The phytotoxicity of added copper (Cu) and nickel (Ni) is influenced by soil properties and field aging. However, the differences in the chemical behavior between Cu and Ni are still unclear. Therefore, this study was conducted to investigate the extractability of added Cu and Ni in 6-year field experiments, as well as the link with their phytotoxicity. The results showed that the extractability of added Cu decreased by 6.63% (5.10%–7.90%), 22.5% (20.6%–23.9%), and 6.87% (0%–17.9%) on average for acidic, neutral, and alkaline soil from 1 to 6 years, although the phytotoxicity of added Cu and Ni did not change significantly from 1 to 6 years in the long term field experiment. Because of dissolution of Cu, when the pH decreased below 7.0, the extractability of Cu in alkaline soil by EDTA at pH 4.0 could not reflect the effects of aging. For Ni, the extractability decreased by 18.1% (10.1%–33.0%), 63.0% (59.2%–68.8%), and 22.0% (12.4%–31.8%) from 1 to 6 years in acidic, neutral, and alkaline soils, respectively, indicating the effects of aging on Ni were greater than on Cu. The sum of ten sequential extractions of Cu and Ni showed that added Cu was more extractable than Ni in neutral and alkaline soil, but similar in acidic soil.
The methanogenesis was severely inhibited with 0.46 mM ASA addition.PO43− didn’t attenuate the methanogenesis inhibition in the existence of ASA.ASA was transformed to As(III), As(V), MMA and DMA in anaerobic digestion.Cu2+ mitigated the methanogenesis inhibition via impeding the degradation of ASA.Arsanilic acid (ASA), copper ion (Cu2+) and phosphate (PO43−) are widely used as feed additives for pigs. Most of these three supplemented feed additives were excreted in feces and urine. Anaerobic digestion is often used for the management of pig manure. However, the interaction of ASA with Cu2+ or PO43− on anaerobic digestion is still not clear. In this study, the influence of ASA, Cu2+, PO43− and their interaction on anaerobic digestion of pig manure and the possible mechanisms were investigated. The initial concentrations of ASA, Cu2+ and PO43− were 0.46 mM, 2 mM and 2 mM in the anaerobic digester, respectively. The methanogenesis was severely inhibited in the assays with only ASA addition, only Cu2+ addition and ASA+ PO43− addition with the inhibition index of 97.8%, 46.6% and 82.6%, respectively, but the methanogenesis inhibition in the assay with ASA+ Cu2+ addition was mitigated with the inhibition index of 39.4%. PO43− had no obvious impacts on the degradation of ASA. However, Cu2+ addition inhibited the degradation of ASA, mitigating the methanogenesis inhibition. The existence of ASA would inhibit methanogenesis and generate more toxic inorganic arsenic compounds during anaerobic digestion, implying the limitation of anaerobic digestion for ASA- contaminated animal manure. However, the co-existence of ASA and Cu2+ could mitigate the inhibition. These results could provide useful information for the management of anaerobic digestion of pig manure containing ASA with Cu2+. 相似文献
High concentrations of copper and tributyltin, two biocides used in antifouling paints, are found in harbors. Efforts are necessary to reduce the adverse impact of biocides from antifouling paints, but little is known about the actual use of such material. I surveyed the operators of 435 boats berthed in San Diego Bay, to determine what paints and maintenance procedures were being used.More than 90% of the respondents used conventional leaching paints. These paints contain 40% to 65% copper compounds and 3% to 7% tributyltin compounds. Few respondents used copolymer paints. Those who did use copolymer paints seemed to repaint less frequently than those using conventional leaching paints.Professional maintenance companies do not initiate repainting as frequently as individuals doing their own maintenance.It appears that the input of antifouling biocides to harbor waters could be reduced by at least one-third simply by educating boat-owners about the chemical mechanisms involved in antifouling paints, by explaining the environmental and economic advantages of using slow-release paints, and by encouraging them not to repaint until their paint's useful life has expired. 相似文献
According to existing estimates, available old copper scrap has more than tripled over the past 40 years. Secondary production (that is, copper produced from recycling old scrap), however, has only doubled. Indeed, over the past 10 years, while copper consumption and primary production have continued to expand briskly, while available old scrap has increased by over 35%, secondary production has actually stagnated.For a world concerned with sustainable development and the quality of the earth's environment, this performance is disappointing and in need of explanation. Other things being equal, one would expect the amount of recycling to increase with the availability of scrap, as many econometric models of the world copper market developed over the past several decades explicitly assume.The key to understanding sluggish growth in secondary production, this paper argues, is distinguishing carefully between (1) the flow of old scrap that arrives each year from products reaching the end of their useful lives during the year and (2) the available stock of old scrap that was not recycled during earlier years presumably because it was too costly to do so. Using an econometric model, the paper shows that old scrap stocks, which have contributed most of the increase in available old copper scrap over the years, have a very modest impact on secondary production. Old scrap flows have a much greater effect, but they account for only about 4% of the available old scrap for any given year. 相似文献
The antiviral properties of zeolite (sodium aluminosilicate) powders amended with metal ions were assessed using human coronavirus
229E, feline infectious peritonitis virus (FIPV), and feline calicivirus F-9. Zeolites containing silver and silver/copper
caused significant reductions of coronavirus 229E after 1 h in suspension. The silver/copper combination yielded a >5.13-log10 reduction within 24 h. It was also the most effective (>3.18-log10) against FIPV after 4 h. Other formulations were ineffective against FIPV. On plastic coupons with incorporated silver/copper-zeolites,
>1.7-log10 and >3.8-log10 reductions were achieved for coronavirus 229E and feline calicivirus within 24 h, respectively. Silver/copper zeolite reduced
titers of all viruses tested, suggesting that it may be effective against related pathogens of interest [i.e., SARS coronavirus,
other coronaviruses, human norovirus (calicivirus)]. Of note, it was effective against both enveloped and nonenveloped viruses.
Metal-zeolites could therefore possibly be used in applications to reduce virus contamination of fomites and thus the spread
of viral diseases. 相似文献
This study investigated the interaction between Cu2+ and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu2+ uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu2+. The uptake of Cu2+ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu2+, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu2+. The presence of Cu2+ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu2+ caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu2+ complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu2+ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu2+ may be contributing to this straining effect. 相似文献
Thirty-two brownfield sites from the city of Wolverhampton were selected from those with a former industrial use, wasteland
or areas adjacent to industrial processes. Samples (<2 mm powdered soil fraction) were analysed, using inductively coupled
plasma–atomic emission spectrometry (ICP–AES) for 20 elements. Loss on ignition and pH were also determined. A five-step chemical
sequential extraction technique was carried out. Single leach extraction with 0.12 M hydrochloric acid of Pb, Cu and Zn in
soil was determined as a first approximation of the bioavailability in the human stomach. Some of the sites were found to
have high concentrations of the potentially toxic elements Pb, Zn, Cu and Ni. The partitioning of metals showed a high variability,
however a number of trends were determined. The majority of Zn was partitioned into the least chemically stable phases (steps
1, 2 and 3). The majority of Cu was associated with the organic phase (step 4) and the majority of Ni was fractionated into
the residue phase (step 5). The majority of Pb was associated with the residue fraction (step 5) followed by Fe–Mn oxide fraction
(step 3). The variability reflects the heterogeneous and complex nature of metal speciation in urban soils with varied historic
histories. There was a strong inverse linear relationship between the metals Ni, Zn and Pb in the readily exchangeable phase
(step 1) and soil pH, significant at P < 0.01 level. There was a significant increase (P < 0.05) in the partitioning of Cu, Ni and Zn into step 4 (the organic phase) in soils with a higher organic carbon content
(estimated by loss on ignition). Copper was highly partitioned into step 4 as it has a strong association with organics in
soil but this phase was not important for the partitioning of Ni or Zn. The fractionation of Ni, Cu and Zn increased significantly
in step 3 when the total metal concentration increases (P < 0.01). The Fe–Mn oxide fraction becomes more important in soils elevated in these metals, possibly due to the scavenging
of metals by oxides. Cu and Pb extracted by HCl was statistically similar to the sum of the metals in steps 1 to 4 (P < 0.01) and HCl available Zn was statistically similar to the sum of Zn in steps 1 to 3 (P < 0.01). Step 4 (the organic phase) was not an important phase for Zn, so it was concluded that any Cu, Zn and Pb present
in soil in a nonresidue phase would be potentially available for uptake into the human system once soil has been ingested. 相似文献