利用历史监测资料分析土壤重金属环境质量——以攀枝花市钒钛产业园区为例

为了解工业园区土壤重金属的污染程度,采集测定了11家企业周边表层土壤Hg、As、Pb、Cd、Cr、V、Zn、Ni、Cu,利用单因子指数、内梅罗综合指数、背景值及标准偏差评价及金属累积性评价对研究区域土壤重金属污染程度进行了分析。结果表明:园区表层土壤重金属污染整体清洁,区域土壤中Zn本底较高,Cd、Pb、Cr、V在不同区域中出现污染现象,Pb、V在不同区域中有明显的累积,黄磷化工行业、镍铁合金冶炼行业及渣场对土壤重金属污染影响较大。

Toxicity and bioaccumulation of heavy metals in Phanerochaete chrysosporium

The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd＋Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.

Cultivation Ages Effect on Soil Physicochemical Properties and Heavy Metal Accumulation in Greenhouse Soils

The intensive management practices in greenhouse production may alter the soil physicochemical properties and contribute to the accumulation of heavy metals(HMs). To determine the HM concentrations in vegetable soil in relation to soil physicochemical properties and cultivation age, we conducted a soil survey for typical greenhouse soils in Shouguang, China. The results indicated that Cd is a major HM pollutant in the tested soils, as the only HM element exceeding the allowed limit for vegetable soil. The surveyed data was analyzed with regression analysis, correlation analysis and canonical correspondence analysis(CCA). A positive correlation is observed between HM pollution level and cultivation age. CCA results suggest that the HM pollution level and distribution in soil are significantly affected by soil physicochemical properties, which was a function of years of cultivation as revealed by regression analysis. In summary, cultivation age is an important factor to affect soil physicochemical properties(organic matter and inorganic nutrients) as well as HM contamination.

Heavy Metal Bioaccumulation and Toxicity with Special Reference to Microalgae

The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.