Controlling factors and sources-specific ecological risks associated with toxic metals in core sediments from cascade reservoirs in Southwest China.

Toxic metals (TMs) in reservoir sediments pose significant risks to ecosystem security and human safety, yet their presence in the cascade reservoirs of the Lancang River remains understudied. This research examined TMs in core sediments from the Manwan (MW) and Dachaoshan (DCS) cascade reservoirs, aiming to elucidate contamination characteristics, controlling factors, and source-specific ecological risks. The study revealed that the concentrations of As, Cd, Cr, Cu, Hg, Ni, and Zn in the MW Reservoir (37.

Antimony isotope fractionation and the key controls in the soil profiles of an antimony smelting area.

The controlling factors of antimony migration and transformation in soil profiles are still unclear. Antimony isotopes might be a useful tool to trace it. In this paper, antimony isotopic compositions of plant and smelter-derived samples, and two soil profiles were measured for the first time.

Health risk assessment of heavy metals in road dust from the fourth-tier industrial city in central China based on Monte Carlo simulation and bioaccessibility.

Health risks caused by heavy metal (HM) exposure in road dust has attracted extensive attention, but few studies have focused on the health risks of residents living in small- and medium-sized cities with rapid industrialization and urbanization. Thus, 140 road dust samples were collected across Anyang, a typical fourth-tier industrial city in central China, which were analysed for 10 different HMs (Mn, Zn, Pb, V, Cr, As, Cd, Ni, Cu and Co). Monte Carlo simulation and bioaccessibility were used to quantify the health risks of heavy metals comprehensively in road dust.

Contamination, sources and health risks of toxic elements in soils of karstic urban parks based on Monte Carlo simulation combined with a receptor model.

Understanding the health risks of toxic elements (TEs) in urban park soils and determining their priority control factors are crucial for public health and pollution management. Soil samples were collected from 33 urban parks in Guiyang, a typical karstic city. For each park, 15-45 topsoil samples were collected according to the area and then thoroughly mixed to obtain a representative sample.

Heavy metal characteristics in porewater profiles, their benthic fluxes, and toxicity in cascade reservoirs of the Lancang River, China.

The construction of cascade reservoirs on the Lancang River (the upper Mekong) has an important influence on the distribution and accumulation of heavy metals. Heavy metal contents in porewater provide vital information about their bioavailability, studies on this aspect are rare until now. In this study, sediment cores were collected from four adjacent cascade reservoirs in the upper Mekong River to study the distribution, potential sources, diffusive fluxes and toxicity of heavy metals in porewater.

Persistent arsenate-iron(iii) oxyhydroxide-organic matter nanoaggregates observed in coal.

Understanding how natural nanoaggregates of iron (Fe) and organic matter (OM), currently identified in organic rich soil or peat, interact with metals and metalloids is environmentally significant. Coal is also organic-rich and exemplifies anoxic sedimentary environments with Fe usually as pyrite and not oxides. Here, we analyze the local structure of Fe (6880-21 700 mg kg) and As (45-5680 mg kg) in representative Guizhou coal samples using X-ray absorption near-edge structure and extended X-ray absorption fine structure (XANES and EXAFS) to illustrate how Fe(iii) and As(v) are preserved in coal formed from reduced, organic-rich precursors.

Abundance and mobility of metal(loid)s in reservoir sediments of Singe Tsangpo and Yarlung Tsangpo in Tibet, China: Implications for ecological risk.

Geogenic arsenic enrichment in soil and river sediments of Tibet compared to its upper crustal abundance has been observed, raising the question whether other trace elements are also enriched and thus may pose ecological risks. Because human activities are limited, the reservoir sediments after the recent construction of the Shiquan dam on the Singe Tsangpo (ST) and the Zam dam on the Yarlung Tsangpo (YT) collect and thus represent material sourced from 14,870 km and 157,668 km of drainage areas, respectively. Bulk concentrations of the metalloid (As) and 13 metals (Li, Be, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Cs, and Pb) are analyzed for 123 samples from 9 mostly silty sediment cores (depth: 11-20 cm) from the Shiquan Reservoir and for 250 samples from 13 mostly sandy sediment cores (depth: 9-28 cm) from the Zam Reservoir.

Using Zn isotopes to trace Zn sources and migration pathways in paddy soils around mining area.

Paddy soils around mining areas suffer from the great threat of heavy metal pollution. The traditional source-tracing methods based on metal concentrations limit our ability to quantify the sources of heavy metals and trace their transport processes to paddy soils. In this study, Zn isotope compositions of paddy soils in Dabaoshan mine area, a typical sulfide deposit in southern China, have been systematically studied.

Effects of dam construction on arsenic mobility and transport in two large rivers in Tibet, China.

Construction of dams on the Singe Tsangpo (ST) and the Yarlung Tsangpo (YT) Rivers, the upper stretch of the Indus and the Brahmaputra Rivers, respectively, are expected to affect material transport. To evaluate the effects of dam construction on arsenic (As) mobility and transport in the ST River and the YT River in Tibet and the downstream river basins, water column and sediment core samples in the Shiquan Reservoir of the ST River and in the Zam Reservoir of the YT River were obtained in August 2017, and January and May 2018, and additionally, at the inflows and outfalls of the reservoirs. The seasonal variation of dissolved As contents in the inflow water of the Zam Reservoir and the Shiquan Reservoir was regulated by the mixing between the low-As river runoff and the high-As hot spring input.

Dietary exposure to arsenic and human health risks in western Tibet.

The health effects of drinking water exposure to inorganic arsenic are well known but are less well defined for dietary exposure. The rising concerns of arsenic risks from diet motivated this study of arsenic concentrations in highland barley, vegetables, meat, and dairy products to evaluate arsenic exposure source and to assess health risks among rural residents of Ngari area, western Tibet. Total arsenic and arsenic speciation were measured by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography combined with ICP-MS (HPLC-ICP-MS) respectively.

Unraveling prevalence and public health risks of arsenic, uranium and co-occurring trace metals in groundwater along riverine ecosystem in Sindh and Punjab, Pakistan.

The current study focuses on the understanding of contamination status, distribution, source apportionment and health perspectives of arsenic (As), uranium (U) and other co-occurring trace metals in the groundwater samples collected along the major rivers in Sindh and Punjab provinces, Pakistan. ICP-MS analysis revealed that the concentrations of As in the groundwater in Sindh and Punjab ranged from 0.2 to 81.

Enrichment of Arsenic in Surface Water, Stream Sediments and Soils in Tibet.

Groundwater in sedimentary deposits in China, Southern, and Southeast Asia down gradient from the Tibetan plateau contain elevated As concentrations on a regional scale. To ascertain the possibility of source region As enrichment, samples of water (n=86), stream sediment (n=77) and soil (n=73) were collected from the Singe Tsangpo (upstream of the Indus River), Yarlung Tsangpo (upstream of the Brahmaputra River) and other drainage basins in Tibet in June of 2008. The average arsenic concentration in stream waters, sediments and soils was 58±70 μg/L (n=39, range 2-252 μg/L), 42±40 mg/kg (n=37, range 12-227 mg/kg), and 44±27mg/kg (n=28, range 12-84 mg/kg) respectively for the Singe Tsangpo and was 11±17 μg/L (n=30, range 2-83 μg/L), 28±11 mg/kg (n=28, range 2-61 mg/kg), and 30±34 mg/kg (n=21, range 6-173 mg/kg) respectively for the Yarlung Tsangpo.

[Distribution of arsenic in surface water in Tibet].

This research was aimed on studying the arsenic distribution of water in Yarlung Zangbo and Singe Zangbo basins in Tibet. Results showed that arsenic concentrations were different in different types of the water. The sequence of arsenic concentration from high to low was hot spring water (4920 microg x L(-1) +/- 1520 microg x L(-1), n =2), salt lake water (2180 microg x L(-1) +/- 3840 microg x L(-1), n =7), well water (194 microg x L(-1), n = 1), freshwater lake water (163 microg x L(-1) +/- 202 microg x L(-1), n =2) and stream water (35.

Thallium pollution in China: A geo-environmental perspective.

It is well known that thallium (Tl) is a non-essential and toxic metal to human health, but less is known about the geo-environmentally-induced Tl pollution and its associated health impacts. High concentrations of Tl that are primarily associated with the epithermal metallogenesis of sulfide minerals have the potential of producing Tl pollution in the environment, which has been recognized as an emerging pollutant in China. This paper aims to review the research progress in China on Tl pollution in terms of the source, mobility, transportation pathway, and health exposure of Tl and to address the environmental concerns on Tl pollution in a geo-environmental perspective.

Medical geology of arsenic, selenium and thallium in China.

Arsenic (As), selenium (Se) and thallium (Tl) are three trace metals (metalloids) of high concern in China because deficiency or excess expose can cause a range of endemic diseases, such as endemic arsenism, selenosis, Keshan disease (KD), Kashin-Beck disease (KBD) and thallotoxicosis. These specific endemic diseases were attributable for overabundance or deficiency (mainly referring to selenium) of these three elements in the local environment as a result of natural geochemical processes and/or anthropologic activities. The geochemistry and human health impacts of these three trace elements have been intensively studied since the 1970s in China, in terms of geochemical sources, distribution, transportation, health impact pathways, and prevention/remediation measures.

Fluoride in chilies from southwestern china.

The purpose of this research is to investigate the fluoride contents in the chilies from southwest China and other countries in order to calculate the difference in fluoride levels in the fresh chilies. The standard method in China for analysis of fluoride in food (GB/T 5009.18-2003) was applied to determinate the fluoride content in chilies.

Distribution and transport of selenium in Yutangba, China: impact of human activities.

Yutangba, one of the typical high-Se areas where a sudden incidence of Se poisoning occurred in 1963, is located in the northern part of Shuanghe town about 81 km SE of Enshi, Hubei Province, China. In this area, a comprehensive investigation was conducted on the distribution of Se in soils, plant species, stream water and sediment. The mean concentrations of Se were: total soil, 4.

Extraction and determination of papaverin in pericarpium papaveris using aqueous two-phase system of poly(ethylene glycol)-(NH4)2SO4 coupled with high-performance liquid chromatography.

Based on aqueous two-phase system (ATPS) of poly(ethylene glycol) (PEG)-(NH4)2SO4, a simple pretreatment approach was developed for the extraction and determination of papaverin in pericarpium papaveris. The influence factors on phase behavior of the ATPS and partition behavior of papaverin was investigated, and partition mechanism based on the hydrophobic interaction between PEG and analyte molecules was proposed. Under the optimal conditions, the extraction efficiencies for papaverin were 93-96%, and the recoveries of the added standard were 97-106% with relative standard deviations of 1.

Extraction and determination of morphine in compound liquorice using an aqueous two-phase system of poly(ethylene glycol)/K2HPO4 coupled with HPLC.

An aqueous two-phase system (ATPS) of poly(ethylene glycol) (PEG)/K(2)HPO(4) coupled with high performance liquid chromatography (HPLC) method was developed for the separation and determination of morphine in compound liquorice. Morphine and its analogs were used as model compounds to investigate influence of various factors on extraction behaviors of ATPS, such as the types and concentrations of salts, PEG molecular mass, temperature and pH. It was observed that the types of salt had much influence on extraction efficiencies of morphine and its analogs.

Arsenic concentrations in Chinese coals.

The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.

Ionic liquid-based aqueous two-phase system, a sample pretreatment procedure prior to high-performance liquid chromatography of opium alkaloids.

An ionic liquid, 1-butyl-3-methylimidazolium chloride ([C4 mim]Cl)/salt aqueous two-phase systems (ATPS) was presented as a simple, rapid and effective sample pretreatment technique coupled with high-performance liquid chromatography (HPLC) for analysis of the major opium alkaloids in Pericarpium papaveris. To find optimal conditions, the partition behaviors of codeine and papaverine in ionic liquid/salt aqueous two-phase systems were investigated. Various factors were considered systematically, and the results indicated that both the pH value and the salting-out ability of salt had great influence on phase separation.

Extraction of testosterone and epitestosterone in human urine using aqueous two-phase systems of ionic liquid and salt.

Based on aqueous two-phase systems (ATPS) consisting of 1-butyl-3-methylimidazolium chloride, a hydrophilic ionic liquid (IL), and K2HPO4, a new and simple extraction technique, coupled with a reversed-phase high performance liquid chromatography (RP-HPLC), was developed for the simultaneous concentration and analysis of testosterone (T) and epitestosterone (ET) in human urine. Under the optimal conditions, the extraction efficiencies for both analytes were 80-90% in a one-step extraction. The method required only 3.

Natural cyanide degradation and impact on Ili River drainage areas from a Goldmine in Xinjiang autonomous region, China.

The Ili River is a very important river to the northwest of China and Kazakhstan. The Axi Goldmine is located in the upstream of a branch of the Ili River. The cyanide from the goldmine effluent is a threat to the downstream areas.