水环境中镉污染处理的研究进展

镉是一种有毒的金属元素,在自然界中主要成硫镉矿而存在,由于它的难降解性,低毒性,高稳定性,以及可蓄积性,水中镉的含量与日俱增,对人类的健康造成很大的危害,目前监测水样中镉的主要方法是原子吸收法和原子荧光法。本文介绍了近年来备受关注的植物修复技术,生物去除技术,吸附法,膜分离法等物理处理技术,化学沉淀法、铁氧化沉淀法、离子交换法等化学处理技术对水中镉的去除,并对今后治理镉污染提出了建议。     

天然黏土联合磷肥对农田土壤镉铅污染原位钝化修复效应研究

为研究天然黏土联合磷肥对农田土壤镉铅污染的原位钝化修复效应,在天津市某地开展了田间示范实验,以油麦菜、油菜和萝卜为模式作物,以海泡石、膨润土和磷肥等作为钝化修复材料,研究其对蔬菜可食部位生物量、镉铅含量和土壤中镉铅形态分布的影响,考察其对土壤镉铅污染的原位钝化修复效果.结果表明:磷肥、海泡石/磷肥复配、膨润土/磷肥复配...     

胡敏酸改性膨润土钝化污染土壤Pb&Cd及机理

通过盆栽试验,探讨了胡敏酸改性膨润土对重金属铅、镉污染土壤的钝化效果及机理。结果表明,铅、镉污染土壤中施加胡敏酸改性膨润土能显著降低小白菜中Pb、Cd的含量,在添加Cd(3 mg/kg)/Pb(250 mg/kg)污染土壤和Cd(1 0 mg/kg)/Pb(5 00 mg/kg)污染土壤上小白菜地上部分Pb含量分别比对照降低19.08%和47.91%,Cd含量分别比对照降低9.79%和14.89%。土壤本身对添加的重金属Pb/Cd有一定的耐受力和自我净化能力,在添加重金属后,添加的Pb/Cd元素大部分直接转化为较为稳定的碳酸盐结合态和铁锰氧化结合态。相关性分析显示小白菜的鲜重与小白菜Pb/Cd含量极显著负相关,进一步说明胡敏酸改性膨润土是通过提高小白菜的生物量,从而降低Pb/Cd在小白菜中的含量。     

土壤镉污染修复方法及生物修复研究进展

土壤镉污染主要由人为活动引起,镉在土壤环境体系中存在复杂多变的形态,文章介绍了土壤镉污染对生物体的危害性及其修复方法,综述了生物修复技术处理镉污染土壤的研究进展,并提出了展望。     

Food chain transfer of cadmium and lead to cattle in a lead–zinc smelter in Guizhou, China

Cadmium (Cd) and Lead (Pb) are environmental pollutants. Environmental samples and bovine tissues were collected from the areas around a lead–zinc smelter in Guizhou, China for Cd, Pb, zinc (Zn) and copper (Cu) analysis. Cd in soil (10 mg/kg) and feed (6.6 mg/kg) from the polluted areas was 10 times higher than the Chinese Standards, resulting in higher Cd in bovine kidney (38 mg/kg) and liver (2.5 mg/kg). Pb in feed (132 mg/kg) from the polluted area was much higher than unpolluted areas, causing higher Pb levels in bovine tissues. Environmental Zn was elevated, but bovine tissue Zn was normal. Cu in bovine liver decreased with increased Cd and Pb. Metals in drinking water and in bovine muscle were within the Standard range. Thus, in the areas of this lead–zinc smelter, the environment has been contaminated with Cd and Pb, which has been transferred to cattle through the food chain.     

Identification of five partial ABC genes in the liver of the Antarctic fish Trematomus bernacchii and sensitivity of ABCB1 and ABCC2 to Cd exposure

Several ABC transporters have been characterized from many aquatic organisms, but no information is yet available for Antarctic fish. The aim of this work was to identify the expression of genes for ABC proteins in Trematomus bernacchii, a bioindicator species of the Southern Ocean. Partial cDNA sequences of ABCB1, ABCC1, ABCC2, ABCC4 and ABCC9 were cloned from liver. Using RACE technology, 3.5 and 2.2 kb contigs were obtained for ABCB1 and ABCC2. Considering the elevated natural bioavailability of cadmium at Terra Nova Bay, responsiveness of ABCB1 and ABCC2 to this element was investigated under laboratory conditions. ABCB1 and ABCC2 mRNA levels were approximately four-fold higher in Cd-exposed fish compared to the controls. Induction of ABCB1 protein was also found by western blot. This study provides the first identification of five ABC genes in the liver of an Antarctic key species, some of which may be involved in cellular detoxification.     

对广东北江镉污染事件的立法评析—兼评《水污染防治法》

本文选取环境问题比较突出的水污染领域进行集中探讨，从分析“广东北江镉污染”这一具有典型意义的水污染突发事件入手，首先分析导致北江污染事件发生的具有普遍意义的共性原因，然后总结1996年《水污染防治法》存在的问题并提出修订法律的必要性，最后通过对2008年新修订的《水污染防治法》相关制度的解读与评说，来提出进一步完善新法的一些立法建议。     

Cadmium accumulation characteristics of floricultural plant Cosmos bipinnata*

The artificially high soil cadmium (Cd) concentration screening method was used to screen Cd-hyperaccumulators from floricultural plants. Among the five species of floricultural plants screened, Cosmos bipinnata showed the characteristics of Cd-accumulators. A pot experiment was conducted to further study Cd accumulation characteristics of C. bipinnata. The results showed that the biomass, chlorophyll content, superoxide dismutase activity, peroxidase activity and soluble protein content of C. bipinnata first increased and later decreased with the increase in soil Cd concentration, but the carotenoid content and catalase activity of C. bipinnata reduced. Cd contents in roots, stems, leaves and shoots of C. bipinnata increased with increasing soil Cd concentration. When the soil Cd concentration was 50?mg?kg^?1, the Cd content in shoots was up to 112.62?mg?kg^?1, which was higher than the Cd-hyperaccumulator critical value. The root and shoot bioconcentration factors exceeded 1 in various Cd treatments, but the translocation factors were less than 1. When the soil Cd concentration was 50?mg?kg^?1, the Cd accumulation in shoots achieved the maximum of 224.30?μg plant^?1. Therefore, considering the tolerance and accumulation of Cd, C. bipinnata is a Cd-accumulator that could be used to remediate Cd-contaminated urban soil.     

Uptake of cadmium into cells in culture∗

Cadmium has been recognized as pollutant of the environment for many years and numerous studies on its toxic effects have been carried out. Little, however, is known about its metabolic behaviour e.g. why the metal is accumulated so extremely rapidly into the organs of men and animals. Since the study of the individual metabolic steps is very difficult in vivo cell cultures may be used to obtain first indications of what happens in the whole animal.

We used CHO cells in monolayer culture to study the conditions under which the uptake of cadmium occurs. From serumfree medium the metal is accumulated rapidly in the cells. The uptake is inhibited very strongly by the presence of serum or albumin. Accumulation occurs against a concentration gradient and is dependent on the incubation temperature. Below 10°C no cadmium uptake is seen. Several substances which are known to affect cell metabolism have been used to influence cadmium accumulation. Neither inhibitors of energy production nor microtubule or microfilament disruptors showed any substantial effect. In contrast SH‐group blocking agents markedly reduced cadmium uptake.

The results show that cadmium uptake does not occur by passive diffusion but by some active mechanism.     

Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy

Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren - Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.