Correlating Agricultural Use of Organophosphates with Outdoor Air Concentrations: A Particular Concern for Children

Abstract

For the organophosphate pesticide chlorpyrifos, median inhalation noncancer, acute children’s exposures in agricultural communities are elevated above reference doses; for diazinon, similar exposures are nearly elevated. We used multivariate linear regression analysis to examine the temporal and spatial associations between agricultural use and measured air concentrations of chlorpyrifos, chlorpyrifos oxon, diazinon, and malathion. Agricultural use within a 3-mile radius on the monitoring day and use on the 2–4 prior days were significantly associated with air concentrations (p < 0.01) for all analytes except malathion; chlorpyrifos oxon showed the strongest association (p < 0.0001). In the final models, which included weather parameters, the proportion of variance (r 2, adjusted for the number of model variables) for all analytes ranged from 0.28 (p < 0.01) for malathion to 0.65 (p < 0.0001) for diazinon. Recent cellular, animal, and human evidence of toxicity, particularly in newborns, supports the public health concern indicated by initial risk estimates. Agricultural applications of organophosphates and their oxon products may have substantial volatization and off-field movement and are a probable source of exposures of public health concern.

Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment

“…In another series of studies of Mexican-American children living in an intensive agricultural area of California, Eskenazi and coworkers evaluated several metrics of exposure to numerous insecticides, including chlorpyrifos, and a variety of neurodevelopmental health outcomes in children, as discussed in Section IV (Bradman et al, 1997;Eskenazi et al, 1999;Castorina et al, 2003;Eskenazi et al, 2004;Harnly et al, 2005;Duramad et al, 2006;Furlong et al, 2006;Holland et al, 2006;Eskenazi et al, 2007). CHAMACOS is "a prospective cohort study of the association of pesticides and other environmental exposures on the health of pregnant women and their children living in the Salinas Valley, CA."…”

“…The CTEPP cohort study (Morgan et al, 2005) also measured outdoor air concentrations of chlorpyrifos at urban homes and day-care centers of 0.5 ± 1 and 0.2 ± 0.2 ng/m 3 , respectively. Harnly et al (2005Harnly et al ( , 2006) measured chlorpyrifos and chlorpyrifos-oxon in outdoor air samples collected in the southeastern portion of California's Central Valley, an agriculturally intensive area. Although few specific airborne concentration data are provided, they reported a median air concentration of 33 and 22 ng/m 3 for chlorpyrifos and chlorpyrifos oxon, respectively.…”

Epidemiological Studies of Anticholinesterase Pesticide Poisoning in Israel

“…Despite their low volatility, a significant portion of applied OPs remain suspended in the atmosphere, a medium for which sparse knowledge exists regarding OP degradation and fate (Harnly et al, 2005). Several studies (1977( -1987Richter, 1993) assessed the neurotoxic effects of long-term, low level OP exposures in workers and residents of several kibbutzim in the region.…”

“…The atmosphere is considered an important transportation medium for pesticides, although most are semi-volatile 31.11 CURRENT OP STUDIES IN ISRAEL compounds (Harnly et al, 2005). In addition to its importance with regard to pesticide transport, the atmosphere is also an important media for transformations of OP (Seiber et al, 1993), especially in view of post-application aspects.…”

Degradation of organophosphorus pesticide diazinon using activated persulfate: Optimization of operational parameters and comparative study by Taguchi's method

“…Just in the USA, almost 6 million pounds of diazinon are used yearly on farming sites [8]. Diazinon is obtainable as a dust, granules, seed dressings, wettable powder and emulsifiable solution [9]. It can be released into the environment not only during the spraying of plants, but also as a result of vanishing from both the ground waters and soil [9].…”