More and more linear alkylbenzene sulfonate (LAS) has contaminated the water and soil ma pollution discharge, making it important to identify the ecological behavior and toxicity of LAS so as to carry out measures tha...More and more linear alkylbenzene sulfonate (LAS) has contaminated the water and soil ma pollution discharge, making it important to identify the ecological behavior and toxicity of LAS so as to carry out measures that will reduce its negative effects on the ecosystem. The ecological behavior of LAS. including degradation, migration, and plant uptake, in both soil-paddy rice and soil-soybean systems was studied. Reduction of LAS in pot and field plots followed the first order reaction kinetics with degradation half-lives of 35-50 days with LAS decreasing to very low concentrations after a season of crop growth. Strong migration ability for LAS was found and the breakthrough time in a 1.5 in soil monolith was significantly shortened to 23 days by preferential flow. Leachate volumes of soil-paddy and soil-soybean systems at preferential breakthrough were much different, while the leachate volumes at equilibrium governed by soil adsorption/desorption processes were very similar. Significant uptake of LAS in both paddy rice and sovbeans was observed in pot and field experiments (P < 0.05). In aquatic culture, 20 μg mL-1 and above of LAS significantly inhibited the growth of paddy seedlings (P < 0.05). The critical concentration for LAS in soil inhibiting the growth and yield of paddy was 160 μg g-1; when higher, there was a strong negative influence, with decreases in height, spike length, and production, when lower than 80 μg g-1, paddy growth was stimulated. There was little effect of LAS on soybeans.展开更多
Advanced closed chamber system was used to study the fate of phenanthrene (3 rings PAHs) in the presence of linear alkylbenzene sulphonates(LAS). The results showed mineralization and metabolism of phenanthrene are f...Advanced closed chamber system was used to study the fate of phenanthrene (3 rings PAHs) in the presence of linear alkylbenzene sulphonates(LAS). The results showed mineralization and metabolism of phenanthrene are fast in the “culture solution lava plant air' model ecological system. The distribution proportions of applied 14 C activity in this simulative ecological system were 41%—45%, 14% to 10% and 1% in plant, lava and culture solution respectively, and 18% to 29%, 11% to 8% recovered in the forms of VOCs and CO 2. Main parts of the applied 14 C activity exist in two forms, one is polar metabolites(25%) which mainly distribute in the root(23%), the other is unextractable part(23%) which have been constructed into plant root(8 98%), shoot(0 53%) or bonded to lava(13 2%). The main metabolites of phenanthrene were polar compounds(25% of applied 14 C activity), and small portion of 14 C activity was identified as non polar metabolites(6% of applied 14 C activity) and apparent phenanthrene(1 91% of applied 14 C activity). Phenanthrene and its metabolites can be taken up through plant roots and translocated to plant shoots. The presence of LAS significantly increased the the concentration of 14 C activity in the plant and production of VOCs, at the same time it decreased the phenanthrene level in the plant and the production of CO 2 at the concentration of 200 mg/L.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 49771044 and 49971038)
文摘More and more linear alkylbenzene sulfonate (LAS) has contaminated the water and soil ma pollution discharge, making it important to identify the ecological behavior and toxicity of LAS so as to carry out measures that will reduce its negative effects on the ecosystem. The ecological behavior of LAS. including degradation, migration, and plant uptake, in both soil-paddy rice and soil-soybean systems was studied. Reduction of LAS in pot and field plots followed the first order reaction kinetics with degradation half-lives of 35-50 days with LAS decreasing to very low concentrations after a season of crop growth. Strong migration ability for LAS was found and the breakthrough time in a 1.5 in soil monolith was significantly shortened to 23 days by preferential flow. Leachate volumes of soil-paddy and soil-soybean systems at preferential breakthrough were much different, while the leachate volumes at equilibrium governed by soil adsorption/desorption processes were very similar. Significant uptake of LAS in both paddy rice and sovbeans was observed in pot and field experiments (P < 0.05). In aquatic culture, 20 μg mL-1 and above of LAS significantly inhibited the growth of paddy seedlings (P < 0.05). The critical concentration for LAS in soil inhibiting the growth and yield of paddy was 160 μg g-1; when higher, there was a strong negative influence, with decreases in height, spike length, and production, when lower than 80 μg g-1, paddy growth was stimulated. There was little effect of LAS on soybeans.
文摘Advanced closed chamber system was used to study the fate of phenanthrene (3 rings PAHs) in the presence of linear alkylbenzene sulphonates(LAS). The results showed mineralization and metabolism of phenanthrene are fast in the “culture solution lava plant air' model ecological system. The distribution proportions of applied 14 C activity in this simulative ecological system were 41%—45%, 14% to 10% and 1% in plant, lava and culture solution respectively, and 18% to 29%, 11% to 8% recovered in the forms of VOCs and CO 2. Main parts of the applied 14 C activity exist in two forms, one is polar metabolites(25%) which mainly distribute in the root(23%), the other is unextractable part(23%) which have been constructed into plant root(8 98%), shoot(0 53%) or bonded to lava(13 2%). The main metabolites of phenanthrene were polar compounds(25% of applied 14 C activity), and small portion of 14 C activity was identified as non polar metabolites(6% of applied 14 C activity) and apparent phenanthrene(1 91% of applied 14 C activity). Phenanthrene and its metabolites can be taken up through plant roots and translocated to plant shoots. The presence of LAS significantly increased the the concentration of 14 C activity in the plant and production of VOCs, at the same time it decreased the phenanthrene level in the plant and the production of CO 2 at the concentration of 200 mg/L.
