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The release of in situ heavy metals (cadmium [Cd], copper [Cu], lead [Pb], manganese [Mn], and zinc [Zn]) from contaminated river sediment near a Cu–iron mine in South China was experimentally studied. The effects of pH values and the kinetics of heavy metal release were investigated. In addition, species of the 5 metals in the sediment were determined as a function of pH and time. Rates and extents of metal desorption were studied over 30 d, and a 3‐parameter, 2‐compartment model was used to analyze the desorption kinetics. The rate constants (ks) for the slowly desorbing fraction of heavy metals were found to be 5 to 6 orders of magnitude lower than the corresponding rate constants (kr) for the rapidly desorbing fraction, suggesting that slow desorption is the rate‐limiting step. The partition coefficients (Kd) varied significantly among metals, on the order Pb > Cu >Zn > Cd > Mn, indicating that the sediment had a much higher retention capability for strongly hydrolyzed metals than for weakly hydrolyzed ones. The amount of metals released from the sediment decreased dramatically at the final pH of 2 to 4 and leveled off in the pH range of 5 to 8. Release time and pH exhibited a varied influence on the fractionation of metals, and had a more remarkable influence on more mobile fractions and hardly any effect on the residual fraction during the desorption process. The fractionation of strongly adsorbing metals like Pb was not as dependent on release time and pH as it was for the weakly bonded metals like Mn and Cd. The results indicate that in situ heavy metals may exhibit a sustainable potential for release and may increase health risks when the pH of the river is lowered. Environ Toxicol Chem 2019;38:464–473. © 2018 SETAC. [ABSTRACT FROM AUTHOR]

Contamination of cadmium (Cd) in paddy soil is a serious environmental problem threatening food safety in some parts of southern China, where rice grain Cd concentration often exceeds the Chinese limit (0.2 mg kg −1 ). We tested the effect of CaCO 3 liming combined with growing low Cd cultivars on Cd accumulation in rice grain in 2-year field trials. A liming model was used to predict the doses of lime required. Lime (2.25–7.5 t ha −1 ) was applied in 2016 only and the effect monitored in both 2016 and 2017. Soil pH was increased from the initial 5.5 to the target value 6.5 by 7.5 t ha −1 CaCO 3 . Liming greatly reduced CaCl 2 -extractable Cd in the rhizospheric soil. Grain Cd concentration in the control exceeded the limit by 2–5 times. Liming at 7.5 t ha −1 decreased grain Cd concentration by 70–80% in both seasons without affecting grain yield. Grain Cd concentration was below the limit in the 7.5 t ha −1 liming treatment in both seasons. Grain Cd concentration correlated closely with CaCl 2 -extractable Cd in rhizospheric soil at the grain maturing stage. Seasonal difference in grain Cd concentration was attributed to the soil water status at the grain maturing stage. Liming had no significant effect on grain arsenic concentration or speciation. A single application of CaCO 3 to raise soil pH to 6.5, combined with low Cd cultivars and delayed drainage of paddy water during late grain filling stage, was highly effective at reducing Cd accumulation in rice grain. [ABSTRACT FROM AUTHOR]

In China, the cadmium (Cd) levels in paddy fields have increased, which has led to the excessive uptake of Cd into rice grains. In this study, we determined the physicochemical properties of soil samples, including the pH, soil organic matter (SOM) content, cation exchange capacity (CEC), and total Cd content (Cd soil ) in order to establish a quadratic discriminant analysis (QDA) model for assessing the risk of Cd in rice and to calculate its prior probability. Decision tree and logistic regression models were also established for comparison. The results showed that the accuracy rate was 74% with QDA, which was significantly higher than that obtained using the decision tree (67%) and logistic regression (68%) models. The correlation coefficients between the soil pH and the other three factors (CEC, SOM, and Cd soil ) were higher in the inaccurate set than the accurate set, whereas the correlation coefficients were smaller in the inaccurate set than the accurate set. [ABSTRACT FROM AUTHOR]

Cadmium is considered an important toxicant of major environmental and occupational concern. It can contaminate water, soil, and the atmosphere through coal mining, beneficiation, combustion, etc. This paper is based on the published literature, especially those data reported during the recent 10 years, including 2999 individual samples from 116 coalfields or mines in 26 provinces in China. The arithmetic mean of cadmium in Chinese coals is 0.43 µg/g. Taking the coal reserves into consideration, the average value of cadmium in coal is estimated as 0.28 µg/g. Cadmium is mostly enriched in the Southern coal-distribution area during the Late Permian. Furthermore, cadmium is highly enriched in Hunan and Chongqing. The modes of occurrence of cadmium in Chinese coals are quite complex. Cadmium in Chinese coals has been found in sulfides, organic matter, silicate minerals, and other minerals. A marine environment may be the most significant factor that influences the cadmium accumulation in coal from the Southern coal-distribution area during the Late Permian. In addition, hydrothermal fluids, source rocks, and volcanic ash have also influenced the content of cadmium in some coalfields in China. [ABSTRACT FROM AUTHOR]

A comprehensive and detailed investigation of cadmium (Cd) pollution in surface riverine sediments of the Haihe Basin in north China was carried out. Total Cd concentrations in these sediments ranged from 0.153 to 22.1 mg/kg, exceeding the soil background value at all sampling sites. The mean Cd concentration of the bioavailable fraction was 0.557 mg/kg, accounting on average for 51.58% of the total Cd. A mean value of the Cd enrichment factor of 11.6 suggested that Cd has accumulated in most riverine sediments, resulting in a high degree of anthropogenic pollution. In fact, there were high levels of Cd pollution in the riverine sediments throughout the Haihe Basin, yielding geo-accumulation index values for Cd from 0.071 to 7.25. According to the potential ecological risk index, risk assessment code, and consensus-based sediment quality guidelines, Cd was a serious pollutant in this ecosystem. Because it occurred as a high proportion in the exchangeable/acid soluble fraction (21.21% on average), it may also have biological toxicity. Our findings indicated that it is important to consider Cd in control strategies for managing riverine sediment pollution in the Haihe Basin. [ABSTRACT FROM AUTHOR]

Vulnerability assessment of simple landfills was conducted using the multimedia, multipathway and multireceptor risk assessment (3MRA) model for the first time in China. The minimum safe threshold of six contaminants (benzene, arsenic (As), cadmium (Cd), hexavalent chromium [Cr(VI)], divalent mercury [Hg(II)] and divalent nickel [Ni(II)]) in landfill and waste pile models were calculated by the 3MRA model. Furthermore, the vulnerability indexes of the six contaminants were predicted based on the model calculation. The results showed that the order of health risk vulnerability index was As > Hg(II) > Cr(VI) > benzene > Cd > Ni(II) in the landfill model, whereas the ecology risk vulnerability index was in the order of As > Hg(II) > Cr(VI) > Cd > benzene > Ni(II). In the waste pile model, the order of health risk vulnerability index was benzene > Hg(II) > Cr(VI) > As > Cd and Ni(II), whereas the ecology risk vulnerability index was in the order of Hg(II) > Cd > Cr(VI) > As > benzene > Ni(II). These results indicated that As, Hg(II) and Cr(VI) were the high risk contaminants for the case of a simple landfill in China; the concentration of these in soil and groundwater around the simple landfill should be strictly monitored, and proper mediation is also recommended for simple landfills with a high concentration of contaminants. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) accumulation and pollution in arable soils are particularly serious in the lower reaches of the Minjiang River in southwest of China. In this study, the remediation efficiency of Cd contamination in arable soils, the distribution pattern of Cd concentration in crops, and the food safety to humans of three typical cropping systems (S1: maize + sweet potato-Chinese cabbage, S2: maize + ginger-stem mustard, and S3: rice) were investigated and evaluated. After 1-year rotation, the percentage of Cd extracted by crops from the plough soil layer was observed in three system fields with the trend of S1 (2.30 %) > S2 (1.16 %) > S3 (0.21 %) and Cd extraction amount in crops was maximum in sweet potato, then in maize. The same kind of crop had the same pattern of Cd distribution in organs, and the edible parts generally accumulated less Cd amount than the inedible parts. Further, the grain crops were found to possibly be suitable one for using as phytoaccumulators of Cd contamination for farmlands. Direct consumption of these crops from the three systems would pose a high health risk to local inhabitants since it would result in the monthly intake of Cd (247 μg kg body weight) being nearly 10 times higher than the recommended tolerable monthly intake (RTMI) (25 μg kg body weight), resulting mainly from the consumption of vegetables rather than the grains, which would be potentially reduced by these foods being consumed by livestock firstly. [ABSTRACT FROM AUTHOR]

In order to evaluate the exposure risk of lead and cadmium in seafood for coastal residents in the coastline of the South China, representative seafood such as sea fish, crustaceans and molluscs were collected and used as research samples in many sampling points. By determining lead and cadmium content in sample using graphite furnace atomic absorption spectrometry, we carried out a safety evaluation of lead and cadmium contamination of seafood by single factor pollution index method. By calculating lead, cadmium intake of the coastal residents eating seafood, their exposure risk of lead, cadmium was assessed. It was found that, firstly, the content of lead and cadmium in mollusks was both higher than sea fish and crustaceans in the same waters. Secondly, the lead and cadmium pollution in seafood near the mouth of Pearl River was the most serious. Thirdly, lead and cadmium intakes of the coastal population eating seafood were at a basic level of security, but there were certain risks on the males less than 17 years old eating molluscs in Shenzhen Bay. [ABSTRACT FROM AUTHOR]

This study was designed to investigate a prevalent brominated flame retardant tetrabromobisphenol A (TBBPA) and four heavy metals of Pb, Cr, As, Cd in dust samples (52 indoor and 52 outdoor) collected from residential houses in an e-waste recycling area in Southeast China. For TBBPA, the mean concentration in indoor dust (3435 ng/g, dw) was higher than that in outdoor dust (1998 ng/g, dw). For heavy metals, the mean concentrations of Pb, Cr, As, Cd were 399, 151, 48.13, and 5.85 mg/kg in indoor dust, respectively, and were 328, 191, 17.59, and 4.07 mg/kg in outdoor dust, respectively. Except for As, concentrations of TBBPA and other metals decreased with the increased distance away from the e-waste recycling center, suggesting significant contribution of e-waste activities. The daily exposure doses of TBBPA ranged from 0.04 to 7.50 ng/kg-bw/day for adults and from 0.31 to 58.54 ng/kg-bw/day for children, representing the highest values reported to date for TBBPA exposure via dust ingestion. Daily exposure doses of Cr, As, and Cd were all below the reference doses. However, daily exposure dose of Pb for children in areas near the e-waste processing center was above the reference dose, posing significant health concern for children in that region. [ABSTRACT FROM AUTHOR]

Background: Itai-itai disease primarily results from cadmium (Cd) exposure and is known as one of the four major pollution diseases in Japan. Cd pollution is more serious in several areas of China than in Japan. However, there is still a lack of information regarding the threshold level of Cd exposure for the adverse health effects in the general Chinese population. This study aims to evaluate the reference value of urinary Cd (UCd) for renal dysfunction in a Chinese population as the benchmark dose lower confidence limit (BMDL) based on a large sample survey. Methods: A total of 6103 participants who lived in five Cd polluted areas of China participated in this study. We analyzed UCd levels as a biomarker of exposure and urinary β2-microglobulin (Uβ2-MG) levels as a renal tubular effect biomarker. The BMD studies were performed using BMD software. The benchmark response (BMR) was defined as a 10 % additional risk above the background. Results: There was a positive correlation between the UCd levels and the prevalence of Uβ2-MG. The BMD of UCd for Uβ2-MG was estimated for each province. The findings showed that the BMD levels were related to the participants' geographic region, which may be partially due to the large differences in Cd exposure level, ethnic group, lifestyle and diet of the sample population in these study areas. The reference level of UCd for the renal effects was further evaluated by combining the five sets of data from all 6103 subjects. The overall BMDLs of UCd for Uβ2-MG with an excess risk of 10 % were 2.00 μg/g creatinine (μg/g cr) in males and 1.69 μg/g cr in females, which were significantly lower than the World Health Organization (WHO) threshold level of 5 μg/g cr for Cd-related renal effects. Conclusions: The selection of the sample population and geographic region affected the BMDL evaluation. Based on the findings of this survey of a large sample population, the UCd BMDLs for Uβ2-MG in males with BMRs at 10 % were 2.00 μg/g cr. The BMD was slightly lower in females, which indicated that females may be relatively more sensitive to Cd exposure than males. [ABSTRACT FROM AUTHOR]

The stress effect of cadmium absorption between aloe and Solarium nigrum L was studied through a simulation experiment with different cadmium contents in soil. The results showed that the growth characteristics, biomass and Cd content in the plants of aloe and S. nigrum L were closely related to Cd content in the soil, and S. nigrum L and aloe had a strong tolerance to Cd in the experiment. pH of rhizosphere soil with S. nigrum L and aloe planted was generally higher than that of non-rhizosphere soil, which is related to the planting pattern. Compared with aloe, S. nigrum L had a stronger capacity to accumulate Cd, and intercropping S. nigrum L and aloe could inhibit aloe's absorption of Cd, which is favorable to the sate planting of aloe. In addition, S. nigrum L has the potential to restore polluted soil. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we estimated atmospheric Cd emissions from anthropogenic sources in China from 1990 to 2010 on the basis of consumption or output data and emission factors. China emitted approximately 2186 t Cd to the atmosphere in 2010, with approximately 77% and 14% of the emissions arising from non-ferrous metal smelting and coal combustion, respectively. Temporal changes in the total Cd emissions were characterized by two periods of increase (1990–2000 and 2001–2010) and a short period of decrease (2000–2001) due to application of energy-saving and cleaner production technologies. Overall, atmospheric Cd emissions increased from 474 t in 1990 to 2186 t in 2010 due to rapid economic growth, whereas energy-saving and cleaner production technologies have been in use since 2000. Spatial distribution of the atmospheric Cd emissions was dominated primarily by non-ferrous metal smelting and coal combustion. Emissions are high in Hunan and Yunnan Provinces because of high production non-ferrous metal smelting and in Shandong Province because of high coal consumption and moderate non-ferrous metal production. [Copyright &y& Elsevier]

Highlights: [•] High concentrations of Cd in soils of a rural area in the Three Gorges region, China, are reported. [•] Lognormal distribution plots and enrichment factors were applied to identify Cd sources. [•] Sedimentary rocks are main source of Cd in the Cd-enriched soils. [•] Results of sequential extractions show that a considerable fraction of the Cd in soils is in a labile form. [ABSTRACT FROM AUTHOR]

The article presents a study which compares the tolerance and accumulation of cadmium (Cd) in carambola cultivars and its potential for phytoextraction. The study conducted a large-scale field survey in December 2005 in the Pearl River Delta (PRD), a carambola-producing area in China to asses the Cd-accumulating capacities of carambola cultivars. It mentions that the woody species of carambola trees, such as Dimocarpus longan and Clausena lansium were used for comparison. Result shows that there is a degree of difference in both tolerance and accumulation of Cd in different carambola cultivars. Moreover, further examinations of cultivars and soils with various levels of Cd contamination are suggested to evaluate the practical potential of the tree for phytoextraction.

Both in-field chemical investigation and in the laboratory toxic tests were carried out to systematically understand the pollution status of cadmium (Cd) and zinc (Zn) in Bohai Bay. Samples collected from surface seawater were determined to describe the distributions of Cd and Zn in Bohai Bay. The average values in our study of Cd and Zn were 0.15 μg/L and 19.68 μg/L, respectively. Both of them were lower than the first class limit of seawater quality standard in China. In the laboratory, antioxidant enzymes [SOD (Cu/Zn-SOD, Mn-SOD), CAT], lipid peroxidation (MDA), phase I and phase II enzymes (CYP4501A and GST) were investigated in the bivalves Chlamys farreri exposed to Cd and Zn at the concentration levels of Bohai Bay seawater, which were obtained from our in-field investigation. The reduced SOD, CAT, and EROD (7-ethoxyresorufin- O-deethylase) activities (with the inhibitory rate of 16.8%, 31.5%, and 51.6%, respectively) in Cd treatment were observed and resulted in obvious lipid peroxidation damage. However, treatment of Zn showed elevations in SOD and GST by 13.3% and 29.9%, respectively, and with no influence on lipid peroxidation. In summary, seawater quality in Bohai Bay seawater was ranked as good in general, but it seemed that Cd might possess a potential environmental risk by effecting pro-oxidant/antioxidant balance and phase I detoxification in C. farreri. [ABSTRACT FROM AUTHOR]

Due to the location of manufacturing in north Hangzhou, many residential areas are close to trunk roads and factory areas. This potentially exposes citizens to pollution sources such as industrial emissions and vehicle exhaust. Because pollution by cadmium (Cd) is of great concern, an extensive survey was conducted in north Hangzhou city to study the current condition of Cd contamination and any resulting hazard. Environmental materials including water, bottom mud, urban green-land soil, street dust and moss were collected. Cd concentration and chemical partitioning in the samples were determined. The results indicate that all the media in north Hangzhou have elevated Cd concentrations, the Cd content trend being: factory area > traffic area > residential area. The chemical partitioning results show that Cd in topsoil and street dust presents are mobile (9 - 61% Cd are bound in acetic acid extractable phase), which suggests a high ecological hazard potential. Environmental bioindicator moss samples were found to be loaded with Cd revealing high bioavailability of Cd in various media in north Hangzhou. This confirms the possibility of Cd being a potential biohazard in this location. [ABSTRACT FROM AUTHOR]

Abstract: Screening hyperaccumulators and accumulators is a key step in the phytoremediation of soils contaminated by heavy metals. A pot experiment was conducted involving a soil Cd concentration gradient (0, 50, 75, 100, 125, 150, 175, and 200mgkg−1) to determine if Malva sinensis Cavan. from two lead–zinc mines in Kangding and Yajiang in western Sichuan, China, is a Cd-hyperaccumulator. The highest Cd concentrations in plant shoots from Kangding and Yajiang were 154.30 and 122.77mgkg−1, respectively, at a soil Cd concentration of 200mgkg−1. The largest amounts of accumulation in plant shoots from Kangding and Yajiang were 700.5 and 1403.2μgpot−1, respectively. The bioconcentration factors in shoots were 0.53–1.03 for Kangding and 0.69–1.25 for Yajiang. Moreover, all translocation factors of plants from the two sites were over 1.0. Therefore, M. sinensis can be classified as a Cd-accumulator or non-standard Cd-hyperaccumulator. [Copyright &y& Elsevier]

The environment in seriously polluted due to improper and inefficient recycling of waste nickel—cadmium (Ni—Cd) batteries in China. The aim of this work is aimed to seek an environmentally-friendly recycling process for resolving the negative impacts on environmental and human health resulting from waste Ni—Cd batteries. This work investigates the fundamentals of waste Ni—Cd batteries recycling through vacuum metallurgy separation (VMS) and magnetic separation (MS). The results obtained demonstrate that the optimal temperature, the addition of carbon powder, and heating time in VMS are 1023 K, 1 wt %, 1.5 h, respectively. More Than 99.2 wt % Cd is recovered under the optimal experimental condition, and The Cd purity is 99.98%. Around 98.0 wt % ferromagnetic materials are recovered Through MS under 60 rpm rotational speed and The recovery ratios of Fe, Ni, and Co are 99.2 wt %, 96.1 wt %, and 86.4 wt %, respectively. The composition of ferromagnetic fractions in the residue after VMS increases from 82.3 to 99.6%. Based on these results, a process (including dismantling and crushing, VMS and MS) for recycling of waste Ni—Cd batteries is proposed. This novel process provides a possibility for recycling waste Ni—Cd batteries in a large industrial scale. [ABSTRACT FROM AUTHOR]

Abstract: The main focus of this study was to evaluate long term effects of cadmium on forearm bone mineral density after stopping ingestion of cadmium-polluted rice for 10 years in a Chinese population. A total of 532 persons (338 women and 194 men), living in control, moderately and heavily polluted areas, were included in this study. The residents living in the polluted area ceased ingesting cadmium-polluted rice in 1996. All participants were require to answer a questionnaire and the bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the proximal radius and ulna. Samples of urine and blood were collected for determination of cadmium in urine (UCd) and blood (BCd).The BMD of subjects living in the heavily polluted area was significantly lower than that of those living in control area in both men and women (p <0.01). For the people living in the moderately polluted area, only the women''s BMD was greatly lower compared to that in the control area (p <0.05). The BMD declined with the increasing BCd and UCd in both sexes, especially in the highest level (BCd >5 µg/L, UCd >10 µg/g crea) groups (p <0.01). It was found that there were significant differences in the prevalence of osteoporosis among the different areas (χ 2 =13.046, p =0.0003) and different UCd groups (χ 2 =4.511, p =0.0337) in women, but not in men (χ 2 =0.962, p =0.3268; χ 2 =1.906, p =0.1675). But a significant difference exists in the prevalence of osteoporosis among different BCd groups in both genders (χ 2 =9.304, p =0.00229, in women; χ 2 =4603, p =0.0319, in men). This study suggested that cadmium could play a long-term role on bone and more attention should be paid to cadmium effects on bone metabolism after reduction of exposure. [Copyright &y& Elsevier]

Mercury, cadmium, and lead concentrations of ashed plants and insects samples were investigated and compared with those of soil to reveal their biogeochemical processes along food chains in Huludao City, Liaoning Province, China. Concentration factors of each fragments of the soil–plant–the herbivorous insect–the carnivorous insect food chain were 0.18, 6.57, and 7.88 for mercury; 6.82, 2.01, and 0.48 for cadmium; 1.47, 2.24, and 0.57 for lead, respectively. On the whole, mercury was the most largely biomagnified, but cadmium and lead were not greatly accumulated in the carnivorous insects as expected when the food chain extended to the secondary consumers. Results indicated that concentration factors depended on metals and insects species of food chains. [ABSTRACT FROM AUTHOR]

A comparative study of the heavy metal (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) concentrations in sediments collected from the mainstream, tributaries, and lakes of the Yangtze River catchment of Wuhan, China, was conducted. Compared with the maximum background values in Wuhan Province soils, Cd was the metal with the highest contamination level, especially in the mainstream, followed by Zn and Cu. In a few samples from tributaries and lakes, the Hg concentration was very high compared to background levels. The concentrations of As and Ni in all sites fluctuated close to background levels. Partitioning of speciation of each heavy metal in sediments was similar for samples taken from the mainstream, tributaries, and lakes. Compared to the other metals studied, Cd, Cu, Zn, and Pb had higher bioavailability in the three zones, which means they pose a higher ecological risk. Significant correlations among group a (Zn, Cu, and Pb, r >0.9) and group b (Cr and Ni, r =0.978) in the mainstream; Hg, Cu, Cd, and Pb in lakes (r >0.9); and Cu and Pb (r >0.9) in tributaries were observed using Cluster and correlation analysis. However, a low correlation between As and the other elements in the three zones was shown. Overall, 63.6% of samples from the mainstream, 75.0% from tributaries, and 88.9% from lakes exhibited low and moderate ecological risk of heavy metals, and the potential ecological risks in the mainstream and tributaries were higher than those in lakes. [Copyright &y& Elsevier]

Metals including major and trace elements were studied in total suspended particulates (TSP) in the atmosphere of Nanjing, China. The results demonstrated that heavy metal concentrations in TSP of the Nanjing atmosphere are higher distinctly in ambient environments of heavy industrial factory areas than the background concentration of the atmosphere. It is suggested that the heavy metals from these factory activities are at a concentration level of at least 20–65% respectively for studied metals (Fe, V, Cr, Ni, Mn, Ba, Cu, Pb, and Zn). The flux of metals generated by factory areas is about at 8.37 g/m2·day for Fe, 11.45 μg/m2·day for V, 25.99 μg/m2·day for Cr, 27.02 μg/m2·day for Ni, 84.08 μg/m2·day for Ba, 222.63 μg/m2·day for Pb, 2304.02 μg/m2·day for Zn, and 3153.81 μg/m2·day for Cu. [ABSTRACT FROM AUTHOR]

The article discusses research that applied a regression model to predict the average cadmium content in rice grains for paddy fields located in China's Zhejiang province. Soils in the Fuyang valley have been contaminated by heavy metals. Cadmium has a tendency to bioaccumulate in rice grains, posing a potential human health risk. A multiple linear model for assessing cadmium content is the most effective predictor, as it examines the sensitivity of calcium chloride-extracted cadmium for changes in oxidation-reduction potential.

An integrated analysis has been carried out on two cores dated by combination of 210Pb and 137Cs in order to characterize the extent of heavy metal accumulation in the Liaodong Bay, Northern China. The concentrations and burial fluxes of Zn, Pb, Cd, and Hg increased abruptly after late 1970s. The enrichment factors of Cd, Hg, Zn and Pb are more than 30, 10, 7, and 3.5, respectively, in the surface sediments. Coincident to the increase of heavy metal contents, the decreasing trend of 206Pb/207Pb ratio indicated lead in the surface sediments mainly come from anthropogenic activities. [Copyright &y& Elsevier]

Paddy rice has been likened to nictiana sp in its ability to scavenge cadmium (Cd) from soil, whereas arsenic (As) accumulation is commonly an order of magnitude higher than in other cereal crops. In areas such as those found in parts of Hunan province in south central China, base-metal mining activities and rice farming coexist. Therefore there is a considerable likelihood that lead (Pb), in addition to Cd and As, will accumulate in rice grown in parts of this region above levels suitable for human consumption. To test this hypothesis, a widespread provincial survey of rice from mine spoilt paddies (n = 100), in addition to a follow-up market grain survey (n = 122) conducted in mine impacted areas was undertaken to determine the safety of local rice supply networks. Furthermore, a specific Cd, As, and Pb biogeochemical survey of paddy soil and rice was conducted within southern China, targeting sites impacted by mining of varying intensities to calibrate rice metal(loid) transfer models and transfer factors that can be used to predict tissue loading. Results revealed a number of highly significant correlations between shoot husk, bran, and endosperm rice tissue fractions and that rice from mining areas was enriched in Cd, As, and Pb. Sixty-five, 50, and 34% of all the mine-impacted field rice was predicted to fail national food standards for Cd, As, and Pb, respectively. Although, not as elevated as the grains from the mine-impacted field survey, it was demonstrated that metal(loid) tainted rice was entering food supply chains intended for direct human consumption. [ABSTRACT FROM AUTHOR]

Lead/cadmium contamination in vegetables grown in peri-urban area of Nanjing, China was assessed and the route for metals entering into plants was investigated through lead isotopic tracing. Results show that agricultural soils have been polluted with Cd. Contents of Pb (22.1–37.5 mg kg−1 dw) and Cd (2.53–4.19 mg kg−1 dw) in vegetables’ edible parts nearby a lead/zinc mining/smelting plant were beyond their maximum allowable limit prescribed in the (EC) No 1881/2006. Pb isotope ratios in plants differed from those in the corresponding soils, suggesting that soils were not the only contamination source of Pb and Cd in plants. [ABSTRACT FROM AUTHOR]

Dust on tree leaves in the urban area of Hangzhou, China, was analyzed in terms of heavy metal contents and magnetic properties. Morphological and chemical composition of the dust particles were analyzed using a high resolution transmission electron microscope equipped with an energy-dispersive X-ray analyzer (HRTEM/EDX). Results indicated that the dusts contained high concentrations of Cd (mean 2.62), Cu (63.7), Zn (535.9) and Pb (150.9mgkg−1). Magnetic susceptibility of the dusts was in a range of (16–856)×10−8 m3 kg−1. It was shown that the dusts close to industrial area and busy road intersection had higher heavy metal contents and magnetic susceptibility. The dusts showed a strong positive inter-correlation for the concentrations of Fe, Mn, Cr, Zn, Pb, and Cu in addition to magnetic susceptibility, which suggests that the dusts had a common source for the heavy metals and magnetic carriers. We found that the dust particles were composed mainly of Fe-rich near-spherical, plate and agglomerate particles, and Ca-rich, S-rich and silicate particles, and that iron oxide spherules (0.2–0.5μm in diameter) and larger iron-bearing particles were the magnetic carriers. Ca in the dusts was present in the forms of CaCO3 and CaCO3/CaSO4 internal mixture. The Fe-rich, Ca-rich and S-rich particles in dusts could be directly related to nearby polluting activities, such as coal combustion, traffic emission and industrial activity. The identification of the main sources of dusts on tree leaves can help in controlling the polluting sources in urban areas. The close correlation between magnetic susceptibility and heavy metal concentration makes it possible to use the magnetic technique as a non-destructive and time-efficient tool for biomonitoring of the atmospheric dust pollutants. [Copyright &y& Elsevier]

Sediments and fish, including tilapia ( Oreochromis mossambicus), bighead carp ( Aristichthys nobilis), grass carp ( Ctenopharyngodon idellus), and mandarin fish ( Siniperca chuatsi) were collected from different fish ponds in the Pearl River Delta (Tanzhou, Sanjiao, Guangzhou, Shipai, Changan, and Mai Po) for the analysis of metalloids and heavy metals [arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb)]. The pollution of As in pond sediments was great; however, As in the edible parts of pond fish were within the international permissible safety levels for human consumption. Axial muscles from 10 species each of freshwater and marine fish purchased from markets in Hong Kong were also analyzed for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. Freshwater fish contained 0.24 to 2.13 mg/kg As, 0.10 to 0.17 mg/kg Cd, 0.09 to 0.36 mg/kg Cr, 0.06 to 0.35 mg/kg Cu, 0.07 to 0.34 mg/kg Hg, 0.04 to 0.36 mg/kg Ni, 0.11 to 0.52 mg/kg Pb, and 2.67 to 19.1 mg/kg Zn (wet weight). Marine fish had higher Hg and lower Pb concentrations than freshwater fish. A few fish species had average concentrations greater than the international standards for Cd and Pb established by the European Union and the China National Standard Management Department. Total Hg concentrations in 10 of 20 market fish species were generally greater than those of the World Health Organization’s recommended limit of 0.2 mg/kg for at-risk groups, such as children and pregnant women. Daily intake through fish consumption of these metals were compared with the Provisional Tolerable Weekly Intake proposed by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives. There appears to be potential threat to local people from Hg contamination because of the high marine fish consumption rate (142 g/d/person). [ABSTRACT FROM AUTHOR]

The Jinding Pb-Zn deposit in Yunnan Province is the representative of a Cd-enriched area and mining activities lead to the release of Cd into the hypergenic ecosystem, resulting in Cd pollution. The concentrations of Cd vary greatly from one type to another type of rocks in the mining district. In the host rock, Cd concentrations range from 50×10−6 to 650×10−6 with an average of 310×10−6. In primary ores, Cd concentrations range from 14×10−6 to 2800×10−6 with an average of 767×10−6. However, in oxidized ores, Cd concentrations are highest, varying within the range of 110×10−6 to 8200×10−6, averaging 1661×10−6. It is shown that the oxidized ores are the main carrier and environmental source of Cd. Leaching test showed that Pb/Zn ores are easy to oxidize and thereafter release Cd and other harmful elements. These leached elements in the leachate may be precipitated rapidly in the order of Zn>Pb>Cd. As for the concentration distribution of Cd in the Bijiang River, it is estimated to be 15.7 μg/L Cd in water, 49.3 mg/L in suspended substances, and 203.7 mg/L in sediments. The average value of Cd in soil from the polluted area is 83.0 mg/kg. Natural weathering of Cd-rich rocks and minerals imposes a potential environmental risk on the aquatic ecosystem of the Bijiang catchment. [ABSTRACT FROM AUTHOR]

Historical zinc smelting in Hezhang, southwestern China, has resulted in significant heavy metal contamination of the surrounding ecosystems. The Caohai wetland system, which is an important national nature reserve close to the Hezhang zinc smelting area, was investigated in the present study. Results showed that sediments from the Caohai wetland system have been seriously contaminated by Cd, Pb and Zn with the highest concentrations in the surface sediments being up to 71, 160 and 1200 μg g−1, respectively. The heavy metals in the sediments were strongly associated with the organic/sulphide and residual fractions. A more oxidized condition induced by aquatic plants tended to cause the Cd, Pb and Zn bound to the Fe–Mn oxide fraction to become more dominant. Pb isotopic compositions in the sediments indicated that the inventories of Pb in the Caohai wetland sediments were mainly derived from the historical zinc smelting in the Hezhang area, although other anthropogenic sources, such as the gasoline Pb, also made a substantial contribution to the Pb in the sediments. Heavy metal contamination in aquatic plants was also studied and the results indicated that heavy metals accumulated by plants may pose a potential threat to the higher trophic-level organisms, including humans. [Copyright &y& Elsevier]

Artificially contaminated soils (A, B) and naturally contaminated soil (S2) in China were used as the tested soils, and the effect of continuous flooding on the changes of Eh, pH and the speciation of cadmium, lead in contaminated soils was studied in the paper. The results indicated that soil Eh decreased with flooding time, and that soil pH increased with flooding time. The changes of soil pH ceased after 60 days of submergence. The exchangeable Cd and Pb decreased obviously during the flooding process from the results of five-step sequential extraction. The calculations of mobility factor (MF) showed that Cd mobility significantly decreased in artificially contaminated soils (A, B) after the flood. But the change of Pb mobility was not significant after the flood, although a decrease of Pb concentration in the exchangeable fraction (SE) was observed. [ABSTRACT FROM AUTHOR]

Huludao Zinc Plant in Huludao City, China is the largest zinc smelting plant in Asia. Heavy metals have contaminated its neighboring environment seriously. We collected 20 vegetables and the corresponding soil samples from eight sampling plots near Huludao Zinc Plant to investigate health risk of Hg, Pb, Cd, Zn, and Cu to the inhabitants around Huludao Zinc Plant in China via consumption of vegetables. Transfer factor (TF) values of Hg, Pb, Cd, Zn, and Cu from soil to vegetable and the target hazard quotients (THQs) to the possible health risks to local population through the food chain transfer were calculated accordingly. TF values of heavy metals from soil to vegetable decrease in the order of Cd>Zn>Cu>Pb>Hg. These TF values of leaves are higher than other tissues. Daily intakes of Hg, Pb, Cd, Zn, and Cu through the consumption of vegetables are 1.322, 574.3, 301.4, 5263, and 292.5 μg, respectively, for adults, and 1.029, 446.8, 234.5, 4095, and 227.6 μg, respectively, for children around Huludao Zinc Plant. This would lead to potential health risk, especially for children, since Cd or Pb individual THQ is high than 1. The total metal THQs (TTHQs) due to consumption of vegetables for adult and child are 5.79–9.90, 7.6–13.0, respectively. Comparing TTHQs in the sampling plots of different distances to Huludao Zinc Plant, it indicate that the health risks to inhabitants close to Huludao Zinc Plant (<500 m) is the highest, and at >1000 m distance is relatively higher than in 500–1000 m distance. However, the inhabitants who lived in 500–1000 m distance to Huludao Zinc Plant is also experiencing the adverse health risk due to TTHQ being higher than 1. [Copyright &y& Elsevier]

This article discusses the concentration of heavy metals found in the Pacific oyster Crassostrea gigas from the Pear River Estuary in China. According to the author, for all three sites they found a significant positive correlation between copper and zinc concentrations. They determined that metal bioavailability (especially cadmium, lead and copper) in the Pearl River Estuary is high when compared globally. They concluded that heavy metal contamination in oysters from the three main distributaries is at alarming levels. They recommend legislation enforcement to regulate the discharge of metals in industrial effluent.

To investigate the variation of Zn and Cd accumulation and tolerance of Sedum alfredii (a newly reported Zn/Cd hyperaccumulator), field surveys and hydroponic experiments were conducted among three populations of this species: two originating from old Pb/Zn mines in Zhejiang (ZJ) and Hunan (HN) Provinces and one from a “clean” site in Guangdong (GD) Province, China. Under field conditions, up to 12,524 and 12,253mg kg−1 Zn, and 1400 and 97mg kg−1 Cd in shoots of ZJ and HN plants were recorded respectively. Under hydroponic conditions, ZJ and HN plants accumulated significantly higher Zn and Cd in their leaves and stems, and possessed significantly higher Zn and Cd tolerance than GD plants. Among the two contaminated populations, ZJ plants showed higher Cd tolerance and accumulation (in leaves) than HN plants. The present results indicate that significant differences in Zn and Cd accumulation and tolerance exist in populations of S. Alfredii. [Copyright &y& Elsevier]

Heavy metal contamination of metal-mined soils is a widespread problem in China. In the restored (over 20years) Lipu manganese mineland, 36 plant species from 22 families were found colonizing, some of which were planted agronomic ones. Heavy metal concentrations in tailings were very high. Minesoils were basically unpolluted, but soils in the remaining mining area and in the vicinity of tailings dumps were polluted by Cd and Mn. Measurements of metal contents in dominant plants showed they were close to those of other mineland plants. Plants tended to have a higher Cd accumulation (as reflected by Biological Accumulation Coefficient) from soil, but have a higher Mn translocation (as indicated by Biological Transfer Coefficient) to aboveground parts. The Chinese chestnut and sugarcane cultivated on the reclaimed mineland were not safe for human consumption, and this agricultural restoration pattern should be carefully reconsidered. [Copyright &y& Elsevier]

Studies of heavy metals and organic pollutants in different benthic mussel species from Bohai Sea show that concentrations of Cd in mussels commonly exceed national biological quality standards. In addition, a site located in Laizhou Bay exhibits higher average concentrations of As, Hg and Pb with respect to the other sites. Residual levels of petroleum hydrocarbons at several sites in Liaodong Bay also exceed quality guidelines. Contents and compositional characteristics of DDT and its metabolites in mussels suggest the probability of recent inputs and potential ecological risks to the local benthic environment. [Copyright &y& Elsevier]

The combined effects of cadmium (Cd, 10 mg/kg of soil) and butachlor (5, 10 and 50 mg/kg of soil) on enzyme activities and microbial community structure were assessed in phaeozem soil. The result showed that phosphatase activities were decreased in soils with Cd (10 mg/kg of soil) alone whereas urease acitivities were unaffected by Cd. Urease and phosphatase activities were significantly reduced by high butachlor concentration (50 mg/kg of soil). When Cd and butachlor concentrations in soils were added at milligram ratio of 2:1 or 1:2, urease and phosphatase activities were decreased, while enzyme activities were greatly improved at the ratio of 1:5. This study indicates that the combined effects of Cd and butachlor on soil urease and phosphatase activities depend largely on the addition concentration ratios to soils. The random amplified polymorphic DNA (RAPD) analysis showed that the changes occurring in RAPD profiles of different treated samples included variation in loss of normal bands and appearance of new bands compared with the control soil. The RAPD fingerprints showed substantial differences between the control and treated soil samples, with apparent changes in the number and size of amplified DNA fragments. The results showed that the addition of high concentration butachlor and the combined applied Cd and butachlor significantly affected the diversity of microbial community. The present results suggest that RAPD analysis in conjunction with other biomarkers such as soil enzyme parameter etc. would prove a powerful ecotoxicological tool. [ABSTRACT FROM AUTHOR]

Studies the copper, lead, zinc, cadmium, mercury and arsenic in marine products of commerce from Zhejiang coastal area in China in May 1998. Environmental quality status in Zhejiang coastal area; Concentrations of the trace elements in fish muscle and cephalopod mantle; Variation in metal levels among different species.

Reports on cadmium exposure among residents of Dayu County, Jiangxi Province, China due to pollution of the river water used to irrigate its arable land. Cadmium from tailings and wastewater of tungsten ore dressing plants; Estimates of oral cadmium intake coming from locally grown rice and vegetables; Deductions on cadmium exposure of local residents; Possible renal effects of cadmium.

The author reflects on issues related to the protection of rivers in China. According to the author, a smelting plant in Guangdong province breached safety rules for treating cadmium waste, resulting in the discharge of cadmium waste into the Beijiang River. The author states that the reduction in river flow has led to an increase in the rate of sea-level rise in coastal areas during the dry season.