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In the Hetao Basin, a grain-producing region plagued by naturally occurring arsenic (As) pollution, understanding the role of agricultural cultivation activities in mobilizing As in groundwater is worthwhile. Here we investigated the impact of cropland use characteristics on groundwater As hazards using a model that combines Random Forest (RF) classification with SHapley Additive exPlanation (SHAP). The analysis incorporated eight cropland use characteristics and three natural factors across 1258 groundwater samples as independent variables. Additionally, an optimized cropland use strategy to mitigate groundwater As hazards was proposed. The results revealed that crop cultivation area, especially within a 2500m-radius buffer around sampling points, most significantly influenced the probability of groundwater As concentrations exceeding an irrigation safety threshold of 50 µg/L, achieving an AUC of 0.86 for this prediction. The relative importance of crop areas on As hazards were as follows: sunflower > melon > wheat > maize. Specifically, a high proportion of sunflower area (>30%), particularly in regions with longer cropland irrigation history, tended to elevate groundwater As hazards. Conversely, its negative driving force on groundwater As hazards was more pronounced with the increase in the proportion of wheat area (>5%), in contrast to other crops. Transitioning from sunflower to wheat or melon cultivation in the northeast of the Hetao Basin may contribute to lower groundwater As hazards. This study provides a scientific foundation for balancing food production with environmental safety and public health considerations.
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Plastic shed production system (PSPS) provide abundant vegetable products for human consumption. Comprehensive and accurate heavy metal (HM) risk assessment of soil and vegetable under plastic sheds is crucial for human health. Pollution assessment, bioavailability and mobility evaluation and health risk assessment of Cd, Cr, Cu, Zn Ni, Pb, and As were performed in a presentative Plastic shed production system. The concentrations of the Cd, Cu and Zn exceeded their background value. Positive Igeo values suggested that soil under plastic sheds was widely contaminated with Cd. The bioavailability of heavy metals in soils was evaluated using DTPA extraction and DGT methods. The results of both methods demonstrated that Cd, Cu, and Zn have high bioavailability, especially Cd. Analogically, the results of mobility assignment based on DIFS showed that Cd has a high migration risk due to the large available pool. Based on specific cultivation and management patterns of plastic shed production system, pH reduction and salt and nutrient accumulation may increase the heavy metals migration risk in soil under plastic sheds, while a high organic matter content may reduce the heavy metals migration risk. The average concentrations of Cd, Cr, Cu, Zn, Ni, Pb, and As in vegetables were 0.023, 0.226, 0.654, 2.984, 0.329, 0.041, and 0.010 mg/kg, respectively. All samples were well below the threshold. The order of target hazard quotient of different heavy metals caused by vegetable consumption was Cd > Cr > As > Cu, Ni, Pb, Zn, and the average total hazard index value was below 1, which demonstrated that risk of vegetable consumption in the study area. However, due to its high concentration and transfer coefficient in spinach, Cd might pose a health risk to humans, which requires special attention. In this study, Cd caused a significant issue than other HMs, whether pollution level, health risk and migration risk. DGT and DIFS can be used as an effective evaluation tool in the research of controlling heavy metals migration in soil-crop systems.
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Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , China , Poluição Ambiental , Humanos , Plásticos , Medição de Risco , Solo/química , Verduras/químicaRESUMO
Pollution resulting from toxic trace elements is an increasing concern around the world especially in developing countries such as China. Rapid industrialisation, urbanisation and agricultural development are the dominant sources of anthropogenic contamination contributed to an increased potential toxicity of trace elements in the irrigation water-soil-food chain. Xin Jiang in China is a reserved cultivated land development area that could provide the most extensive strategic support for food production and arable land security in China. Thus, it is crucial to investigate the bioaccumulation and translocation of trace elements in order to assess the ecological and human health risks in the traditional oasis system of the agricultural areas in Bay Cheng County, Xin Jiang. This study analysed the levels of trace elements in different layers of the soil, the irrigation water and the wheat plants, and the relationships among them. The results indicated that cadmium (Cd) and chromium (Cr) were the primary pollutants in soils and wheats respectively, and they fell into the serious pollution category. However, no trace elements over the pollution limits were detected in irrigation water. The maximum values of trace elements appeared in the soil layers at 5-10 cm and 10-15 cm. The pollution levels of trace elements in the soil layers were found at 0-5 cm and 0-20 cm, which were higher than those at 20-80 cm. In wheat, high amounts of absorption for Se, Cr, Zn and Cu, but low for Pb were detected in different parts of a plant. The roots of wheats were more eco-toxic to Cd, Co and Pb than other tissues, indicating that roots were more effective at absorbing Cd, Co and Pb, as these metals are usually toxic in the soil. Se, Cu and Zn showed a higher ability of being transferred from soils to the edible parts of crops. The bio-transfer factors of Zn, Mo, Cu, Mg and Mn were considerably higher than those of other elements. The average cancer risk of As, Cd, Co, Ni and TCR in wheat grains exceeded the safety reference limit (1 × 10-4). For the exposed population, Cr in wheat was the major contributor to total cancer risk. The average values of HQ of Cr, Mn and As, and total non-cancer risk index exceeded the corresponding effective safe reference doses (HQ > 1).
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Metais Pesados , Poluentes do Solo , Oligoelementos , Agricultura , Bioacumulação , China , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Triticum , ÁguaRESUMO
Water quality improvement is the most efficient way to prevent arsenic exposure. After the cessation of arsenic ingestion, arsenic methylation capacity of the exposed population can change significantly. The factors associated with these changes remain poorly understood. Therefore, arsenic methylation capacity in a study cohort was estimated before and after water quality improvement in the present study. Results indicated that urinary content of the arsenic species in the study cohort significantly decreased after water quality improvement. In addition, the proportions of inorganic arsenic (%iAs) and monomethyl arsenic acid (%MMA) were significantly decreased, while proportions of dimethyl arsenic (%DMA) increased. The primary methylation index (PMI) and secondary methylation index (SMI) increased from 0.85 to 0.92 and 0.82 to 0.84, respectively. Arsenic species urinary content and arsenic methylation index varied slightly between the study cohort after water quality improvement and the control cohort. The rate of increase in PMI was higher than that in SMI. The study group aged 31-50 years had the highest increase in PMI. Logistic regression revealed that %DMA before water quality improvement was negatively associated with the increase in PMI, while %iAs were positively related, and %MMA were positively associated with the increase in SMI. It is concluded that urinary arsenic species content and arsenic methylation capacity increased to the levels of the control cohort after water quality improvement. An increase in primary arsenic methylation capacity may be a burden on the secondary arsenic methylation capacity. The main role of arsenic methylation capacity recovery may be the cessation of arsenic exposure.
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Arsênio/urina , Exposição Ambiental/análise , Qualidade da Água , Adolescente , Adulto , Idoso , Arsênio/metabolismo , Arsenicais/urina , Criança , China , Estudos de Coortes , Água Potável/análise , Feminino , Humanos , Modelos Logísticos , Masculino , Metilação , Pessoa de Meia-Idade , Melhoria de Qualidade , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/urina , Adulto JovemRESUMO
BACKGROUND: Selenium (Se) is essential for humans, with many critical roles in physiological and pathophysiological processes. Fish, eggs and meats are usually the rich food sources of Se. To improve the nutritional status of population, a new version of balanced dietary pattern in the form of the Chinese Food Pagoda (2016) was proclaimed. This study aimed to evaluate the contribution of this balanced dietary pattern to daily Se intake, and to assess Se intake status of Chinese residents under this Food Pagoda scenario. METHODS: Based on the food consumption recommended in the Food Pagoda, this study collected the data of Se contents in various food composites and estimated dietary Se intakes (EITDS) in 12 provinces from the 4th China Total Diet Study. The estimated Se intakes based on the Chinese Food Pagoda (EICHFP) in 12 provinces were calculated. EITDS and EICHFP in various food groups among different regions were compared. RESULTS: The average EICHFP in all regions, within the range of 66.23-145.20 µg/day, was greater than the China recommended nutrient intake (RNI) (60 µg/day). None of the highest EICHFP went beyond the tolerable upper intake level of Se (400 µg/day). Animal source foods should be the primary source of daily Se intake according to the EICHFP. The average EITDS in China (88 µg/day) was in line with its range of EICHFP (81.01-124.25 µg/day), but that in half of the regions failed to achieve their lowest EICHFP. Significant differences between EITDS and EICHFP were observed in cereal food, aquatic and dairy products (P < 0.05), among which Se intake from aquatic and dairy products presented seriously insufficient in almost all regions. CONCLUSIONS: The ideal dietary pattern recommended in the Food Pagoda can meet the daily requirements of Chinese population for Se intake to maintain optimal health. From the perspective of the balanced diet and Se-rich sources, the consumption of aquatic products should be increased appropriately to improve the general Se intake level of Chinese population.
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Dieta , Política Nutricional , Selênio/administração & dosagem , Animais , China , Laticínios , Inquéritos sobre Dietas , Grão Comestível , Ovos , Peixes , Humanos , Carne , Estado NutricionalRESUMO
Little information about the development of skin lesions in relation to arsenic exposure duration is available. Therefore, skin lesions in a cohort from the Bameng region of China were diagnosed in 2012 and 2017. The results indicated that the prevalence of hyperkeratosis, pigmentation and depigmentation in 2017 was 64.67, 6.67 and 12.67%. There were 42 and 34% of male subjects and female subjects suffered from skin lesions in 2012. Their morbidity rates were 10.43 and 8.98 per 1000 person-years. In 2017, the values were significantly increased. The prevalence and morbidity rate of skin lesions were positively correlated with age and arsenic levels in drinking water. Males had higher prevalence of skin lesions compared with female. However, the ≤ 40 years female group had higher prevalence of skin lesions. In addition, the increased rate of skin lesions prevalence was negatively correlated with arsenic levels in drinking water. The odds ratios (ORs) showed that the risks of skin lesions were positively associated with the proportion of inorganic arsenic (%iAs) and monomethylarsonic acid (%MMA) in urine, and negatively correlated with arsenic methylation capacity in both 2012 and 2017. It can be concluded that females immigrated from other areas were more susceptible to developing skin lesions. A certain cumulative arsenic exposure dose, which may be existing, significantly increased the prevalence of skin lesions. Longer arsenic exposure duration might elevate the toxicity of iAs to skin lesions and reduce the positive effects of arsenic methylation capacity on skin lesions.
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Arsênio/toxicidade , Exposição Ambiental , Poluentes Ambientais/toxicidade , Dermatopatias/epidemiologia , Adulto , Idoso , China/epidemiologia , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Dermatopatias/induzido quimicamente , Dermatopatias/patologia , Adulto JovemRESUMO
To investigate the interaction between skin lesion status and arsenic methylation profiles, the concentrations and proportions of arsenic metabolites in urine and arsenic methylation capacities of study subjects were determined. The results showed that the mean urinary concentrations of iAs (inorganic arsenic), MMA (monomethylarsonic acid), DMA (dimethylarsinic acid), and TAs (total arsenic) were 75.65, 68.78, 265.81, and 410.24 µg/L, respectively, in the skin lesions subjects. The highest values were observed in the multiple skin lesions subjects. Higher %iAs and %MMA, and lower %DMA, PMI (primary methylation index), and SMI (secondary methylation index) were found in skin lesions subjects. The multiple skin lesions subjects had highest %iAs and %MMA, and lowest %DMA, PMI, and SMI. The prevalence of skin lesions strongly, positively correlated with arsenic levels in drinking water. The elder persons also had higher frequency of skin lesions compared with younger persons. It can be concluded that arsenic levels in drinking water significantly affected the prevalence of skin lesions. Male subjects usually had higher proportions of skin lesions when compared with female subjects. Moreover, it may be concluded that MMA was significantly related to single skin lesion, whereas DMA and iAs were associated with multiple skin lesions. It seemed that MMA had greater toxicity to hyperkeratosis, whereas DMA and iAs had higher toxicity to depigmentation or pigmentation. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 28-36, 2017.
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Arsênio/toxicidade , Arsenicais/metabolismo , Água Potável/análise , Dermatopatias/induzido quimicamente , Dermatopatias/patologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Arsênio/urina , China/epidemiologia , Feminino , Humanos , Masculino , Metilação , Pessoa de Meia-Idade , Prevalência , Pele/patologia , Dermatopatias/epidemiologia , Adulto JovemRESUMO
Kashin-Beck disease (KBD), which is still active and severe in the Tibetan Plateau, is considered to be a kind of selenium (Se)-deficient disease. Highland barley as the most popular staple food in the Tibetan Plateau is one of the dominant Se sources for local people. To improve Se levels in crops in the Tibetan Plateau KBD area, the distribution and translocation of Se from soil to highland barley in both non-KBD and KBD endemic areas were investigated. The results showed that Se levels in highland barley were too low to meet the minimum requirements of human for daily intake of Se. The total Se concentrations of highland barley fractions in KBD areas were lower than that in non-KBD areas (grain P = 0.238; straw P = 0.087; root P = 0.008). However, no significant difference was observed in corresponding cultivated soil Se between the two areas (P = 0.993). The calculation of Se transfer factors indicated that the restricting step for Se translocation was from soil to root. Water-soluble, exchangeable and fulvic acid-bound Se fractions in the soil are key species dominating in this transfer process, according to their significant correlations with root Se. Se transfer from soil to root significantly increases as the pH value of soil increases (P = 0.007), and soil organic matter content decreases (P = 0.019). The information obtained may have considerable significance for proposing effective agricultural measures to increase grain Se in KBD endemic areas.
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Produtos Agrícolas/química , Hordeum/química , Selênio/química , Solo/química , TibetRESUMO
In order to figure out the prevalence of skin lesions and methylation capacity for migrant and native adult women in an endemic area for arsenic poisoning in Inner Mongolia, China, 207 adult women were selected for study subjects. The results showed that the prevalence of skin lesions for the external group, provincial group and native group was 36.54, 26.15 and 35.56 %, respectively. The nail content of arsenic and urinary concentrations of dimethylarsenic (DMA), monomethylarsenic (MMA) and inorganic arsenic (iAs) were significantly higher in women with skin lesions than in those without skin lesions. The highest urinary concentrations of DMA, MMA and iAs were 213.93, 45.72 and 45.01 µg/L in the native group. The arsenic methylation capacity index revealed that the external group had the greatest capacity, while the native group had the lowest. The odds ratios of skin lesions in relation to arsenic metabolites and arsenic methylation capacity varied widely among the three groups. Urinary MMA and iAs concentrations were positively associated with risk of skin lesions in the three groups of adult women, while primary and secondary methylation capacities were negatively related to risk of skin lesions in native and provincial groups. The external group might be more susceptible to MMA and iAs, while the provincial and native groups were more tolerance to MMA and iAs. Lower primary and secondary arsenic methylation capacities increased the risk of skin lesions in native and provincial groups. Moreover, higher nail arsenic concentration increased the risk of skin lesions of adult women.
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Arsênio/toxicidade , Dermatopatias/induzido quimicamente , Adulto , Arsênio/urina , China/epidemiologia , Feminino , Humanos , Metilação , Prevalência , Dermatopatias/epidemiologiaRESUMO
OBJECTIVE: To understand the relationship between food preference and lung cancer or malignant pleural mesothelioma and the interactive effect between food preference and asbestos exposure in a rural area with naturally occurring asbestos. METHODS: At the basis of the cohort of Dayao in Yunnan, we performed a 1 ⶠ2 casecontrol study including 53 cases( 23 cases for lung cancer and 26 cases for mesothelioma)and 106 age-and sex-matched normal healthy controls. In order to study the protective effect of food preference and the interactive effect between food preference and asbestos exposure, conditional logistic regression was used to estimate adjusted odds ratios( OR)and their 95% confidence intervals( CI) in both unvaried and multivariate analyses. RESULTS: Both green tea and wild mushroom were inversely associated with lung cancer ormalignant pleural mesothelioma, and the adjusted ORs were: 0. 88( 95% CI 0. 66-0. 87) for green tea, 0. 85( 95% CI 0. 23- 0. 95) for wild mushroom intake. Food preference to wild mushroom modified the associations of Crocidolite ' s contacting, Respectively, relative excess risk due to interaction( RERI), attributable proportion due to interaction( API), synergy index( S) were 0. 86, 0. 26 and 0. 61. CONCLUSION: Both green tea and wild mushroom might serve as protective factors on lung cancer or malignant pleural mesothelioma.
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Amianto/toxicidade , Preferências Alimentares , Neoplasias Pulmonares/etiologia , Mesotelioma/etiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Estudos de Casos e Controles , China/epidemiologia , Feminino , Humanos , Neoplasias Pulmonares/etnologia , Masculino , Mesotelioma/etnologiaRESUMO
OBJECTIVE: To explore the relationship of crocidolite pollution in drinking water with the risk of gastrointestinal cancer's death in Dayao County. METHODS: A 1:2 matched case-control study involving 54 death cases of gastrointestinal cancer from a population-based cohort of twenty-seven years and 108 controls matched by age, gender, death time, etc was conducted to analyze the effect of local water condition on the risk of gastrointestinal cancer in Dayao County. RESULTS: Results from logistic regression analysis suggested the longer of asbestos furnace use over time, the higher the mortality risk of gastrointestinal cancer (6 - 10 years: OR = 2.920, 95% CI 1.501 - 5.604. 11 - 15 years: OR = 3.966, 95% CI 2.156 -7.950. Over 15 years: OR = 4.122, 95% CI 1.211 - 7. 584). Drinking unboiled water leaded to an increased risk of gastrointestinal cancer (OR = 1.43, 95% CI 1.07 - 1.88). Type of drinking water was associated with gastrointestinal cancer. When compared with drinking tap water, OR for drinking well water was 1.770 (95% CI 1.001 - 2.444), 2.442 for drinking river water (95% CI 0.956 - 3.950), 2.554 for drinking house and field ditch water (95% CI 1.961 - 6.584), and 3.121 for drinking pond water (95% CI 1.872 - 6.566). CONCLUSION: Related factors of drinking water in crocidolite-contaminated area in Dayao County were significantly associated with the mortality of gastrointestinal cancer.
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Asbesto Crocidolita/efeitos adversos , Neoplasias Gastrointestinais/induzido quimicamente , Poluentes Químicos da Água/efeitos adversos , Abastecimento de Água , Asbesto Crocidolita/análise , Estudos de Casos e Controles , Água Potável , Poluição Ambiental , Neoplasias Gastrointestinais/epidemiologia , Humanos , Poluentes Químicos da Água/análise , Qualidade da ÁguaRESUMO
Combination of hydroxyapatite (HAP) and potassium chloride (KCl) was used to stabilize lead and cadmium in contaminated mining soils. Pot experiments of chilli (Capsicum annuum) and rape (Brassica rapachinensis) were used to evaluate the stabilization efficiency. The results were the following: (1) the optimal combination decreased the leachable lead by 83.3 and 97.27 %, and decreased leachable cadmium by 57.82 and 35.96% for soil HF1 and soil HF2, respectively; (2) the total lead and cadmium concentrations in both plants decreased 69 and 44 %, respectively; (3) The total lead and cadmium concentrations in the edible parts of both vegetables also decreased significantly. This study reflected that potassium chloride can improve the stabilization efficiency of hydroxyapatite, and the combination of hydroxyapatite and potassium chloride can be effectively used to remediate lead and cadmium contaminated mining soil.
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Cádmio/química , Durapatita/química , Recuperação e Remediação Ambiental/métodos , Chumbo/química , Mineração , Cloreto de Potássio/química , Poluentes do Solo/química , Brassica , Cádmio/análise , Monitoramento Ambiental , Poluição Ambiental , Chumbo/análise , Solo/química , Poluentes do Solo/análise , VerdurasRESUMO
Rice is a staple food for a significant portion of the global population. Arsenic (As) accumulated in rice grains influences rice quality which threatens human health. In this study, we used three machine learning models to predict arsenic accumulation in rice based on over 300 surveys. The prediction results of soil arsenic indicate that high-arsenic soil areas are mainly distributed in South and Southeast Asia such as India, China, and Thailand. In addition, higher bioaccumulation factors (BAF), associated with higher temperature, are predominantly observed in eastern India and southern Myanmar. However, arsenic content in soil is relatively lower in these areas. About 5.5 billion population may be threatened by the consumption of high-arsenic rice. It can be concluded that temperatures may influence the BAF except for soil arsenic, and soil physicochemical properties. Further research on the relationship between climate parameters and BAF should be conducted to address and adapt to future climate change. Additionally, understanding the mechanism of arsenic accumulation under different climatic conditions is crucial for developing agricultural technologies to reduce arsenic accumulation in rice.
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Rare earth minerals have been mined for more than 50 years in Inner Mongolia of China. In the mining area rare earth elements (REE) may be significantly accumulated in humans. Therefore, the aim of this paper is to characterize the REE concentrations in hair of local residents. REE concentrations in hair of 118 subjects were determined. The results showed that the mean concentrations of the determined REE in the hair of both females and males were usually higher from mining area than from control area. The mean concentrations of all the fifteen REE were much higher in hair of males than in hair of females from mining area. This suggested that males might be more sensitive to REE than females. In addition, the mean contents of the REE in hair of miners, particularly light REE (La, Ce, Pr and Nd), were usually much higher than the values in hair of non-miners from both mining area and control area, indicating that the miners were exposed to higher concentrations of REE in occupational environment. Among age groups, the relationships between REE concentrations and age groups showed that more and more concentrations of light REE accumulated in body of both females and males with age until 60 years, while heavy REE concentrations decreased with age in males who were exposed to low concentrations of heavy REE.
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Elementos Químicos , Cabelo/química , Mineração , Adulto , Fatores Etários , China , Feminino , Cabelo/metabolismo , Humanos , Masculino , Metais Terras Raras/análise , Metais Terras Raras/metabolismo , Pessoa de Meia-Idade , Minerais/análise , Minerais/metabolismo , Fatores SexuaisRESUMO
Asbestos fibers and metals in drinking water are of significant importance to the field of asbestos toxicology. However, little is known about asbestos fibers and metals in drinking water caused by naturally occurring asbestos. Therefore, concentrations of asbestos fibers and metals in well and surface waters from asbestos and control areas were measured by scanning electron microscopy (SEM), inductively coupled plasma (ICP) optical emission spectrometer, and ICP-mass spectrometry in this study. The results indicated that the mean concentration of asbestos fibers was 42.34 millions of fibers per liter by SEM, which was much higher than the permission exposure level. The main compositions of both asbestos fibers in crocidolite mineral and in drinking water were Na, Mg, Fe, and Si based on energy dispersive X-ray analysis. This revealed that the drinking water has been contaminated by asbestos fibers from crocidolite mineral in soil and rock. Except for Cr, Pb, Zn, and Mn, the mean concentrations of Ni, Na, Mg, K, Fe, Ca, and SiO2 were much higher in both surface water and well waters from the asbestos area than in well water from the control area. The results of principal component and cluster analyses indicated that the metals in surface and well waters from the asbestos area were significantly influenced by crocidolite mineral in soil and rock. In the asbestos area, the mean concentrations of asbestos fibers and Ni, Na, Mg, K, Fe, Ca, and SiO2 were higher in surface and well waters, indicating that asbestos fibers and the metals were significantly influenced by crocidolite in soil and rock.
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Asbesto Crocidolita/análise , Água Potável/química , Metais/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Poluição Química da Água/análise , Monitoramento Ambiental , Solo/químicaRESUMO
Higharsenic (As) sinter deposited from geothermal water is a potentially overlooked hazardous matrix and there remain substantial gaps in our comprehension of the stability of As sequestered within it. In this study, qualitative and quantitative analysis of the mineralogy of As-bearing sinter was conducted by Mineral Liberation Analyzer (MLA) in geothermal areas of the Tibetan Plateau to reveal the geochemical stability of As. Our results indicated that the contents of As in sinter were 3 orders of magnitude higher than the local soil. The dominant host minerals of As were calcite (40.9 %), thenardite (22.5 %), calcium silicate (13.0 %), and halite (8.1 %). Additionally, it was found that a relatively higher As bioavailability was extracted by ethylene diamine tetraacetic acid (EDTA), with a leaching rate of 41.2 %. Notably, the X-ray diffraction (XRD) showed that the thenardite and halite were decomposed after the leaching. The combination of mineralogy and geochemistry data suggested that calcite and calcium silicate were a crucial mechanism for As retention in sinter, while the dissolution of saline minerals (e.g., thenardite, halite, and calcium chloride) served as the primary sources for As release. This finding unveils the potential risks and mechanisms associated with high-As sinter, providing scientific guidance for risk management of sinter.
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Accessibility and capacity of medical resources are key for the health care and emergency response, while the efficiency of the medical resources is very much limited by hypoxia in Tibet, China. Through introducing exercise efficiency, this study explores the accessibility of township residence to county-ship medical resources in Tibet using weighted mean travel time (WMT), and evaluates the medical capacity accordingly. The results show that: 1) the average travel time of township residence to county-level hospital is around 2 h by motor vehicle in Tibet. More than half of the population can not reach the county-ship hospital within 1 h, 33.24% of the population can not reach within 2 h, and 3.75% of the population can not reach within 6 h. 2) When considering the catchment of the medical resources and the population size, the WMT of the county-ship medical resources ranges from 0.25 h to 10.92 h. 3) After adjusted by travel time and exercise efficiency, the county-ship medical capacity became more unequal, with 38 out of 74 counties could not meet the national guideline of 1.8 medical beds per 1000. 4) In total, there are 17 counties with good WMT and sufficient medical resources, while 13 counties having very high WMT and low capacity of medical resources in Tibet. In the end, suggestions on medical resources relocation and to improve the capacity are provided. This study provides a method to incorporate exercise efficiency to access the accessibility and evaluate medical capacity that can be applied in high altitude ranges. Electronic Supplementary Material: Supplementary material is available in the online version of this article at 10.1007/s11769-022-1321-1.
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The seasonal variations of shallow groundwater arsenic have been widely documented. To gain insight into the monthly variations and mechanisms behind high groundwater arsenic and arsenic exposure risk in different climate scenarios, the monthly probability of high groundwater arsenic in Hetao Basin was simulated through random forest model. The model was based on arsenic concentrations obtained from 566 groundwater sample sites, and the variables considered included soil properties, climate, topography, and landform parameters. The results revealed that spatial patterns of high groundwater arsenic showed some fluctuations among months under different future climate scenarios. The probability of high total arsenic and trivalent arsenic was found to be elevated at the start of the rainy season, only to rapidly decrease with increasing precipitation and temperature. The probability then increased again after the rainy season. The areas with an increased probability of high total arsenic and trivalent arsenic and arsenic exposure risk under SSP126 were typically found in the high-arsenic areas of 2019, while those with decreased probabilities were observed in low-arsenic areas. Under SSP585, which involves a significant increase in precipitation and temperature, the probability of high total arsenic and trivalent arsenic and arsenic exposure risk was widely reduced. However, the probability of high total arsenic and trivalent arsenic and arsenic exposure risk was mainly observed in low-arsenic areas from SSP126 to SSP585. In conclusion, the consumption of groundwater for human and livestock drinking remains a threat to human health due to high arsenic exposure under future climate scenarios.
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Arsênio , Água Subterrânea , Poluentes Químicos da Água , Humanos , Arsênio/análise , Clima , Estações do Ano , Temperatura , Poluentes Químicos da Água/análise , Monitoramento AmbientalRESUMO
The Tibetan Plateau (TP) is known as the water tower of Asia, and the water quality has long been a focus of public concern, especially in the Yarlung Tsangpo River Basin (YTRB), a unique area that is climate-sensitive, geologically complex, eco-fragile, and densely populated. Thallium (Tl) is a typical metal that is more toxic than Pb, Cd, and As and often occurs in sulfide minerals. Although large-scale polymetallic sulfide mineralization developed in the YTRB, the geochemical dispersion and potential risk of Tl in aquatic environments of the YTRB remain poorly understood. In this study, the concentration, distribution, source, and health risk of Tl and associated metal(loid)s in the hot springs and surface water in the YTRB were systematically analyzed. The results showed that the trace elements (Cd, Cr, Zn, Cu, Al, Sr, Ni, Co, Mn, Pb) in water environments are within the recommended limits, except for Tl and As. Principal component analysis (PCA) and correlation analysis (CA) showed that the elements of Tl and As were positively related to each other in either both hot spring water and surface water, indicating their common origin. Spatial variations suggested that high levels of Tl and As observed in the north YTRB, which may be relevant to the reduction-dissolution of Tl (As)-bearing minerals and the magmatic hydrothermal system formed in the shallow part of the northern YTRB. Furthermore, source apportionment identified natural sources of Cu, Ni, Cr, Co, Mn, Zn, and Cd and anthropogenic inputs of Al and Pb. Exposure assessment studies have found that ingestion is the primary route of As and Tl exposure to local population, and balneological and bathing purposes do not constitute a human health concern. This study offers valuable insights into the risk of naturally occurring Tl enrichment being hidden in As-rich hydrosphere in the YTRB and other regions with similar geoenvironmental contexts.
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Metais Pesados , Poluentes Químicos da Água , Humanos , Tálio/análise , Metais Pesados/análise , Tibet , Cádmio/análise , Rios , Chumbo/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Medição de Risco , Sulfetos/análise , ChinaRESUMO
Drip irrigation is a valuable method for optimising water and fertiliser usage, motivating its increasing use. However, the ecological effects of drip irrigation fertilisation have not been sufficiently evaluated, limiting its effective and widespread use. Within this context, we aimed to determine the effects and potential ecological risks of using polyethylene irrigation pipes and mulch substrate under various drip irrigation conditions as well as burning of waste pipes and mulch substrate. Laboratory simulations of field conditions were used to determine the distribution, leaching, and migration pattern of heavy metals (Cd, Cr, Cu, Pb, and Zn) from plastic drip irrigation pipes and agricultural mulch substrate into various solutions. Maize samples obtained from drip-irrigated fields were analysed to determine the presence of heavy metal residues and assess the risk of heavy metal contamination. Heavy metal leaching from pipes and mulch substrate was high under acidic conditions, while the migration of heavy metals from plastic products was low in alkaline water-soluble fertiliser solutions. After combustion, heavy metal leaching from pipes and mulch residues increased considerably, with the migration capacity of Cd, Cr, and Cu increasing by >10-fold. Heavy metals in plastic pipes migrated primarily to the residue (bottom ash), whereas those from mulch substrate migrated to the fly ash component. Under experimental conditions, the migration of heavy metals from plastic pipes and mulch substrate had a negligible effect on the heavy metal content in aqueous environments. Although heavy metal leaching increased, the effect on water quality under actual irrigation conditions was relatively minor (in the order of 10-9). Thus, the use of plastic irrigation pipes and mulch substrate did not result in significant heavy metal contamination and potential risk to the agriculture ecosystem. Our study findings provide evidence for the effective application and widespread promotion of drip irrigation and fertiliser technology.