Copper in the terrestrial environment: Verification of a laboratory-derived terrestrial biotic ligand model to predict earthworm mortality with toxicity observed in field soils

This study was set up for validation of a regression model to predict mortality in the terrestrial earthworm Aporrectodea caliginosa following exposure to copper. This model was derived from a terrestrial biotic ligand model and incorporates the protective effects of H⁺ and Na⁺ on copper toxicity.Three soil sets were used for the experiments, all of which had a different copper contamination history over more than 20 years and were considered to be aged field soils. The soils were characterized by analysis of various copper pools in the solid phase and in the pore water, analysis of physical and chemical soil properties and by regression analysis. Measured and calculated copper activities (expressed as pCu) correlated reasonably well. Measured copper activities correlated with the total copper concentration in the pore water and the pH. The organic matter in the solid phase had no influence on the pCu in these soil sets.Earthworms were exposed to the soils for 28 days, after which survival was scored. Observed earthworm mortality after 28-days exposure was plotted as a function of the log-transformed difference between predicted (log₁₀ transformed) LC50-values and measured values of pCu for validation of the regression model. The results obtained were in agreement with the assumption that mortality is to be observed in those soils where the predicted LC50 exceeds the measured pCu. However, a structural underestimation of toxicity was apparent, which is most likely due to mixture effects related to the presence of additional substances in field soils. Nevertheless, the trend of the results in the validation tests demonstrates that the newly developed toxicity model is a useful tool in predicting lethality of copper contamination to earthworms in field soils.     

生物有机肥中磷细菌对难溶性磷的有效化研究

通过土壤盆栽试验，在生物有机肥中加入固氮菌、磷细菌、硅酸盐细菌等有益微生物并与磷矿粉混合施用来栽培玉米，研究其中的磷细菌对土壤中难溶性磷的有效化作用。结果表明，在不施肥、施用磷矿粉、含磷细菌生物有机肥、不含磷细菌生物有机肥4个处理中，处理3更能促进玉米的生长、增加植株体内NPK养分的积累，特别是在肥力较低的土壤上表现更为显著。处理3也提高了土壤中的速效磷养分含量。     

Changes in the succession and diversity of protozoan and microbial populations in soil spiked with a range of copper concentrations

We studied microbial and protozoan activity, diversity and abundance as affected by Cu²⁺ amendments ranging from 0 to 1000 μg g⁻¹ over a 70-day period. At the end of the experiment the microbial population size, as indicated by substrate-induced respiration, had normalized for all Cu²⁺ concentrations, but 1000 μg g⁻¹. Protozoan abundance was negatively affected by Cu²⁺, although, only in the first few weeks. A more detailed analysis of the individual components that make up the microbial and micro-faunal populations (phospholipid fatty acid (PLFA) profile and protozoan morphotypes), however, yielded a somewhat more complex picture. For the three highest Cu²⁺ amendments (160, 400 and 1000 μg g⁻¹), there still was a significant reduction in number of differentiable protozoan morphotypes. The bacterial PLFA pattern suggested a shift from Gram-negative towards Gram-positive bacteria for the high amendments, a process where protozoan grazing most likely played a significant role. The ratio of the trans/cis isomers of the 16:1ω7 fatty acid indicated that Cu²⁺, even at low and medium concentrations, induced physiological changes in the microbial population. The relatively slight changes in total microbial and micro-faunal abundance and activity, also at the highest Cu²⁺ concentrations, probably reflected the ability of the community to compensate for loss of taxa by functional substitution.     

石英砂-腐殖酸-Cupriavidus gilardii CR3复合体对铜离子的吸附特性及机理研究

[目的]研究pH、初始铜离子浓度和吸附时间对石英砂-腐殖酸-Cupriavidus gilardii CR3复合体吸附铜离子的影响。[方法]利用等温吸附模型和动力学模型拟合试验数据,通过测定复合体吸附铜离子前后的Zeta电位、扫描电子显微镜-能谱(SEM-EDS)和傅里叶红外光谱(FTIR),研究吸附剂对铜离子的吸附特性及机理。[结果]pH是影响吸附能力的主要因素,静电作用可使复合体表面负电荷增多,提高吸附量。在最适pH(5.0)下,复合体对铜离子的最大吸附量为13.08 mg/g。复合体对铜离子的吸附过程符合化学单分子吸附的Langmuir模型和二级动力学模型。[结论]该研究认为静电作用和单分子化学吸附是石英砂-腐殖酸-Cupriavidus gilardii CR3复合体吸附铜离子的主要机制。     

电解质浓度对土壤吸附铜离子时氢离子释放的影响

研究了不同铜离子浓度、不同电解质浓度情况下,吸附铜离子时氢离子释放对两种可变电荷土壤和4种恒电荷土壤悬液pH的影响。研究结果表明,除了黄棕壤外,含铁量越高,由于吸附铜离子后所引起的土壤ΔpH最大值越小。加入的铜离子浓度为10-4 mol L-1时,铜离子吸附对中和曲线形状没有根本影响。在较低浓度时,铜离子吸附时氢离子的释放较少;而在较高浓度时,当体系pH大于一临界值时,开始释放大量氢离子。氧化铁是引起恒电荷土壤和可变电荷土壤在吸附铜离子时氢离子释放差异产生的主要原因。电解质浓度的变化对恒电荷土壤和可变电荷土壤吸附铜离子后中和曲线变化影响有很大的区别,含铁量越高,电解质浓度对土壤吸附铜离子后的氢离子释放的影响越小。     

化学镀铜中Cu（Ⅱ）—EDTA电还原机理

The mechanism of electrochemical reduction for species Cu(I)-EDTA in eiectroless copper plating was studied by means of polarization curve,rotating disc electrode,chrono-potentiometry and chronocoulometry.The result of reaction order determination indicat     

Association between liver copper concentration and subclinical hepatitis in Doberman Pinschers

The prevalence of subclinical hepatitis was investigated in a group of 106 randomly selected 3-year-old Doberman Pinschers. Histopathologic examination of liver samples from 65 dogs (52 dogs with high bile acids, alkaline phosphatase activity, or alanine aminotransferase activity or with copper granules in hepatocytes in a liver aspirate and 13 normal dogs) revealed subclinical hepatitis in 22 dogs (19 females and 3 males). Liver copper concentrations measured by instrumental neutron activation analysis was significantly higher (mean +/- SD; 419 +/- 414 microg/g dry matter) in dogs with hepatitis than those without liver disease (197 +/- 113 microg/g; P = .0008). At 2.6 +/- 0.6 years hepatitis persisted in 5 of 16 dogs available for examination. One dog with a high copper concentration but normal liver subsequently developed subclinical hepatitis after 3 years. During the follow-up period, the average copper concentration of the 6 dogs with persistent subclinical hepatitis was 939 +/- 299 microg/g and had continued to rise significantly (P = .02). The hepatitis in these dogs was associated with apoptotic hepatocytes and copper-laden Kupffer cells in centrolobular regions. The results of this study suggest that there is a relationship among copper storage, hepatocellular damage, and hepatitis in Doberman Pinschers.     

基于SPSS的城市滨水开放空间“使用效度”研究——以合肥环城公园为例

对合肥市环城公园使用人群及使用状况进行调研与统计,采用SPSS的方法分析出影响城市滨水空间“使用效度”的主要关联因子.以关联因子为问卷内容,利用问卷调查的方式对合肥市环城公园景区进行初步评价,并运用环境行为学理论分析验证评价结果.最后从可视度、交往度、亲水度三方面对提升城市滨水空间的“使用效度”提出建议.     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

Assessment of microbial activity and bacterial community composition in the rhizosphere of a copper accumulator and a non-accumulator

Soil microorganisms may play an important role in the uptake of heavy metals from soils. However, assessments of bacterial activity and community composition in the rhizosphere of accumulators have been largely ignored. We studied potential effects of a copper (Cu)-accumulator, Elsholtzia splendens, and a non-Cu-accumulator plant, Trifolium repens, on soil microbial activity and community composition with increasing Cu addition. The results showed that concentrations of Cu in the shoots of E. splendens were 2.1, 2.2 and 2.4 times those of T. repens under the treatment of different Cu concentrations. Soil microbial biomass and phosphatase activity in the rhizosphere of E. splendens were higher than those of T.repens. PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprint analysis revealed that addition of Cu decreased the number of bands in bare soil and soil with T. repens. However, there was a significant increase in the number of bands in soil with E. splendens incorporated with either 200 or 500 mg kg⁻¹ Cu. The abundances of five phylogenetic groups related most closely to -, β-, γ-proteobacteria, Gram-positive bacteria and CFB group, respectively, were determined in the rhizosphere of plants. Some specific clone such as E13 (metal-contaminated soil clone K20-64) was found in the rhizosphere of E. splendens. Results indicated that E. splendens, as a Cu-accumulator, played an important role in governing soil microbial activity and bacterial community composition in the rhizosphere in response to Cu stress.