In the present study efforts have been made to ascertain the seasonal abundance and population dynamics of zooplankton community and its relationship with physico-chemical factors of the water bodies of Santragachi Jheel in the District Howrah, W.B., INDIA. The zooplankton abundance showed distinct seasonal or temporal variation in the Jheels. A total of 18 species belonging to 12 families and 15 genera were recorded. The population density of total zooplankton showed summer maxima in the Jheel. Maximum abundance of rotifer fauna was recorded during summer season in sewage sites whereas Cladocera population showed maximum density at non-sewage sites. Copepods showed postmonsoon maxima in sewage sites in the Jheels. Some species i.e., Polyarthara vulgaris were quite abundant in the polluted water of the Santragachi Jheel. Out of 15 genera of Zooplankton, Brachionus, Keratella, Polyarthra, Diaphanosoma, Ceriodaphnia, Bosmina, Heliodiaptomus and Mesocyclops were found to be dominant in Santragachi Jheel. Highest percentage of similarity was recorded between S1 and S3 sites of the Jheel. Results of ANOVA (2 - way) indicated that zooplankton population differs significantly in relation to stations and seasons of the Jheel. Population of Rotifera, the most dominant group was found to be positively influenced by Biological Oxygen demand (BOD), Free Carbon-di-oxide FCO2), CaCO3 hardness (CaHa), Total suspended solid (TSS), Chloride(Cl) and Phosphate (PO4) in the Jheels. Total Cladocera showed positive correlation with PO4 in the Jheel. The Copepods expressed positive correlation with BOD and ammonia. Increment of population density of several zooplankton organisms (i.e., Keratella tropica, Polyarthra vulgaris) and low value of community indices especially species diversity and species richness indicated the rise of pollutional stress on the Santragachi Jheel. Keywords: Zooplankton; Rotifera; BOD; COD; Shannon - Wiener index; Evenness index DOI: http://dx.doi.org/10.3126/jowe.v5i0.4595 J Wet Eco 2011 (5): 20-39

The present study deals with the seasonal limnological investigation related to physico-chemical characteristics of water of the Santragachi and Joypur Jheel, West Bengal, India. Besides temperature and meteorological data, 17 limnological parameters were tested following standard methods at 3 sampling sites/stations of each Jheel. The physico-chemical parameters (transparency, pH, DO, BOD, COD, free CO2, total alkalinity, conductivity, CaCO3, TSS, TDS, Chloride, Ammonia, Nitrite, Nitrate, Phosphate, etc.) showed distinct temporal or seasonal variation in both the Jheels. Higher nutrient contents (nitrate, phosphate) are present in Santragachi Jheel. This finding also signifies eutrophication/higher trophic level. Water transparency, dissolved oxygen, BOD, total alkalinity, conductivity, CaCO3 hardness, TSS, nitrate and phosphate was correlated with various physico-chemical parameters in both the Jheels.  The physico-chemical characteristics of water of the two Jheels revealed the poor water quality in Santragachi Jheel than the Joypur Jheel. These characteristics showed maximum contamination of water due to sewage effluents in Santragachi Jheel. The two years (February, 2000 - January, 2002) survey reflects higher degree of pollution in Santragachi Jheel.DOI: 10.3126/on.v8i1.4328

To examine the effects of α-chlorohydrin on testis and cauda epididymis in the male house rat (Rattus rattus), 24 adult male rats were segregated into two groups. Group I rats were force-fed daily by intragastric intubation with α-chlorohydrin at a single dose of 1.0 mg/100 g body weight/d for 5, 15, and 45 days. Another group was fed with distilled water, which served as the control. The treated male rats were paired with 24 adult proestrus female rats for 5 days after the last oral treatment and fertility was tested. At the end of the experiments, all of the male rats were weighed and killed by cervical dislocation. The right testes were removed, weighed, and processed for ultrastructural changes of spermatozoa from the cauda epididymis and testis under scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The seminiferous tubular area, nuclear diameter of the Sertoli and Leydig cells, percentage of spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, spermatozoa, and Sertoli cells in each group were compared morphometrically. Our results showed that the percentages of primary spermatocytes steadily increased from 5 to 15 days, but primary and secondary spermatocytes decreased significantly at 45 days. There was a steady decline in the percentages of spermatozoa and spermatids at all fixation intervals in the treated animals, but the percentages of spermatogonia and Sertoli cells increased significantly at 15 and 45 days. Seminiferous tubular areas, nuclear diameter of Leydig and Sertoli cells, and fertility rates were reduced after 45 days of treatment. SEM and TEM studies revealed severe morphological abnormalities in the spermatozoa, including deglutination of the acrosomal part, loss of head capsules, and fragmentation of tail fibrils. There was an enhanced anti-fertility effect and a lower number of implantation sites in the rats treated for 5 days. Our results validate α-chlorohydrin as a successful anti-fertility agent that prevents spermatogenesis.

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