Trace metals in surface sediments of the Taiwan Strait: geochemical characteristics and environmental indication

The concentration and geochemical fractionation of six trace metals related with environmental quality assessment, namely Cd, Cr, Cu, Ni, Pb, and Zn, in 30 surface sediments from both inshore and offshore areas of the Taiwan Strait were measured to investigate their distribution characteristics, evaluate their potential mobility, and assess their pollution status. The geoaccumulation index results indicated that, on average, the studied metals presented an order of Cd?>?Pb?>?Ni?>?Zn?>?Cu?>?Cr and were practically in uncontaminated status except Cd. The results of the sequential extraction analysis indicated that, on average, the studied metals were mostly accumulated in residual fraction except Cd whose concentration was the highest in the acid soluble fraction presenting a high risk to the environment, and their mobility decreased in the sequence of Cd?>?Pb?>?Ni?>?Cu?>?Zn?>?Cr. Based on the mean probable effect level quotients, the combination of the studied metals had an 8 % probability of being toxic at two sampling sites and had a 21 % probability of being toxic at the rest of sites. The spatial distribution of the studied metals in total concentrations and different geochemical fractions corroborated the previous findings about the possible sediment transportation routes in and around the Taiwan Strait.     

Heavy metals in sediments,soils, and aquatic plants from a secondary anabranch of the three gorges reservoir region,China

We investigated the occurrence of cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), Znic (Zn), iron (Fe), manganese (Mn), and magnesium (Mg) in sediments, as well as in related soils and aquatic plants in the Liangtan River, a typical secondary anabranch of the Yangtze River in the Three Gorges Reservoir Region (TGRR) of China. We found that sediments accumulated more metals than soils and aquatic plants. Concentrations of the nine metals in sediments and soils followed the same sequence, while their concentrations in aquatic plants followed a different sequence. Potential adverse effects of contaminated sediments on benthic fauna were evaluated, and the results showed that the toxic effect on benthic organisms followed the sequence Zn?>?Ni?>?Cr?>?Cu?>?Cd?>?Pb. The potential ecological risk index analysis indicated that Cd in sediments had considerable ecological risk, whereas Cr, Cu, Zn, Ni, and Pb had low ecological risk. The potential ecological risk index (RI) of the heavy metals in sediments of the Liangtan River was 174.9, indicating moderate ecological risk. The transfer factor trend of metals for aquatic plants showed that Cd and Ni had the most and least accumulation, respectively. For Cu, Cd, Mg, Pb, and Cr, a significant positive correlation of the metal concentrations was observed between sediments and soils, but no correlations (excluding Cr) were detected between sediments and aquatic plants. Our study indicated that anthropogenic input may be the primary source of metal contamination in the Liangtan River, and that Zn and Cd pollution in the Liangtan River should be further explored.     

Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto’s Mar Piccolo (Ionian Sea,Southern Italy)

In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment–water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m^?2 day^?1) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area.     

Distribution coefficients of potentially toxic elements in soils from the eastern Amazon

The solid-solution distribution or partition coefficient (Kd) is a measure of affinity of potentially toxic elements (PTE) for soil colloids. Kd plays a key role in several models for defining PTE guideline values in soils and for assessing environmental risks, and its value depends on edaphic and climatic conditions of the sites where the soils occur. This study quantified Kd values for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn from representative soil samples from Brazil’s eastern Amazon region, which measures 1.2 million km². The Kd values obtained were lower than those set by both international and Brazilian environmental agencies and were correlated with the pH, Fe and Mn oxide content, and cationic exchange capacity of the soils. The following order of decreasing affinity was observed: Pb?>?Cu?>?Hg?>?Cr?>?Cd?≈?Co?>?Ni?>?Zn.     

Assessing heavy metal pollution in the surface soils of a region that had undergone three decades of intense industrialization and urbanization

Heavy metals in the surface soils from lands of six different use types in one of the world’s most densely populated regions, which is also a major global manufacturing base, were analyzed to assess the impact of urbanization and industrialization on soil pollution. A total of 227 surface soil samples were collected and analyzed for major heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) by using microwave-assisted acid digestion and inductively coupled plasma–mass spectrometry (ICP-MS). Multivariate analysis combined with enrichment factors showed that surface soils from the region (>7.2?×?10⁴ km²) had mean Cd, Cu, Zn, and As concentrations that were over two times higher than the background values, with Cd, Cu, and Zn clearly contributed by anthropogenic sources. Soil pollution by Pb was more widespread than the other heavy metals, which was contributed mostly by anthropogenic sources. The results also indicate that Mn, Co, Fe, Cr, and Ni in the surface soils were primarily derived from lithogenic sources, while Hg and As contents in the surface soils were controlled by both natural and anthropogenic sources. The pollution level and potential ecological risk of the surface soils both decreased in the order of: urban areas?>?waste disposal/treatment sites?～?industrial areas?>?agricultural lands?～?forest lands?>?water source protection areas. These results indicate the significant need for the development of pollution prevention and reduction strategies to reduce heavy metal pollution for regions undergoing fast industrialization and urbanization.     

Trace metals in Ganges soft-shell turtle (Aspideretes gangeticus) from two barrage: Baloki and Rasul, Pakistan

The concentration of nine metals was measured in liver, kidney, heart, muscle, plastron, and carapace of Aspideretes gangeticus from Rasul and Baloki barrages, Pakistan. The results indicated that metal concentration were significant different among tissues of Ganges soft-shell turtles. However, higher concentrations of Co (5.12 μg/g) and Ni (1.67 μg/g) in liver, Cd (0.41 μg/g) in heart, Fe (267.45 μg/g), Cd (2.12 μg/g) and Mn (2.47 μg/g) in kidney, Cd (0.23 μg/g), Cu (2.57 μg/g), Fe (370.25 μg/g), Mn (5.56 μg/g), and Pb (8.23 μg/g) in muscle of A. gangeticus were recorded at Baloki barrage than Rasul barrage. Whereas mean concentrations of Pb (3.33 μg/g) in liver, Co (1.63 μg/g), Cu (11.32 μg/g), Pb (4.8 μg/g) and Zn (144.69 μg/g) in heart, Co (4.12 μg/g) in muscle, Ni (1.31 μg/g), Pb (2.18 μg/g), and Zn (9.78 μg/g) in carapace were recorded higher at Rasul barrage than Baloki barrage. The metals followed the trend Fe > Zn > Ni > Cu > Mn > Pb > Cr > Co > Cd. Metals of toxicological concern such as Cr, Pb, and Cd were at that level which can cause harmful effects to turtles. The results provide baseline data of heavy metals on freshwater turtle species of Pakistan.     

Trace elements in size-segregated urban aerosol in relation to the anthropogenic emission sources and the resuspension

Size segregated particulate samples of atmospheric aerosols in urban site of continental part of Balkans were collected during 6 months in 2008. Six stages impactor in the size ranges: Dp?≤?0.49 μm, 0.49?2?≈?30 %) followed by traffic (PC2, σ²?≈?20 %) that are together contributing around 50 % of elements in the investigated urban aerosol. The EF model shows that major origin of Cd, K, V, Ni, Cu, Pb, Zn, and As in the fine mode is from the anthropogenic sources while increase of their contents in the coarse particles indicates their deposition from the atmosphere and soil contamination. This approach is useful for the assessment of the local resuspension influence on element’s contents in the aerosol and also for the evaluation of the historical pollution of soil caused by deposition of metals from the atmosphere.     

Heavy metal content in vegetables and fruits cultivated in Baia Mare mining area (Romania) and health risk assessment

Information about heavy metal concentrations in food products and their dietary intake are essential for assessing the health risk of local inhabitants. The main purposes of the present study were (1) to investigate the concentrations of Zn, Cu, Pb, and Cd in several vegetables and fruits cultivated in Baia Mare mining area (Romania); (2) to assess the human health risk associated with the ingestion of contaminated vegetables and fruits by calculating the daily intake rate (DIR) and the target hazard quotient (THQ); and (3) to establish some recommendations on human diet in order to assure an improvement in food safety. The concentration order of heavy metals in the analyzed vegetable and fruit samples was Zn?>?Cu?>?Pb?>?Cd. The results showed the heavy metals are more likely to accumulate in vegetables (10.8–630.6 mg/kg dw for Zn, 1.4–196.6 mg/kg dw for Cu, 0.2–155.7 mg/kg dw for Pb, and 0.03–6.61 mg/kg dw for Cd) than in fruits (4.9–55.9 mg/kg dw for Zn, 1.9–24.7 mg/kg dw for Cu, 0.04–8.82 mg/kg dw for Pb, and 0.01–0.81 mg/kg dw for Cd). Parsley, kohlrabi, and lettuce proved to be high heavy metal accumulators. By calculating DIR and THQ, the data indicated that consumption of parsley, kohlrabi, and lettuce from the area on a regular basis may pose high potential health risks to local inhabitants, especially in the area located close to non-ferrous metallurgical plants (Romplumb SA and Cuprom SA) and close to T?u?ii de Sus tailings ponds. The DIR for Zn (85.3–231.6 μg/day kg body weight) and Cu (25.0–44.6 μg/day kg body weight) were higher in rural areas, while for Pb (0.6–3.1 μg/day kg body weight) and Cd (0.22–0.82 μg/day kg body weight), the DIR were higher in urban areas, close to the non-ferrous metallurgical plants SC Romplumb SA and SC Cuprom SA. The THQ for Zn, Cu, Pb, and Cd was higher than 5 for <1, <1, 12, and 6 % of samples which indicates that those consumers may experience major health risks.     

Elemental distribution in the edible leaves of Celosia trigyna from the western and northern regions of Nigeria

Celosia trigyna, which belongs to the plant family Amaranthaceae, is a plant used in traditional medicine to treat several conditions such as sores, chest pains, diarrhoea and menstrual cramps in many countries in Africa. It is also consumed by the local people in Nigeria as soups, sauces and stews. In this study, the distribution and bioaccumulation of the elements in C. trigyna species and growth soil from the western and northern regions of Nigeria was investigated to determine the effects of geographical location on the uptake of elements by the plant. Elemental concentrations in the leaves from the western region were found to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?>?Cu?>?Pb?>?As?>?Ni. Concentrations of elements in the leaves from the northern region were found to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?> Cu?>?As?>?Pb?>?Ni?>?Co?>?Cd. Proximate analysis of leaves from both regions compared well with the recommended dietary allowance making the leaves safe for human consumption. Principal component analysis was used to group elements having the same sources irrespective of their geographical locations. Cd, Co and Cr were not detected in the leaves from the western region. Concentrations of As and Pb were above maximum permissible limits in both regions, while Ayegunle and Bida (in the northern region) had the highest concentrations of Cd. The high level of these toxic metals may be attributed to anthropogenic activities. It is therefore important that the Nigerian agricultural extension system emphasizes the dangers of heavy metal contamination in leafy vegetables to farmers. Activities of the manufacturing industries in the study area should be adequately monitored under standard environmental protection laws.     

施用垃圾堆肥土壤重金属在不同温度和酸雨条件下的淋溶特征

采用淋洗法,研究了垃圾堆肥中重金属在不同温度与模拟酸雨条件下的淋溶特征。结果表明,随着淋洗次数的增加,淋洗液中Cd、Cr、Cu、Ni和Pb的含量都有很大程度的减少。Cd、Cr、Cu和Ni 4种金属在模拟酸雨的情况下淋出量明显高于蒸馏水的情况,增幅都在116%和351%之间,差异显著(P<0.05)或极显著(P<0.01),而酸雨对Pb的淋出影响较小。在酸雨淋洗下,重金属的淋出率在30℃时达到最大,其中Ni随着温度的变化相对较小。而在蒸馏水淋洗下,重金属的淋出率随着温度的变化相对平稳。此外,5种重金属的淋出率明显不同,其中Cr和Ni的淋出率相对较大,Pb最小。     

Elemental analysis of the edible fruit of Carpobrotus dimidiatus (from Kwazulu-Natal,South Africa) and the influence of soil quality on its elemental uptake

Abstract

Carpobrotus dimidiatus is an indigenous South African medicinal plant species from the Aizoaceae family that bears edible fruit that is consumed for nutritional value. In this study, the elemental distribution in C. dimidiatus fruit and growth soil from fifteen sites in KwaZulu-Natal (South Africa) was determined along with soil pH, soil organic matter and cation exchange capacity, to assess for nutritional value and the effect of soil quality on elemental uptake. The results showed elemental concentrations in fruit to be in decreasing order of Ca (6235–32755?mg kg^?1) > Mg (2250–5262?mg kg^?1) > Fe?>?Mn?>?Zn (20.9–50.6?mg kg^?1) > Cu (3.83–20.6?mg kg^?1) > Pb?>?Cr?>?Cd?>?As?～?Co?～?Ni?～?Se and no potential health risk due to metal toxicity from average consumption. For sites that had high levels of Cd and Pb, bioaccumulation occurred from atmospheric deposition. Concentrations of elements in soil were found to be in decreasing order of Fe (1059–63747?mg kg^?1) > Ca (1048–41475?mg kg^?1) > Mg?>?Mn (9.76–174?mg kg^?1) > Cr (1.55–135?mg kg^?1) > Zn (0.76–58.2?mg kg^?1) > Se?>?Cu?>?Ni?>?Pb?>?Co?>?As?～?Cd with no evidence of heavy metal contamination. This study revealed that the plant inherently controlled uptake of essential elements according to physiological needs and that the concentrations of essential elements in the fruit could contribute positively to the diet.     

Evaluating levels and health risk of heavy metals in exposed workers from surgical instrument manufacturing industries of Sialkot,Pakistan

The study aimed to monitor heavy metal (chromium, Cr; cadmium, Cd; nickel, Ni; copper, Cu; lead, Pb; iron, Fe; manganese, Mn; and zinc, Zn) footprints in biological matrices (urine, whole blood, saliva, and hair), as well as in indoor industrial dust samples, and their toxic effects on oxidative stress and health risks in exposed workers. Overall, blood, urine, and saliva samples exhibited significantly higher concentrations of toxic metals in exposed workers (Cr; blood 16.30 μg/L, urine 58.15 μg/L, saliva 5.28 μg/L) than the control samples (Cr; blood 5.48 μg/L, urine 4.47 μg/L, saliva 2.46 μg/L). Indoor industrial dust samples also reported to have elevated heavy metal concentrations, as an example, Cr quantified with concentration of 299 mg/kg of dust, i.e., more than twice the level of Cr in household dust (136 mg/kg). Superoxide dismutase (SOD) level presented significant positive correlation (p?≤?0.01) with Cr, Zn, and Cd (Cr?>?Zn?>?Cd) which is an indication of heavy metal’s associated raised oxidative stress in exposed workers. Elevated average daily intake (ADI) of heavy metals resulted in cumulative hazard quotient (HQ) range of 2.97–18.88 in workers of different surgical units; this is an alarming situation of health risk implications. Principal component analysis-multiple linear regression (PCA-MLR)-based pie charts represent that polishing and cutting sections exhibited highest metal inputs to the biological and environmental matrices than other sources. Heavy metal concentrations in biological matrices and dust samples showed a significant positive correlation between Cr in dust, urine, and saliva samples. Current study will help to generate comprehensive base line data of heavy metal status in biomatrices and dust from scientifically ignored industrial sector. Our findings can play vital role for health departments and industrial environmental management system (EMS) authorities in policy making and implementation.     

Assessment of trace metal contamination in the sea cucumber (<Emphasis Type="Italic">Holothuria tubulosa</Emphasis>) and sediments from the Dardanelles Strait (Turkey)

This study was performed to determine the concentrations of some trace metals (Cd, Cu, Pb, Ni, Zn, and Fe) in Holothuria tubuosa (Gmelin, 1788) belonging to Echinoderm species and in sediments that they live at three different stations (Gelibolu, Umur Bey/Lapseki, and Dardanos) on Dardanelles Strait between April 2013 and March 2014. The mean trace metal concentrations determined in H. tubulosa and sediment were as follows: Cd 0.18 mg/kg, Cu 2.43 mg/kg, Pb 2.09 mg/kg, Ni 14.58 mg/kg, Zn 16.86 mg/kg, and Fe 73.46 mg/kg and Cd 0.70 mg/kg, Cu 5.03 mg/kg, Pb 14.57 mg/kg, Ni 27.15 mg/kg, Zn 54.52 mg/kg, and Fe 3779.9 mg/kg, respectively. It was detected that the statistical difference between trace metals determined seasonally in muscle tissue of H. tubulosa was significant (p?>?0.05). As a result of the study, it was detected that H. tubulosa is a bioindicator species in determining Ni trace metal in sediment. The results were compared to the limit values of National and International Food Safety, and it was detected that Cd and Ni concentrations measured in sediment were above LEL of Ni and Cd concentrations according to Sediment Quality Guidelines.     

Effects of sediment burial disturbance on macro and microelement dynamics in decomposing litter of <Emphasis Type="Italic">Phragmites australis</Emphasis> in the coastal marsh of the Yellow River estuary,China

From April 2008 to November 2009, a field decomposition experiment was conducted to investigate the effects of sediment burial on macro (C, N) and microelement (Pb, Cr, Cu, Zn, Ni, and Mn) variations in decomposing litter of Phragmites australis in the coastal marsh of the Yellow River estuary. Three one-off sediment burial treatments [no sediment burial (0 mm year^?1, S₀), current sediment burial (100 mm year^?1, S₁₀), and strong sediment burial (200 mm year^?1, S₂₀)] were laid in different decomposition sites. Results showed that sediment burials showed significant influence on the decomposition rate of P. australis, in the order of S₁₀ (0.001990 day^?1)?≈?S₂₀ (0.001710 day^?1)?>?S₀ (0.000768 day^?1) (p?<?0.05). The macro and microelement in decomposing litters of the three burial depths exhibited different temporal variations except for Cu, Zn, and Ni. No significant differences in C, N, Pb, Cr, Zn, and Mn concentrations were observed among the three burial treatments except for Cu and Ni (p?>?0.05). With increasing burial depth, N, Cr, Cu, Ni, and Mn concentrations generally increased, while C, Pb, and Zn concentrations varied insignificantly. Sediment burial was favorable for C and N release from P. australis, and, with increasing burial depth, the C release from litter significantly increased, and the N in litter shifted from accumulation to release. With a few exceptions, Pb, Cr, Zn, and Mn stocks in P. australis in the three treatments evidenced the export of metals from litter to environment, and, with increasing burial depth, the export amounts increased greatly. Stocks of Cu and Ni in P. australis in the S₁₀ and S₂₀ treatments were generally positive, evidencing incorporation of the two metals in most sampling times. Except for Ni, the variations of C, N, Pb, Cr, Cu, Zn, and Mn stocks in P. australis in the S₁₀ and S₂₀ treatments were approximated, indicating that the strong burial episodes (S₂₀) occurred in P. australis marsh in the future would have little influence on the stocks of these elements. With increasing burial depths, the P. australis was particularly efficient in binding Cu and Ni and releasing C, N, Pb, Cr, Zn, and Mn, implying that the potential eco-toxic risk of Pb, Cr, Zn, and Mn exposure might be very serious. This study emphasized the effects of different burials on nutrient and metal cycling and mass balance in the P. australis marsh of the Yellow River estuary.     

Occurrence, distribution, and ecological risk assessment of DDTs and heavy metals in surface sediments from Lake Awassa—Ethiopian Rift Valley Lake

Dichlorodiphenyltrichloroethanes (DDTs) and heavy metals are ubiquitous contaminants with high bioaccumulation and persistence in the environment, which can have adverse effects on humans and animals. Although applications of DDTs have been banned in many countries, developing countries like Ethiopia are still using these for agricultural and medicinal purposes. In addition, heavy metals are naturally present in the aquatic environment and distributed globally. In this study, the occurrence, distribution, and ecological risk of DDTs and heavy metals in surface sediments from one of the Ethiopian rift valley lakes were studied. Twenty-five surface sediment samples from Lake Awassa, Ethiopia were collected and analyzed for DDTs and heavy metals. Results showed that concentrations of total DDTs ranged from 3.64 to 40.2 ng/g dry weight. High levels of DDTs were observed in the vicinity of inflow river side and coastal areas with agricultural activities. The heavy metals content were followed the order Zn?>?Ni?>?Pb?>?Cu?>?Cr?>?Co?>?As?>?Cd?>?Hg. Correlation analysis and principal components analysis demonstrated that heavy metals were originated from both natural and anthropogenic inputs. The levels of DDE and DDD in surface sediments exceeded the sediment quality guideline values, indicating that adverse effects may occur to the lake. A method based on toxic-response factor for heavy metals revealed that the calculated potential ecological risk indices showed low ecological risk for the water body.     

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd?>?Zn?>?Cu?>?Pb for fishpond 1 and Zn?>?Cd?>?Cu?>?Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one.     

Hazardous substances in indoor dust emitted from waste TV recycling facility

Various hazardous substances contained in waste TV sets might be released into environment via dust during recycling activities. Two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and tetrabromobisphenol A (TBBPA), and five kinds of heavy metals (Cu, Pb, Cd, Cr, and Ni) were detected in indoor dust collected from two workshops (TV dismantling workshop and subsequent recycling workshop). PBDEs concentrations in dust from waste wires recycling line (722,000 ng/g) were the highest among the studied sites, followed by those in manual dismantling–sorting line (117,000 ng/g), whereas TBBPA concentrations were the highest in manual dismantling–sorting line (557 ng/g) and printed circuit board (PCB) recycling line (428 ng/g). For heavy metals, Cu and Pb were the most enriched metals in all dust samples. The highest concentration of Pb (22,900 mg/kg) was found in TV dismantling workshop-floor dust. Meanwhile, Cu was the predominant metal in dust from the PCB recycling line, especially in dust collected from electrostatic separation area (42,700 mg/kg). Occupational exposure assessment results showed that workers were the most exposed to BDE-209 among the four PBDE congeners (BDE-47, BDE-99, BDE-153, and BDE-209) in both workshops. The hazard quotient (HQ) indicated that noncancerous effects were unlikely for both BFRs and heavy metals (HQ?<?1), and carcinogenic risks for Cd, Cr, and Ni (risk?<?10^?6) on workers in two workshops were relatively low.     

Heavy metals and polycyclic aromatic hydrocarbons in sediments from the Shenzhen River,South China

With the analysis of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and sixteen polycyclic aromatic hydrocarbons (PAHs) in sediments from the Shenzhen River, South China, the ecological risks associated were evaluated using Hakanson’s method (for the metals) and the Effect Range Low/Effect Range Median (ERL/ERM) method (for the PAHs). The result shows concentrations of heavy metal in the order Zn?>?Cu?>?Cr?>?Ni?>?Pb?>?As?>?Cd?>?Hg, and among which the Zn, Cu, Ni, and Pb are exceeding the maximum contaminant level for sediments while those of PAHs are far below. The potential ecological risk index value for the heavy metals in the sediment samples was 261.90, which is in the moderate risk category. Total PAH concentrations in the sediments ranged from 1,028 to 1,120 ng/g, which are all far lower than the sediment guideline concentration of 4,022 ng/g, indicating that the risks of biological impacts caused by PAHs in Shenzhen River sediments are, therefore, relatively low. Besides, the fluorene concentration was above the ERL, and would potentially cause negative biological effects in the Shenzhen River. Heavy metals risks are suggested among the most important concerns that the environmental recover measures pay attention to.     

Open-pit coal-mining effects on rice paddy soil composition and metal bioavailability to Oryza sativa L. plants in Cam Pha, northeastern Vietnam

This study quantified Cd, Pb, and Cu content, and the soil–plant transfer factors of these elements in rice paddies within Cam Pha, Quang Ninh province, northeastern Vietnam. The rice paddies are located at a distance of 2 km from the large Coc Sau open-pit coal mine. Electron microprobe analysis combined with backscattered electron imaging and energy-dispersive spectroscopy revealed a relatively high proportion of carbon particles rimmed by an iron sulfide mineral (probably pyrite) in the quartz–clay matrix of rice paddy soils at 20–30 cm depth. Bulk chemical analysis of these soils revealed the presence of Cd, Cu, and Pb at concentrations of 0.146?±?0.004, 23.3?±?0.1, and 23.5?±?0.1 mg/kg which exceeded calculated background concentrations of 0.006?±?0.004, 1.9?±?0.5, and 2.4?±?1.5 mg/kg respectively at one of the sites. Metals and metalloids in Cam Pha rice paddy soils, including As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, were found in concentrations ranging from 0.2?±?0.1 to 140?±?3 mg/kg, which were in close agreement with toxic metal contents in mine tailings and Coc Sau coal samples, suggesting mining operations as a major cause of paddy soil contamination. Native and model Oryza sativa L. rice plants were grown in the laboratory in a growth medium to which up to 1.5 mg/kg of paddy soil from Cam Pha was added to investigate the effects on plant growth. A decrease in growth by up to 60 % with respect to a control sample was found for model plants, whereas a decrease of only 10 % was observed for native (Nep cai hoa vang variety) rice plants. This result suggests an adaptation of native Cam Pha rice plants to toxic metals in the agricultural lands. The Cd, Cu, and Pb contents of the native rice plants from Cam Pha paddies exceeded permitted levels in foods. Cadmium and Pb were highest in the rice plant roots with concentrations of 0.84?±?0.02 and 7.7?±?0.3 mg/kg, suggesting an intake of these metals into the rice plant as shown, for example, by Cd and Pb concentrations of 0.09?±?0.01 and 0.10?±?0.04 mg/kg respectively in the rice grain endosperm. The adaptation of native rice plants, combined with bioaccumulation ratios of 1?±?0.6 to 1.4?±?0.7 calculated for Cd transfer to the rice grain endosperm, and maximum Cd transfer factors of 4.3?±?2.1 to the plant roots, strongly suggest a continuous input of some toxic metals from coal-mining operations to agricultural lands in the region of Cam Pha. In addition, our results imply a sustained absorption of metals by native rice plant varieties, which may lead to metal accumulation (e.g., Cd) in human organs and in turn to severe disease.