Distribution of HCH and DDT in the coastal marine environment of Mumbai,India

Organochlorine pesticides (OCPs) in sediment, water and biota samples from the coastal marine environment of Mumbai were analysed to elucidate their distribution in various environmental compartments. HCH isomers, dichlorodiphenyltrichloroethane (DDT) and its metabolites were the predominantly identified compounds in all the samples. High ratios of DDT to dichlorodiphenyldichloroethylene (DDE) were found in seawater samples. This indicates the presence of a significant source of DDT in this region. In sediment samples, the gamma-isomer contributed almost 55% to the total HCH, indicating a high affinity of the gamma-isomer towards the sediment. The levels of organochlorines in fish obtained from this region were found to be lower than the levels of organochlorines in fish in temperate regions.     

Nickel recovery from spent nickel catalyst.

A process for nickel recovery from a spent catalyst of definite composition has been developed using the hydro-metallurgical route. The processing steps includes direct sulphuric acid leaching followed by separation of iron as well as silica and other impurities. For a 152 microm particle size catalyst, extraction of about 98% nickel was achieved at 363 K in 2 h using a sulphuric acid concentration (v/v) of 8% and a pulp density of 10%. The dissolution of nickel followed diffusion-controlled leaching kinetics. Increase in temperature and sulphuric acid concentration resulted in increase in the nickel recovery. The activation energy for nickel dissolution was calculated to be 62.8 kJ mol(-1). Finally, nickel was recovered as value-added products such as sulphide and oxalate with overall recovery of 90 and 88% of nickel, respectively.     

Interaction of pH with mercuric chloride toxicity to penaeid prawns from a tropical estuary, East Coast of India: enhanced toxicity at low pH

Toxicity tests were conducted to study the interaction of pH and the response of two size groups of penaeid prawns i.e. Penaeus monodon and Penaeus indicus to different sets of five concentrations of HgCl2 (0.01-0.09 mg l(-1)) under a broad range of pH conditions (5-9). Behavioural responses varied according to test solution concentration and nominated values of pH. Abnormality was detected in the higher concentrations with lower pH in smaller size group of P. monodon. High mortality was observed at higher concentration of test solution with low pH. Irrespective of species and size group LC50 demonstrated similar trend of variation with respect to time period. At pH 9 the threshold limit for 65-75 mm size group of P. monodon and P. indicus was 0.043 and 0.049 mg l(-1) respectively while it was 0.041 and 0.035 mg l(-1) respectively at pH 8; and 0.038 and 0.044 mg l(-1) respectively at pH 7. Relative toxicities were significantly varied except for bigger size groups in the studied pH ranges. The result was pronounced at pH 5 with maximum 1.61 times for inter-hour relative toxicity in contrast to all. At pH below 7 of mercury resulted more toxic compared to high pH range (>7) might be due to acid toxicity itself. At each pH smaller size groups were sensitive while bigger shown tolerant. P. monodon were more sensitive than P. indicus. The toxic order of pH effect was 9<8<7<6<5. Toxicity increased significantly (p>0.01) in acidic medium compared to alkaline.     

Comparison of a plant based natural surfactant with SDS for washing of As(Ⅴ) from Fe rich soil

This study explores the possible application of a biodegradable plant based surfactant, obtained from Sapindus mukorossi, for washing low levels of arsenic （As） from an iron （Fe） rich soil. Natural association of As（Ⅴ） with Fe（Ⅲ） makes the process difficult. Soapnut solution was compared to anionic surfactant sodium dodecyl sulfate （SDS） in down-flow and a newly introduced suction mode for soil column washing. It was observed that soapnut attained up to 86% efficiency with respect to SDS in removing As. Full factorial design of experiment revealed a very good fit of data. The suction mode generated up to 83 kPa pressure inside column whilst down-flow mode generated a much higher pressure of 214 kPa, thus making the suction mode more efficient. Micellar solubilisation was found to be responsible for As desorption from the soil and it followed 1st order kinetics. Desorption rate coefficient of suction mode was found to be in the range of 0.005 to 0.01, much higher than down-flow mode values. Analysis of the PT-IR data suggested that the soapnut solution did not interact chemically with As, offering an option for reusing the surfactant. Soapnut can be considered as a soil washing agent for removing As even from soil with high Fe content.     

Cardiovascular Load During Summer Work of Two Age Groups of Van-Rickshaw Pullers in West Bengal,India

Van-rickshaw is a popular mode of transport of people and merchandise in developing countries. The purpose of this study was to assess the effect of age on cardiovascular load of van-rickshaw pullers in the summer season (March-June) in real situations. In 142 participants, divided into 2 age groups (25-40 and 41-55 years), cardiovascular load was assessed on the basis of working and partial recovery heart rate (HR), predicted maximal HR, working maximal HR, average working HR, percentage of reserved HR, sum of recovery heart beats, percentage of recovery, relative and net cardiac cost, etc. Except for percentage of recovery, all parameters differed significantly between the groups and were significantly correlated with age. As this activity is very stressful, it places a heavy demand on the cardiovascular system. Therefore, age is an important factor for sustainability of the work, especially in a hot environment. Some ergonomic interventions are necessary to reduce cardiovascular load.     

An overview on the production of pigment grade titania from titania-rich slag.

To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-based technology is considered to be attractive because of low waste generation and low chemical cost due to high titanium content and is poised to replace the conventional technology. This paper provides a review of the slag-based technology with the specific aim to produce leachable slag and achieving high titania yield from recovered wastes. Leachable oxides of the lower oxidation state, such as TiO and Ti2O3, facilitate the leaching process. However, during smelting these oxides increase the viscosity of the slag. Formation of titanium carbide or carbonitride is also not desirable as it leads to resistance to the leaching of titanium. This report highlights the problems and their possible solutions to obtain leachable slag.     

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions

Environmental Science and Pollution Research - Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement...     

Transformation of recovered cobalt from lithium-ion batteries into zeolitic imidazolate framework-67

Journal of Material Cycles and Waste Management - Electrical and electronic equipment with axillaries at their end of life are considered as e-waste. Utilization/reutilization of e-waste especially...     

Field and GIS based post-tsunami assessment of Scleractinian coral cover in the Aerial Bay group of Islands, North Andaman, India

The Aerial Bay group of Islands are one of the diverse environments of Andaman & Nicobar Islands, where the coral reefs degraded much due to the natural calamity of tsunami on 26 December 2004. After this event, the entire North Andaman Islands got elevated, which resulted in the exposure of coral reefs during low tide, causing mass mortalities and destructions to this pristine environment. In order to understand the current status, bio-physical monitoring of coral reefs was carried out and compared with classified coral map of pre-tsunami period. A decline from 411.14 to 68.25 hectares (ha) of live coral area was observed in the Aerial Bay group of Islands. The dead corals and other abiotic factors (sand, mud and rubble) were observed to be 317.33 and 25.56 ha respectively, based on comparisons between ground truthed and classified pre-tsunami coral map (2004) processed in ArcGIS®. The detrended correspondence analysis of coral life form categories showed maximum cover of dead coral with algae, in comparison with the live corals. Bray-curtis cluster analysis revealed three different groups of study sites with 60 % similarity based on life-form categories within the coral reef environment.     

Environmental conditions of Chilika Lake during pre and post hydrological intervention: an overview

Chilika Lake, the largest brackish water lagoon in Asia, is a prominent biodiversity hotspot along the Indian east coast. The geomorphology, water quality and biological productivity of the lake had undergone significant changes over the years under the influence of natural events and anthropogenic interventions. Decades of research have shown that the ecological changes of the lake system and its fisheries were influenced mainly by the water exchange between the lake and the sea that controls the salinity, siltation, macrophyte infestation and recruitment of marine forms. Depletion of fisheries and loss of biodiversity in 1980s and 1990s have been linked to the northward shifting of lake’s inlet and silting up of the outer channel. In order to improve the health of the lagoon and restoration of its biodiversity, a new mouth was dredged open in September 2000. Opening of the new mouth has resulted in some improvements with substantial increase in capture fishery, reduction in weed infestation, growth of seagrasses, appearance of dolphins and increase in the population of migratory birds. But, many stake holders claim that the problems associated with the lake ecology and its contribution to the socio-economic development of the stake holders still persist which could escalate in future.