Pesticide levels

The solubility of methyl parathion is not sufficient to pose a problem in runoff water as determined by an empirical model of Wauchope and Leonard (1980). Some recent monitoring data, however, indicate that methyl parathion has been detected in surface waters (Senseman et al. 1997). In a study to determine the residue levels of pesticides in shallow groundwater of the United States, water samples from 1,012 wells and 22 springs were analyzed for methyl parathion. No methyl parathion was detected in any of the water samples (Kolpin et al. 1998). In a study of water from near-surface aquifers in the Midwest, no methyl parathion was detected in any of the water samples from 94 wells that were analyzed for pesticide levels (Kolpin et al. 1995). Leaching to groundwater does not appear to be a significant fate process. 

Fig. 4 Percentage of water samples with total pesticides levels >5 pg/L in the six sampling sites investigated...

In several AT studies, pesticide levels in the Ebro were found to be high. Hildebrandt et al. [50] found a homogeneous contamination pattern from atrazine (and also from simazine from May 2000) in intensive Rioja cultivation areas throughout the Ebro. Nearer to the delta, Barata et al. [72] found high levels of bentazone, methyl-4-chlorophenoxyacetic acid, propanil, molinate and fenitrothion in water, while Kuster et al. [71] found low concentration levels of atrazine and simazine at the delta, but high levels of other pesticides used in rice cultivation. Importantly, Hildebrandt et al. [50] found that levels of pesticides in groundwater... 

Nalley, L., G. Hoff, W. Bigler, and N. Schneider. 1978. Pesticide levels in the omental fat of urban gray squirrels. Bull. Environ. Contam. Toxicol. 19 42-46. 

Other studies further indicate that the occurrence of endrin in the U.S. food supply is very low. In a 1990-91 FDA survey of pesticide residues in milk representing most of the U.S. supply consumed in metropolitan areas, endrin was detected at trace levels (0.0005-0.001 ppm [0.5-1.0 ppb]) in only 2 of 806 composite samples (one sample each from Atlanta, Georgia and Dover, Delaware) (Trotter and Dickerson 1993). In another statistically based FDA study in 1992-93, endrin was not found as a violative residue in any of 710 domestic or 949 imported pear samples (Roy et al. 1995). Endrin was not reported among the pesticides detected in a 1994 FDA survey of pesticide levels in 160 samples of catfish, crayfish, shrimp, trout, salmon, oysters, and various other species from important aquaculture areas of the United States (FDA 1995). Comparable results were found in similar studies conducted by the FDA in 1990-93 (FDA 1995). 

Mirex levels in the blood of pregnant women in Jackson, Mississippi, and the Mississippi Delta area where mirex was extensively used were correlated with the health of the infants they bore. The mean mirex level in maternal blood was 0.54 pg/L (ppb) for 106 samples however, mirex levels in the blood of the infants were not correlated with differences in gestation times, Apgar score, or other problems at birth. Only three children with neurological problems had mothers with pesticide levels, including mirex, above the mean levels (Lloyd et al. 1974). 

Golt, J. S., J. Lubin, et al. (2004). Gomparison of pesticide levels in carpet dust and self-reported pest treatment practices in four US sites. Journal of Exposure Analysis and Environmental Epidemiology 14(1) 74-83. 

In order to assess the potential extent of human exposures and health effects, members of dairy farm families who consumed raw dairy products known to be contaminated with heptachlor epoxide were studied (Stehr-Green et al. 1986). These individuals and an unexposed urban reference population were compared with regard to serum pesticide levels and liver toxicity. The farm family members had significantly higher mean serum levels of heptachlor epoxide (0.81 0.94 ppb), oxychlordane (0.70 0.75 ppb), and transnonachlor (0.79 0.60 ppb) than the unexposed population. This study is limited because exposure level, duration, and frequency of exposure are not known. There was no increase in prevalence of abnormal liver function tests in the dairy farm families... 

Code Groundwater bodies Aquifer code Sampling Total Pesticide levels pesticides (ng/L) ... 

Another example of the potential pernicious effects of pesticides upon human health is the study conducted at the University of Colorado where researchers have found that higher concentrations of four pesticides - atrazine, simazine, alachlor and metolachlor - in groundwater are significantly associated with higher levels of Parkinson disease. For every 10 pg/L increase of pesticide levels in the drinking water, they found that the risk for Parkinson disease increased by 3% and their water samples had pesticide concentrations ranging from 0.0005 to 20 pg/L [38]. 

Pesticide levels often exceed the requirements posed by the Ground Water Directive (2006/118/EC), thus constituting a serious threat to ground water quality. This becomes especially relevant in those cases in which groundwater are used as human supply source. Of particular concern is the fact that the commercialisation of formulations containing some of the most commonly found pesticides, such as triazines (atrazine, simazine, etc.), lindane have been aheady banned in Europe. 

In spite of these many variables, there did appear to be some major conclusions from the study. First, with the exception of the Llndcove bed, the evaporation beds had low soil pesticide levels for a disposal facility of this magnitude. Table Xll Is a summary of those pesticides found In each bed which had average residues In excess of 5 ppm during the two-year sampling period. 

Finally, an equally Important component of ground water risk assessment Is toxicity. Only rarely have levels of pesticides In well water been detected which would cause acute toxicity, unless Improper disposal caused the contamination. Rather, as can be seen In Table III, the pesticide levels are usually In the low ppb range. Therefore, our current toxicity concerns are usually for chronic human toxicity or, occasionally, aquatic toxicity. There Is also the possibility of organisms receiving toxic amounts of pesticide residues over time via blomagnlf1catIon. 

The USEPA surveys identified nine pesticide plants using full-scale hydrolysis treatment systems [7]. In the industry, a detention time of up to 10 days is used to reduce pesticide levels by more than 99.8%, resulting in typical effluent less than 1 mg/L. The effluents are treated further in biological treatment systems, GAC systems, or chemical oxidation systems, or are discharged to POTWs, if permitted. 

IngersoU, Bruce. 1998. Study Warns on Pesticide Levels in Food. Wall Street Journal (January 30) A16. 

In the West Bank and Gaza, the list of problems in connection to groundwater includes high pesticide levels, and nitrate concentrations four times the WHO limit. In some central... 

In a study of pesticide levels in ambient suburban air, diazinon was detected in 80, 80, and 40% of samples collected in three cities (Miami, Florida Jackson, Mississippi and Fort Collins, Colorado), respectively. The maximum diazinon concentration detected in each city was 3.9, 2.0, and 2.2 ng/m3 for Miami, Florida Jackson, Mississippi and Fort Collins, Colorado, respectively (Kutz et al. 1976). During 1973-1974, diazinon concentrations in air were measured in urban Miami, Florida, and in the adjacent Everglades National Park. Urban diazinon levels ranged from not detectable to 3.3 ng/m3 (1.5 ng/m3 mean) corresponding levels in Everglades National Park ranged from not detectable to 1.9 ng/m3 (0.6 ng/m3 mean) (Lewis and Lee 1976). Nationwide, diazinon was detected in 48% of 123 urban air samples collected in ten U S. cities during 1980. The maximum diazinon concentration reported was 23 ng/m3 (mean 2.1 ng/m3) (Carey and Kutz 1985). 

Greizerstein, H. B., C. Stinson, P. Mendola, G. M. Buck, P. J. Kostyniak, and J. E. Vena, Comparison of PCB congeners and pesticide levels between serum and milk from lactating women , Environ. Res. A., 80,280-286 (1999). 

The influence of six fungicides (azoxystrobin, cyprodinil, fludioxonil, mepanipyrim, pyrimethanil, and tetraconazole) on two lactic bacteria (L. oenos and L. plantarum) was studied (Cabras et ah, 1999). During MLF, no degradative effect on pesticide levels was determined. 

When solutions of individual pesticides were used, concentrations as low as 0.5 pgl-1 (10 9 M) could be determined. When binary mixtures with pesticide levels from 0 to 5 pgl-1 were measured, the concentration of each pesticide could be determined within the range with errors of 0.4 pgl-1 for paraoxon and 0.5 pgl-1 for carbofuran. Similar levels were obtained when river water samples spiked with pesticide were used but with a higher degree of inaccuracy. When different mutant AChEs were utilised, binary mixtures of the very similar pesticides paraoxon and malaoxon could be analysed in the range 0-5 pgl-1, with resolution of the two components with accuracies of the order of 1 pgl-1. The use of more sensitive and selective mutant enzymes together with the addition of extraction and concentration steps to the assay could greatly enhance the methods range and accuracy. 

Microelectrode arrays containing AChE were also utilised within a flow injection system [40]. A system was developed where a sample was separated and flushed simultaneously through eight cells, each containing a screen-printed electrode and fitted with a separate bespoke mini-potentiostat (Fig. 15.3). This allowed multiple measurements to be made on a single water sample using multiple electrodes, each specific for a different pesticide due to inclusions of different AChE mutants in each of the electrodes. Pattern-recognition software could then be utilised to deduce the pesticide levels in a potentially complex sample. 

Knaak, J. B. Schlocker, P. Ackerman, C. R. Seiber, J. N. Reentry Research Establishment of safe pesticide levels on foliage. Bull. Environm. Contam. Toxicol., 1980, 24, 796. 

Reentry research establishment of safe pesticide levels... 

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