An investigation was conducted from 2001 to 2005 for determining the residual concentration of five pesticides, viz., total-HCH, total-DDT, total-Endosulfan, Dimethoate and Malathion in fish samples collected from various points of the river Ganga. Fish samples were analyzed for pesticide residues using standard laboratory procedures by GC method. It was found that total-HCH concentration remains above the MRL values for maximum number of times in comparison to four other pesticides. The pesticide contamination to fish may be due to indiscriminate discharge of polluted and untreated sewage-sludge to the river. The pesticide contents in some places are alarming. Thus proper care, maintenance, treatment and disposal of sewage water and sludge are most vital and should be the prime thrust for the nation.

A total of 75 animals between 1.5 and 8 years old were randomly selected for the study. Of these, 57.8% were cross-bred animals and the rest were non-descript. Moreover, 61.8% of the animals under study were brought for slaughter from local sources and the rest from farm houses. Samples collected from five districts revealed contamination with traces of organochlorine pesticides (0.01-0.22 microg g(-1)) and organophosphorus pesticides (0.111-0.098 microg g(-1)). In general, all the raw meat samples possessed dichlorodiphenyltrichloroethane at the highest level. Contamination was highest in cow meat samples and lowest in chicken samples. No particular district-wise trend was obtained for the pesticides selected for analysis. Subsequent decontamination study revealed that cooking is the best option in reducing pesticide load in raw meat samples. Cooked chicken is the safest foodstuff for consumption.

Dissipation of Quinalphos (Ekalux 20 AF) and Methomyl (Lannate 12.5 L) residues were studied in/on Okra (var. Pusa Sawani) fruits and cropped soil at Baruipur, West Bengal, India. The insecticides were applied at 21 days after sowing by foliar spray at the recommended and double the recommended dose (i.e. 500 and 1,000 g a.i. ha(-1) in both the cases). Four sprays were given at 15 days interval in all the cases. The initial build-up residue on Okra fruits was to the magnitude of 3.20 and 7.50 microg g(-1) for Quinalphos, 5.61 and 8.42 microg g(-1) for Methomyl at lower and higher doses respectively. The half-lives (t(1/2)) in Okra fruit were found to be 1.25-1.43 days for Quinalphos and 0.88-0.94 days for Methomyl. The safe waiting period (T(MRL)) determined were 6.7 and 5.3 days at the lower dose of Quinalphos. The corresponding waiting period for Methomyl were 5.7 and 4.9 days. Decontamination process like washing and cooking dislodged 25.50%-81.50% residue depending on insecticides and doses, whereas 20.00%-69.60% surface residue was removed by washing alone. The residues of both insecticides in soil persisted for 6-8 days depending on dose. The half-lives in soil were found to be 1.07-1.20 days for Quinalphos and 0.97-1.25 days for Methomyl.

Quinalphos 20 AF was applied at the rate of 500 and 1,000 g a.i. ha(-1) in cabbage for two consecutive seasons and the samples harvested at intervals of 0 (3 h after application), 2, 4, 6, 8, and 10 days interval after application. The calculated half-life values were 1.27-1.38 days and 1.12-1.24 days for cabbage heads and cropped soil, respectively. The calculated safe waiting period based on field dissipation study was 5.28-6.7 days, which indicated its persistence nature. Thus, to reduce the safe waiting period, efforts were made to decontaminate the Quinalphos residue from cabbage head by various household preparations (viz. washing, cooking, washing plus cooking, salt water dipping, dipping in boiled salt water, dipping in detergent solution, and dipping in boiled detergent solution). Statistical analysis of the data using Duncan's multiple range test revealed that various household processing substantially reduced the residue of Quinalphos in cabbage heads in the range of 27.72-75.01% irrespective of any dose and seasons, but none were able to satisfactorily bring down the residue below the tolerance level of 0.05 mg kg(-1).

Laboratory degradation studies were performed in water at pH 4.0, 7.0 and 9.2 using Prochloraz (450 EC) formulation at the concentration of 1.0 (T1) and 2.0 (T2) µg/mL. Water samples collected on 0 (2 h), 3, 7, 15, 30, 45, 60 and 90 days after treatments were processed for residue analysis of Prochloraz by HPLC-UV detector. In 60 days, dissipation was 89.1–90.5% at pH 4.0, 84.1–88.2% at pH 7.0, and 92.4–93.8% at pH 9.2 in both treatments. The results indicate that at pH 7.0 the degradation of Prochloraz was much slower as compared to other two. Between pH 4.0 and 9.2 the degradation of compound is little faster at pH 9.2. The half-life periods observed were 18.35 and 19.17 days at pH 4.0, 22.6 and 25.1 days at pH 7.0 and 15.8 and 16.6 days at pH 9.2 at T1 and T2 doses respectively.