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

Abstract

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.

Chlorpyrifos exposure in farmers and urban adults: Metabolic characteristic, exposure estimation, and potential effect of oxidative damage

“…Similar levels of urinary TCPy were also detected in people living in agricultural regions of Thailand (Panuwet et al, 2008;Rohitrattana et al, 2014).…”

“…In the current study, the GM EI of the baseline level in farmers and urban adults were calculated as 0.261 μg/kg-bw/day and 0.150 μg/kg-bw/ day, respectively, which are at the same level with that reported in recent studies on Asian countries (Liu et al, 2014;Rohitrattana et al, 2014), but lower than those in the U.S. populations reported in 2006 (Alexander et al, 2006) and 2007(Curwin et al, 2007a before the ban of domestic use of chlorpyrifos in the US. According to Eq.…”

“…(2) has been used in studies of occupational and nonexposure to chlorpyrifos in farmers and common populations (Alexander et al, 2006;Curwin et al, 2007a;Farahat et al, 2011;Phung et al, 2012;Liu et al, 2014;Rohitrattana et al, 2014). In the current study, the GM EI of the baseline level in farmers and urban adults were calculated as 0.261 μg/kg-bw/day and 0.150 μg/kg-bw/ day, respectively, which are at the same level with that reported in recent studies on Asian countries (Liu et al, 2014;Rohitrattana et al, 2014), but lower than those in the U.S. populations reported in 2006 (Alexander et al, 2006) and 2007(Curwin et al, 2007a before the ban of domestic use of chlorpyrifos in the US.…”

“…Exposure estimation of chlorpyrifos exposed by pesticide spraying As a widely used organophosphorus pesticide, human exposure to chlorpyrifos has been estimated various studies on the basis of the urinary level of the TCPy. In most studies (Morgan et al, 2005;Alexander et al, 2006;Curwin et al, 2007a;Farahat et al, 2011;Phung et al, 2012;Liu et al, 2014;Rohitrattana et al, 2014), the intake of chlorpyrifos was commonly estimated according to the following equation:…”

Concentrations of organophosphorus pesticides in rice (Oryza sativa) and human health risk assessment from Songhua River, Northeast China

“…Suspected effects of OPs exposures for human include headaches, allergies and nausea, adverse physiologic effects, increased frequency of cancer, neurobehavioral and cognitive abnormalities, teratogenicity, endocrine modulation and immunotoxicity (Alavanja et al, 2004;Bouchard et al, 2011;Engel et al, 2011;Handal et al, 2007;Jurewicz and Hanke, 2008). OP had adverse effects for human health mentioned above, especially for young children who were more sensitive than adults (Fiedler et al, 2015;Panuwet et al, 2012;Rohitrattana et al, 2014).…”