Distribution Of Pesticide Residues Research Articles

Pesticide residues in Volta Lake, Ghana

AbstractThe Volta River basin comprises ≈ 70% of mainland Ghana, being inhabited by a majority of the country's population. The purpose of this study was to analyse water and sediment samples at six locations in Volta Lake for residues of persistent organochlorine pesticides. Residues were extracted by use of two types of extractions, including a standardized solid phase extraction procedure for water samples and a Soxhlet extraction procedure for sediment samples. All samples were analysed by gas chromatography. Lindane and endosulfan were identified in concentrations ≤ 0.008 p.p.b. and 0.036 p.p.b., respectively, in water, and ≤ 2.3 p.p.b. and 0.36 p.p.b., respectively, in sediments. Dichlorodiphenyltrichloroethane and dichlorodiphenyldichloroethylene were also found in sediment samples (in concentrations ≤ 9.0 p.p.b. and 52.3 p.p.b., respectively). No significant contamination was noted in the lake. The distribution of pesticide residues in water and neighbouring sediment are briefly discussed. Different bioconcentration factors obtained in this study allowed the confirmation of the complex processes already reported in the literature regarding the partitioning of chemicals between sediment and water.

Distribution of Pesticide Residues Within Homes in Central New York State

Residues for 17 pesticides were analyzed in 41 households in central New York State that represented farm, rural, and urban houses. Samples were taken in both summer and winter of 2000-2001 from the same households from four locations; family room carpet; adjacent smooth floor; flat tabletop surface; and settled dust collected in a Petri dish on a tabletop. Pesticide residues were analyzed to identity factors that influence both the transport into and the redistribution of pesticides in the indoor environment. Differences were observed between the various pesticides and pesticide classifications relative to location within and between households as well as by season. Variations in the pesticide residues were related to a number of factors. Higher residues were observed in the farm households, particularly in summer, with the highest amount observed for chloropyrifos in carpet (33 microg/m2). For many pesticides, the frequency of detection and the amount of residues were higher in summer, which relates to usage patterns in agriculture and horticulture; however, larger amounts of insecticides such as mecoprop, resmethrin, and tetramethrin were found on flat surfaces in winter, indicating household use and possible redistribution within the home. Distribution patterns suggest that routines within a household may cause high variation in residues; these practices include indoor pets and treatment for fleas and ticks, use of termiticides, and fastidiousness of occupants. Frequency of pesticide detection was highest in carpet for both summer and winter for all households, indicating that carpets hold pesticides over time. Adsorbent fibrous materials such as textiles hold pesticides by macro- and micro-occlusion in their complex structures. Amounts of pesticide residue were higher in carpets than on smooth floors, particularly for rural farm households where the farmer was a certified pesticide applicator. The maximum amount of pesticide residue on a smooth floor surface was 13.6 microg/m2 malathion while the maxima on wiped surfaces and in settled dust were 1.8 microg/m2 2, 4 D and 3 microg/m2 pendimethalin, respectively. Physical properties of individual pesticides such as vapor pressure influenced the distribution of the pesticide within the households. Evidence of volatilization of pesticides and redeposition on surfaces was observed, indicating that this is a mechanism for contamination of surfaces in addition to adsorption on airborne particles and tracking. High residues in winter are evidence that closure of households in winter that reduces ventilation results in redistribution of pesticides within households.

Monitoring tricyclazole residues in rice paddy watersheds

Pesticide application to rice paddies may affect the quality of environmental resources such as groundwater and surface water. The distribution of residues of tricyclazole, an environmentally persistent fungicide used widely in Italy, was monitored in the network of surface water bodies surrounding the main rice production area in Italy. The location of monitoring sites was based on the potential risk for contamination with tricyclazole. This was determined as a function of the area of rice grown, the geographical distribution of rice crops susceptible to the pest, and sales of tricyclazole. Monitoring sites were also located to represent different spatial scales (farm, catchment and basin). For water samples taken shortly after application in July and August, the highest concentrations of tricyclazole were measured at the farm sites. However, residues were also detected at the catchment and basin scale. The 95% of the measured residue levels was below 9.80, 1.20 and 1.15 μg l −1, at the farm, catchment and basin scales, respectively. In sediment, tricyclazole residues were detected in 12 out 176 samples collected with the 95% of the measured residue levels below the concentration of 0.03 mg kg −1. Residues were sporadically detected in samples taken after the crop was harvested in November and December. Variables such as the scale of sampling, the season and the year, were significant in determining pesticide residue distribution. The type of water body was less significant.

Contribution of Sampling to the Variability of Pesticide Residue Data

The uneven distribution of pesticide residues among the treated objects leads to an inevitable variability of pesticide residue levels measured in the samples, which may significantly contribute to the combined uncertainty of the analytical results. A total of 8844 unit-crop residue data derived from 57 lots and 19 field trials were evaluated to determine the characteristic features of residue distribution in unit crops and composite samples. The average residue levels and the corresponding coefficient of variation (CV) values obtained for individual units taken from a given lot showed wide variation from lot to lot. There was no significant difference between the CVs of residue levels in sample sets of various unit crops or composite sample populations of different sizes taken from various crops. The CV values for levels of residues taken from individual lots followed normal distribution. Very good correlation was found between the CVs of the parent and sample populations. The experimentally obtained values were very close to those expected on the basis of the central limit theorem. The estimated typical relative standard uncertainties of sampling medium-size crops for pesticide residue analysis in the cases of sample sizes of 5, 10, and 25 were 37, 25, and 16%, respectively.

The potential of pesticides to contaminate the groundwater resources of the Axios river basin. Part II. Monitoring study in the south part of the basin

A monitoring study was conducted during 1992–1994 in the south part of the Axios river basin, which constitutes one of the main rice-cultivated basins of Greece. The potential of pesticides to contaminate groundwater resources was assessed under realistic agricultural conditions using suction lysimeters. Pesticide residues were also measured in local drainage canals, the phreatic horizon and Axios river. Carbofuran, atrazine, alachlor, prometryne and propanil were regularly detected at concentrations exceeding 1 μg/l in the soil water of deeper soil layers and in the phreatic horizon of the fields. Residues of those pesticides were measured in the soil water and the phreatic horizon of all the studied fields even though they had only been applied in certain fields. This almost uniform distribution of pesticide residues across the whole of the studied area was attributed to rice cultivation. Soil water and its pesticidal content was horizontally transported from saturated soil conditions beneath rice paddies to adjacent corn or cotton-cultivated fields with lower soil moisture contents. The presence of high pesticide concentrations in the water of the Axios river, which was used for the irrigation of the studied area, had probably contributed to the generalized pesticide contamination of the soil water in the studied area. These results suggest that there is a high risk for groundwater contamination in the basin.

Assessment of organochlorine pesticide residues in West African city farms: Banjul and Dakar case study.

Validated analytical procedures for the determination of 21 organochlorine pesticides have been applied to 74 water samples, 76 soil samples, and 160 vegetable samples from nine Sene-Gambian farms. Mean pesticide residue levels found were compared to the results of other studies. The main contaminants were DDTs in water (231.9 ng/L), in soil (71.4 ng/g), and in vegetables (5.03 ng/g). The distribution of pesticide residues in water and neighboring soils and the soil-plant transfer of these pesticides is briefly discussed. Different bioconcentration factors for sum HCHs, sum DDTs, and sum endosulfans obtained in this study allow us to confirm the complex processes already reported in the literature concerning the uptake and translocation of chemicals from soil to plant.

Development and characterization of immunoaffinity columns for the selective extraction of a new developmental pesticide: Thifluzamide, from peanuts

The registration of new pesticides requires sensitive and reliable assay methods to determine the distribution of pesticide residues and their corresponding metabolites in soil and crop extracts. We have prepared specific columns to selectively extract a new developmental pesticide: Thifluzamide, from peanut samples. Antibodies generated against the target analyte were covalently immobilized on a silica-based solid support and were evaluated for the selective extraction of the parent compound using high performance liquid chromatography. The specificity of the antibodies was demonstrated as interferents of similar polarity were selectively removed from percolated samples. A simple elution protocol, involving only 4 ml of methanol/water (80/20) was shown to be efficient in recovering 100% of retained parent compound from percolated standard solutions. Such columns could be re-used for more than 10 times with no significant alteration in capacity or elution profile. Column to column reproducibility was also investigated and demonstrated the reliability of the column preparation procedure. Applied to peanut extracts, these columns allowed the development of a simple clean-up procedure consisting of two steps. Sample extracts were first de-fatted before application on the immunoaffinity cartridges. Two different types of cartridges were assayed based on two different solid support materials. Clean chromatograms allowed the quantification of the target analyte in the extracts. Recoveries averaged 77% ( n=5, R.S.D.=14%) for the clean-up procedure and proved the usefulness of this technique in the isolation and purification of this new pesticide in a typical registration study.

Occurrence and spatial and temporal distribution of pesticide residues in groundwater of major corn-growing areas of Greece (1996-1997).

During 1996-1997, residues of selected pesticides were monitored, at 3-month intervals, in 80 wells, including both irrigation and drinking water wells, distributed among the main corn-growing areas (Pieria, Thessaloniki, Serres, Kavala, and Evros) of Greece. Pesticide residues were found in 48% of the wells; however, in most cases residues were very low ranging from LOQs (quantification limits of the analytical methods) to <0.1 microg/L, while in 11% (nine wells) pesticide residues higher than 0.1 microg/L were present. Most of the latter wells were found in Evros and specificallythe Ardas Valley. The frequency of occurrence, in descending order, was atrazine > DEA > alachlor = metolachlor; however, the order of descending concentrations was atrazine > metolachlor > DEA > alachlor. The occurrence and the spatial and temporal distribution patterns of pesticide residues indicate that at the present the situation of groundwater quality is favorable throughout the corn-growing areas of Greece with the exception of the Ardas Valley.

Migration of Pesticide Residues from Agricultural Soil to Groundwater

Abstract The pesticide content of agricultural soil and groundwater was investigated by monitoring three sampling sites located in the Northern Italy and cultivated with maize crop. The GC analyses of soil samples allowed the description of vertical distribution of pesticide residues in the soil profile. High concentrations of pesticide were determined in the superficial horizons while in the deeper layers the contamination reached values less than 0,2 μg/kg. The gas chromatographic results were positively correlated to the ELISA test ones, proving the possibility of utilizing immunoassay tests as a screening procedure.

Pollution potential of selected pesticides in soils

Pollution potential and profile distribution of pesticide residues of atrazine, metolachlor, and cyanazine and atrazine metabolites namely deethylatrazine, deisopropylatrazine and hydroxyatrazine, were studied in a clay loam soil. The field (70 ha) was treated with atrazine for three years (1985–1987) at the rate of 2.22 kg/ha and with metolachlor (dual) and cyanazine (bladex) at the rate of 1.24 and 2.47 kg/ha, respectively in 1987 and 1988. Soil samples were collected, four years after application of the herbicides, at each intersection of a grid (100 m × 100 m) and analyzed for pesticide residues. The results showed that the soil contained the pesticides residues and metabolites in sufficient quantities which potentially contaminate the surface and ground waters with these residues. Atrazine and metolachlor were detected in almost all surface samples, whereas cyanazine was present in only 50 % of the samples. Metolachlor residues were found to be highest among the herbicides studied with an average 103 μg/kg of soil. Atrazine and cyanazine residues concentrations averaged 16 and 10 μg/kg of soil respectively. The concentration of deethylatrazine residues averaged 3.70 μg/kg of soil and that of deisopropylatrazine averaged 0.74 μg/kg. Hydroxyatrazine residues averaged 5.41 μg/kg of soil and were highest among the metabolites studied. The distribution down the soil profile was found to be irregular for all the three herbicides and the metabolites investigated.

Spatial Distribution of Pesticide Residues in a Former Apple Orchard

AbstractDuring the period 1900–1950, considerable amounts of Pb arsenate pesticides were used in apple orchards. Many of these orchards are not in fruit production any longer and are used for home gardening, pasture, or forage and vegetable cropping. This paper examines the spatial distribution of inorganic pesticide residues in an abandoned orchard in central Massachusetts.Maximum Pb and As concentration in surface soils sampled in a grid‐like pattern, were 870 µg g−1 and 120 µg g−1, respectively. Areas high in contaminants were either former tree sites or low spots where spray residues collected. A transect through the approximate location of a former tree site showed Pb and As concentrations under the dripline of 1400 µg g−1 and 330 µg g−1, respectively, and lower values of 170 µg g−1 and 50 µg g−1 outside the periphery of the crown. Lead, arsenic, and zinc concentrations decreased with increasing depth, with maximum concentrations in the upper 5 cm. No evidence of significant leaching of Pb, As, Zn, or Cu was observed below the 20‐cm depth. The rather insoluble Pb orthoarsenate appeared to be the predominant species for the Pb and As residues.

Preliminary experiments on the application of zonal ultracentrifugation to studies of pesticide distribution in subcellular components of mammalian tissues

Differential and zonal ultracentrifugations were used in preliminary studies of the distribution of cholinergic carbamate insecticides in subcellular regions of rat brain and liver. Following acute intoxication with carbonyl- 14C labeled Banol, radioactivity was observed to be present in various subcellular fractions. Radiometric and enzymic assay of microsomal subunits indicated that an esterase enzyme and carbamate migrated with the solubilized endoplasmic reticulum. The zonal ultracentrifuge proved valuable in separating and isolating large quantities of biological material and should continue to be useful in studies of distribution of pesticide residues in animal (and possibly plant) tissues.