Leaching behaviour of pendimethalin causes toxicity towards different cultivars of Brassica juncea and Brassica campestris in sandy loam soil

Assessment of the ameliorative effect of curcumin on pendimethalin-induced genetic and biochemical toxicity

The present study aimed to assess the toxic effects of pendimethalin herbicide and protective role of curcumin using the Allium test on cytological, biochemical and physiological parameters. The effective concentration (EC₅₀) of pendimethalin was determined at 12 mg/L by the root growth inhibition test as the concentration reducing the root length by 50%. The roots of Allium cepa L. was treated with tap water (group I), 5 mg/L curcumin (group II), 10 mg/L curcumin (group III), 12 mg/L pendimethalin (group IV), 12 mg/L pendimethalin + 5 mg/L curcumin (group V) and 12 mg/L pendimethalin + 10 mg/L curcumin (group VI). The cytological (mitotic index, chromosomal abnormalities and DNA damage), physiological (rooting percentage, root length, growth rate and weight gain) and oxidative stress (malondialdehyde level, superoxide dismutase level, catalase level and glutathione reductase level) indicators were determined after 96 h of treatment. The results revealed that pendimethalin treatment reduced rooting percentage, root length, growth rate and weight gain whereas induced chromosomal abnormalities and DNA damage in roots of A. cepa L. Further, pendimethalin exposure elevated malondialdehyde level followed by antioxidant enzymes. The activities of superoxide dismutase and catalase were up-regulated and glutathione reductase was down-regulated. The molecular docking supported the antioxidant enzymes activities result. However, a dose-dependent reduction of pendimethalin toxicity was observed when curcumin was supplied with pendimethalin. The maximum recovery of cytological, physiological and oxidative stress parameters was recorded at 10 mg/L concentration of curcumin. The correlation studies also revealed positive relation of curcumin with rooting percentage, root length, weight gain, mitotic activity and glutathione reductase enzyme level while an inverse correlation was observed with chromosomal abnormalities, DNA damage, superoxide dismutase and catalase enzyme activities, and lipid peroxidation indicating its protective effect.

Dissipation of Pendimethalin in Soybean Crop Under Field Conditions

Persistence of pendimethalin was studied in soil, soybean pods, straw and water under field conditions. Pendimethalin was applied at 1 and 2 kg a.i. ha(-1). Residues in soil were detected up to 60 and 90 days at the recommended and double dose, respectively. Dissipation followed first order kinetics and was accounted for by a biphasic pattern. The half-life for the initial phase and later phase was 12.73 and 26.60 days, respectively, for recommended and 7.25 and 37.91 days, respectively, for double dose. The limit of quantification was 0.005 µg g(-1) of sample. Percent recovery from soil, oil, defatted cake, straw and water samples fortified with 0.01-1.0 mg kg(-1) varied from 84.5 %-89.6 %, 84.6 %-88.7 %, 79.4 %-86.0 %, 78.2 %-85.6 % and 90.2 %-93.0 %, respectively. At harvest, pendimethalin residue in soybean pods, straw, and soil were below detectable limits. No residues of pendimethalin were detected in ground water. Current application of pendimethalin in the environment is not expected to cause adverse health effects form the consumption of soybeans.