Induction of sperm impairments in mice as a sensitive biomarker of arsenic toxicity

The ubiquitous presence of arsenic (a toxic metalloid) in our environment, particularly in our drinking water, is a serious health hazard of global concern. The present work deals with the assessment of arsenic toxicity through the analysis of induced sperm impairments in sperm head morphology and sperm count in mice at low exposures compared to the magnitude of response at high exposure levels. The animals were exposed to four doses of arsenic, ranging from lowest dose of 0.3 μg kg^?1 day^?1 (the human reference dose) to higher dose of 30 μg kg^?1 day^?1 for 15 consecutive days. The epididymal sperms were harvested after one spermatogenic cycle on the 36th day and were scored for the presence of any abnormality in their head morphology as well as changes in their count. Exposure to arsenic significantly induced, in a dose-dependent manner, increases in the frequency of sperms with abnormal head morphology from 5.12 % in control to 9.23 % in lowest dose group and 23.02 % in highest dose group. In contrast, the mean sperm counts in the epididymal wash were decreased from 6.05 million per milliliter in the control to 4.95 million per milliliter in the lowest dose group and 3.07 million in the highest dose group. The analysis of sperm impairments in mice was, therefore, found to be a highly sensitive assay to assess arsenic toxicity, exhibiting a marked male reprotoxic effect of arsenic even at its low exposure levels including the human reference dose.     

Water pollution of Sabarmati River—a Harbinger to potential disaster

River Sabarmati is one of the biggest and major river of Gujarat that runs through two major cities of Gujarat, Gandhinagar and Ahmedabad and finally meets the Gulf of Khambhat (GoK) in the Arabian Sea. A study was conducted to evaluate the water quality of this river, as it could possibly be one of the major sources for filling up Kalpasar, the proposed man-made freshwater reservoir supposed to be the biggest one in the world. A total of nine sampling stations were established covering 163 km stretch of the river from upstream of Gandhinagar city to Vataman near Sabarmati estuary. Physicochemical (temprature, pH, salinity, chloride, total dissolved solids, turbidity, dissolved oxygen, biochemical oxygen demand, phenol, and petroleum hydrocarbons), biological (phytoplankton), and microbiological (total and selective bacterial count) analyses indicated that the river stretch from Ahmedabad-Vasana barriage to Vataman was highly polluted due to perennial waste discharges mainly from municipal drainage and industries. An implementation of sustainable management plan with proper treatment of both municipal and industrial effluents is essential to prevent further deterioration of the water quality of this river.     

Impact of different types of polluted irrigation water on soil fertility and wheat grain yield in clayey black soils of central India

This study was carried out in three different cities of western Madhya Pradesh (India) to investigate the effects of long-term irrigation with industrial waste water (IWW), contaminated groundwater (CGW), and untreated municipal sewage water (USW) on soil fertility as well as on wheat crop yield. Irrigation with these three types of polluted water increased organic matter content as well as contents of available P (with IWW and USW only), available K, available S, available Zn, available Cu (IWW only), and available Mn (IWW and CGW only). The magnitude of improvement in soil fertility status was the highest in the case of USW, followed by IWW and finally, by CGW. Concentrations of Na in wheat leaf tissue increased by 198 and 58 % whereas concentrations of Ca decreased significantly by 16 and 13 % due to the use of IWW and CGW, respectively, resulting in poor Ca nutrition to the crop. Although wheat grain yield increased considerably due to USW, the same recorded significant decreases with IWW and CGW. In spite of the enhancement in the available nutrient status, decrease in wheat grain yield with the use of IWW and CGW could be due to the build-up of salts in the soil and an imbalance in the Na/Ca ratio in wheat crops irrigated with IWW and CGW. The adverse effect on wheat productivity was more pronounced with IWW as compared to CGW.     

Transport of dissolved nutrients and chlorophyll a in a tropical estuary,southwest coast of India

Intra-tidal variability in the transport of materials through the Cochin estuary was studied over successive spring and neap tides to estimate the export fluxes of nutrients and chlorophyll a into the adjoining coastal zone. The results showed that there was a substantial increase in the freshwater flow into the estuary following heavy rains (~126 mm) prior to the spring tide observations. The estuary responded accordingly with a relatively larger export through the Cochin inlet during spring tide over neap tide. Despite an increased freshwater discharge during spring tide, the export fluxes of phosphate and ammonia were high during neap tide due to their input into the estuary through anthropogenic activities. The significance of this study is that the export fluxes from the Cochin estuary could be a major factor sustaining the spectacular monsoon fishery along the southwest coast of India.     

Carbon density and accumulation in agroecosystem of Indo-Gangetic Plains and Vindhyan highlands,India

In agroecosystems, the annual carbon (C) inputs to soil are one of the most promising greenhouse gas mitigation options. Net primary productivity (NPP) provides the inputs of C in ecosystems that can potentially be sequestered in soil organic matter. In this study, we estimates the C density and accumulation rate in rice–wheat agroecosystem at four sites of Indo-Gangetic Plains and Vindhyan highlands through amalgamation of ground truth (GT) and remote sensing (RS) approach. In addition to this, we validated field-measured aboveground net production (ANP) with remotely sensed SPOT-Vegetation data. ANP of the sites ranged from 6.8 to 11.1 and 3.3 to 8.8 t-C ha^?1 year^?1 for GT and RS, respectively. Both estimates (GT and RS) were linearly and significantly related with each other (y?=?1.33x???5.82, R ²?=?0.93, P?=?0.04; where x?=?GT ANP and y?=?RS ANP). For the whole region, total NPP (rice?+?wheat) was ranged from 7.9 to 12.5 t-C ha^?1 year^?1. The C accumulation potential of the present agroecosystems was 9.1 and 1.9 t-C ha^?1 year^?1 in the form of ANP and belowground NPP (BNP), respectively. The aboveground C stock of agroecosystem allocated in foliage (7.8 %), stem (57.6 %), and grain (35.1 %). Survey about the fate of post-harvested materials indicated that aboveground portion of the crop is almost used completely within the year for different purposes including human consumption and cattle feeding. Therefore, only BNP and litter contribute to long-term C sequestration. Since agroecosystem has enormous potential to sequester C, better management of aboveground portion NPP of the crop may enhance C sequestration potential of agroecosystem.     

Physicochemical and microbiological assessment of recreational and drinking waters

The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml)^− 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were under safe limits having <3 TC (100 ml)^− 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263 bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial measures.     

Metal speciation studies in the aquifer sediments of Semria Ojhapatti,Bhojpur District,Bihar

The pollution of aquifer sediments by heavy metals has assumed serious concern due to their toxicity and accumulative behavior. Changes in environmental conditions can strongly influence the behavior of both essential and toxic elements by altering the forms in which they occur and therefore quantification of the different forms of metal is more meaningful than total metal concentrations. In this study, fractionation of metal ions in aquifer sediments of Semria Ojhapatti area, Bhojpur district, Bihar has been studied to determine the ecotoxic potential of metal ions. The investigations suggest that iron, copper, and arsenic have a tendency to remain associated in the following order residual > reducible > acid-soluble > oxidizable; manganese and zinc have tendency to be associated as residual > acid-soluble > reducible > oxidizable. The risk assessment code reveals that manganese and zinc occur in significant concentration in acid-soluble fraction and therefore comes under the high risk category and can easily enter the food chain. Most of the iron, copper, and arsenic occur as immobile fraction (i.e. residual) followed by its presence in reducible fraction and would pose threat to the water quality due to changing redox conditions. The metal enrichment factor in the study area shows moderate to significant metal enrichment in the aquifer sediments which may pose a real threat in near future. The geo-accumulation index of metals also shows that the metals lie in the range of strongly contaminated (for iron at shallow depths) to moderately contaminated to uncontaminated values.     

Tropical storm off Myanmar coast sweeps reefs in Ritchie’s Archipelago, Andaman

The reefs in some islands of Andaman and Nicobar suffered severe damage following a tropical storm in the Bay of Bengal off Myanmar coast during 13–17 March 2011. Surveys were conducted at eight sites in Andaman, of which five were located in the Ritchie’s Archipelago where maximum wind speeds of 11 m?s^-1 was observed; and three around Port Blair which lay on the leeward side of the storm and had not experienced wind speeds of more than 9 m?s^-1. Corals in the shallow inshore reefs were broken and dislodged by the thrust of the waves. Significant damage in the deeper regions and offshore reefs were caused by the settlement of debris and sand brought down from the shallower regions. The fragile branching corals (Acropora sp.) were reduced to rubbles and the larger boulder corals (Porites sp.) were toppled over or scarred by falling debris. The reefs on the windward side and directly in the path of the storm winds were the worst affected. The investigation exposes the vulnerability of the reefs in Andaman to the oceanographic features which generally remain unnoticed unless the damage is caused to the coastal habitats.     

Arsenic occurrence and accumulation in soil and water of eastern districts of Uttar Pradesh, India

Arsenic in the soil and water of eastern districts of Uttar Pradesh (Ballia and Ghazipur) was estimated. Survey results revealed that arsenic in soil samples ranged from 5.40 to 15.43 parts per million (ppm). In water samples, it ranged from 43.75 to 620.75 parts per billion (ppb) which far exceeded the permissible limit of 10 ppb as recommended by the World Health Organization. Maximum concentration of arsenic in water was found in Haldi village of Ballia (620.75 ppb). However, mean arsenic concentration in water followed the order: Karkatpur (257.21 ppb) < Haldi (310.15 ppb) < Sohaon (346.94 ppb) < Dharmarpur (401.75 ppb). In case of soil, maximum arsenic was detected in soil of Sohaon (15.43 ppm). Mean arsenic levels in soils followed the order: Karkatpur (9.24 ppm) < Haldi (9.82 ppm) < Dharmarpur (11.32 ppm) < Sohaon (14.08 ppm). Arsenic levels were higher in soils collected from 15–30 cm depth than 0–15 cm from the soil surface.