Distribution of pesticide residues

Vryzas Z, Vassiliou G, Alexoudis C, Papadopoulou-Mourkidou E (2009) Spatial and temporal distribution of pesticide residues in surface waters in northeastern Greece. Water Res 43(1) 1—10... 

Distribution of Pesticide Residues in Human Body Tissues from Montgomery County, Ohio... 

USEPA (2000d). Analysis of Aged In-home Carpets to Determine the Distribution of Pesticide Residues and their Potential Availability for Human Exposure, Report No. 600/R-00/030, National Exposure Research Laboratory, Research Triangle Park, NC, USA. 

Table II shows the distribution of pesticide residues detected above 0.01 pg/g by percent of MRL 8). In domestic samples, the concentrations of 53% of the detectable residues were less than 10% of the MRL, and 9% were within the range of 10-50% of the MRL. There was no MRL for 37% of the total residues detected. In imported samples, the levels of 37% of the detectable residues were <10% of the MRL, and 39% were 10-50% of the MRL. Most of the residues distributed in the range of 10 to 50% were antifungal agents used for citrus fruits. No MRLs were set for 20% of the total residues detected and the ratio was high especially for imported vegetables.

Table II. Distribution of Pesticide Residues. Olppm) by percent of MRL...

Accurate, precise and sensitive analytical methods are important to the collection of data needed for regulatory decisions about pesticide registration. This article describes the various components of analytical method development, validation and implementation that affect the collection of pesticide residue distribution data for regulatory assessment of environmental fate and water quality impacts. Included in this discussion are both the technical needs of analytical methods and the attributes of study design and sample collection needed to develop data that are useful for regulatory purposes. 

Distributions of pesticide concentrations in potential food items for avian species are required to estimate the contribution of food to exposure of birds in different regions where the test chemical may be used. On treated fields, detectable CEF residues were found in 102 of 207 earthworm samples. No earthworm samples collected from control fields (N = 28) contained detectable CEF. Average CEF concentrations in earthworms reached maxima 1-4 days post-application (Table 3). Mean CEF residues in earthworms fell below 0.1 qg g after 8 days post-application. This... 

Parkinson RW, Wang TC, White JR, et al. 1993. Distribution and migration of pesticide residues in mosquito control impoundments. St. Lucie County, Florida, USA. Environmental Geology 22 26-32. 

Fig. 8.48 Summary data of pesticide residues in the soil environment, sho wing the distribution between mineralization and extractabihty (A) atrazine, (B) dicamba, (C) isoproturon, (D) hndane, (E) paraquat and (F) tiifluralin. Reprinted from Mordaunt CJ, Gevao B, Jones KC, Semple KT (2005) Formation of non-extractable pesticide residues observations on compound differences, measurement and regulatory issues. Entiron Pollution 133 25-34. Copyright 2005 with permission of Elsevier...

West (12) has reviewed some of the evidences of the world-wide distribution of pesticides. Blubber from a gray whale washed up on the California shore, she reported, contained 0.2 p.p.m. of DDT, 0.5 p.p.m. of DDE, and 0.2 p.p.m. of lindane. Moreover, DDT has been found in the oil of fish caught off the coast of the Americas, Europe, and Asia in concentrations ranging from 1 to 300 p.p.m. Residues of DDT have been found in duck eggs on the Yukon River, in 75% of 2300 species of birds collected from 22 states and three provinces of Canada, and in 31 of 32 eagles examined. 

They conclude that, "in view of the world-wide use of organo-chlorine insecticides and the extensive distribution of their residues in soil, together with the foregoing evidence, it is possible that they might now contaminate the atmosphere continuously. This conclusion is entirely consistent with their data and with the evidence of organo-chlorine compounds in the rainfall samples reported by Weibel (11) and Cohen (4). Similar results were obtained from rain samples collected in the metropolitan area of London by Abbott et al. (1). These authors were also able to demonstrate the presence of pesticides in the atmosphere (2). 

Sorbed pesticides are not available for transport, but if water having lower pesticide concentration moves through the soil layer, pesticide is desorbed from the soil surface until a new equiUbrium is reached. Thus, the kinetics of sorption and desorption relative to the water conductivity rates determine the actual rate of pesticide transport. At high rates of water flow, chances are greater that sorption and desorption reactions may not reach equihbrium (64). NonequiUbrium models may describe sorption and desorption better under these circumstances. The prediction of herbicide concentration in the soil solution is further compHcated by hysteresis in the sorption—desorption isotherms. Both sorption and dispersion contribute to the substantial retention of herbicide found behind the initial front in typical breakthrough curves and to the depth distribution of residues. 

Woolson et al. (1971) used a modified soil P procedure to study distribution of As in U.S. soils. The mass of the residual As in both uncontaminated and soils contaminated with arsenic pesticides from Washington and Oregon is found as the Fe oxide bound As (0.1 N NaOH extractable), followed by the Al oxide and the Ca bound As (extracted by NH4F and H2S04, respectively). 

Robertson, G. Lebowitz, M. Needham, L. O Rourke, M.K. Rogan, S. Petty, J.D. Huckins, J.N. 2002, Distribution of Residential Organochlorine Pesticide Residuals along the Arizona/Mexico Border. Proceedings 9th International Conference on Indoor Air Quality and Climate Monterey, CA, June 2002 pp. 63-68. 

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