Distribution Pattern of Heavy Metals in the Surface Sediments of the Jiaozhou Bay

Grain size analysis and chemical analysis of heavy metals are made for 312 surface samples of the Jiaozhou Bay. Nineteen samples of the waste water taken from the sewage discharge outlets along the eastern coast of the bay are also analyzed for heavy metals. Results show that heavy metals are richer in the east and poorer in the west of the bay. Sedimentary dynamic studies reveal that the distribution of heavy metals in the surface sediments of the Jiaozhou Bay is under the control of hydrodynamics.

Distribution and accumulation of heavy metals in Avicennia marina community in Shenzhen,China

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Nanosize-effect on the distribution of heavy metals in copper smelting dust:Based on sophisticated dust sorting approach

Dust particles emitted from smelters can be hazardous to ecosystems and humans,as they are often enriched in metallic compounds.Here,we combined multi-method mineralogical analysis with a sophisticated size sorting approach for copper smelting dust to study the nanosize-effect on heavy metal distribution,which has hitherto been underestimated.Three types of dust were collected from a copper flash smelter and then size-sorted using a Dekati low-pressure impactor.Results showed that all three samples could easily sort out nanoscale dust particles(<1μm,grades 10–2)and even those smaller than 100 nm(grades 5–2).Especially for electrostatic precipitators dust,the mass fraction of nanoscale dust(<1μm)could reach 10.71%.The presence of heavy metals(Pb,Zn,Cu,and As)and their mineral species in dust was examined at various particle sizes.It was discovered that different heavy metals are enriched on nanoparticles in specific sizes.In micron-sized particles,heavy metals are generally found in discrete phases(e.g.,CuSO_(4),PbSO_(4),and As_(2)O_(3)).In nanoscale particles,the dominant phase is Fe_(3)O_(4),while heavy metals are mostly found in lattice substitution(e.g.,CuFe_(2)O_(4)and ZnFe_(2)O_(4)).Two distinct nano-dust morphologies were found:One with irregular mesh or chain structures consisting of particles of a few nanometers,and the other with polygonal crystals in larger sizes of hundreds of nanometers.The enrichment of heavy metals in the latter morphology is more pronounced,possibly because lattice substitution of heavy metals is more likely to occur when polycrystalline particles are formed.

Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park

Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments（RDSs） of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents＇ and tourists＇ health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size（〈150 μm） were the dominant fraction. The length of dry period was one of the main factors affecting the particle size distribution, as indicated by the variation of size fraction with the increase of dry days. The amount of heavy metal（i.e., Cu, Zn, Pb and Cd） content was the largest in particles with small size（〈150 μm） among all samples. Specifically, the percentage of Cu, Zn, Pb and Cd in these particles was 74.7%, 55.5%, 56.6% and 71.3%, respectively.Heavy metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index（I geo） decreased in the order：Cd〉Pb〉Cu〉Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order： Cd〉Zn≈Pb〉Cu.

Soil Heavy Metal Pollution and Bioavailability in Baoshantao Mining Area, China

In areas with a high geological background of heavy metals,some edible plants could pose a serious threat to human health.In order to find effective methods to remove heavy metals or reduce their harm,this study investigated the enrichment conditions of five soil heavy metals,Cd,Pb,Cu,Zn and Cr,in four edible plants in a mining area,Baoshantao,in eastern China that has a high geological background of metals,and two groups of experiments were designed to investigate the effects of passivators on their enrichment.The results showed that the soil heavy metal content in the study area has a certain degree of spatial variability.The five heavy metal element contaminants in the soil are in the order of Cd>Cu>Zn>Pb>Cr.The enrichment coefficients and the transfer coefficients of different edible plants were different for the different heavy metals.The two groups of passivators showed better passivating effects with an increase in passivating agent dosage.The smaller the enrichment coefficient of water spinach,the lower the bioavailability.The results of this study can provide a scientific basis for the restoration of soil heavy metal pollution and the safe use of land in areas with a high geological background of heavy metals.