Impact of waterlogging on the uptake of arsenic by hyperaccumulator and tolerant plant

A significant proportion of arsenic (As)-contaminated sites are temporarily or permanently under reducing condition, which may affect phytoextraction efficiency using the As-hyperaccumulator Pteris vittata L. In this work, a pot experiment was conducted to investigate the solubility and redox species of As in soil. The uptake of As by two populations of P. vittata and As-tolerant grass Holcus lanatus under different water regimes was examined. Waterlogging decreased the redox potential from 350 to?50 mV, leading to an approximately 40% reduction of As(V) to As(III) and an increased dissolved As concentration by 150%–300%. The changes in the speciation and concentration of As influenced its uptake by plants. A population collected from a temporarily waterlogged riverside in Guangxi province (GX population) had ninefold higher shoot As concentration under the waterlogged condition than that under the non-waterlogged condition, indicating that it preferred taking up As in the form of As(III). By contrast, a population of P. vittata collected from a dry land in Yunnan province (YN population) and H. lanatus demonstrated a preference to As(V). The GX population was an appropriate species for the phytoextraction of waterlogged sites. These results implied the importance of habitat ecology on the extraction efficiency of hyperaccumulators.     

Vehicle-Induced Lead and Cadmium Contamination of Roadside Soil and Plants in Italy

Lead and cadmium concentrations in spontaneous vegetation and in soil sampled at various distances (0–208 m) from several motorways throughout Italy were measured. Lead and cadmium concentrations appear to be correlated to distance from the motorway and to traffic levels. A comparison with data from a remote and unpolluted site shows that foliar lead concentrations can be up to 40 times higher, and foliar cadmium concentrations up to 3 times higher. Plants behave differently in their accumulation of lead and cadmium; conifers present the highest levels. Also the various receptors and compartments of the roadside ecosystem differ in their accumulation of lead and cadmium; soil and bark have consistently higher concentrations, while the leaves and twigs of trees have consistently lower levels. the data recorded by ad hoc introduced bio-accumulating plants (Lolium multiflorum L.) are consistent with those of the spontaneous vegetation. the concentrations of both lead and cadmium in Lolium vary from June to November, following in part the fluctuation in traffic density.     

Changing of Lead and Cadmium Pools of Swedish Forest Soils

The aims of the paper are to; i)evaluate the rate and direction of present changesin lead (Pb) and cadmium (Cd) soil pools of Swedishforests; ii) discuss processes of importance forleaching of Pb and Cd in Swedish forest soils. Thepresently ongoing changes of Pb and Cd pools ofSwedish forest soils are evaluated by compilationof data from the literature and unpublishedsources. It is concluded that Cd pools arepresently decreasing in larger areas of Sweden. Therate of decrease is mainly determined by soilacidity status; Cd leaching is regulated by ionexchange with Ca²⁺, Mg²⁺, Al³⁺ andH⁺, and is higher in acid soils. The Pb poolsare presently increasing with 0.1 to 0.3 percentannually in the soil down to 0.5 meter. Pb isredistributed from the O horizon to the B horizon,most pronounced in spruce forests; the Pb pools ofthe O horizon are presently not increasing, but isslightly decreasing by 0.1 to 0.2 percent annually. The leaching of Pb in the soil is controlled byfactors regulating the solubility of organicmatter.     

铅蓄电池工业清洁生产与污染治理技术研究

装备和技术落后是中国铅蓄电池企业清洁生产水平不高的主要原因.在该行业推动强制性清洁生产审核,针对生产过程中污染物产生的关键工艺环节,采用先进成熟技术实施清洁生产改造,从源头削减污染物的产生量,同时优化末端治理实现达标排放,事关铅蓄电池企业的生存发展.本文在分析铅蓄电池生产工艺过程和产污环节的基础上,介绍了各工序清洁生产关键装备和技术,对常用的废气、废水治理方法作了比较分析,为铅蓄电池工业环境影响评价及清洁生产审核提供参考.     

典型冰川退缩区铅的来源、累积及历史沉降——以青藏高原海螺沟冰川退缩区为例

为探究青藏高原东部陆地生态系统中铅的来源、累积分配过程及百年来大气铅的沉降状况，以贡嘎山海螺沟冰川退缩区为对象，利用冰川退缩区样地年龄可确定的优势，对160年来完整的植被演替序列进行了系统研究.采用电感耦合等离子体质谱法（ICP-MS）测定了土壤和植物样品中的铅以及其他微量元素的含量，明确了铅在该地区生态系统中的含量和储量变化格局，并采用主成分分析（PCA）解析了土壤铅的潜在来源，评估了历史沉降铅的累积速率.结果表明，森林有机土壤是大气铅的重要汇集区域.大气沉降的铅主要累积于O层中，而C层土壤铅含量相对较低；植物地上部以树枝和树皮铅含量最高，树干铅含量最低.植被序列中不同树种的铅储量变化趋势和植被演替趋势成正相关.在植被生长期，铅储量因生物量增加而不断升高，而随着演替过程中植被的死亡而降低.整个演替系统铅的储量随冰川退缩时间显著增加，至1936年样地的云冷杉顶极群落达到最大值.PCA源解析表明有机土壤中57%左右的铅来自于人为来源铅的大气沉降过程，即外源污染的大气沉降是贡嘎山中铅的主要来源.进一步分析表明，中国西南地区和南亚地区（印度、孟加拉国等）是主要的污染潜在源区.在百年尺度上，大气来源沉降铅在冰川退缩区的平均累积速率为（8.87±3.55） mg/（m²·a）.此研究为探究铅在陆地生态系统中的来源、分配及累积，理解未来全球变化对铅的环境地球化学过程影响提供了经典范例与数据依据.     

Evaluation of Scalp and Pubic Hair as Bioindicators for Estimating Exposure to Lead

Blood lead concentration is still most commonly used to assess the degree of exposure to environmental lead. However, blood lead levels are relatively transient and so tissues such as hair which store lead over longer periods need to be explored as bioindicators of lead toxicity. The results of such an investigation into hair are presented. These results indicate that there are significant differences in scalp-hair levels between the African, East Indian and Chinese racial groups in the multiracial adult population of Trinidad, West Indies. However, no significant differences were found for the pubic hair levels among the three races. The percentage of sulphur or the carbon: sulphur ratios in scalp hair did not influence the scalp-hair lead levels in the general population, although a significant difference in the carbon:sulphur ratios was observed between the African and East Indian racial groups.     

Eiseniella tetraedra (Savigny, 1826) (Oligochaeta: Lumbricidae) as a bioindicator of heavy metals

The objective of this study was to assess the potential of the earthworm Eiseniella tetraedra (Savigny, 1826) as a bioindicator for cadmium (Cd) and lead (Pb) exposure. The importance of earthworms in metal pollution monitoring is widely recognized in terrestrial ecosystems. In this study, the levels of Cd and Pb in soils and earthworm tissues were studied at two locations, Polur Falls and a riverside area located in Abali, in the Elburz Mountains in Iran. At both locations the concentration of Cd and Pb in earthworms was higher than in the surrounding soils and a significant difference was found between the two stations, the latter probably attributable to the (1) amount of pesticides that are used for crop treatment in Abali and (2) presence there of clay, which is known to be rich in Cd. Data indicate that E. tetraedra is an efficient bioaccumulator of Cd and Pb and might act thus serve as a bioindicator of exposure.     

Acute and chronic toxic effect of lead (Pb) and zinc (Zn) on biomarker response in post larvae of Penaeus monodon (Fabricus, 1798)

Metal pollution produces damage to marine organisms at the cellular level possibly leading to ecological imbalance. The present investigation focused on the acute and chronic toxicity of lead (Pb) and zinc (Zn) by examining the effects of biomarker enzymes in post-larvae of Penaeus monodon (Tiger prawn). Antioxidant biomarker responses such as lipid peroxidation (LPO) and catalase (CAT) activity for Pb and Zn were determined following chronic exposure. Acute Lethal Concentration ₅₀ (LC₅₀) values observed in the study at 96?h for Pb and Zn at 5.77?±?0.32?mg?L^?1 and 3.02?±?0.82?mg?L^?1, respectively. The estimated No Observed Effect Concentration and Lowest Observed Effect Concentration values for Pb were 0.014 and 0.029?mg?L^?1 and that recorded for Zn was 0.011 and 0.022?mg?L^?1, respectively. Among the two metals studied, toxicity of Zn was found to be greater to P. monodon than Pb. The activities of antioxidant defense enzymes and total protein content differed significantly from control following exposure to both metals. Overall, the biomarker studies demonstrated that alterations in antioxidant enzymes and induction of LPO reflect the consequences of heavy metal exposure in P. monodon.     

Lead and cadmium bioaccumulation in fowl eggs depending on different food concentrations

Cadmium and lead bioaccumulation in eggs from four groups of laying hens was studied. The birds were fed on foods containing different quantities of cadmium and lead, exceeding the official technological standards for three of the groups. Bioaccumulation was studied using two criteria: coefficient of biological intake (CBI), which is the ratio between the concentration of the chemical element in a unit of dry biomass and its fodder concentration, and Klarck of concentration /Kc/ ‐ a dynamic value which includes both the fodder and water concentrations of the elements needed for acquiring a unit of biomass. For the high cadmium and lead concentrations, dissipation of the studied elements in the egg mass was established with lower values of both CBI and Kc.