has been widely recommended as a preliminary step in toxicological studies on fishes (McLeay, 1976; Whittle and Flood, 1977; USEPA, 1973, 2005; APHA, 1998, 2005; Chapman, 2000; Ali and Sree- Krishnan, 2001; ASTM, 2002; Parrott et al., 2006; Moreira et al., 2008). The static bioassay procedures to study the toxicity of pulp and papermill effluent to variety

Acute toxicity and behavioral response of freshwater fish, Mystus vittatus exposed to pulp mill effluent

The gonads of spawning Mystus vittatus exposed for 96 h to the LC50-96 h dose (i.e. 550 ppm) of NPK, the agricultural fertilizer, were biochemically analysed for their carbohydrate content. The glucose and glycogen contents of the spawning fish were found to be lowered significantly, and the total carbohydrate and lactic acid contents altered insignificantly, under the pollutional stress. The stressed fish also exhibited the presence of some additional free sugars within their gonads.

Biochemical study of the gonads of Mystus vittatus exposed to the fertilizer NPK during the spawning season. Part 1: Carbohydrates

Increased use of fertilizers to increase plant production causes important environmental pollution not only in soil but also in water resources. Soil structure, water quality, water systems, and biodiversity are adversely affected by the unconscious use of fertilizers. In this study, Capoeta capoeta (Guldenstaedt 1773) were used to investigate the degenerative effects of nitrogen fertilizer. Twentyfour fish were equally allocated into three groups; group 1 (control), group 2 (15 mg/L nitrogen fertilizer in water) and group 3 (15 mg/L nitrogen fertilizer in water). Fish were exposed to the fertilizer for 15 days and then the tissues of gill, liver and intestine were investigated by immunohistopathological and biochemical means to assess the tissue degenerative effects of nitrogen fertilizers in water. Varying degrees of degenerative changes were observed in all of the investigated organs. In histopathological examinations, hydropic degeneration was observed in hepatocytes in fish exposed to fertilizer. Blunting and association in the gill tissue and occasional blunting in the intestinal tissue were detected. Catalase and SOD immunoreactivities increased in liver and gill tissues. There was also an increase in SOD immunoreactivity in the intestine of nitrogen fertilizer exposed fish. Total antioxidant status (TAS) also increased in both of the experimental groups (p < 0.05), but total oxidant status (TOS) did not change. The results of the experiment showed that nitrogen fertilizer in water resources may impair health status of fish by adversely affecting tissues in cellular level. 

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Effects of nitrogen fertilizer on Capoeta capoeta: an immunohistopathological and biochemical investigation

The tolerance level of the fertilizer NPK for the freshwater siluroid Mystus M. vittatus (BL.) and histopathological changes in the gill of this fish against two concentrations of NPK were investigated. It was found that at 400 ppm (24 h) mortality in the fish started, and at 700 ppm (96 h) all the fish died. Hence the concentration of NPK at 400 ppm was taken as an experimental concentration for this fish.



Curling towards the upperside in the secondary lamellae resulting in the joining with each other and profuse mucus secretion and subsequent death of 40% of the fish (96 h) were observed.



At 700 ppm (96 h) NPK, which is far higher than the highest tolerance limit of the fish, all the fish died. Profuse mucus secretion, formation of subepithelial spaces, sloughing of epithelial layer, leaving only the rows of pilaster cells, resulting in the death of the fish, were observed.



The mortality of the fish was due to asphyxiation and damage in the gill tissues resulting in the alteration in the respiratory and osmoregulatory metabolism.

R. K. Pande

Papers

Tolerance measurement and histopathological observations on the gills of Mystus M. vittatus under the toxic stress of the fertilizer NPK