Heavy metals pose a serious risk to the environment and living biota. Potstudies were carried out to determine the competence of Fe-coated ricehusk in Pb spiked soils vegetated with Ricinus communis. Physicochemicalpr...Heavy metals pose a serious risk to the environment and living biota. Potstudies were carried out to determine the competence of Fe-coated ricehusk in Pb spiked soils vegetated with Ricinus communis. Physicochemicalproperties of Fe- coated rice husk ash (Fe-RHA) were characterizedon dry weight basis. Pot experiments were carried out with seedlings ofR.communis for 60 days amended with Fe-RHA (0, 2.5% and 5% w/w)and Pb(NO3) [0, 400 and 800 mg kg?1]. Addition of Fe-coated rice huskash to Pb cntaminated soils improved soil pH and fertility. Treatment with5% Fe-RHA decreased Pb accumulation in roots by 84%. Addition of Fe-RHA significantly (p<0.05) increased plant physiological parameters suchas height, leaf diameter, nodes, and leaf number by 64%, 49%, 62% and66% and chlorophyll contents (12–29%) compared to unamended plants.Our findings conclude that Fe-RHA is a low-cost, environmentally friendlyand efficient adsorbent for stabilization of Pb spiked soils.展开更多
The environmental influx of hazardous contaminants viz PAHs and HMs occurs due to oil and gas drilling,and processing of petroleum products in industrial facilities and refineries.This problem plagues crude oil drilli...The environmental influx of hazardous contaminants viz PAHs and HMs occurs due to oil and gas drilling,and processing of petroleum products in industrial facilities and refineries.This problem plagues crude oil drilling sites as PAHs are an essential component of and HMs coexist with crude oil.We analyzed the spatial distribution of 16 PAHs and 8 HMs in 10 contaminated sites of Assam,a state in India.These included Digboi,where crude oil was drilled in 1867 and the first oil well in Asia that was drilled.TheƩ16 PAHs in soil were detected with a minimum of 13.48 and a maximum of 86.3 mgkg1 andƩ8 heavy metal concentrations in the soil ranged between 69.51 and 336.06 mgkg1.A negative correlation was detected between the relative concentrations of PAHs and HMs.The results confirmed that the nonbiodegradable nature of HMs made them stay in the soil for longer periods of time.In our study,we found that the levels of lead,copper,nickel,and chromium(total)in soil were 73.62,11.86,58.97 and 158.66 mgkg1.The recovery percentage for PAHs and HMs were in the range of 67e97%and 90e95%respectively.Spatial distribution indices for Phenanthrene/Anthracene,Naphthalene/Acenapthhylene,Chyrsene/Benzo(g,h,i)perylene and Fluranthene/Pyrene)calculated for soil samples indicated that the spatial distribution of PAHs in soil is uneven which might be due to variations in contaminates disseminated in soil.Such regionalized concentration has serious implications on the bio-economy both in terms of health and economy,especially since the proximity of crude oil sites to paddy fields and/or tea plantations uniquely marks the landscape of upper Assam.展开更多
基金The author grateful acknowledges the RGNF-UGC and University of Hyderabad,India。
文摘Heavy metals pose a serious risk to the environment and living biota. Potstudies were carried out to determine the competence of Fe-coated ricehusk in Pb spiked soils vegetated with Ricinus communis. Physicochemicalproperties of Fe- coated rice husk ash (Fe-RHA) were characterizedon dry weight basis. Pot experiments were carried out with seedlings ofR.communis for 60 days amended with Fe-RHA (0, 2.5% and 5% w/w)and Pb(NO3) [0, 400 and 800 mg kg?1]. Addition of Fe-coated rice huskash to Pb cntaminated soils improved soil pH and fertility. Treatment with5% Fe-RHA decreased Pb accumulation in roots by 84%. Addition of Fe-RHA significantly (p<0.05) increased plant physiological parameters suchas height, leaf diameter, nodes, and leaf number by 64%, 49%, 62% and66% and chlorophyll contents (12–29%) compared to unamended plants.Our findings conclude that Fe-RHA is a low-cost, environmentally friendlyand efficient adsorbent for stabilization of Pb spiked soils.
基金The authors are grateful to Department of Biotechnology,Government of India for financial support(Grant no.BT/489/NE/TBP/2013 dt 16-4-2014)and to Dolikajyoti Sharma,Gauhati University for technical support.
文摘The environmental influx of hazardous contaminants viz PAHs and HMs occurs due to oil and gas drilling,and processing of petroleum products in industrial facilities and refineries.This problem plagues crude oil drilling sites as PAHs are an essential component of and HMs coexist with crude oil.We analyzed the spatial distribution of 16 PAHs and 8 HMs in 10 contaminated sites of Assam,a state in India.These included Digboi,where crude oil was drilled in 1867 and the first oil well in Asia that was drilled.TheƩ16 PAHs in soil were detected with a minimum of 13.48 and a maximum of 86.3 mgkg1 andƩ8 heavy metal concentrations in the soil ranged between 69.51 and 336.06 mgkg1.A negative correlation was detected between the relative concentrations of PAHs and HMs.The results confirmed that the nonbiodegradable nature of HMs made them stay in the soil for longer periods of time.In our study,we found that the levels of lead,copper,nickel,and chromium(total)in soil were 73.62,11.86,58.97 and 158.66 mgkg1.The recovery percentage for PAHs and HMs were in the range of 67e97%and 90e95%respectively.Spatial distribution indices for Phenanthrene/Anthracene,Naphthalene/Acenapthhylene,Chyrsene/Benzo(g,h,i)perylene and Fluranthene/Pyrene)calculated for soil samples indicated that the spatial distribution of PAHs in soil is uneven which might be due to variations in contaminates disseminated in soil.Such regionalized concentration has serious implications on the bio-economy both in terms of health and economy,especially since the proximity of crude oil sites to paddy fields and/or tea plantations uniquely marks the landscape of upper Assam.
