This study was conducted to analyze the metals in selected vegetables available in Powai area, Mumbai, India.The total 9 samples viz., 5 vegetables, 3 cereals and 1 medicinal plant were collected which are commonly consumed in the locality. These were digested using microwave acid digester with nitric acid and hydrochloric acid and analyzed with the aid of ICP-AES to determine toxic metals. Highly toxic metals such as arsenic and silver were below detectable limit while two of the samples had high mercury and lead content. The results obtained were compared with their permissible levels set by the FAO and WHO and were found to be within safe limits for some metals while concentrations of some of the metals were much greater than permissible limits and were, hence, not safe to consume. It was found that the overall toxic metal accumulation was greater in leafy vegetables viz. spinach, coriander and tubers such as potato.

The utility of a physiologically based extraction test for evaluating the bioaccessibility of metals from fly ash in the human gastrointestinal system was evaluated in the present research. Calcium-rich and silica-rich fly ashes collected from eight power plants in India and United States of America were assessed for bioaccessibility for arsenic, chromium, lead, selenium and zinc. The results from the physiologically based extraction test were compared with those from a sequential extraction procedure that is often applied to solid wastes. Based on the physiologically based extraction test results, more than 40 % of the arsenic was found to be bioaccessible for all the ashes while selenium was very accessible for the calcium-rich ashes. Lead was found to be insignificantly bioaccessible in calcium-rich as well as silica-rich fly ashes. The mobilization of metals in the first three steps of the sequential extraction procedure was similar to the mobilization in the physiologically based extraction test for selenium for all ashes and for arsenic and chromium for most ashes, but the sequential extraction procedure mobilized more zinc than did the physiologically based extraction test. These results indicate that while sequential extraction procedures can provide good estimates of the bioaccessibility of many elements, extraction tests that more closely simulate physiological conditions can provide more accurate measures of bioaccessible concentrations of metals.

Thermal power plants are the major source of electricity generation in India and most of them use pulverized coal as the fuel producing enormous quantities of coal fly ash every year. The method of disposal adopted is by wet sluicing in on-site fly ash ponds. This disposal in the form of dilute slurry has a high potential for leaching into the surrounding soil and groundwater. The coal fly ash contains trace metals like As, Cr, Zn, Cd, etc which are toxic in nature and thus, the wet disposal of coal fly ash has serious environmental concerns. This paper assesses the leaching potential of coal fly ash from six thermal power plants in Maharashtra, India. The maximum leachable quantities of some trace metals present in coal fly ash are computed by a Sequential Extraction Procedure (SEP) and results are compared with values obtained by Toxicity Characteristics Leaching Procedure(TCLP).

The study demonstrates the efficiency of the Soil Aquifer Treatment (SAT) towards removal of Heavy metals within Electroplating wastewater thereby rendering it suitable for ground water discharge. The unique proposition of this research is to use combination of soil and adsorbent properties to enhance the remediation of heavy metals such as Nickel, Copper and Zinc. A comparative study through statistical analysis is employed to illustrate the effectiveness of the various SAT systems build using various combinations of SM and SC soil types along with Bioadsorbents such as Eucalyptus Leaves, Sawdust and Mosambi peel. Further, the Mass balance analysis of heavy metals is carried out to comprehend the course of expulsion. The study through statistical approach endorses that the SAT in conjunction with adsorbent gives most extreme removal efficiency than the SAT without adsorbent. Additional removal efficiency of 14% to 30% can be achieved with introduction of adsorbents within the SAT system. The optimal removal efficiency of Nickel, Copper and Zinc was observed to be at 87, 98 and 93% respectively when passed through the combination of SM soil with sawdust.

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