Behavior of the organophosphorus insecticide fenitrothion in stored faba beans and its biological effects towards experimental animals

Sound whole-seed faba beans were treated with (methyl-¹⁴C) fenitrothion [O, O-dimethyl-O-(3-methyl-4-nitrophenyl) phosphorothioate] at 5 and 10 mg insecticide/kg seeds, a dose normally used in practice. During the 30 weeks of storage period, the penetration and distribution of insecticide residues were studied. The amount of surface residues, internal residues and bound insecticide residues was estimated. Surface residues were found to decrease with the increase in time of storage, whereas internal residues showed a gradual increase with time apparently not dose dependent. Grain-bound residues increased with time and reached to its maximum (14–18%) after 24 weeks of storage. Chromatographic analysis of the internal extracts revealed the presence of the parent compound together with three main metabolites which were found in both free and conjugated form. Feeding mice for 90 days with a diet mixed with total internal fenitrothion residues in stored faba beans led to a reduction in body weight gain, and an appreciable decrease in cholinesterase activity of 32% for plasma and 15% for red blood cells (RBC_S) after two months of experiment. Also, a significant decrease was showed in both total protein and albumin concentration at the end of feeding period (90 days). Liver and kidney function, as well as lipid profile of treated mice significantly increased at the end of feeding period. After a one-month recovery period, all the examined blood parameters returned to about the control values except blood urea and serum triglyceride.     

Degradation kinetics of forchlorfenuron in typical grapevine soils of India and its influence on specific soil enzyme activities

The rate of degradation of forchlorfenuron, a cytokinin-based plant growth regulator (PGR) was explored in typical grapevine soils of India with simultaneous evaluation of its effect on biochemical attributes of the test soils in terms of the activities of specific soil microbial enzymes. In all the test soils, namely clay, sandy-loam and silty-clay, the dissipation rate was faster at the beginning, which slowed down with time, indicating a non-linear pattern of degradation. Degradation in soils could best be explained by two-compartment 1st + 1st order kinetics with half-life ranging between 4–10 days. The results suggest that organic matter might be playing a major role in influencing the rate of degradation of forchlorfenuron in soil. The rate of degradation in sandy-loam soil was fastest followed by clay and silty-clay soils, respectively. Comparison of the rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Changes in soil enzyme activities as a consequence of forchlorfenuron treatment were studied for extra-cellular enzymes namely acid phosphatase, alkaline phosphatase and β -glucosidase and intracellular enzyme-dehydrogenase. Although small changes in enzyme activities were observed, forchlorfenuron did not have any significant deleterious effect on the enzymatic activity of the test soils. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily the effect of the incubation period rather than the effect of forchlorfenuron itself.     

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), β -glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils. The MBC of the soils ranged from 295.5 to 767.5 μ g g^{? 1}. The BSR and SIR ranged from 1.65 to 3.08 μ g CO₂-C g^{? 1} soil h^{? 1} and 3.08 to 10.76 μ g CO₂-C g^{? 1}h^{? 1} respectively. The β -glucosidase and FDHA of the soils varied from 33.3 and 76.3 μ g para-nitrophenol g^{? 1} soil h^{? 1} and 60.5 to 173.5 μ g fluorescein g^{? 1}h^{? 1}respectively. The tea garden soils contained variable residues of organophosphorus and organochlorine pesticides, which negatively affected the MBC, BSR, SIR, FDHA and β -glucosidase activity. Ethion and chlorpyriphos pesticide residues in all the tea garden soils varied from 5.00 to 527.8 ppb and 17.6 to 478.1 ppb respectively. The α endosulfan, β endosulfan and endosulfan sulfate pesticide residues in the tea garden soils ranged from 7.40 to 81.40 ppb, 8.50 to 256.1 ppb and 55 to 95.9 ppb respectively. Canonical correlation analysis shows that 93% of the total variation was associated with the negative impact of chlorpyriphos, β and α endosulfan and endosulfan sulfate on MBC, BSR and FDHA. At the same time ethion had negative impact on SIR and β -glucosidase. Data demonstrated that the pesticide residues had a strong impact on the microbial and biochemical components of soil quality.     

Persistence and distribution of pesticide residues in fresh agricultural food consumed in the province of Bologna

The presence of pesticide residues in fresh vegetables and fruit have been qualitatively and quantitatively determined at the laboratories of the Regional Agency for Environmental Protection (ARPA), Division of the Province of Bologna. More than 1,700 samples have been tested by routine analyses. The possible risks for consumers have been evaluated by various parameters. The most important ones were: the amount of each residue; the respective ADI (Acceptable Daily Intake) limit; the contemporary presence of different residues; an estimation of the daily intake, based on the amount of fruit and vegetables consumed per person. It has been possible to evaluate that the daily intake of pesticide residues in the province of Bologna during the period 2003–06 resulted lower than the ADI limits concerning the vegetables. According to the information on fruit consumption the daily intake of omethoate (O,O-dimethyl S-methylcarbamoylmethyl phosphorothioate) resulted higher than its ADI limit, of dicofol (2,2,2-trichloro-1,1-bis(trichloromethyl)benzenemethanol) very close to the admitted limit, under the respective limits for all the other residues.     

A simple HPLC method for determination of permethrin residues in wine

An isocratic High Performance Liquid Chromatographic (HPLC) method was optimized for 3-phenoxybenzyl (1RS)-cis-trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylate (permethrin) residues identification and quantification in wine matrix. Analytical reverse phase (RP) C-18 column was used (25 cm × 4 mm i.d., 5 μ m) with mobile phase consisting of acetonitrile and water in ratio 70 %/30 % (v v^?1), flow-rate 2.0 mL min^?1, UV-detection at 215 nm and controlled oven temperature at 25°C. The peaks of isomers were identified with the retention times as compared to standard cis-/trans- mixture and confirmed with characteristic spectra using photodiode array detector. Under these conditions, permethrin isomers were well separated with resolution 2.8 and no interference with the naturally present wine compounds was observed. The method was validated for linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ). Linear regression analysis data proved a good linear relationship (correlation coefficients, r², for cis- and trans-isomer are: 0.9995 and 0.9997, respectively) between response of the detector and concentration of permethrin isomers over a wide concentration range for both isomers (0.55 mg L^?1 ?4.40 mg L^?1). Experimental data showed mean recoveries between 93.95% and 96.58% with RSD values in range: 0.89% ?3.69%. The effect of ethanol content in the solvent on permethrin isomers peak areas was also studied and 60% v v^?1 ethanol was found to be optimal for sample preparation. The method was successfully tested on 20 commercial wine samples from the market in which no permethrin was detected. Thus, it was proved that it is suitable for routine permethrin residues analysis. The proposed method is suitable for routine analysis because of the simple sample preparation, acceptable run-time, low cost and its applicability with conventional instruments.     

Sorption of atrazine and metolachlor by earthworm surface castings and soil

Abstract

Atrazine and metolachlor were more strongly retained on earthworm (Lumbricus terrestris L.) castings than on soil, suggesting that earthworm castings at the surface or at depth can reduce herbicide movement in soil. Herbicide sorption by castings was related to the food source available to the earthworms. Both atrazine and metolachlor sorption increased with increasing organic carbon (C) content in castings, and Freundlich constants (K_f values) generally decreased in the order: soybean‐fed > corn‐fed > not‐fed‐earthworm‐castings. The amount of atrazine or metolachlor sorbed per unit organic carbon (K_oc values) was significantly greater for corn‐castings compared with other castings, or soil, suggesting that the composition of organic matter in castings is also an important factor in determining the retention of herbicides in soils. Herbicide desorption was dependent on both the initial herbicide concentration, and the type of absorbent. At small equilibrium herbicide concentrations, atrazine desorption was significantly greater from soil than from any of the three casting treatments. At large equilibrium herbicide concentrations, however, the greater organic C content in castings had no significant effect on atrazine desorption, relative to soil. For metolachlor, regardless of the equilibrium herbicide concentration, desorption from soybean‐ and corn‐castings treatments was always less than desorption from soil and not‐fed earthworm castings treatments. The results of this study indicate that, under field conditions, the extent of herbicide retention on earthworm castings will tend to be related to crop and crop residue management practices.     

Agricultural Pesticide Residues in Farm Ditches of the Lower Fraser Valley,British Columbia,Canada

Transient and permanent farm ditches flowing to the Lower Fraser River tributary fish streams of British Columbia, Canada, were sampled at several locations in 2003–2004 to determine the occurrence and concentration of residues of selected pesticides, their transformation products, and soluble/extractable Cu⁺⁺ ions. Of the 43 compounds analyzed, 28 and 22 pesticides were detected in transient farm ditch water and sediments, respectively. About 34% fewer pesticides, however, were found in both matrices of permanent farm ditches. Average concentrations (μ g L^?1) of those most frequently detected in permanent farm ditch water were atrazine (0.20), α -chlordane (0.06), desethylatrazine (0.13), diazinon (0.55), dieldrin (0.28), endosulfan sulfate (0.16), glyphosate (6), metalaxyl (0.27); and soluble Cu⁺⁺ ions (25). Those most often found in ditch sediments (μ g kg^?1) were aminomethylphosphonic acid (AMPA) (2,300), 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) (250), endosulfan sulfate (500), glyphosate (1,225); and extractable Cu⁺⁺ ions (58,000). The risk potential of these pesticide residues to non-target aquatic organisms inhabiting Fraser River tributary fish streams contiguous to permanent farm ditches is evaluated and discussed.     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

Bioavailability to rats of 14C‐lindane residues in stored potato tubers

Abstract

Potato tubers were applied with radiolabelled lindane (U‐¹⁴C γ‐ 1,2,3,4,5,6 hexachlorocyclohexane) at three dose levels 30, 150, and 300 ppm and stored for 30, 60 and 90 days at room temperature. The data revealed that lindane penetrated into the pulp tissues through the epidermal layer. The amounts recovered in the peel were found to increase with a greater storage period up to 60 days followed by a drop at 90 days. On the other hand, there was a slight increase in radioactivity in the pulp tissue from 30 to 60 days followed by significant increase after 90 days. The incorporation of the compound in the tubers was dose independent. Methanol extraction showed binding of about 8.1% and 5.8% ofthe applied dose in peel and pulp tissues, respectively. The insecticide was found to be bioavailable when rats health hazard. It is therefore, desirable to demonstrate that the quantity of the terminal residues may be safe for the consumer. In the present investigation an attempt was made to determine the fate and bioavailability of lindane when applied to stored potato tubers.     

Dissipation of chlorpyrifos,oxon, and 3,5,6‐trichloro‐2‐pyridinol in litter and elm forest soil

Abstract

After chlorpyrifos was applied to the basal 1 meter of elm tree trunks for control of elm bark beetles at two different application times and sites, initial chlorpyrifos residues in forest floor litter ranged from 120 to 916 μg/g depending on the application time. Residues dissipated by approximately 99% after 791 d with the DT₅₀ from 3.9 to 59 d and DT₉₀ from 55 to 310 d. The initial residues of chlorpyrifos in elm forest soil varied from 0.8 to 28 μg/g and were 1 to 2 μg/g at 791 d after application. The dissipation half‐lives of chlorpyrifos in fortified soil placed in the field ranged from 116 to 121 d.