Impact of diesel oil effluent in the mucosal surface of the alimentary canal of Oreochromis nilotica (Linnaeus): a scanning electron microscopic study

Adverse effects of diesel oil on microanatomical structure of the alimentary canal of O. nilotica were studied using SEM observations. The study revealed irregular arrangement of the stratified epithelial cells along with fragmentation of the normal concentric pattem of microridges of the same cells in buccopharynx and oesophagus. The excessive secretion of mucus of buccopharynx and oesophagus were the salient changes caused by diesel oil pollution. The destruction and degeneration of the mucosal folds of stomach and intestine along with their epithelial cells exhibited a concrete hyperactivity resulting in abundant' secretion of mucus over the microridges of the epithelial cells. In the intestinal region the columnar epithelial cells showed tumefaction and microvilli of the plasma membrane of epithelial cells get heavily damaged. Disarray of the microridges of epithelial cells, excessive secretions of mucus formation of even cell sheet were the most conspicuous changes in rectum. It was concluded that chronic exposure of diesel oil may hamper the absorption of the nutrients through alimentary canal resulting into ill-growth and production of the fish.     

Methane and nitrous oxide emissions from an irrigated rice of North India

Upland rice was grown in the kharif season (June-September) under irrigated condition in New Delhi, India (28 degree 40'N and 77 degree 12'E) to monitor CH4 and N2O emission, as influenced by fertilizer urea, ammonium sulphate and potassium nitrate alone (at 120 kg ha-1) and mixed with dicyandiamide (DCD), added at 10% of applied N. The experimental soil was a typic ustochrept (Inceptisol), clay loam, in which rice (Oryza sativa L., var. Pusa-169, duration: 120-125 days) was grown and CH4 and N2O was monitored for 105 days by closed chamber method, starting from the 5 days and 1 day after transplanting, respectively. Methane fluxes had a considerable temporal variation (CV=52-77%) and ranged from 0.05 (ammonium sulphate) to 3.77 mg m-2 h-1 (urea). There was a significant increase in the CH4 emission on the application of fertilizers while addition of DCD with fertilizers reduced emissions. Total CH4 emission (105 days) ranged from 24.5 to 37.2 kg ha-1. Nitrous oxide fluxes were much lower than CH4 fluxes and had ranged from 0.18 to 100.5 g m-2 h-1 with very high temporal variation (CV=69-143%). Total seasonal N2O emission from different treatments ranged from 0.037 to 0.186 kg ha-1 which was a N loss of 0.10-0.12% of applied N. All the fertilizers significantly increased seasonal N2O emission while application of DCD reduced N2O emissions significantly in the range of 10-53%.     

Chemopreventive role of Indigofera aspalathoides against 20-methylcholanthrene-induced carcinogenesis in mouse

This investigation was undertaken to evaluate the chemopreventive effect of hydroalcoholic extract of Indigofera aspalathoides (HAIA) against 20-methylcholanthrene (20-MC)-induced carcinogenesis in mice. Tumor was induced by single subcutaneous administration of 20-MC (200 µg per mouse) in Swiss albino mice. After 24 h of 20-MC administration, HAIA was administered at the doses of 250 and 500 mg kg^?1 body weight orally for 90 consecutive days. Mice of all groups were observed for 15 weeks to record tumor incidence (fibrosarcoma) and survival time. After 15 weeks the mice were sacrificed for the estimation of hematological profiles like hemoglobin (Hb), white blood cell (WBC), red blood cell (RBC), and liver biochemical parameters, namely lipid peroxidation, reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT). HAIA treatment markedly reduced tumor incidence and prolonged the life span of sarcoma-bearing mice as compared to 20-MC control mice. Hematological profiles were significantly (p < 0.001) restored to normal levels in HAIA-treated mice as compared to 20-MC control mice. HAIA treatment significantly (p < 0.001) modulated the aforesaid liver biochemical parameters as compared to 20-MC control. The results concluded that I. aspalathoides demonstrated a remarkable chemopreventive effect in chemical-induced carcinogenesis in mouse. The potential chemopreventive action may be due to its antioxidant and detoxifying properties.     

Effect of long-term application of treated sewage water on heavy metal accumulation in vegetables grown in Northern India

Use of industrial and wastewater for irrigation is on the rise in India and other developing countries because of scarcity of good-quality irrigation water. Wastewaters contain plant nutrients that favour crop growth but leave a burden of heavy metals which can enter the food chain and is a cause of great concern. The present study was undertaken on the long-term impact of irrigation with treated sewage water for growing vegetables and the potential health risk associated with consumption of such vegetable. Treated sewage water (TSW), groundwater (GW), soil and plant samples were collected from peri urban vegetable growing areas of Northern India (Varanasi) and analysed to assess the long-term effect of irrigation with TSW on Cd, Cr, Ni and Pb build-up in soils and its subsequent transfer into commonly grown vegetable crops. Results indicate that TSW was richer in essential plant nutrients but contained Cd, Cr and Ni in amounts well above the permissible limits for its use as irrigation water. Long-term application of TSW resulted in significant build-up of total and DTPA extractable Cd, Cr, Ni and Pb over GW irrigated sites. TSW also resulted in slight lowering in pH, increase in organic carbon (1.6 g kg^− 1) and cation exchange capacity (5.2 cmol kg^− 1). The tissue metal concentration and relative efficiency of transfer of heavy metals from soil to plant (transfer factor) for various groups of vegetables were worked out. Radish, turnip and spinach were grouped as hyper accumulator of heavy metals whereas brinjal and cauliflower accumulated less heavy metals. Health risk assessment by consumption of vegetables grown with TSW indicated that all the vegetables were safe for human consumption. However, significant accumulation of these heavy metals in soil and plant needs to be monitored.