value of 1-year dog studies in pesticide human health risk assessments

The 1-year dog toxicity study is no longer required by certain pesticide regulatory jurisdictions, including the United States and the European Union. Health Canada’s Pest Management Regulatory Agency (PMRA) examined its current requirement for this study to determine if it could be refined or eliminated. A retrospective analysis was conducted to examine the impact of the 1-year dog study on human health risk assessment. The Acceptable Daily Intake (ADI), a measure of the amount of a pesticide in food that can be ingested on a daily basis over a lifetime without an appreciable health risk, was the metric for this analysis. For 143 pesticides evaluated by the PMRA between 2008 and 2015, the supporting toxicology databases were examined to determine if other toxicology studies were protective of the findings in the 1-year dog study. When this criterion was not met, further investigation was undertaken to determine the potential impact of not having the 1-year dog study. For most of the pesticides, effect levels in the 1-year dog study were not substantially different from those in other toxicology studies, when considering factors such as dose-spacing and known experimental variability. The results of this analysis suggest that absence of the 1-year dog study would have minimal impact on the assessment of human health risk. Therefore, Health Canada’s PMRA has removed the routine requirement for the 1-year dog study from its pesticide data requirements.     

有机磷对作业工人红细胞乙酰胆碱酯酶和血清对氧磷酶活力的影响

目的探讨接触有机磷对作业工人红细胞乙酰胆碱酯酶(eAChE)和血清对氧磷酶(sPON)活力的影响。方法采用GC-NPD(气相色谱-氮磷检测器)监测作业场所空气中有机磷农药浓度,试剂盒和标准曲线法测定作业工人和对照者eAChE和sPON活力。结果对硫磷包装车间呼吸带的浓度为(0.022±0.012)mg/m3,敌敌畏包装车间呼吸带的浓度为(1.960±1.180)mg/m3;有机磷暴露使作业工人的eAChE及sPON活力降低并与接触工龄呈负相关;对硫磷暴露组中≥35岁作业工人的eAChE活力高于<35岁的作业工人,饮酒可以降低eAChE活力而升高sPON活力。结论eAChE及sPON活力可以作为评价有机磷农药中毒程度的生物标志物。     

水中12种有机磷农药的毛细管气相色谱测定法

目的建立同时测定水中多种有机磷农药的气相色谱测定方法。方法水中的微量有机磷化合物经液-液萃取后,用DB-1701毛细管色谱柱,同时在程序升温和恒线速度氮载气条件下进行气相色谱分析,以保留时间定性,外标法定量。结果该方法12种有机磷农药的线性范围为0.2～50.0μg/L,相关系数≥0.9991,最低检出浓度为0.009～0.04μg/L,水样加标回收率为78.4%～93.9%,RSD为3.4%～7.5%。结论该方法一次性完成水中12种有机磷化合物的分离和测定,分析时间仅为32.5min,操作简便、灵敏。     

Dietary intake of organophosphorus pesticide residues through vegetables from Kumasi, Ghana

Contamination and health risk hazards of organophosphorus pesticides residues in vegetables were studied. Ethyl-chlorpyrifos, observed at an average level of 0.211 ± 0.010 mg kg⁻¹ in 42% of tomato, 0.096 ± 0.035 mg kg⁻¹ in 10% of eggplant and 0.021 ± 0.013 mg kg⁻¹ in 16% of pepper was below the 0.5 mg kg⁻¹ MRL. Dichlorvos was the most frequently detected residue in all the samples analyzed. Levels of malathion in tomatoes (0.120 ± 0.101 mg kg⁻¹) and pepper (0.143 ± 0.042 mg kg⁻¹) exceeded the MRL of 0.1 mg kg⁻¹. Health risks were found to be associated with methyl-chlorpyrifos, ethyl-chlorpyrifos, and omethioate in tomatoes and methyl-chlorpyrifos, ethyl-chlorpyrifos, dichlorvos, monocrotophos and omethioate in eggplant. Routine monitoring of these pollutants in food items is required to prevent, control and reduce the pollution and to minimize health risks.     

长期接触低剂量有机磷农药对人体健康影响的研究进展

有机磷农药（OPs）是我国使用量最大的一类农药之一，广泛使用于水果、蔬菜、烟草、棉花等作物。近年来，由OPs引起的急性中毒事件已逐步减少，而长期低剂量暴露OPs对人体健康的危害逐渐引起了人们的重视。越来越多的研究发现长期低剂量暴露OPs与人体肿瘤的发生，不良生殖结局，神经及神经行为功能的异常有密切关系。     

Dermal in vitro penetration of methiocarb, paclobutrazol, and pirimicarb

OBJECTIVES—The dominant route of occupational exposure to pesticides in horticulture is dermal. However, preventive measures are seldom used when handling plant cultures recently treated with pesticides, thus causing significant dermal exposure and potential absorption. Assessment of exposure often depends on biological monitoring of blood or urine samples. The skin often acts as a temporary reservoir for chemicals before absorption. Failure to consider the lag time between dermal exposure and appearance of pesticide or metabolites in the general circulation may lead to false conclusions about assessment of exposure.
METHODS—In an experimental model in which in vitro static diffusion cells were mounted with human skin, dermal penetration of three extensively used pesticides (methiocarb, paclobutrazol, pirimicarb) was evaluated.
RESULTS—Pirimicarb and paclobutrazol had comparable rates of dermal penetration and lag times of around 18 hours. Methiocarb had a considerably shorter lag time. Dermal penetration continued for extended periods after exposure had ended.
CONCLUSIONS—With lag times sometimes considerably longer than a normal working day, biological monitoring at the end of exposure may seriously underestimate the actual exposure. There may be implications for regulatory guidelines, which often require only 24 hour observation periods.


Keywords: dermal penetration; pesticides; in vitro