Springer Science and Business Media LLC

Groundwater is crucial water supply source in the Tarim Basin in Xinjiang. Due to the existence of high-fluoride groundwater, the shortage of water resources is more prominent, which brings challenge to safe groundwater supply. A total of 1326 groundwater samples were collected in the oasis zone to investigate the sources, driving factors, and health hazards of high-fluoride groundwater. Results showed that the high-fluoride groundwater was widely distributed around the edge of the oasis belt. The exceeding rates of fluoride in single-structure phreatic water (SSPW), phreatic water in confined groundwater area (PWCGA), shallow confined groundwater (SCG), and deep confined groundwater (DCG) were 31.6%, 51.5%, 35.0%, and 14.8%, respectively. Fluoride concentration showed a gradually decreasing trend from PWCGA to DCG. High-fluoride concentrations were closely related to weakly alkaline groundwater environment, high HCO3−, high Na+, and low Ca2+. The continuous dissolution of fluoride-containing minerals such as fluorite was the main driving mechanism of high-fluoride groundwater. Competitive adsorption of OH−/HCO3− and F−, evaporation concentration, precipitation of calcium-containing minerals, and cation exchange were conducive to the enrichment of groundwater fluoride. Human activities such as irrigation of high-fluoride groundwater also had a certain degree of effect on the shallow high-fluoride groundwater formation. Drinking high-fluoride groundwater would cause non-carcinogenic risks to different populations, health risks of fluoride through drinking water were increased with decreasing age. To effectively utilize groundwater resources and provide healthy drinking water for local residents, it is recommended to adopt the measures of water supply with different quality and fluoride reduction.

Regional water pollution and use of unregulated water sources can be an important mixed metals exposure pathway for rural populations located in areas with limited water infrastructure and an extensive mining history. Using censored data analysis and mapping techniques we analyzed the joint geospatial distribution of arsenic and uranium in unregulated water sources throughout the Navajo Nation, where over 500 abandoned uranium mine sites are located in the rural southwestern United States. Results indicated that arsenic and uranium concentrations exceeded national drinking water standards in 15.1 % (arsenic) and 12.8 % (uranium) of tested water sources. Unregulated sources in close proximity (i.e., within 6 km) to abandoned uranium mines yielded significantly higher concentrations of arsenic or uranium than more distant sources. The demonstrated regional trends for potential co-exposure to these chemicals have implications for public policy and future research. Specifically, to generate solutions that reduce human exposure to water pollution from unregulated sources in rural areas, the potential for co-exposure to arsenic and uranium requires expanded documentation and examination. Recommendations for prioritizing policy and research decisions related to the documentation of existing health exposures and risk reduction strategies are also provided.

Groundwater currently provides 98% of all drinking-water supply in Bangladesh. Groundwater is found throughout Bangladesh but its quality (i.e., arsenic and salinity contamination) and quantity (i.e., water-storage depletion) vary across hydrological environments, posing unique challenges to certain geographical areas and population groups. Yet, no national-scale, multi-parameter groundwater hazard maps currently exist enabling water resources managers and policy makers to identify vulnerable areas to public health. We develop, for the first time, groundwater multi-hazard maps at the national scale of Bangladesh combining information on arsenic, salinity, and water storage. We apply geospatial techniques in ‘R’ programming language and ArcGIS environment, linking hydrological indicators for water quality and quantity to construct risk maps. A range of socioeconomic variables including access to drinking and irrigation water supplies and social vulnerability (i.e., poverty) are overlaid on these risk maps to estimate exposures. Our multi-parameter groundwater hazard maps show that a considerable proportion of land area (5–24% under extremely high to high risks) in Bangladesh is currently under combined risk of arsenic and salinity contamination, and groundwater-storage depletion. As small as 6.5 million (2.2 million poor) to 24.4 million (8.6 million poor) people are exposed to a combined risk of high arsenic, salinity, and groundwater-storage depletion. Our groundwater hazard maps reveal areas and exposure of population groups to water risks posed by arsenic and salinity contamination and depletion of water storage. These geospatial hazard maps can potentially guide policy makers in prioritizing mitigation and adaptation measures in order to achieve the United Nation’s Sustainable Development Goals across the water, agriculture, and public health sectors in Bangladesh.

Breast cancer (BC) is not a single disease, but a set of molecular subtypes that could differ within their risk factors, which may include several metals. Our objective was to evaluate the association between BC molecular subtypes and metal mixtures, and to identify their main metal contributors within the mixture. The present report develops from our previous work based on a case–control study performed in Northern Mexico from 2007 to 2011. We included 498 population-based controls and 497 histologically confirmed BC cases. We gathered information about hormonal receptors (HR) and epidermal growth factor receptor 2 (HER2) from clinical records. Breast cancer molecular subtypes were determined as follow: HR + /HER2−, HER2 + or HR−/HER2− (TN). Urinary concentrations of ten metals were measured by inductively coupled plasma mass spectrometry. We used the weighted quantile sum (WQS) regression to obtain the metal mixtures, as well as to identify the main metal contributor within each mixture. We found two weighted indices of metal mixtures contrastingly associated with BC molecular subtypes. One had tin as the main contributor and showed a positive association with BC (OR = 1.14 CI95% 1.10, 1.18), that remained only among HR + /HER2− subtype. The other weighted index was mainly determined by molybdenum followed by vanadium and cobalt. This second WQS index was negatively related to BC (OR = 0.78 CI95% 0.73, 0.83) regardless of its molecular subtypes. This work is among one of the first reports that provides evidence of associations between metal mixtures and BC, which are heterogenous according to BC molecular subtypes.

Silver nanoparticles (AgNPs) find applications in many consumer products due to their unique properties. It is imperative to contend with the safety issues in respect of AgNPs during manufacturing, usage, and after disposal, as manufacturers as well as consumers are likely to be exposed to these particles. This review seeks to scrutinize the current challenges in obtaining input parameters for conducting risk assessment of exposure to Ag NPs and specifically focuses on exposures of humans to Ag NPs through oral ingestion of Ag NPs via edible parts of plants, water, soil ingestion, and fish, and through dermal uptake exposure pathways. The present status of toxicological studies of silver nanoparticles and challenges in assessing risks of exposure to silver nanoparticles has been discussed in detail. The limited and contradictory existing data imply that prudence must be exercised when potential exposures to silver nanoparticle emerge from different routes.

Dithiocarbamates (DTC) are the most commonly used synthetic fungicides in the Prosecco District (PD) of Treviso. The DTC biomarker is urinary ethylenethiourea (u-ETU). The aims of this biomonitoring study are to describe the level of u-ETU in residents in PD and to identify the factors associated with DTC exposure. In 2012 (baseline), we randomly extracted data for 126 children (3–5 years) and their families (260 adults), who were resident in 8 municipalities of PD and not occupationally exposed to DTC, from the local health database. For each subject, we obtained urine samples and socio-demographic, lifestyle and dietary information. In 2014 (after intervention), we evaluated the possible changes in u-ETU in 54 adults and 55 children at high risk of DTC exposure. The median baseline u-ETU was 0.35 µg/L. Approximately 5% of the samples had a u-ETU concentration > 5 µg/L. No u-ETU concentration exceeded 21 µg/L. Determinants of a higher u-ETU concentration were wine consumption (OR 2.04) and personal use of pesticides (OR 2.70) for adults; and living within 30 m from a vineyard (OR 9.51) and the pesticides use in the family (OR 6.25) for children. A significant u-ETU reduction in 49 adults and 25 children was observed from baseline to after intervention (p = 0.01). Wine consumption and production and DTC use in gardening influenced u-ETU concentrations in this population, although the levels were relatively low. The reduction in u-ETU from baseline to time after intervention probably reflects the effects of public health interventions.

Previous studies have shown that arsenic and cadmium can accumulate in rice grain to levels that cause health concerns. Furthermore, geographical survey has shown that there is considerable variation (~ 100-fold) in accumulation of these carcinogens in rice grain. This variance must be due to heterogeneity in soil biogeochemistry and contrasting rice management regimens. Here we present the first systematic global study to investigate the impact of soil biogeochemistry on accumulation of these elements in rice grain. Matched grain, shoot, root and soil samples were collected across a latitudinal gradient from East Africa to Europe and soil, shoot, grain chemistry and soil microbial community (prokaryotes and fungi) assessed within the context of arsenic and cadmium biogeochemistry. European and Vietnamese grain sum of arsenic species (inorganic arsenic plus dimethylarsonic acid) concentration medians, ~ 0.1 mg/kg, were found to be around ten-fold higher compared to those in East Africa and Sri Lanka. Arsenic concentrations were linked to higher levels of soil arsenic, and to higher abundance of soil sulphur-oxidising and sulphate reducing bacteria and methanogenic archaea. For cadmium, Sri Lanka showed highest (median 0.0156 mg/kg) and Europe lowest (median of 0.001 mg/kg) levels in grain, with the other regions showing intermediate values. Interestingly, grain cadmium was unrelated to soil cadmium concentrations, with Europe having the highest levels of cadmium in soil. Instead, grain cadmium correlated with higher oxidation/reduction potential, lower -log[hydrogen ion], lower soil calcium, and to a higher abundance of aerobic bacteria and fungi (lowest abundance of these organisms in European soils).

Both arsenic and cadmium are reported to be toxic to humans. The use of saliva as a biomarker of low-level exposures to these elements has not been adequately explored, and the putative relationship between exposure and obesity is unclear. This cross-sectional study aims to investigate the relationship between salivary arsenic and cadmium concentrations and their association with obesity. Arsenic and cadmium concentrations were analyzed in human saliva samples by Inductively Coupled Plasma-Mass Spectrometry on 270 randomly selected women who participated in the Arkansas Rural Community Health Study. Multivariable logistic regression was performed to evaluate the association between heavy metal concentrations and obesity. Stratified logistic regression was performed based on menopausal status. Generalized linear models were used to evaluate weight gain velocity. Significant positive associations were observed in postmenopausal women for both arsenic (OR = 4.43, 95% CI 1.91–10.28) and cadmium (OR = 2.72, 95% CI 1.23–5.99) concentrations, as well as significant trends among tertiles (p < 0.01 and p  = 0.01, respectively). No relationship with obesity was evident among premenopausal women for either metal. A dose–response relationship was observed between increasing weight gain velocity and increasing metal concentrations. At concentrations well below governmental and industrial standards for acute toxicity, significant associations between obesity and concentration of these heavy metals are evident. The rate at which individuals gain weight is affected by metal concentrations and may play a role in the rapid increase in weight in postmenopausal women. These results might explain, in part, the missing variability in the increasing obesity pandemic in certain population exposed to these environmental toxicants.