Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption chara...Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils, an Acrisol (a variable-charge soil) and a Phaeozem (a constant-charge soil). Their thermodynamics and some of the factors influencing them (i.e., initial pH value, ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils. The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem. Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate. In contrast, soil organic matter and ionic strength had no significant effect on adsorption. This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces. Therefore, monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.展开更多
Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic(As) and cadmium(Cd) in Brazilian upland rice growing in soils polluted with both A...Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic(As) and cadmium(Cd) in Brazilian upland rice growing in soils polluted with both As and Cd. In the pot experiment constant and intermittent flooding treatments gave 3–16 times higher As concentrations in soil solution than did aerobic conditions but Cd showed the opposite trend. Compared to arsenate, there were more marked changes in the arsenite concentrations in the soil solution as water management shifted, and therefore arsenite concentrations dominated the As speciation and bioavailability in the soil. In the field experiment As concentrations in the rice grains increased from 0.14 to 0.21 mg/kg while Cd concentrations decreased from 0.21 to 0.02 mg/kg with increasing irrigation ranging from aerobic to constantly flooding conditions. Among the various water regimes the conventional irrigation treatment produced the highest rice grain yield of 6.29 tons/ha. The As speciation analysis reveals that the accumulation of dimethylarsinic acid(from 11.3% to 61.7%) made a greater contribution to the increase in total As in brown rice in the intermittent and constant flooding treatments compared to the intermittent-aerobic treatment. Thus, water management exerted opposite effects on Cd and As speciation and bioavailability in the soil and consequently on their accumulation in the upland rice. Special care is required when irrigation regime methods are employed to mitigate the accumulation of metal(loid)s in the grain of rice grown in soils polluted with both As and Cd.展开更多
Toxic effect of lead(Pb) pollution on Collembola in soils has seldom been studied in depth, which is especially true for growth responses since the juveniles are very small and numerous. A single species test was cond...Toxic effect of lead(Pb) pollution on Collembola in soils has seldom been studied in depth, which is especially true for growth responses since the juveniles are very small and numerous. A single species test was conducted using the collembolan Folsomia candida as the indicator species, and soil Pb pollution(at Pb concentrations of 0, 300, 600, 1 200, 2 400, and 4 800 mg kg^(-1)) was simulated by mixing Pb(NO_(3))_(2) with a natural unpolluted soil. Adult survival, reproduction, body length, and body Pb concentration were determined. Adult survival and reproduction started to decrease at soil Pb concentrations of 1 200 and 600 mg kg^(-1), respectively. Lead concentrations in adult and juvenile bodies increased with increasing Pb concentration in soil. The percentage and individual abundances based on body length analysis showed that the larger adults(2.1–2.6 mm, P < 0.01) were more sensitive to soil Pb concentration than the intermediate(1.9–2.1 mm, P < 0.001) and smaller(1.7–1.9 mm, P < 0.001) adults. Similarly, the larger juveniles(1.0–1.4 mm, P < 0.001) were more sensitive to soil Pb concentration than the intermediate(0.6–1.0 mm, P < 0.001) and smaller(0.3–0.6 mm, P < 0.001) juveniles. For both adults or juveniles, the abundance and percentage of larger individuals declined significantly with increasing soil Pb concentration, suggesting that larger individuals were more sensitive to soil Pb pollution. Therefore, body length features, especially the percentage and abundance of larger individuals, would be potential bio-indicators of soil Pb pollution and possibly other types of soil pollution.展开更多
The development of nanotechnology has accelerated the use of silver nanoparticles(AgNPs)in household chemicals and the accumulation of Ag in sewage treatment systems.The application of sewage sludge products to soils ...The development of nanotechnology has accelerated the use of silver nanoparticles(AgNPs)in household chemicals and the accumulation of Ag in sewage treatment systems.The application of sewage sludge products to soils raises concerns over the safety of Ag in the function and biogeochemical cycles of the soil belowground ecosystem.Here,we assess the potential risk of the accumulation and transfer of Ag under AgNPs exposure and its effects on the trophic transfer of nitrogen(N)through a soil animal food chain(Folsomia candida–Hypoaspis aculeifer).The formation of stable silver sulfide(Ag_(2)S)was also studied via a single species test using F.candida.Concentrations of Ag in F.candida increased with increasing AgNPs concentration,as did those in the predator H.aculeifer,but the Ag bioaccumulation factors of both animals were<1.Folsomia candida body tissue 15 N abundance declined markedly compared with that of H.aculeifer.Silver sulfide did have adverse effects on the survival and reproduction of F.candida.The Ag concentrations of F.candida increased with increasing Ag_(2)S concentration in sludge-treated soils.Silver sulfide showed ecotoxicity to the collembolan,therefore ecotoxicity resulting from the transformation and fate of AgNPs in soils needs to be considered before biosolid products are applied to agricultural soils.展开更多
基金supported by the National Natural Science Foundation of China (No. 41171248,40810180)the Ministry of Environmental Protection Special Funds for Scientific Research on Public Causes (No. 2010467016)
文摘Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils, an Acrisol (a variable-charge soil) and a Phaeozem (a constant-charge soil). Their thermodynamics and some of the factors influencing them (i.e., initial pH value, ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils. The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem. Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate. In contrast, soil organic matter and ionic strength had no significant effect on adsorption. This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces. Therefore, monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.
基金supported by the National Natural Science Foundation of China (Nos. 41201300 and 41325003)the High Technology Research Development Program of the People's Republic of China (No. 2012AA06A204)
文摘Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic(As) and cadmium(Cd) in Brazilian upland rice growing in soils polluted with both As and Cd. In the pot experiment constant and intermittent flooding treatments gave 3–16 times higher As concentrations in soil solution than did aerobic conditions but Cd showed the opposite trend. Compared to arsenate, there were more marked changes in the arsenite concentrations in the soil solution as water management shifted, and therefore arsenite concentrations dominated the As speciation and bioavailability in the soil. In the field experiment As concentrations in the rice grains increased from 0.14 to 0.21 mg/kg while Cd concentrations decreased from 0.21 to 0.02 mg/kg with increasing irrigation ranging from aerobic to constantly flooding conditions. Among the various water regimes the conventional irrigation treatment produced the highest rice grain yield of 6.29 tons/ha. The As speciation analysis reveals that the accumulation of dimethylarsinic acid(from 11.3% to 61.7%) made a greater contribution to the increase in total As in brown rice in the intermittent and constant flooding treatments compared to the intermittent-aerobic treatment. Thus, water management exerted opposite effects on Cd and As speciation and bioavailability in the soil and consequently on their accumulation in the upland rice. Special care is required when irrigation regime methods are employed to mitigate the accumulation of metal(loid)s in the grain of rice grown in soils polluted with both As and Cd.
基金supported by the National Key R & D Program of China (No.2018YFC1802602)the National Natural Science Foundation of China (No.41977136)。
文摘Toxic effect of lead(Pb) pollution on Collembola in soils has seldom been studied in depth, which is especially true for growth responses since the juveniles are very small and numerous. A single species test was conducted using the collembolan Folsomia candida as the indicator species, and soil Pb pollution(at Pb concentrations of 0, 300, 600, 1 200, 2 400, and 4 800 mg kg^(-1)) was simulated by mixing Pb(NO_(3))_(2) with a natural unpolluted soil. Adult survival, reproduction, body length, and body Pb concentration were determined. Adult survival and reproduction started to decrease at soil Pb concentrations of 1 200 and 600 mg kg^(-1), respectively. Lead concentrations in adult and juvenile bodies increased with increasing Pb concentration in soil. The percentage and individual abundances based on body length analysis showed that the larger adults(2.1–2.6 mm, P < 0.01) were more sensitive to soil Pb concentration than the intermediate(1.9–2.1 mm, P < 0.001) and smaller(1.7–1.9 mm, P < 0.001) adults. Similarly, the larger juveniles(1.0–1.4 mm, P < 0.001) were more sensitive to soil Pb concentration than the intermediate(0.6–1.0 mm, P < 0.001) and smaller(0.3–0.6 mm, P < 0.001) juveniles. For both adults or juveniles, the abundance and percentage of larger individuals declined significantly with increasing soil Pb concentration, suggesting that larger individuals were more sensitive to soil Pb pollution. Therefore, body length features, especially the percentage and abundance of larger individuals, would be potential bio-indicators of soil Pb pollution and possibly other types of soil pollution.
基金This research was funded by the National Natural Science Foundation of China(41977136).
文摘The development of nanotechnology has accelerated the use of silver nanoparticles(AgNPs)in household chemicals and the accumulation of Ag in sewage treatment systems.The application of sewage sludge products to soils raises concerns over the safety of Ag in the function and biogeochemical cycles of the soil belowground ecosystem.Here,we assess the potential risk of the accumulation and transfer of Ag under AgNPs exposure and its effects on the trophic transfer of nitrogen(N)through a soil animal food chain(Folsomia candida–Hypoaspis aculeifer).The formation of stable silver sulfide(Ag_(2)S)was also studied via a single species test using F.candida.Concentrations of Ag in F.candida increased with increasing AgNPs concentration,as did those in the predator H.aculeifer,but the Ag bioaccumulation factors of both animals were<1.Folsomia candida body tissue 15 N abundance declined markedly compared with that of H.aculeifer.Silver sulfide did have adverse effects on the survival and reproduction of F.candida.The Ag concentrations of F.candida increased with increasing Ag_(2)S concentration in sludge-treated soils.Silver sulfide showed ecotoxicity to the collembolan,therefore ecotoxicity resulting from the transformation and fate of AgNPs in soils needs to be considered before biosolid products are applied to agricultural soils.