Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natu...Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natural environment;their interactions with organic pollutants,especially sorption and desorption processes,have been extensively studied from the perspectives of thermodynamics and kinetics.Recently,the aging of organic pollutants in geosorbents has drawn increased attention,leading to an improved understanding of interactions between organic pollutants and geosorbents and informing remediation criteria.Aging has been deemed important in accurately assessing ecologic and health risks of organic pollutants,and both positive and negative impacts have been reported in studies of natural and artificial sorbents.This paper summarizes recent research progress on organic pollutant aging in geosorbents,including related mechanism research,influence factors,bioavailability assessments,and biological and physicochemical remediation of aged organic pollutants.We also discuss issues in the current research and bring forward suggestions for future study.展开更多
Horton Plains (HP), one of the two montane forests in Sri Lanka and habitat to many endemic species of plants and animals, has been severely affected by forest dieback. Past research has identified a direct link betwe...Horton Plains (HP), one of the two montane forests in Sri Lanka and habitat to many endemic species of plants and animals, has been severely affected by forest dieback. Past research has identified a direct link between soil pollution with Cadmium (Cd) and the phenomenon of forest dieback. As a consequence, forest dieback is increasing proportionately to the soil pollution. Hence, this study focuses on identifying a cost-effective remediation technique to neutralize soil Cd, and thereby reducing forest dieback. Soil samples were collected from HP, mainly Thotupolakanda site which shows more than 90% severity of forest die back, and bulked together. The soil was high (13.4) in organic matter and low (5.42) in pH, and three soil amendments were tested in this research as;bio char prepared using 1) rubber nut shells, 2) rice husk, and 3) dead wood from HP. Each sample was spiked with 20 ml of 5 ppm (parts per million) Cd solution, and four treatments a) soil + rubber-nut shell biochar (T1), b) soil + rice husk biochar (T2), c) soil + wood-from-HP biochar (T3), and d) soil only (T4), with five (05) replicates, were setup. During the first eight weeks after the application of treatments, it was observed that T1 showed the best performance, by showing a consistent trend in reducing the available soil Cd, with T2 following closely. The interesting observation was that the natural forest soil (T4) was also able to buffer the loading of Cd. At the close of the experiment, it was observed that the available soil Cd goes almost to zero, in less than 24 months.展开更多
文摘Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natural environment;their interactions with organic pollutants,especially sorption and desorption processes,have been extensively studied from the perspectives of thermodynamics and kinetics.Recently,the aging of organic pollutants in geosorbents has drawn increased attention,leading to an improved understanding of interactions between organic pollutants and geosorbents and informing remediation criteria.Aging has been deemed important in accurately assessing ecologic and health risks of organic pollutants,and both positive and negative impacts have been reported in studies of natural and artificial sorbents.This paper summarizes recent research progress on organic pollutant aging in geosorbents,including related mechanism research,influence factors,bioavailability assessments,and biological and physicochemical remediation of aged organic pollutants.We also discuss issues in the current research and bring forward suggestions for future study.
文摘Horton Plains (HP), one of the two montane forests in Sri Lanka and habitat to many endemic species of plants and animals, has been severely affected by forest dieback. Past research has identified a direct link between soil pollution with Cadmium (Cd) and the phenomenon of forest dieback. As a consequence, forest dieback is increasing proportionately to the soil pollution. Hence, this study focuses on identifying a cost-effective remediation technique to neutralize soil Cd, and thereby reducing forest dieback. Soil samples were collected from HP, mainly Thotupolakanda site which shows more than 90% severity of forest die back, and bulked together. The soil was high (13.4) in organic matter and low (5.42) in pH, and three soil amendments were tested in this research as;bio char prepared using 1) rubber nut shells, 2) rice husk, and 3) dead wood from HP. Each sample was spiked with 20 ml of 5 ppm (parts per million) Cd solution, and four treatments a) soil + rubber-nut shell biochar (T1), b) soil + rice husk biochar (T2), c) soil + wood-from-HP biochar (T3), and d) soil only (T4), with five (05) replicates, were setup. During the first eight weeks after the application of treatments, it was observed that T1 showed the best performance, by showing a consistent trend in reducing the available soil Cd, with T2 following closely. The interesting observation was that the natural forest soil (T4) was also able to buffer the loading of Cd. At the close of the experiment, it was observed that the available soil Cd goes almost to zero, in less than 24 months.
