Variation of antioxidant biomarkers in the edible oyster Saccostrea cucullata collected from three different water bodies of Sundarbans

Variations of antioxidant biomarkers such as catalase (CAT), superoxide dismutase (SOD) activities and lipid peroxidation (LPO) were studied in edible part of mangrove oyster Saccostrea cucullata, collected from three different water bodies, such as Namkhana (S-I), Frazergaunge (S-II) and Sajnekhali (S-III) of Indian Sundarbans which are exposed to different degrees of anthropogenic activity. The study was conducted for consecutive two years (2010 and 2011) in the respective water bodies. Characteristics of biomarkers in oyster from the two polluted water bodies, i.e. S-I and S-II, are similar in nature in comparison to less polluted site (S-III). The catalase, superoxide dismutase activity and lipid peroxidation in oyster flesh exhibit significant (p<0.01) spatial and temporal variation among the three stations. Oysters from S-I were significantly higher (p<0.05) in antioxidant enzyme activities than oysters from S-III, which differ in their amount of pollution sources. Maximum antioxidant enzymes activity of all collected samples were recorded in pre-monsoon time and decreased in monsoon season. But maximum lipid peroxidation was noted during monsoon followed by post-monsoon and pre-monsoon.     

A Study of Eichhornia crassipes Growing in the Overbank and Floodplain Soils of the River Yamuna in Delhi, India

River Yamuna, like most of the major rivers of India, has become increasingly polluted over the years from both point and non-point sources, particularly in the urban sectors such as Delhi. Field studies, conducted in January, 1994 have investigated the impact of wastewater discharges from four major drains (Najafgarh, Power House, Barapula, Kalkaji) on the overbanks, floodplains and Eichhornia in River Yamuna in Delhi, with particular reference to elemental contamination. It is concluded that except for Cd and Co, overall mean soil concentrations along the full stretch of the river in Delhi are within the world background levels of uncontaminated soils. However, the wastewater discharges from the drains, with the exception of Barapula drain, generally increase the elemental concentrations of overbank soils downstream of the discharges. Eichhornia plants growing along the banks receiving wastewaters from the Najafgarh and Barapula drains are unhealthy and reduced in population which can be attributed to a combination of alkaline pH of the growth medium, metal toxicity and high BOD at the site receiving effluents from the Najafgarh drain, and alkaline pH, metal toxicity and the turbid conditions of water with fly ash particle deposition on the plant surfaces at the site receiving effluents from the Barapula drain. Generally, considering the entire stretch of the river in Delhi, the roots of these plants growing on the overbank soils are found to be accumulators of all elements except Co, Al and Fe, with Co uptake being minimal. There are marked differences in elemental uptake of the water hyacinths growing on the overbanks and floodplains of the river.     

Studies on the removal of nickel from aqueous solutions using modified riverbed sand

This paper highlights the utility of riverbed sand (RS) for the treatment of Ni(II) from aqueous solutions. For enhancement of removal efficiency, RS was modified by simple methods. Raw and modified sands were characterized by scanning electron microscope (SEM), Energy Dispersive Spectroscopy (EDS), and Fourier Transform Infrared Spectroscopy (FTIR) to investigate the effect of modifying the surface of RS. For optimization of various important process parameters, batch mode experiments were conducted by choosing specific parameters such as pH (4.0–8.0), adsorbent dose (1.0–2.0 g), and metal ion concentrations (5–15 mg/L). Removal efficiency decreased from 68.76 to 54.09 % by increasing the concentration of Ni(II) in solution from 5 to 15 mg/L. Removal was found to be highly dependent on pH of aqueous solutions and maximum removal was achieved at pH 8.0. The process of removal follows first-order kinetics, and the value of rate constant was found to be 0.048 min^?1 at 5 mg/L and 25 °C. Value of intraparticle diffusion rate constant (k _id) was found to be 0.021 mg/g min^1/2 at 25 °C. Removal of Ni(II) decreased by increasing temperature which confirms exothermic nature of this system. For equilibrium studies, adsorption data was analyzed by Freundlich and Langmuir models. Thermodynamic studies for the present process were performed by determining the values of ΔG°, ΔH°, and ΔS°. Negative value of ?H° further confirms the exothermic nature of the removal process. The results of the present investigation indicate that modified riverbed sand (MRS) has high potential for the removal of Ni(II) from aqueous solutions, and resultant data can serve as baseline data for designing treatment plants at industrial scale.     

Comparison of drinking water,raw rice and cooking of rice as arsenic exposure routes in three contrasting areas of West Bengal,India

Remediation aimed at reducing human exposure to groundwater arsenic in West Bengal, one of the regions most impacted by this environmental hazard, are currently largely focussed on reducing arsenic in drinking water. Rice and cooking of rice, however, have also been identified as important or potentially important exposure routes. Quantifying the relative importance of these exposure routes is critically required to inform the prioritisation and selection of remediation strategies. The aim of our study, therefore, was to determine the relative contributions of drinking water, rice and cooking of rice to human exposure in three contrasting areas of West Bengal with different overall levels of exposure to arsenic, viz. high (Bhawangola-I Block, Murshidibad District), moderate (Chakdha Block, Nadia District) and low (Khejuri-I Block, Midnapur District). Arsenic exposure from water was highly variable, median exposures being 0.02 μg/kg/d (Midnapur), 0.77 μg/kg/d (Nadia) and 2.03 μg/kg/d (Murshidabad). In contrast arsenic exposure from cooked rice was relatively uniform, with median exposures being 0.30 μg/kg/d (Midnapur), 0.50 μg/kg/d (Nadia) and 0.84 μg/kg/d (Murshidabad). Cooking rice typically resulted in arsenic exposures of lower magnitude, indeed in Midnapur, median exposure from cooking was slightly negative. Water was the dominant route of exposure in Murshidabad, both water and rice were major exposure routes in Nadia, whereas rice was the dominant exposure route in Midnapur. Notwithstanding the differences in balance of exposure routes, median excess lifetime cancer risk for all the blocks were found to exceed the USEPA regulatory threshold target cancer risk level of 10⁻⁴–10⁻⁶. The difference in balance of exposure routes indicate a difference in balance of remediation approaches in the three districts.     

Degradation kinetics of forchlorfenuron in typical grapevine soils of India and its influence on specific soil enzyme activities

The rate of degradation of forchlorfenuron, a cytokinin-based plant growth regulator (PGR) was explored in typical grapevine soils of India with simultaneous evaluation of its effect on biochemical attributes of the test soils in terms of the activities of specific soil microbial enzymes. In all the test soils, namely clay, sandy-loam and silty-clay, the dissipation rate was faster at the beginning, which slowed down with time, indicating a non-linear pattern of degradation. Degradation in soils could best be explained by two-compartment 1st + 1st order kinetics with half-life ranging between 4–10 days. The results suggest that organic matter might be playing a major role in influencing the rate of degradation of forchlorfenuron in soil. The rate of degradation in sandy-loam soil was fastest followed by clay and silty-clay soils, respectively. Comparison of the rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Changes in soil enzyme activities as a consequence of forchlorfenuron treatment were studied for extra-cellular enzymes namely acid phosphatase, alkaline phosphatase and β -glucosidase and intracellular enzyme-dehydrogenase. Although small changes in enzyme activities were observed, forchlorfenuron did not have any significant deleterious effect on the enzymatic activity of the test soils. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily the effect of the incubation period rather than the effect of forchlorfenuron itself.     

Dissipation of flubendiamide residues in/on cabbage (Brassica oleracea L.)

Residues of fubendiamide and its metabolite desiodo flubendiamide were estimated in cabbage and soil using high-performance liquid chromatography with UV–vis detector. The initial deposits of flubendiamide residues on cabbage were found to be 0.16 and 0.31 μg g^?1 following two applications of flubendiamide 20 WG at 12.5 (standard dose) and 25 (double dose) g a.i. ha^?1 respectively at 10-days interval. The half-life values (t _1/2) of flubendiamide on cabbage ranged from 3.4 to 3.6 days. When flubendiamide applied at both the standard and double dose, no detectable residues were found in cabbage and soil at harvest. Thus, a waiting period of 1.63 days was suggested for the safe consumption of flubendiamide-treated cabbage. These data could provide guidance for the proper and safe use of this pesticide on cabbage crops in India.     

Maternal and cord blood levels of Aldrin and Dieldrin in Delhi population

Aldrin and dieldrin, structurally similar organochlorine pesticides belong to cyclodiene family and were widely used for agriculture and public health program in India. Although the manufacturing, use and import of aldrin and dieldrin have been banned in India since 2003, these pesticides are still persistent in environment and may be associated with adverse neurological and reproductive effects. The aim of this study is to assess the recent exposure level of aldrin and dieldrin and their placental transfer to fetus in normal healthy full-term pregnant women belonging to north Indian population undergoing normal delivery at Obstetrics and Gynecology department of UCMS and GTB hospital, Delhi. Quantitative analysis of aldrin and dieldrin residues in maternal and cord blood samples were carried out by gas chromatography system equipped with electron capture detector. The results of our study clearly revealed that maternal and cord blood levels of aldrin and dieldrin of pregnant women are age and dietary habit dependent. The aldrin level in maternal blood and dieldrin level in cord blood are higher in women in the age group 25–30 years than in women in age group of 19–24 years. Similarly, aldrin level in maternal blood is significantly higher in women with non-vegetarian dietary habit than in women with vegetarian dietary habit. No significant association is found for maternal and cord blood level. The results of the present study clearly demonstrate prenatal uptake of aldrin and dieldrin and provide recent information on the subsequent transplacental transfer.     

Perspectives of recycling gamma irradiated sewage-sludge in agricultural applications: a study on methi (Trigonella foenum-graecum L.: leguminosae)

The effects of gamma-irradiated sludge on the growth and yield of methi (Trigonella foenum-graecum L.) in pot cultures have been studied. Gamma-irradiated sludge was found to inhibit the shoot length after 45 and 90 days of plant growth compared to plants grown in soil containing unirradiated sludge. The untreated sludge did not exhibit any detrimental effect on the shoot length of plants compared to the control. The root length of plants grown in soil supplemented with either gamma-irradiated or unirradiated sludge was found to be inhibited after 45 days of growth. However, irradiation of sludge resulted in the higher inhibition of root length of plants compared to when unirradiated sludge was used. The gamma-irradiated sludge appeared to negatively affect the physical growth parameters of the plant. The significant positive effect of gamma-irradiated sludge was observed on the biochemical growth parameters and yield of methi plants. There was a 3.5-, 1.7- and 2-fold increase in the total protein content, total soluble sugars and starch content, respectively, of plants grown in soil supplemented with gamma-irradiated sludge after 45 days of growth. The gamma-irradiated sludge did not show any detrimental effect on any of the three biochemical parameters studied, even after 90 days of plant growth. The sludge obtained from the conventional treatment process was found to be inhibitory to the protein and starch content of plants in the latter stages of plant growth. A significant increase in the yield of methi plants, after 45 as well as 90 days, grown in the presence of gamma-irradiated sludge indicates a beneficial effect of recycling of irradiated sludge for agricultural applications.