Elements characteristics and potential environmental risk assessment of jarosite residue and arsenic sulfide residue based on geochemical and mineralogical analysis.

The waste slag known as jarosite residue (JR) and arsenic sulfide residue (ASR) were produced following the creation of zinc by hydrometallurgical procedures. The increasing annual zinc mining has led to growing pressure to dispose of the resulting JR and ASR from zinc smelting, making it crucial to assess their environmental impact and feasibility for utilization. The main components, distribution characteristics of elements, and potential environmental risks of zinc smelting wastes are studied through toxicity leaching tests, sequential extraction procedures, and various characterization technologies such as XRF, XRD, and SEM-EDS. The mineral compositions of JR are natrojarosite, franklinite, and gunningite, and zinc mainly adheres to the crevices of the natrojarosite mineral. Meanwhile, the ASR of flocculent structures is composed of orpiment, greenockite, arsenic oxide, and calvertite, and As appears in the form of the S-As-O phase. The Zn, Cu, and Cd in JR were dominated by exchangeable bound (81.53-96.6 %), and the main form of As, Cd, Se, and Tl in ASR was organic matter bound (87.0-99.21 %). The Risk Assessment Code (RAC) method confirmed the risk of Cd, Cu, Zn, and Mo in JR is high, while the risk of Cd, Pb, and Cr in ASR is moderate. Compared to the standard value of "Identification Standard for Toxicity of Hazardous Waste Leaching (GB5085.3-2007)", the leachate concentrations of Zn in JR as well as Cd and As in ASR were exceeded, suggesting that the JR and ASR were in the type of hazardous waste and posed an environmental risk. The study provides theoretical guidance for the future rational management and effective utilization of hazardous waste.

Distribution, source identification, water quality, and risk assessment of trace elements in the surface-groundwater-sediments multifunctional system in Guohe River Basin.

Within the Huaihe River Basin, Guohe River, as its second-largest tributary, serves as a critical water supply source. Recent industrial and agricultural advancements have led to increased trace element contamination, adversely impacting the water quality within Guohe River Basin. Therefore, this study aimed to investigate the distribution characteristics, sources, water quality and risk assessment of trace elements in the surface water, groundwater, and sediments across the basin. The results showed that the spatial distribution of trace elements in the surface water and groundwater of Guohe River Basin was that most of the high concentrations appeared in Qiaocheng District of Bozhou City, the mean concentration of Fe in Guohe River sediments was the highest, the mean concentration of Sb was the lowest. The PMF source analysis results showed that the main source of trace elements in Guohe River Basin was natural geological processes, followed by human activities. The sodium adsorption ratio (SAR) indicated that the surface water samples of Guohe River in two seasons had high sodium and salinity hazards. The water quality index (WQI) showed that surface water and groundwater samples in the northwestern of Guohe River Basin had poor water quality. The results of the risk assessment showed that As and Mn posed great ecological risks to surface water and groundwater, respectively, and that F- was the pollutant with the most potential health risk hazard in the basin. The Geo-accumulation index (Igeo) results showed that Cd, Se and As should be taken seriously as the main contaminants of the sediments in Guohe River Basin. KEYWARDS: Trace elements; Source analysis; Sodium adsorption ratio; Water quality index; Risk assessment; Geo-accumulation index.

Hydrochemistry, quality, and integrated health risk assessments of groundwater in the Huaibei Plain, China.

Groundwater is an essential freshwater resource utilized in industry, agriculture, and daily life. In the Huaibei Plain (HBP), where groundwater significantly influences socio-economic development, information about its quality, hydrochemistry, and related health risks remains limited. We conducted a comprehensive groundwater sampling in the HBP and examined its rock characteristics, water quality index (WQI), and potential health risks. The results revealed that the primary factors shaping groundwater hydrochemistry were rock dissolution and weathering, cation exchange, and anthropogenic activities. WQI assessment indicated that only 73% of the groundwaters is potable, as Fe2+, Mn2+, NO3-, and F- contents in the water could pose non-carcinogenic hazards to humans. Children were more susceptible to these health risks through oral ingestion than adults. Uncertainty analysis indicated that the probabilities of non-carcinogenic risk were approximately 57% and 31% for children and adults, respectively. Sensitivity analysis further identified fluoride as the primary factor influencing non-carcinogenic risks, indicating that reducing fluoride contamination should be prioritized in future groundwater management in the HBP.

Spectroscopic fingerprinting, pollution characterization, and health risk assessment of potentially toxic metals from urban particulate matter.

The unprecedented stride of urbanization and industrialization has given rise to anthropogenic input of tiny particulates into the air. Urban particulate matter (PM) armored with potentially toxic metals (PTMs) could be lethal to the environment and human health. Therefore, the present study was planned to investigate the spectroscopic fingerprinting, pollution status and health risk of PM-associated PTMs collected from ten functional areas of Lahore, Pakistan. The diverged results of studied qualitative and quantitative analyses showed distinct compositional and pollution characteristics of PTMs in urban PM with respect to selected functional areas. The XRD results evident the fractional presence of metal-containing minerals, i.e., pyrite (FeS2), calcite (CaCO3), zinc sulfate (ZnSO4), and chalcostibite (CuSbS2). Several chemical species of Zn, Pb, and As were found in PM of various functional areas. However, morphologies of PM showed anthropogenic influence with slight quantitative support of PTMs presence. The cumulative representation of PTMs pollution of all selected areas depicted that Cd was heavily polluted (Igeo=3.21) while Cr (Igeo=1.82) and Ni (Igeo=2.11) were moderately polluted PTMs. The industrial area having high pollution status of Cd (Igeo=5.54 and EF=18.07), Cu (Igeo=6.4 and EF=32.61), Cr (Igeo=4.03 and EF=6.53), Ni (Igeo=5.7 and EF=20.17), and Zn (Igeo=4.87 and EF=11.27) was prominent among other studied areas. The PTMs were likely to pose a high non-cancerous risk in IndAr (HI = 7.48E+00) and HTV (HI = 1.22E +00) areas predominantly due to Zn with HQ > 1. However, Cr was prominent to cause cancerous risks with values beyond the tolerable range (1.00E-04 to 1.00E-06).

Characteristics and health risk assessment of heavy metals in dust of a waste printed circuit board recycling workshop, China.

Physical separation is the most widely used technology concerning waste printed circuit board (WPCB) recycling in practical terms. The dust generated from the process poses a significant environmental and human health risk. Amounts of heavy metals in dust present in each processing zone of the workshop showed differences. However, to date, few studies have reported this. The mean metal concentrations in workshop dust from different processing zones were investigated in this study and it was found that Zn, Pb, and Sn appeared in higher levels than other metals, followed by Mn > Cr > Ni > V > As > Cd. The enrichment factors (EFs) ranged from 1.15 to 207.4, and decreased in the order of Cu > Sn > Pb > Zn > Cd > Cr > Ni > V > As, which was exactly consistent with the geo-accumulation index values. The comparison of the EF values of workshop dust in and outside showed that the EFs in workshop dust were mostly smaller. Metals in the dust of the crushing zone (CrZ) showed significant and strong enrichment. The non-carcinogenic risk for different processing zones was all less than 1, which is recognized safety for people's health. The total carcinogenic risk from Cr, and Ni in all zones and As in the CrZ exposure was not negligible. The carcinogenic and non-carcinogenic risks in the CrZ were significantly higher than in the other zones. Masks to filter dust, a ventilation system, daily work hours reduction, and automation improvement was proposed for reducing workers' exposure to heavy metal.

Spatial-temporal distribution, source identification, risk assessment and water quality assessment of trace elements in the surface water of typical tributary in Yangtze River delta, China.

As China's first cross-province ecological compensation mechanism pilot area in the hinterland of the Yangtze River Delta, Xin'an River has been hotspot in the study of rational utilization of ecological resources, and the functional value of its ecosystem services has been widely concerned. As an important tributary of the upper reaches of Xin'an River, Fengle River may affect the whole basin. The spatial-temporal distributions, occurrence, water quality and risk assessment of trace elements were studied in Fengle River in three seasons. High element concentrations were found in the downstream. Traceability models results showed that the major sources of trace elements were related to different human activities. The water quality was worse downstream in the wet season, and was more suitable for irrigation in the dry season. Risk assessment results showed that Zn, Cu, Mn, Co, and As were able to pose the risk to the ecological environment and human.

Material flow analysis and characteristics of multiple-source organic solid wastes from a perspective of ecological network analysis: A case study in Hefei, China.

The numerous resources are consumed and a large number of multiple-source organic solid wastes are discharged during urban metabolic, which put pressures to environment. This study combined material flow analysis and ecological network analysis to comprehensively analyse the metabolism of multiple-source organic solid waste in Hefei. Analysing current metabolic characteristics of urban multiple-source organic solid waste and relationships between the components of metabolic system can help urban environmental management. The internal material flows of the system were analysed by a metabolic network containing 5 nodes and 18 pathways, which revealed metabolic characteristics of multiple-source organic solid waste in Hefei. The study showed that the metabolic system of multiple-source organic solid waste was relatively stable though distribution of internal flows changed in 8 years. The metabolic environment and agricultural sector covered a relatively large weight in this model. The control and exploitation relationships dominated the metabolic system. The urban metabolic mechanism reflected in this research can improve efficiency of urban metabolic resource, optimize waste management and provide data support for sustainable urban development. This study provided scientific guidance for metabolic research in Hefei and similar cities in China's rapid economic development.

Spatial-temporal distribution, occurrence, water quality, and risk assessment of trace elements in ten rivers surrounding Chaohu Lake in China.

As one of the five great lakes in China, the Chaohu Lake Basin is the main water source for regional economic and ecological development in Hefei city and is considered a source of drinking water. The spatial-temporal distributions and occurrence of soluble trace elements were studied in the surrounding ten rivers in the Chaohu Lake Basin as well as water quality and risk assessment during the normal and wet seasons. Principal component analysis (PCA) showed that the main source of river pollution during the two seasons was the mining industry. High values of most elements were found in the northwestern rivers in the two seasons. The temporal changes in the elements showed that the distributions of As, Mn, Cd, and Cu in the two seasons were very different, but the trends of Ni, Co, and V were basically the same. The sodium adsorption ratio (SAR) showed that almost all river samples needed to be treated before irrigation, and the water quality index (WQI) showed that most samples were of excellent water quality for drinking. The ecological risk assessment results showed that the risks in the two seasons were all slight. The results of the health risk evaluation suggested that no noncarcinogenic risks were found in the normal season and that the carcinogenic risks from Cr and As reached their highest levels in the normal and wet seasons, respectively. This research can provide vital data for rational water control and water quality conservation, offer a scientific basis for ecological environment safety, and offer a reference for carcinogenic and noncarcinogenic health risks to regional residents.

Occurrence and risk assessment of antibiotics in the surface water of Chaohu Lake and its tributaries in China.

The extensive use of antibiotics for treating humans, animals, and plants has resulted in the contamination of aquatic environments, posing a potential threat to public health and aquatic life; hence, this topic is of great concern worldwide. Lakes are considered to be antibiotic-rich reservoirs because many of the antibiotics discharged from rivers enter lakes. Chaohu Lake is one of the top five freshwater lakes in China. This study aims to provide a current evaluation of the antibiotics present in the surface water of the Chaohu Lake basin. To this end, the occurrences of 18 antibiotics categorized into 5 different groups were investigated in the study area, and the impact of inflowing rivers on their distribution was assessed. The results showed that the concentrations of 14 antibiotics in water samples ranged from 0 to 892 ng/L, and that antibiotics were detected at most sampling sites. Among them, the Nanfeihe and Shiwulihe rivers, which are close to the city, contributed the most to antibiotic pollution, indicating the widespread occurrence of antibiotics in the study area. A risk assessment based on the risk quotient method indicated that ofloxacin, ciprofloxacin, sulfamethoxazole, erythromycin, and norfloxacin in the lake water posed a high ecological risk to algae, while sulfamethazine posed a high risk to plants (RQ >1).

[Spatial Distribution and Pollution Assessment of Dissolved Heavy Metals in Chaohu Lake Basin During the Wet Season].

The spatial distribution characteristics of the mass concentration of V, Cr, Mn, Ni, Cu, Zn, Pb, Cd, Fe, and Sb in the Chaohu Lake basin and ten surrounding rivers during the wet season were explored. The results showed that the average mass concentration of heavy metals in the western and northwestern Chaohu Lake surrounding rivers was higher than that in the central and eastern regions. The correlation analysis showed a significant positive correlation between the concentrations of Cu, Ni, Zn, Pb, and Cd, which indicated a similarity of spatial distribution among the five elements. The single-factor pollution index evaluation results classified Cr in the ten surrounding rivers as Grade I based on the Environmental Quality Standards for Surface Water. Pb was classified as Grade Ⅰ-Ⅱ; Cu and Zn as Grade Ⅰ-Ⅴ; Fe, Sb, and V were far below the standard limit; Ni slightly exceeded the standard at some sampling points of the Nanfei River; Mn slightly exceeded the standard at some points of the Shiwuli and Pai River; Cd exceeded the standard at some points of the Nanfei River. Except Mn at one point of the Tangxi River, V, Cr, Ni, Cu, Zn, Pb, and Fe were all<1, which indicated clean and pollution-free level. The integrated pollution index of the rivers surrounding the lake in the northwestern part was the highest compared to the southwestern, central, and eastern parts.

Interactive assessment of lignite and bamboo-biochar for geochemical speciation, modulation and uptake of Cu and other heavy metals in the copper mine tailing.

This study was designed to examine the combined effect of bamboo-biochar (BC) and water-washed lignite (LGT) at copper mine tailings (CuMT) sites on the concentration of Cu and other metals in pore water (PW), their bioavailability, and change in geochemical speciation. Rapeseed (first cropping-season) and wheat (second cropping-season) were grown for 40-days each and the influence of applied-amendments on both cropping seasons was observed and compared. A significant increase in pH, water holding capacity (WHC), and soil organic carbon (SOC) was observed after the applied amendments in second cropping-seasons. The BC-LGT significantly reduced the concentration of Cu in PW after second cropping seasons; however, the concentration of Pb and Zn were increased with the individual application of biochar and LGT, respectively. BC-LGT and BC-2% significantly reduced the bioavailability of Cu and other HMs in both cropping seasons. The treated-CuMT was subjected to spectroscopic investigation through X-ray photoelectron spectroscopy (XPS), Fourier transform Infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). The results showed that Cu sorption mainly involved the coordination with hydroxyl and carboxyl functional groups, as well as the co-precipitation or complexation on mineral surfaces, which vary with the applied amendment and bulk amount of Mg, Mn, and Fe released during sorption-process. The co-application of BC-LGT exerted significant effectiveness in immobilizing Cu and other HMs in CuMT. The outcomes of the study indicated that co-application of BC-LGT is an efficacious combination of organic and inorganic materials for Cu adsorption which may provide some new information for the sustainable remediation of copper mine tailing.

Levels of metals in fish tissues of Liza haematocheila and Lateolabrax japonicus from the Yellow River Delta of China and risk assessment for consumers.

The Yellow River Delta (YRD) is an important spawning and nursery area for numerous fishes. The concentrations of Fe, Al, Mn, Zn, Ni, Cr, Cu, Co, Pb and Cd in muscle, liver, gills and skin of two broadly distributed commercial fish in the YRD were analyzed. The results demonstrated that liver and gills displayed higher accumulation ability of metals than other tissues, while muscle always accumulated the lowest concentrations of metals. Generally, significant opposite relationships (p < 0.05) were observed between fish size and metals in fish tissues especially in muscles of both fish species which may be explained by the lower feeding rate, stronger detoxification and elimination mechanisms in the bigger individuals. All metals in muscles were well below the proposed toxic limit. Besides, the toxic effects were not expected to occur for the consumption of muscles of studied fish according to the results of human health risk assessment.

Distribution, Sources, and Health Risk Assessment of Volatile Organic Compounds in Hefei City.

Volatile organic compounds (VOCs) are involved in the formation of ozone formation, which plays a significant role in regional air contamination and poses a great threat to human health. The VOCs were collected from the urban area of Hefei city via an off-line sampling method (SUMMA canister) and determined by gas chromatography-mass spectrometer. The average concentrations of VOCs were 17.65 ± 28.36 ppbv, which were mainly contributed by aromatics (10.02 ± 13.37 ppbv), haloalkane (5.37 ± 8.90 ppbv), ally halide (1.25 ± 3.36 ppbv), and aryl halid (1.02 ± 2.73 ppbv). According to the principal component analysis, three major sources were identified, including solvent use, vehicle exhaust, and industrial release, accounting for 70.6% of the total variance of the data. Health risk assessment was utilized to evaluate the potential adverse health effects of the individual VOC. The total hazard ratio in the selected area was higher than 1, where could pose health threat to exposed population. The cancer risk for benzene, carbon tetrachloride, trichloromethane, and 1, 2-dichloroethane were 4.8 × 10-5, 4.5 × 10-5, 3.3 × 10-5, and 2.5 × 10-5, respectively, indicating definite health risks.

Characterizing pollution indices and children health risk assessment of potentially toxic metal(oid)s in school dust of Lahore, Pakistan.

Toxic metal pollution is a renowned environmental concern, especially to sensitive environments like school classrooms and their association with children's health. The study was planned to determine the pollution characteristics of 13 potentially toxic metal (oid)s (PTMs) and their associated children's health risk assessment from school dust samples of considerably three land-use types (residential, roadside, and industrial areas) of Lahore, Pakistan. Geo-accumulation (Igeo), pollution (PI), integrated pollution (IPI) and pollution load (PLI) indexes were used to determine the PTMs contamination and USEPA health risk assessment models were employed to assess the health risks in children. The mean concentrations of Cd, Cr, Cu, Ni, Pb, and Zn for three land-use types were found much higher than the permissible limits. Results of pollution indices revealed that school dust was strongly contaminated with Cd, Pb, and Zn whilst moderately contaminated with Cr and Cu. Moreover, the health risk assessment models revealed no significant non-cancerous risks in children with predominantly highest hazardous index (HI) of Cr in industrial (4.61E-01) and Pb in both roadside (4.30E-01) and residential (2.26E-01) area schools. According to cumulative HI of all PTMs and exposure routes, the land-use areas were in descending order as industrial > roadside > residential. The calculations of hazardous quotient (HQ) showed ingestion was the leading pathway of PTMs exposure through school dust. For carcinogenic health risk (CR), the most prominent PTM was Cr with values of 1.53E-06 in industrial area schools, found close to the tolerable range (1.0E-06). Hence, school dust of Lahore prominently contaminated with eminent PTMs triggering slight health risks predominantly by ingestion exposure to children.

Characteristics and health risk assessment of heavy metals in indoor dust from different functional areas in Hefei, China.

Metals in indoor dust pose potential health risks to humans. Dust deposition on air conditioner filters can represent the resuspended particulate matter in indoor air. However, few studies have examined this until now. This study investigated the total concentrations and different chemical fractionations of Cd, Cr, Mn, Ni, Pb, Sb, V, and Zn in indoor dust from three different functional zones (the Chief District, Commercial District (CmD), and Industrial District) in Hefei. The mean metal concentrations in indoor dust decreased in the following order: Zn > Mn > Pb > Cr > Ni > V > Cd > Sb. Cd, Pb, and Zn mainly existed in the mobile fraction. Cr and V mainly existed in the residual fraction. The enrichment factor and geo-accumulation index values of heavy metals were all ranked in the order of Cd > Zn > Pb > Sb > Ni > Cr > V, and these values in indoor dust were larger than those in outdoor dust. In addition, the enrichment patterns of these elements were similar in the three functional areas. The orders of non-carcinogenic risk (hazard index; HI) for the different functional areas for children were roughly the same, but there were clear differences for adults. In general, all the HIs were less than 1, which were within the internationally recognized safe range. The total carcinogenic risk (TR) was in the order of Cr > Pb > Cd for both children and adults in the three functional zones. The TRs from Cr exposure were not negligible. The TRs were significantly higher in the CmD.

Assessment of organophosphorus flame retardants and plasticizers in aquatic environments of China (Pearl River Delta, South China Sea, Yellow River Estuary) and Japan (Tokyo Bay).

The concentrations and spatial distribution of 14 organophosphorus flame retardants (OPFRs) and plasticizers were studied in aquatic environments of China, namely, the Pearl River Delta (PRD), South China Sea (SCS) and Yellow River Estuary (YRE), as well as Tokyo Bay (TB) in Japan. These locations were characterized by different levels of socioeconomic development and human activities. The spatial pattern of OPFRs revealed their ubiquity along the coasts of China and Japan; the concentrations ranged from 15 to 1790, 1 to 147, 253 to 1720, and 107 to 284 ng L-1 in the PRD, SCS, YRE and TB, respectively. The most frequently detected OPFR was triethyl phosphate (TEP), followed by triphenylphosphine oxide (TPPO) and tris(2-chloroethyl) phosphate (TCEP). A positive relationship (R2 = 0.668, p = 0.004) was observed between OPFR contamination and socioeconomic activity, measured by gross domestic product (GDP) per capita, for the studied cities in China and Japan. The results suggest that an increase in manufacturing and construction activities in the studied areas may aggravate coastal contamination with OPFRs. The potential threat to aquatic organisms from exposure to TCEP, a suspected carcinogen, was revealed by the hazard quotient (HQ) and probabilistic assessments. Further investigation of OPFR exposure in the aquatic environment of China is urgently required.

Health risk assessment of potentially harmful elements in subsidence water bodies using a Monte Carlo approach: An example from the Huainan coal mining area, China.

Enrichment of potentially harmful elements in surface water results in ecological risk to the surrounding environment. Assessing the environmental risk of these elements is of great importance. In this study, surface water samples from 6 different subsidence water bodies in the Huainan coal mining area were collected. The concentrations of Cu, Ni, Pb, Cd, Co, Cr, V, Fe, Mn and Zn were measured by atomic absorption spectrophotometry, and those of As and Hg were analyzed by atomic fluorescence spectrometry. Then, human health risks through the ingestion and dermal contact pathways were assessed and analyzed on the basis of a Monte Carlo simulation. The mean and 95th percentile risks were reported. The results showed that the total carcinogenic risk values in every subsidence water body summed for Cr, Ni and As via two exposure pathways were greater than the maximum acceptable level (1 × 10-4), and Xinji'er water body had the highest carcinogenic risk. Among three elements, Ni was the highest contributor to carcinogenic risk. All non-carcinogenic health risk (hazard quotients) values except for one water area of Co (Xinji'er) were less than 1; however, the total non-carcinogenic health risks of two water bodies (Xinji'er, Xinjiyi) summed for all the elements based on mean concentrations were higher than 1. Xinji'er had the highest hazard index. The extent of the impacts of the total hazard quotients followed the order of Co > As > Cd > Hg > Pb > V >Fe > Ni > Mn > Zn > Cr. Furthermore, the total hazard quotients of Co and As via ingestion pathway summed for the six subsidence water areas were greater than 1, which should be a concern.

Biomonitoring and health risks assessment of trace elements in various age- and gender-groups exposed to road dust in habitable urban-industrial areas of Hefei, China.

The current study investigates the concentration of eleven trace elements in biomaterials including hair (85) and nails (85) along with seventy five (75) road dust samples collected from a healthy population of habitable urban-industrial areas of Hefei, China. The samples were acid digested and analyzed using ICP-MS for trace elements content. The mean concentration of Elements followed descending order of Zn > Mg > Fe > Cr > Al > Sn > Sr > Ti > Cu > As > Cd and Mg > Zn > Fe > Cr > Al > Sn > Ti > Cu > Sr > As > Cd in hair and nails, respectively. Overall, the concentration of elements was found to be high in female subject as compared to male. The concentration of trace elements in hair and nail exceeded the maximum permissible limits in most cases. The corresponding mean values from dust samples were fairly high as compared to background values of trace elements. Middle age groups (21-30 years and 31-40 years) were observed to be the most vulnerable there-by posing a high health risk, as the concentration of trace elements was significantly high in these groups except for Al, which was detected high in age < 20 in case of both male and female. A significantly high correlation was found between trace elements in biomaterials and those detected in dust samples. In hair samples, a significantly positive correlation was noticed for As with Mg, Zn, Sn and Fe, Sn/Mg and Mg/Ti. In the case of nails, a significant correlation was observed for elements like Al, Mg, Zn, Cr, and Cu. The Cluster and principal component analysis revealed industrial and vehicular emissions as main sources for trace elements exposure in humans.

[Temporal-spatial Distribution and Pollution Assessment of Dissolved Heavy Metals in Chaohu Lake].

Surface water samples were collected in different seasons from Chaohu Lake to determine the concentrations and potential environmental impacts of nine dissolved heavy metals (As, Hg, Cd, Cu, Pb, Zn, Cr, Ni, and Co). The concentrations of the selected heavy metals were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES, ICAP6000 series). The single pollution index method and integrated pollution index method were used to evaluate the potential environmental impacts. The results indicated that the contents of dissolved As, Cd, Pb, and Cr in Chaohu Lake were lower than the limitations of GradeⅠof the Environmental Quality Standards for Surface Water (GB 3838-2002), while Cu and Zn were within the limitations of GradeⅠ-Ⅱ and Hg was within the limitations of GradeⅠ-Ⅲ. The contents of Ni and Co were far below the limitations. The concentrations of the selected heavy metals (Cu, Pb, Zn, Cr, Ni, and Co) varied among seasons and areas. Elevated concentrations of Cu, Zn, and Ni were found in summer, while elevated contents of Pb, Cr, and Co were found in autumn, autumn, and spring, respectively. Trace elements in the western part of Chaohu Lake (especially in the northwestern part) were higher than those in the middle and eastern parts for autumn, winter, and summer. Significant positive correlations were found among Cu, Pb, Zn, Cr, and Ni in the surface water, suggesting that these elements may derive from similar sources. The values of both the single factor pollution index and integrated pollution index of the selected elements in the surface water were far less than 1, suggesting that the environmental impacts could be regarded as negligible. The integrated pollution indices in the western part of the lake were higher than those of the middle and eastern parts on a one-year timescale, and the integrated pollution indices in each lake area followed a pattern of wet season (summer) > normal season (spring and autumn) > dry season (winter).

Distribution of heavy metals, stable isotope ratios (δ13C and δ15N) and risk assessment of fish from the Yellow River Estuary, China.

This study measured the concentrations of eight heavy metals, including copper (Cu), zinc (Zn), lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), manganese (Mn) and nickel (Ni), and the stable isotope ratios of δ13C and δ15N in 129 fish samples collected from the Yellow River Estuary (YRE) of China. Accumulation characteristics and possible sources of these heavy metals (HMs) were analyzed. The levels of HMs presented high variations among sampling sites, higher concentrations of ∑HMs were observed at the sites closest to the estuary. Cu and Cd in fishes of the YRE were much higher than those found in the fishes of other rivers of China. Furthermore, the mean concentrations of Cu, Zn, Pb, Cr and Cd were also significantly higher than those measured in the fishes of the same region twenty years ago. According to the results of correlation analysis and principal components analysis (PCA), Pb, Cr, Fe, Mn and Ni might be originated from similar sources. The values of δ13C and δ15N presented high variation in fishes, indicating a wide range of energy sources and trophic status of the investigated fish species. The mean concentrations of Pb, Cr and Cd in fishes were all lower than the recommended values enacted by the Chinese government. The human health risk assessment showed that the estimated daily intake (EDI) of these HMs did not exceed the permissible tolerable daily intake (PTDI) and oral reference dose (RfD), indicating a situation of no potential health risk for consumption of these fish species.