Search

As typical metalloid toxic elements widely distributed in environmental media, the geochemical behaviour of antimony (Sb) and arsenic (As) affects environmental safety. We selected the surface waters and sediments at the river-lake junction of Dongting Lake as the research objects, analysed the concentration and chemical partitioning of Sb and As, assessed its contamination and ecological risk levels, and discussed its sources and potential influencing factors. The concentrations of dissolved Sb and As in surface waters were low (< 5.46 µg/L), and the concentrations of Sb and As in surface sediments were 2.49-22.65 mg/kg and 11.10-136.34 mg/kg, respectively. Antimony and As in sediments were mainly enriched in the fraction of residues, but the proportion of As in bioavailability was significantly higher than that of Sb. Although the contamination level of Sb was higher than that of As, the risk assessment code (RAC) showed that the ecological risk level of As was higher than that of Sb. Rainwater erosion and mining activities (in the midstream of Zijiang River) were the main contaminated sources of Sb, while As was affect mainly by rainwater erosion. The contamination and ecological risk of Sb in the inlet of the Zijiang River should receive considerable attention, while those of As in the inlet of the Xiangjiang River should also be seriously considered. This study highlights the need for multi-index-based assessments of contamination and ecological risk and the importance of further studies on the environmental behaviour of metalloids in specific hydrological conditions, such as river-lake junctions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Due to its ubiquity and carcinogenicity, the geochemical behavior and health risks of arsenic (As) have been a research focus worldwide. A comprehensive investigation was conducted on the contamination and ecological and health risks of As in the Zijiang River (ZR)-a natural water source. The concentration ranges of As were separately 1.36-6.23 μg/L, 11.42-74.53 mg/kg, and 1.26-130.68 μg/L in surface waters (dissolved), sediments, and pore waters. The concentrations of As in the midstream pore waters and sediments were relatively high, which was related to mining, dam interception, and sediment resuspension. The Monte Carlo simulation results showed that the occurrence probability of As contamination and static risk in sediments was low, however, in the midstream, the secondary risk caused by the release of As should be given more consideration. In the sediments, the transformation paths and the dynamic risk of As were explored based on the delayed geochemical hazard model, showing that there was a probability of a potential burst of 26.47% - 55.88% in the sediments of the ZR. Although at the detected surface waters, the total risk of the noncarcinogenicity and carcinogenicity of As were low, overall adults have lower health risks than children, and As exposure in children should be of concern. This study complements the further understanding of the geochemical behavior of arsenic, which can be extended to other toxic metal(loid)s., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Currently, metalloid co-contamination, such as antimony and arsenic in soil, poses a serious threat to ecological stability and human health. Stabilization, a low-cost, effective, environmentally mild remediation strategy, shows enormous potential for mitigating environmental concerns. In this study, a novel FeMg modified porous biochar with different Fe/Mg proportions was prepared using the co-precipitation method to investigate the stabilizing efficiency in aqueous solutions and real soils. The optimal removal performance for Sb(V) and As(V) was the 1/3 mol ratio of Fe/Mg (3FMKBC), in which the maximum adsorption capacities of Sb(V) and As(V) were 296.9 and 195.4 mg/g, respectively. Detailed morphological and BET analyses suggested that BC effectively reduced Fe and Mg oxide agglomeration and endowed more interfacial active sites. Meanwhile, detailed adsorption behavior and surface analysis of 3FMKBC indicated that electrostatic interactions, hydrogen bonds, surface hydroxyl complexation, and ligand exchange induced by ≡C-O-Fe/Mg-OH dominated the stabilization process. Moreover, according to a 40-day incubation study in soil, 3FMKBC (1 wt. ml) decreased the available Sb (28.5% and 23.0%) and As (83.1% and 31.1%) extracted by toxicity characteristic leaching procedure (TCLP) and 0.1 M Na 2 HPO 4 , respectively. The above results indicated that 3FMKBC was an optimal amendment for limiting the migration and bioavailability of Sb and As. In addition, the sequential extraction and soil properties confirmed that 3FMKBC could realize the redistribution of resolved Sb and As between the soil solution and solid particles effectively, thereby converting the bioavailable/labile fraction of Sb and As to a more stabilized fraction. All results demonstrated that 3FMKBC could be a prospective material for Sb and As co-contamination stabilization., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Emerging evidence indicates that chronic low-dose arsenic (As) exposure can pose adverse health effects to children. This study aimed to systematically study the exposure risk induced by As ingestion in children living in Hubei Province, central China. The feasibility of first morning spot urine instead of 24-h urine as an environmental exposure biomarker was also explored. A total of 120 children aged 2-17 years were recruited from an urban area for the collection of biomarker samples (first morning and 24-h urine samples), environmental exposure samples (duplicate diets, drinking water, and soil), and related child-specific exposure factors. The external exposure risk, internal exposure level, and source of exposure to As in children were analyzed. The results indicated that As concentration in duplicated diets, water, and soil were 29.2 μg kg -1 , 1.3 μg L -1 , and 9.3 mg kg -1 , respectively; these were all below the corresponding maximum allowable levels in China (the threshold value of As in most food, drinking water and soil are 0.5 mg⸱kg -1 , 0.01 mg L -1 , and 20 mg⸱kg -1 , respectively). Dietary intake was the predominant exposure route, accounting for 90% of the total daily dose. The combined oral non-carcinogenic and carcinogenic risks all exceeded the corresponding maximum acceptable risk level. Therefore, As bioavailability should be investigated and used in health risk assessment. Multiple linear regression analysis indicated that urinary As was positively associated with dietary As, with a one-unit increase in daily As intake from the diet associating with 4.82 and 5.21 μg g -1 increases in 24-h urine and first morning urine, respectively. Furthermore, significant correlations with 24-h urine and external exposure metrics suggested that creatine-adjusted As concentrations in first morning urine could be an appropriate substitute of 24-h urine as exposure biomarkers., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Arsenic (As) and antimony (Sb) are toxic metalloids widely distributed in coastal sediments, but are seldom studied for their geochemical baselines. In this study, sediment samples were collected from Jiaozhou Bay (JZB) to evaluate their baselines, contamination, and ecological risk. Results showed that the As and Sb concentrations were between 3.15 and 11.94 mg/kg and 0.20-0.61 mg/kg, respectively. Sc and Fe showed good performance in developing geochemical baseline functions for the metalloids. Organic matter content and clay had significant positive correlations with metalloid abundance in sediments (p < 0.01). In the JZB, As and Sb were not enriched in the sediments, with the enrichment factors below 1. Furthermore, the contamination degrees of As and Sb were low in the JZB. In addition, the ecological risks of As and Sb were relatively low in the JZB, with the risk index between 4.02 and 12.70 and 1.68-5.09, respectively., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

China has been the major fishery producer in the Northwest Pacific Ocean for decades and the seafood safety deserves continuous concern. In this study, 188 organism and 27 sediment samples were collected from the Jiaozhou Bay, a typical semi-enclosed bay adjacent to the Northwest Pacific Ocean, to study the arsenic (As) pollution level and trophodynamics in the coastal regions of China combined with a meta-analysis. Results showed that arsenic was the most abundant in crustaceans with the average of 28.84 ± 4.95 mg/kg in dry weight, in comparison with molluscs (18.68 ± 2.51 mg/kg) and fish (9.31 ± 1.45 mg/kg). Additionally, based on a meta-analysis, arsenic in coastal organisms generally decreased from north to south in China. With increasing values of δ 15 N, arsenic was significantly biomagnified in the molluscs but bio-diluted in the groups of crustaceans and fish. When all the species were taken into consideration, overall bio-dilution of As was observed through the simplified food chain in the Jiaozhou Bay. Based on the target hazard quotient (THQ), the health risk of consuming seafood from the Jiaozhou Bay was not significant except for several kinds of crustaceans. The smaller THQs indicated lower health risk of eating molluscs and fish than crustaceans. Besides, urban households tended to undertake much higher risk than rural households. Based on our results, it is recommended for urban citizens to reduce the frequency of consuming crustaceans and give preference to fish when choosing seafood., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Little is known about the variation of Chinese children's exposure to arsenic by geography, age, gender, and other potential factors. The main objective of this study was to investigate the total arsenic concentration in Chinese children's urine by geographic locations, ages, and genders. In total, 259 24-h urine samples were collected from 210 2- to 12-year-old children in China and analyzed for total arsenic and creatinine concentrations. The results showed that the upper limit (upper limit of the 90% confidence interval for the 97.5 fractile) was 27.51 µg/L or 55.88 µg/g creatinine for Chinese children. The total urinary arsenic levels were significantly different for children in Guangdong, Hubei, and Gansu provinces (P < 0.05), where the upper limits were 24.29, 58.70, and 44.29 µg/g creatinine, respectively. In addition, the total urinary arsenic levels were higher for 2- to 7-year-old children than for 7- to 12-year-old children (P < 0.05; the upper limits were 59.06 and 44.29 µg/g creatinine, respectively) and higher for rural children than for urban children (P < 0.05; the upper limits were 59.06 and 50.44 µg/g creatinine, respectively). The total urinary arsenic levels for boys were not significantly different from those for girls (P > 0.05), although the level for boys (the upper limit was 59.30 µg/g) was slightly higher than that for girls (the upper limit was 58.64 µg/g creatinine). Because the total urinary arsenic concentrations are significantly different for general populations of children in different locations and age groups, the reference level of total urinary arsenic might be dependent on the geographic site and the child's age.

Toxic elements have caused great concern due to their adverse health effects. Biological monitoring is generally considered to be a useful tool to assess human exposure to these elements during risk assessment. To better interpret the biological monitoring data, elemental reference values are critical. The major objectives of this study were to clarify whether first-spot morning urine can serve as a surrogate for 24-h urine and to determine the concentration reference interval of some elements in Chinese children's urine. In total, 259 first-spot morning urine samples and 24-h urine samples were collected from 210 2- to 12-year-old healthy children in China and analyzed for creatinine, aluminum, barium, manganese, titanium, cerium, scandium, vanadium, yttrium, and arsenic. The results showed that the creatinine-adjusted concentrations of aluminum, barium, manganese, titanium, cerium, scandium, vanadium, yttrium, and arsenic in the first-spot urine were significantly correlated with those in the 24-h urine. This showed that first-spot morning urine is a favored matrix for monitoring element exposure due to its easy collection and low collection cost. The reference interval using ng/mg creatinine as the unit for Chinese children's urine was 1.63-2653 for aluminum, 3.71-116.8 for barium, 0.67-91.77 for titanium, 0.20-53.42 for arsenic, 1.36-25.29 for manganese, 0.24-8.59 for vanadium, 0.02-2.27 for cerium, 0.01-0.65 for yttrium, and 0.002-0.483 for scandium. These reference intervals may provide reference levels to assess Chinese children's exposure to these elements., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

Incidental oral ingestion is the main exposure pathway by which human intake contaminants in both soil and indoor dust, and this is especially true for children as they frequently exhibit hand-to-mouth behaviour. Research on comprehensive health risk caused by incidental ingestion of both soil and indoor dust is limited. The aims of this study were to investigate the arsenic concentration and to characterize the health risks due to arsenic (As) exposure via soil and indoor dust in rural and urban areas of Hubei province within central China. Soil and indoor dust samples were collected from schools and residential locations and bioaccessibility of arsenic in these samples was determined by a simplified bioaccessibility extraction test (SBET). The total arsenic content in indoor dust samples was 1.78-2.60 times that measured in soil samples. The mean As bioaccessibility ranged from 75.4% to 83.2% in indoor dust samples and from 13.8% to 20.2% in soil samples. A Pearson's analysis showed that As bioaccessibility was significantly correlated with Fe and Al in soil and indoor dust, respectively, and activity patterns of children were utilised in the assessment of health risk via incidental ingestion of soil and indoor dust. The results suggest no non-carcinogenic health risks (HQ<1) or acceptable carcinogenic health risks (1×10(-6)

The wetland Argialbolls pedon was chosen to investigate the effects of pedogenic processes and anthropogenic activities on the vertical distribution of As concentrations. Two wetland Argialboll cores (90 cm long) were collected from the Sanjiang Plain in northeastern China and analyzed for pH, soil organic matter (SOM), Fe, Mn, and As. The results indicate that SOM accumulated in the upper horizons, while Fe and Mn were reductively leached from the upper horizons and significantly accumulated in the lower argillic horizons. Atmospheric As deposition and As redistribution during the pedogenic process led to the unique vertical distribution of As concentrations in the wetland Argialbolls. Overall, As was leached from upper horizons and then accumulated in the lower argillic horizons. However, continual atmospheric As deposition maintained a slightly elevated As concentration in the top layer. In detail, As concentration in the upper horizons ranged from 1.1 to 5.3 mg kg(-1), while it ranged from 18.2 to 65.7 mg kg(-1) in the lower argillic horizons. The high As concentration in the argillic horizons might pose a risk to shallow groundwater in the area.

This study investigated the arsenic (As) distribution and adsorption behavior in sediments of the Daliao River System (DRS). Results indicated that the total As was 2.6-83.1 mg kg(-1) in the sediments of the DRS. The pseudo-first order model and intra-particle diffusion model give a good fit of the experimental kinetics data for As, indicating that particle diffusion mechanism may not be the rate controlling step while this mechanism is involved. By comparing the zero equilibrium As concentration (EAsCo) with the actual As concentration in the overlying water of the DRS, all the sediments showed a trend of releasing As. Arsenic exhibited strong adsorption on sediment at pH 4.5-7. Arsenic retention by sediment was much enhanced by Ca2+ compared to Na+. More As was desorbed by phosphate at low and high pH extremes. The added or sorbed As was mainly transferred to the specifically sorbed fraction and amorphous Fe (Al) oxyhydroxides bound fraction, indicating Fe oxides are a major sorbent of As in sediment.

The chemical forms and ecological risk of As were characterized in the sediment of the Daliao River System (DRS), which has been affected by long-term intensive industrial, urban, and agricultural activities. Twenty-seven samples of surface sediment were collected and analyzed for total As content and that of its chemical forms. The results indicated that the average total As content in the sediment was 9.83 mg kg(- 1) but that the levels ranged from 1.57 to 83.09 mg kg(- 1). At the sites near cities, mining sites, and the estuary of the DRS, it is likely that adverse effects on aquatic organisms occur, due to As levels in the sediment that are often higher than the threshold effect level and occasionally higher than the probable effect level. A selectively sequential extraction indicated that the majority of As in the sediment was bound to Fe oxides (62.1%), with moderate proportions of residual As (19.8%), specifically adsorbed As (17.9%), and a low proportion of non-specifically adsorbed As (1.1%). In addition, the content of Fe in the sediment was positively and significantly correlated with the contents of amorphous and crystalline Fe oxide-bound As, confirming the crucial role of Fe oxides in immobilizing high amounts of As in superficial environments. The average molar ratio of As to Fe was 1.18 × 10(- 4) in the surface sediment of the DRS, similar to that of natural Fe oxides, but much lower than that of synthesized Schwertmannite. Therefore, the release of As under reduced and low pH conditions can cause serious problems for water resources and for living organisms.

The Guangzhou section of the Pearl River (GSPR) has been seriously affected by long-term intensive industrial and urban activities. The objectives of this study were to determine the total As (TAs) content and the forms of that As in order to investigate the geochemical relationships between As forms and sediment mineral phases of the surface sediments of the GSPR. Fifteen samples of surface sediment were collected and analyzed for TAs as well as As chemical forms. Results indicated that TAs in the sediment samples averaged 24.6 mg kg(-1) and ranged from 16.7 to 33.4 mg kg(-1). These values are generally higher than the probable effect level of 17.0 mg kg(-1). The As was mostly associated with iron oxides (53.5%), followed by association with the residual fraction (36.2%). Amor-Fe bound As and Cry-Fe bound As quantities were positively correlated to the Amor-Fe and Cry-Fe quantities, respectively. In addition, organic matter (OM), clay and Sum-Fe contents were positively correlated to TAs in the sediment fractions. The molar ratios of iron oxide-bound As to iron content approached the maximum molar ratios of As to Fe for natural hematite, magnetite, and goethite. Adverse effects caused by As will likely frequently occur at these high levels of As contamination. Thus, it is necessary to remediate the sediment of the GSPR to reduce the potential risks of As contamination., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Heavy metal levels in the rural soils are associated with the quality of agricultural products. In this study, soil samples were collected from the rural soils of Beijing; distribution of As, Co, Cr, Cu, Hg, Mn, Ni, Pb, V, Zn and their changes over the last two decades have been investigated. The results indicated that the concentrations of Co, Cr, Mn, Ni, and V were primarily controlled by the parent materials of soils, while concentrations of Hg, As, Cu, Pb, and Zn were affected by anthropogenic activities. Hg concentration in the surface soils was 2-3 times the subsurface soils; slight accumulations of As, Cu, Pb, and Zn in the top soils were also observed. The bioavailable fractions of heavy metals including exchangeable and carbonate-bounded fraction were lower than 10% except for Cr, Mn and Zn. In general, the concentrations of heavy metals in the rural soils of Beijing met environmental quality standard (grade II) for soils of China. Although some elements such as Hg and As have increased significantly in several sample sites, the average concentrations of all heavy metals had no significant change over the past 20 years due to effective environmental protection for many years in Beijing., (2010 Elsevier B.V. All rights reserved.)

Lake Qinghai in the Qinghai-Tibet plateau is the largest lake in China, but the geochemical understanding of arsenic (As) in the lake is lacking. Water, sediment, and soil samples were collected from Lake Qinghai, rivers flowing into the lake, and lands around the lake. Water samples were analyzed for major ions and As, while sediment and soil samples were analyzed for major elements and As. The average As concentration (25.55 μg L−1) in the lake water was significantly higher than that (1.39 μg L−1) in the river water (p < 0.05), due to the evaporative concentration of lake water. The average As concentration (107.8 μg L−1) in the pore water was significantly higher than that in the lake water, due to its secondary release from sediment solid phases in the reductive condition. The average As/Cl−, As/SO42− and As/Na molar ratios in the lake water were significantly lower than that in the river water, indicating As was partially transferred from dissolved phase to solid phase in the evaporative concentration process of the lake water. The average As/Ca molar ratio in the lake water was significantly higher than that in the river water, indicating more Ca than As precipitated in the lake water. Furthermore, the average As/Ca molar ratio in the lake water was significantly lower than that in the pore water, indicating more As than Ca was secondarily released from sediment solid phases. The average concentration of As(III) and As(V) were 0.35 and 1.04 μg L−1 for the river water, respectively, and 6.99 and 18.56 μg L−1 for the lake water, indicating As(V) was the predominant As form. The average As concentration was 16.75 mg kg−1 for the lake sediment and 13.14 mg kg−1 for the soil around the lake. Arsenic concentration was significantly negatively correlated with S and Ca concentration in the lake sediments, due to solid dilution effect induced by carbonate and sulfate precipitation. The average As/Sc molar ratio in the sediment (2.06) was significantly higher than that in the soil (1.32), indicating that relatively more As was enriched in the lake sediment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Resource recovery and application of iron-containing heating pad waste are realized. • BM-HPW/PMS system achieved simultaneous removal of ROX and inorganic arsenic. • Ball milling modification catalyst improved the removal efficiency of ROX. • Non-radical pathway dominated the degradation of ROX in the BM-HPW/PMS system. The simultaneous removal of roxarsone (ROX) and inorganic arsenic was achieved by designing a heterogeneous catalytic system. In this study, iron-rich heating pad waste (HPW) was modified by ball milling (BM), and a BM-HPW activated peroxymonosulfate (PMS) system was constructed to control ROX pollution. Results show that during the ball milling process, Fe0 and Fe 3 O 4 crystalline phases were formed, and the surface area of the material got improved. BM-HPW/PMS system performed effectively in ROX degradation and inorganic arsenic adsorption. Sulfate radical (SO 4 −), surface-bound species, singlet oxygen (1O 2) and Fe(IV) were generated in the BM-HPW/PMS system, and the surface-bound species played a dominant role in ROX degradation. In addition, the possible degradation pathways of ROX were proposed according to the detected intermediates. This study adopted a green and environmentally-friendly mechanochemical method to achieve the recycle application of waste iron resources, which provides a new insight for PMS activation in water treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heating pad waste (HPW) was first used to eliminate roxarsone (ROX) in water. • ROX degradation and inorganic arsenic adsorption were achieved simultaneously. • HPW displayed effective and stable catalytic performance for ROX degradation. • Mechanisms of ROX degradation and inorganic arsenic adsorption were proposed. Heating pad waste (HPW), a magnetically recyclable material collected from disposable heating pads, is produced in amounts of millions of tons every year globally. HPW is mainly composed of Fe, C and O, directly disposal caused a waste of resource. In this paper, HPW was used to activate peroxymonosulfate (PMS) for roxarsone (ROX) degradation and as a functional adsorbent for the simultaneous adsorption of the released inorganic arsenic. After 2 h, 20 μM (1.5 mg-As/L) ROX was completely degraded, and the released inorganic arsenic was effectively adsorbed by HPW. Mechanism study proved •OH, SO 4 •−, and 1O 2 were all existed in the HPW/PMS system, and •OH was the dominant reactive species. And the possible degradation pathways of ROX were further proposed based on the identified intermediates. Furthermore, the result of TCLP test showed that the leaching As concentration of the used HPW (0.146 mg/L) is far below the current identification standards for hazardous wastes-identification for extraction toxicity value on As (GB 5085.3-2007, 5 mg/L). This study adopted the strategy of "treat waste by waste", achieved the resource utilization of HPW, brought economic and environmental benefit to environment remediation. [ABSTRACT FROM AUTHOR]

• Concentration of arsenic in multiple medium decreased from estuaries to bay. • Sedimentary particles were more capable of absorbing arsenic than suspended particulate sediment (SPS). • Effects of coastal environmental factors on arsenic allocation in different phases were evaluated. • Spatial patterns of arsenic in the bay and enrichment factors demonstrated its source and distribution. Under the gradients of salinity and redox, the transportation and distribution of dissolved, particulate, and sedimentary arsenic present differences from estuary to bay. Samples of water, suspended particulate sediment (SPS), and sediment from the Jiaozhou Bay were analyzed. The concentrations of arsenic decreased significantly from the estuaries toward the bay. The sedimentary arsenic mostly existed as hydrous oxide-bound and residual fractions and tended to be attached to smaller particles. Sedimentary particles were more capable of absorbing arsenic than SPS and the capacity increased from the estuaries toward the bay. The spatial distribution of arsenic was impacted by the residual currents, resulting in higher contents of dissolved arsenic in the eastern coastal zone and higher concentrations of sedimentary arsenic in the inner bay. In water, total phosphorus (TP), dissolved organic carbon (DOC), and alkalinity had significant positive correlations with the dissolved arsenic. In sediments, Fe oxides and sediment organic matter (SOM) would promote adsorption of arsenic. The significant correlation between non-residual fractions and enrichment factors of arsenic indicated that the sedimentary arsenic was more likely to originate from anthropogenic sources, mainly impacted by riverine transport from the eastern urban regions and agricultural production in the western farmland. [ABSTRACT FROM AUTHOR]