RESUMO
The chronic toxic effect of Metanil Yellow on the gills of freshwater teleost Heteropneustes fossilis (Bloch) was studied. The ?shes were exposed for 45 days treatment in 2g/L of Metanil Yellow. However, after 45 days treatment, marked pathological changes in the gills were found. Necrosis found in the primary gill lamellae. Shortened and clubbing ends of the secondary gill lamellae. Buldging tip of primary gill ?laments and distortion was occurred in the shape of secondary ?lament. Pycnotic nuclei, vacuolization and degenerative epithelial cells were found
RESUMO
The extraction of chromite is being carried out since 1950 in Sukinda valley region of Odisha in India. Different physico-chemical parameters and level of metals in groundwater (tube well and dug well), surface water (Damsal nala), mining drainage water and bottom sediment of Damsal nala were analysed. The results revealed that the total Cr content of groundwater (0.04-0.07 ppm), Damsal nala (0.10 - 0.20 ppm) and mine drainage water (20.12-56.51 ppm) exceeded the permissible limit in all seasons. The Cr (VI) content of mine drainage water exceeded the permissible limit (0.05 ppm as per the recommendation of WHO). The pH (6.5-7.9), available N (6.27-18.82 kg ha-1), available PO4-3 (15.39-123.11 kg ha-1), available K+ (21.07-410.89 kg ha-1) and organic matter (0.20-1.55%) content of bottom sediment of Damsal nala varied seasonally and the lowest values were found during monsoon. The physico-chemical characteristics of water from Damsal nala, groundwater and mine drainage, like COD, total Fe, TDS, TSS, F-, available PO4-3, available K+ etc., including pH are a serious concerned in this study area.
RESUMO
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.