Morpho-histological and enzymatic alterations in earthworms Drawida willsi and Lampito mauritii exposed to urea, phosphogypsum and paper mill sludge

Abstract

ABSTRACTThe effects of varying concentrations of urea, phosphogypsum and paper mill sludge (PMS) on the morphology, histology, tissue protein content, lipid peroxidation (LPX), activities of lactate dehydrogenase (LDH), acetylcholinesterase (AChE) and catalase in earthworms Drawida willsi and Lampito mauritii have been studied over an exposure period of 24 hr. Integumentary lesions, clitellar swelling and loss of pigmentations were found to be major morpho-pathological changes in the worms. Histology indicated cuticular damage, ruptured epithelium and muscle fibres with accumulation of cellular debris. Lowest tissue protein content (57.02 ± 4.02 mg/g tissue) and highest LPX (0.113 ± 0.04, 0.137 ± 0.08 nmol/mg protein) were noticed in D. willsi at a high concentration of PMS, whereas highest tissue protein content was observed in L. mauritii (115.32 ± 7.18 mg/g tissue) with the same treatment. In both the species, LDH activity was minimum at a high concentration of urea (0.172 ± 0.02; 0.247 ± 0.08 U/mg protein). AChE activity was highest (0.099 ± 0.002 U/mg protein) at a high concentration of PMS in D. willsi, whereas catalase activity was the maximum (0.338 ± 0.02 U/mg protein) at high concentrations of PMS in L. mauritii. The study indicated that morpho-histological and enzymatic alterations in these earthworms exposed to agrochemicals could be useful biomarkers to evaluate soil toxicity.