Airborne residues resulting from use of methyl parathion, molinate and thiobencarb on rice in the sacramento valley, California

Abstract

In connection with requirements of California's Toxic Air Contaminant Act, 24‐h ambient air samples were collected using an XAD‐4 resin trap technique capable of simultaneously collecting methyl parathion, methyl paraoxon, molinate and thiobencarb. Sampling was conducted on rooftops of public buildings located in four towns in two counties where methyl parathion, molinate and thiobencarb were used in significant quantities, and at a background site located in a county where no use occurred, for four intervals each week for 5 weeks during the springtime application period of 1986. Satisfactory recoveries (greater than 66%) were obtained from dynamic spiking experiments, and the precision from field replicates was consistently less than 50% relative standard deviation using a protocol designed to accommodate a large number of samples. Daily maximum average concentrations (and the range in averages for all sites over the 19 and 20 sampling days in the two‐county use area) were 25.7 ng/m3 (0.2‐6.2 ng/m3) for methyl parathion, 3.1 ng/m3 (<0.5‐0.8 ng/m3) for methyl paraoxon, 1,720 ng/m3 (60‐650 ng/m3) for molinate and 250 ng/m3 (12.9‐67.8 ng/m3) for thiobencarb. Concentrations correlated well with reported uses of methyl parathion and molinate in the general vicinity of the sampling sites. The likely sources of observed residue levels, based upon the method of application and pesticide physicochemical properties, were spray drift during application for methyl parathion, vapor‐phase oxidation of parent thion for methyl paraoxon, and postapplication volatilization from field water for molinate and thiobencarb.

Agricultural Pesticide Use in California: Pesticide Prioritization, Use Densities, and Population Distributions for a Childhood Cancer Study

“…Information on residential pesticide use in the home and garden is not collected. Agricultural pesticide use is reported to a square-mile section, but air monitoring data from application sites suggest that pesticide concentrations may decrease significantly within a mile (18,(42)(43)(44). Nonagricultural pesticide applications, including structural fumigations and landscaping uses on golf courses and along highways, are reported only at the county level in the PUR data.…”

Pathways for the Oxidation of Sarin in Urban Atmospheres

“…However, oxidation of the thion can occur incidentally in transit. It is the family of oxon phosphorus esters which is most dangerous (Seiber et al, 1989). Their atmospheric degradation has been quantified empirically and it occurs in on the order of hours to days depending on local conditions and on molecular structure (Woodrow et al, 1983).…”

“…However, oxidation to oxon can also take place in the atmosphere prior to consumption (Klisenko and Pismennaya, 1979;Atkinson et al, 1989). Lower electrophilicity also means that the thions hydrolyze more slowly in the environment (Seiber et al, 1989).…”

Worker Exposure and Volatilization Pattern of Cadusafos, Ethoprophos and Probenazole after Applying Granular Type Formulation on Soil in Greenhouse

“…선진국에서는 농약살포자와 살포한 농장이나 온실에서 작업하는 농작업자에 대한 위해성을 평가 하여 안전성이 인정되는 농약에 한해 등록되도록 하고 있다 (Woodrow et al, 2001). 미국 EPA에서는 농작업자 보호를 위해서 Worker Protection Standard (WPS)을 만들어 농 약의 재출입기간(Restricted-Entry Intervals, REIs), 보호장 비, 응급처치 요령 등을 대학교와 연계하여 농민들에게 교육 시키고 있다 (Seiber et al, 1989;Baker et al, 1996;Woodrow et al, 1997 (Fig. 1).…”