Anulipi Aich

Ecotoxicological Assessment of Tannery Effluent Using Guppy Fish (Poecilia reticulata) as an Experimental Model: A Biomarker Study

Tannery wastewater in the East Calcutta Wetlands (a Ramsar site of West Bengal; number 1208) exerts adverse effects on commercial fish production and subsequently affects humans. The present study was conducted to investigate acute and chronic toxicity of tannery effluent on a fish biosystem by examining oxidative stress enzyme expression in different organs including liver, gills, and muscle following exposure. Phosphatases, both alkaline phosphatase and acid phosphatase, and antioxidant superoxide dismutase and catalase enzyme activities were determined in guppy fish (Poecilia reticulata) exposed to sublethal concentrations of composite tannery effluent. Data demonstrated that tannery effluent was capable of interfering with metabolic processes of fish by altering stress enzyme activities in fish organs, resulting in cellular injury. Data suggest that elevated activities of stress enzymes in fish upon exposure to environmental pollutants may serve as important biomarkers for oxidative stress.

Assessment of the spatio-temporal distribution of soil properties in East Kolkata wetland ecosystem (A Ramsar site: 1208)

The present investigation was made to characterize spatial and temporal variations in soil properties and to evaluate possible differences that could be dependent on the tannery effluent discharges, municipal sewage discharges, vegetation cover, soil settlement rate, crop rotation, etc. Soil total organic matter (TOM), cations like, Sodium (Na), Ammonium (NH4), Potassium (K), Calcium (Ca) and Magnesium (Mg) contents in the bank soils and bottom sediments were recorded from seven different characteristic sites in East Kolkata wetland ecosystem, a Ramsar site (Ramsar site No. 1208). The profile maps were constructed by geostatistical methods to describe the spatial distribution as well as temporal variations of all the factors to identify the influences of composite wastewaters. The work was initiated to identify causes and consequences of the waste dumping in the concerned region for the past hundred years and thereby to suggest necessary precautionary measures to prevent further loss of soil quality.

Antioxidant response to oxidative stress in zooplankton thrived in wastewater-fed ponds in East Calcutta Wetland Ecosystem, a Ramsar site

The municipal sewage of Calcutta city together with industrial effluents traversed the East Calcutta Wetlands (ECW) (Ramsar Site No. 1208) for nearly a century. The composite wastewater at the ECW, was used for pisciculture and agriculture after natural stabilization. Such uses have always been thought to be a source of contamination to biota and humans. Some water-borne pollutants generate reactive oxygen species including superoxide radical anion (O2−.), hydrogen peroxide (H2O2), and hydroxyl radical (.OH), which are highly reactive and potentially deleterious to biological systems. The present study was initiated to examine the antioxidant activities against oxidative stress during different seasons in body fluids of two zooplankters, Moina micrura and Mesocyclops leuckarti thriving in wastewater-fed ponds of ECW. Results showed significantly higher electrical conductivity, chloride and metal (Cr, Cu, and Pb) concentrations in contaminated wastewater-fed pond (CP) at ECW compared to the uncontaminated village pond (UP). Zooplanktons thriving in CP displayed significantly higher superoxide dismutase and catalase activities at all seasons compared to those in UP. Seasonal variations in antioxidant activities were found to be in agreement with variations in limnochemical factors. Hence, antioxidant activity was used as a biomarker against oxidative damage in plankters surviving under pollutant stress.

Impact of composite tannery effluent on the amino-transferase activities in a fish biosystem, using Guppy fish (Poecilia reticulata) as an experimental model

Tannery effluents cause serious effects on metabolic functions at the cellular level. Tannery wastewater in East Calcutta wetland, a Ramsar site (no. 1208), is used for pisciculture as well as for irrigating adjacent agricultural farms after natural stabilization. This study was conducted to determine the acute and chronic toxicity of composite tannery wastewater on a fish (Poecilia reticulata) biosystem. The adverse effects of composite tannery effluents on aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities of the liver and gill of P. reticulata were examined. Composite tannery effluent was characterized by exceedingly high total dissolved and suspended solids, chloride, total hardness, and biochemical oxygen demands. The activities of ALT and AST in fish tissues exposed to tannery effluents showed a significant rise with increasing effluent concentrations but they decreased when the exposure period was increased from 4 to 15 days. Our study indicated that the tannery effluent was capable of interfering with the metabolic processes by altering the enzyme activity in liver and gills attributed to cellular injury and following chronic exposure there is evidence of an adaptation mechanism.

Changes in physicochemical characteristics of wastewater carrying canals after relocation of Calcutta tannery agglomerates within the East Calcutta Wetland ecosystem (a Ramsar site)

Calcutta Leather Complex (CLC) near Bantala, Calcutta was constructed in the late 1990s. The ostensible purpose was to bring together the widely dispersed and haphazardly located tanning industry of Calcutta in a single location and to facilitate hazardous waste management by establishing a Common Effluent Treatment Plant. Unfortunately, for a number of reasons, the CLC is not yet fully operational. Further, the continued operation of illegal tanneries outside CLC has worsened matters. This study was undertaken to assess the physicochemical conditions of wastewater carrying canals within the East Calcutta Wetland (ECW) ecosystem (a Ramsar site) with special reference to the relocation of tanneries. Results revealed a great change in the values for physicochemical conditions; most changes were statistically significant (p < 0.05) when compared with available data, previous to tannery relocation. Moreover, the amelioration efficiency of ECW ecosystem was found to be mostly disturbed both by the illegal tannery operations and shifting of tannery agglomerates.

Comparison of Avifauna at the Edges of Contrasting Forest Patches in Western Ghat Hills of India

Comparison of Avifauna at the Edges of Contrasting Forest Patches in Western Ghat Hills of India Avifauna of shola and semi-evergreen forest patches belonging to three different sanctuaries and National Parks in the southern part of Western Ghat range of Tamil Nadu and Kerala was studied. Altogether 36 species from 17 families were recorded. One globally threatened species (A1), two restricted range species (A2) and one Palearctic-Asian migrant species have been recorded from forest edges during the relatively short study period. The highest population density of 47.59 ind./ha at Varagaliar Shola was followed by 43.69 ind./ha at Anapaddy, 27.53 ind./ha at Karian Shola, and 23.25 ind./ha at Punnumalai Shola. As Punnumalai Shola is least disturbed by human activity it got the highest number of avian families (15) and was followed by Karian Shola (9) and Vargaliar Shola and Anapaddy - 8 in both cases. Punnumalai Shola having varied bird families showed lower dominance (0.075) and higher evenness value (0.957). In contrast, the edge of semi-evergreen forest at Anapaddy, although very much disturbed by various human activities, showed almost comparable diversity value (2.890) to that of Punnumalai Shola (2.913). More open canopy and much vegetational intergradations at the ecotone of semi-evergreen biotope inherently shelter avian community of high diversity. Conversely, the edges of Karian Shola and Varagaliar Shola having much anthropogenic interferences and with edges showing much lower intergradations of vegetations, exhibited a low avian diversity.

Effect of a total solar eclipse on the surface crowding of zooplankton in a freshwater lake ecosystem

Zooplankton surface crowding in a freshwater lake ecosystem during a total solar eclipse (maximum eclipse at 06:28:43 Indian Standard Time, 22 July 2009) was studied in relation to ambient physicochemical conditions and compared with the crowding that occurred during pre- and post-eclipse days. Rapid light attenuation on the eclipse day led to changes in zooplankton surface crowding, which manifested as alterations to community structure and statistical parameters. Zooplankton diversity and density varied depending on the day (either the pre-eclipse day, the eclipse day, or the post-eclipse day) and the sampling time considered. A total of 20 zooplankton species were recorded during the study. On the day of the eclipse, the highest zooplankton density in the surface water was recorded just after the end of totality at 06:30 IST. The populations of two adult cladoceran species (Alona rectangula rectangula and Chydorus sphaericus) were particularly prominent in the zooplankton, whereas rotifers were almost absent from the surface water during the eclipse. Rather than decreasing, the primary production of the phytoplankton increased on the day of the TSE compared to that seen on the control days. Comparatively high Lindeman’s efficiency values were observed during the eclipse, indicating particularly efficient utilization of photons in photosynthesis.