Sewage sludge, rich in organic matter and nutrients, is widely used as a fertilizer to increase the fertility of soil. The direct application of sewage sludge without any treatment causes soil contamination as well as significantly affects the earthworm population. In the present study, the effect of sewage sludge-amended soil on growth, enzyme activities, and the DNA damage in Pheretima posthuma earthworms was studied under wheat straw and biochar treatment of 30-day laboratory incubation. Wheat straw, biochar, and sewage sludge were applied at 0 (control), 5, 10, and 25% w/w along with combined treatment of sewage sludge with biochar and wheat straw, respectively at 25% each. After the incubation period, the percentage change in mean weight and length was measured and esterase and phosphatase enzyme activities were quantitatively determined. RAPD-PCR and the comet assay were performed to assess the genotoxicity. A significant weight loss was observed (26%) at a 25% rate of sewage sludge and biochar (11%). Similarly, a maximum decrease in length was observed with sewage sludge (2.5%) followed by biochar (0.80%) at a 25% application rate. Mean weight and length both decreased by increasing the rate of sewage sludge and biochar. In addition, no change was observed in the weight and length of P. posthuma in the treatment consisting of sewage sludge and wheat straw. Moreover, sewage sludge caused inhibition of esterase and phosphatase activities as well as induced DNA damage. The comet parameters showed that wheat straw and biochar ameliorated the toxic effects of sewage sludge. It is, therefore, concluded that sewage sludge has a tangible impact on earthworms which ultimately disrupts ecosystem functions and wheat straw and biochar can thus be utilized to reduce the toxicity of sewage sludge in Pheretima posthuma earthworms.

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Moringa is a known medicinal plant utilized for the food supplementation and treatment of various diseases. A study was conducted to evaluate the toxicity of moringa leaf extract (MLE) and moringa seed extract (MSE). For the purpose, male Sprague-Dawley rats were used and both MLE and MSE up to 2200 mg/kg were orally administered in an acute toxicity trial of the extracts. A sub-acute toxicity trial was also done by daily administration of the extracts at 600, 1000 and1800 mg/kg body weight orally for 21 days and distilled water was given to the control group. In acute toxicity test, moringa extracts caused no death in animals even at 2200 mg/kg dose. In sub-acute toxicity study non-significant differences were observed in all the haematological and biochemical parameters at all doses of MLE and MSE in rats group compared to the control. Moreover, food intake of all the treated rats was reduced compared with the control and significant changes were observed in the body weight of the rats. Hence, the study concluded that both moringa leaf and seed extracts were safe for remedial purpose and can safely be used for human and animal feed purpose.

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Authors' Contribution CA, Asmatullah and SA conceived the idea, executed the research and wrote the manuscript. SH, MA and SA performed experimental work. CA, SH, MA, BZ performed enzyme assays, statistical analysis, manuscript editing.