Experiences of the Flint Water Crisis Among Reproductive-Age Michigan Women in Communities Outside of Flint: Differences by Race and Ethnicity.

We sought to understand how women in Michigan communities outside of Flint experienced the Flint water crisis, an avoidable public health disaster widely attributed to structural racism. Using survey data from 950 Michigan women aged 18-45 from communities outside of Flint, we examined racial and ethnic differences in personal connections to Flint, perceived knowledge about the water crisis, and beliefs about the role of anti-Black racism in the water crisis factors that could contribute to poor health via increased psychological stress. We found that White (OR = 0.32; 95% CI: 0.22, 0.46) and Hispanic (OR = 0.21; 95% CI: 0.09, 0.49) women had lower odds than Black women of having family or friends who lived in Flint during the water crisis. Compared to Black women, White women were less likely to be moderately or very knowledgeable about the water crisis (OR = 0.58; 95% CI: 0.41, 0.80). White women (OR = 0.26; 95% CI: 0.18, 0.37), Hispanic women (OR = 0.38; 95% CI: 0.21, 0.68), and women of other races (OR = 0.28; 95% CI: 0.15, 0.54) were less likely than Black women to agree that the water crisis happened because government officials wanted to hurt Flint residents. Among those who agreed, White women (OR = 0.47; 95% CI: 0.30, 0.74) and women of other races (OR = 0.33; 95% CI: 0.12, 0.90) were less likely than Black women to agree that government officials wanted to hurt people in Flint because most residents are Black. We conclude that the Flint water crisis was a racialized stressor, with potential implications for the health of reproductive-age Black women.

Occurrence, distribution, and ecological risk assessment of pharmaceuticals and personal care products in the surface water of the middle and lower reaches of the Yellow River (Henan section).

Pharmaceuticals and personal care products (PPCPs) are commonly seen emerging organic contaminants in aquatic environments. The transects for the occurrence and distribution of 24 PPCPs along the middle and lower reaches of the Yellow River (Henan section) were investigated in this study. All 24 targeted compounds were detected in surface water, with concentrations in the range from not detected (ND) to 527.4 ng/L. Among these PPCPs, caffeine is found to have the highest concentration and its detection frequency is 100%. The total PPCP concentration ranged from 136 ng/L to 916 ng/L (median, 319.5 ng/L). Spatial analysis showed that the pollution level of PPCPs in the trunk stream was lower than that in most tributaries in the middle and lower reaches of the Yellow River (Henan section). The ecotoxicological risk assessment indicated that norfloxacin, azithromycin, estrone, and triclosan posed high risks to aquatic organisms (RQ > 1), roxithromycin and oxytetracycline imposed moderate risks (0.1 ≤ RQ < 1), and the tributary Jindi River had the highest mixed risk (MRQ = 222).

Estimation of some trace metal pollutants in River Atuwara southwestern Nigeria and spatio-temporal human health risks assessment.

Over twenty thousand persons rely on water from Atuwara River for drinking and other domestic purposes, hence the need to ascertain the human health risk inherent in such practice. Seventy-two water samples were collected from River Atuwara during the dry and wet seasons of 2018, and the concentration of heavy metals (Pb, As, Ni, Cr, Zn, Cu, and Cd) were measured using ICP-OES. A newly developed human health risk assessment method, HHRISK code was used to estimate the health risks associated with consumption of water from Atuwara River. Results obtained revealed that the concentration of heavy metals in the river was as follows: Cd < Ni < Pb < Cr < Cu < As < Zn in the wet season and Cd < Pb < Ni < Cu < Cr < As < Zn during the dry season. Principal component analysis suggested that industrial effluents, agricultural activities and base-rock interaction are responsible for pollution of Atuwara River. The cumulative hazard index (HIcum) obtained was 678.0 ±â€¯36.8 (for adult) and 1392.0 ±â€¯132 (for child) for non-carcinogenic risks. A cumulative carcinogenic risk (CRcum) of 1.01E-1±5.26E-3 and 4.96E-2±5.05E-3 was obtained for adult and children respectively, suggesting that up to 1 in 10 adults and 1 in 20 children may suffer from cancer over their lifetime as a result of consumption and exposure to water from River Atuwara. These results highlight the fact that unavailability of safe drinking water in many parts of the world remains a real and persistent risk which must be tackled.

Assessment of microplastic pollution: occurrence and characterisation in Vesijärvi lake and Pikku Vesijärvi pond, Finland.

In the last few years, several studies have investigated microplastics (MPs) in marine ecosystems, but data monitoring and assessing the occurrence in freshwater environments are still scarce. The present study aims to investigate the occurrence, distribution, and chemical composition of MP pollution in Vesijärvi lake and Pikku Vesijärvi pond close to the city of Lahti (Finland) in winter. Sediment, snow, and ice core samples were collected near the shore of these two aquatic systems. MPs were analysed and identified by a non-destructive method using Fourier transform infrared spectroscopy (FTIR) 2D imaging. The mean concentrations of MPs detected in sediment, snow, and ice samples were 395.5 ± 90.7 MPs/kg, 117.1 ± 18.4 MPs/L, and 7.8 ± 1.2 MPs/L, respectively. FTIR results showed the predominant abundance of microplastics, such as polyamides (up to 53.3%), polyethylene and polypropylene (up to 17.1%), and natural fragments such as cellulose (up to 45.8%) and wool (up 18.8%) in the same size range. The potential release of MPs arising from stormwaters and sport and recreational activities was evidenced.

Arsenic concentration, speciation, and risk assessment in sediments of the Xijiang River basin, China.

In order to acquire the spatial distribution, speciation, and risk assessment of arsenic (As), 18 sediment samples were collected in the middle and upper reaches (Nanpan River, Beipan River, Hongshui River, Diaojiang River, and Duliu River) of the Xijiang River basin, China. The chemical fractions of As in the collected sediments were mainly dominated by the residual fraction and the Fe (Mn, Al) oxide/oxyhydroxides fractions. The correlation analysis results showed that the chemical fraction of As in sediments had close correlations with Mn, good correlations with Fe and organic matter (OM), while weak correlations with Al and carbonate. In addition, it also showed that Diaojiang River basin was found to have an extremely high As pollution status and suffered from high ecological risk. Duliu River and Nanpan River had moderately polluted levels of As and showed a low ecological risk. The other sample sites of Xijiang River basin were uncontaminated of As. The assessment results from this study indicated that the different types of species present based on the chemical fractionation of As from the Xijiang River basin showed different risks. Graphical abstract.

[Presence of microplastics in water and the potential impact on public health]. / Presencia de microplásticos en aguas y su potencial impacto en la salud pública.

The use of plastics has increased exponentially over recent years. Difficulties in their recycling and their low degradability result in their accumulation in the environment. Despite their great stability, they are subject to physical and chemical erosion resulting in smaller fragments. Although there is no standard definition of microplastics, the maximum limit of 5 mm has been accepted as a criterion. Plastics, in addition to the consequences on the environment, have a direct effect on living beings, either by ingestion or toxicity. They may also act as a vehicle for invasive species and adsorb other contaminants on their surface such as PCBs, PAHs or DDT. This, increases the toxic effect of their own components such as plasticizers, additives, heavy metals, etc. There is disparity in the published results regarding the presence of microplastics in both water supplies and drinking water and bottled water. There are no standard analytical methods, nor a consensus in the definition and description of microplastics that allow an appropriate comparison of results. In the absence of scientific evidence, it is necessary to study in depth the presence of microplastics in water and the potential effects on health, in order to be able to consider microplastics as a monitoring parameter in drinking water.

El uso de plásticos se ha visto incrementado de manera exponencial en los últimos años. Su difícil reciclaje y su baja capacidad de degradación tienen como consecuencia una acumulación de estos en el medio ambiente. Pese a su gran estabilidad, se ven sometidos a erosión física y química, dando lugar a fragmentos más pequeños. Aunque no hay una definición estandarizada del concepto de microplástico, se ha aceptado el límite máximo de 5 mm como criterio. Los plásticos, además de las consecuencias sobre el medio ambiente, tienen un efecto directo sobre los seres vivos, ya sea por ingestión o por toxicidad. También, pueden actuar como vehículos de especies invasoras y adsorber en su superficie otros contaminantes como los BPCs, los HAPs o el DDT, incrementando así el efecto tóxico propio debido a los componentes que poseen tales como plastificantes, aditivos, metales pesados, etc. Existe disparidad en los resultados publicados en cuanto a la presencia de microplásticos tanto en abastecimientos como en agua de consumo y embotellada. No existe una metodología normalizada de métodos analíticos, como tampoco rigor en la definición y descripción de los microplásticos que permitan la comparación de resultados. Ante la falta de evidencia científica, es necesario profundizar en el estudio sobre la presencia de estos y sus efectos potenciales en la salud, para ser considerado como un parámetro a vigilar en las aguas de consumo humano.

Assessment of DDT and mercury levels in fish and sediments in the Iriri River, Brazil: Distribution and ecological risk.

In order to assess the risk of exposure of human populations to dichlorodiphenyltrichloroethane (DDT) and mercury, muscles of five fish species were analysed, along with the surface sediment of 14 Iriri River sampling sites. The fish specimens were sacrificed by the spinal section, prior to sex identification, body weight determination and total length. Considering the fish specimens studied, 11% of them showed concentrations of mercury higher than the maximum established by the World Health Organization for safe human consumption. A positive correlation between fish body weight and mercury concentration was observed, besides a positive correlation between the fish size and Hg concentration. Significant differences (P < 0.05) were found between mean concentrations of DDT and metabolites among species of fish studied. In the Plagioscion squamossissimus species, the highest concentration of total DDT (151.4 ng/g) was found, while in Eugerres Brasilianus species, the lowest. However, the DDT levels in fish muscle of studied species are below the maximum set by FAO-Alimentarius CODEX. In the sediments, total DDT ranged from 11.58 ng/g to 48.4 ng/g, which is associated with the historical DDT use in the Amazon. According to sediment quality guidelines, these levels have a moderate toxic effect in almost all of the studied region.

Assessment and management of nonpoint source pollution based on multicriteria analysis.

Assessing the potential impacts of nonpoint source (NPS) pollution and proposing sound control strategies are significant global challenges. However, few studies have provided insights into the quantitative risk analysis and efficient management of NPS pollution. This study formulated four evaluation criteria to characterize both the generation and migration of diffuse phosphorus. Multicriteria analysis and the technique for order preference by similarity to ideal solution were combined to develop a NPS pollution risk index model for the evaluation of the potential phosphorus loss at the basin scale. The proposed model is a simple and efficient tool that considers most factors that affect diffuse phosphorus. In the GIS environment, the spatial distribution of the risk index of diffuse phosphorus could be mapped and visualized in the Huai River Basin. With the natural breaks classification method, the study area was divided into the following five regions: a potentially polluted region (3.5%), a lightly polluted region (15.4%), a moderately polluted region (40.7%), a highly polluted region (31.5%), and a seriously polluted region (8.9%). Based on land use composition, geographical location, and sources of diffuse phosphorus of these five regions, corresponding prevention measures were introduced, thus facilitating the management of NPS pollution for policy makers.

Water quality trend assessment in Jakarta: A rapidly growing Asian megacity.

Megacities are facing serious water pollution problems due to urbanization, rapid population growth and economic development. Water is an essential resource for human activities and socio-economic development and water quality in urban settings has important implications for human and environmental health. Urbanization and lack of sewerage has left the water in Jakarta, Indonesia in a heavily polluted condition. Rigorous assessment of urban water quality is necessary to understand the factors controlling water quality conditions. We use trend analysis to assess the current water quality conditions in Jakarta, focusing on Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), and Total Suspended Solids (TSS). In most monitoring stations analyzed, BOD and TSS concentrations have decreased over time, but from large starting concentrations. DO in most monitoring stations has increased. Although Jakarta's water quality has shown some improvement, it remains heavily impaired. The average value of BOD is low in upper stream stations compared to middle and lower stream stations. BOD and TSS trends of some water quality stations in middle and lower streams show increasing trends. Cluster analysis results suggest three groups for BOD and TSS, and four groups for DO. Understanding water quality conditions and factors that control water quality suggest strategies for improving water quality given current trends in climate, population growth and urban development. Results from this study suggest research directions and management strategies to address water quality challenges.

Using the HPTLC-bioluminescence bacteria assay for the determination of acute toxicities in marine sediments and its eligibility as a monitoring assessment tool.

For an integrated ecological risk assessment of marine sediment contamination, the determination of target-compound concentrations by e.g. mass spectrometric methods is not sufficient to explain sediment toxicity. Due to the presence of a multitude of environmental contaminants in this complex matrix causing a mixed toxicity, the identification and assessment of main toxicants is a challenge. One approach in identifying main toxicants is the application of effect-directed analysis (EDA). In this study, an EDA approach was developed using high performance thin layer chromatography (HPTLC) coupled to bioluminescence bacteria detection with Aliivibrio fischeri for the determination of marine sediments acute toxicity. In a first attempt, the HPTLC separation was optimized with a fast, two-step gradient to separate main hydrophobic organic contaminant (HOC) classes found in marine sediments. An easy-to-use evaluation script for the resulting bioluminescence inhibition images was programed using R. The developed method was applied to sediment extracts of two different sample sets: (i) Fourteen marine sediment samples from the German Bight representing a wide range of contaminant loads and sediment properties and (ii) sediment samples from a core representing temporal trends of contamination. Results from the HPTLC-bioluminescence bacteria assay were compared to HOC concentrations determined by GC-MS/MS. A correlation of the determined inhibition Γ-values for the PAH inhibition zone to PAH concentrations showed a very good agreement (R2 = 0.91). The results of this study were used to evaluate the suitability of the EDA approach to be used as an assessment tool for marine sediments.

Heavy metal accumulation in surface sediments of the Ganga River (India): speciation, fractionation, toxicity, and risk assessment.

We investigated the distribution of different fractions of eight heavy metals (Zn, Cr, Cu, Pb, Cd, Ni, Fe, and Mn) in the bed sediment of the Ganga River. The study was conducted during summer low flow (March to June 2017) considering a 285-km middle stretch of the Ganga River between the Allahabad upstream and the Varanasi downstream. To assess the metal levels from a toxicological perspective, we tested the relationships between metals and sediment microbial/extracellular enzyme activities. Most of the metals showed a large fraction in residual form. However, Zn, Pb, and Cd showed about 20-30% share in the exchangeable form. The total metal concentration poorly reflected the toxicity but the exchangeable fractions did show strong negative correlations (r = - 0.83 to - 0.63; p < 0.01) with microbial/enzyme activities. Also, the nutrients and organic carbon showed strong positive correlations (r = 0.62 to 0.89; p < 0.001) with microbial/enzyme activity. The phosphate showed a strong negative correlation (r = -0.82; p < 0.001) with alkaline phosphatase. The principal component analysis (PCA) and the indices such as contamination factor (CF), enrichment factor (EF), pollution load index (PLI), geoaccumulation index (Igeo), and risk assessment code (RAC) revealed moderate to severe contamination with strong anthropogenic influence. As per the United States Environmental Protection Agency, the metal concentrations at many locations were in the highly toxic range. The study has relevance from a toxicological perspective and for the management of the Ganga River.

A dualistic water cycle system dynamic model for sustainable water resource management through progressive operational scenario analysis.

A reliable system simulation of the reciprocal mechanism between water resource utilization and dualistic water cycle is essential to the basin water resource sustainability management. In this study, a system dynamic model was built to simulate the water cycle change and lake water environmental pressure under the influence of water resources utilization, and the procedure of a progressive operational scenario analysis of how to relieve water environment pressure was illustrated. Dianchi Lake, which is the sixth largest and the most severely polluted freshwater lake in China, was employed as a case study to demonstrate the applicability of the model. The change of runoff components and pollution load of total nitrogen from 2000 to 2030 were discussed. Also, the sustainable water resource management was ultimately realized in the planning period through three progressive levels of water resource regulation scenarios. Compared with business-as-usual scenario, the TN pollution load into lake and total water demand decrease by 27.1 and 27.3%, and the domestic water use, industry water use, tertiary industry water use, and irrigation decrease 9.0, 16.8, 29.5, and 30% in the scenario 3.

The leakage of sewer systems and the impact on the 'black and odorous water bodies' and WWTPs in China.

China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to 'black and odorous water bodies'. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.

Distribution and pollution assessment of heavy metals in the intertidal zone environments of typical sea areas in China.

The heavy metals (Cu, Cr, Zn, Cd, Pb) were analysed for 217 surface sediment samples collected across 14 typical intertidal zone areas in China. The data reveals the heavy metals spatial distribution patterns and correlations among their concentrations. Cu, Zn, Cd and Cr showed similar trends of spatial variation and the correlations between the concentrations of every two heavy metals were significantly positive except for the correlation between Pb and Cr concentrations. By using Nemerow index method, Enrichment factor and Sediment Quality Guidelines, it is found that Hangzhou Bay and Jiulong River Estuary were polluted, Yingluo Bay and Dongzhaigang Bay were Cd-rich areas. Except Beidaihe shoal, Sishili Bay and Yingluo Bay that were not exposed to any ecological risk of heavy metals and had no adverse biotoxic effects, the other 11 typical intertidal zone areas were exposed to moderate ecological risk of heavy metals in the sediment with potential adverse biotoxic effects.

Prospective biomonitor and sentinel bivalve species for pollution monitoring and ecosystem health disturbance assessment in mangrove-lined Nicaraguan coasts.

This research aims at contributing to the use of Polymesoda arctata, Anadara tuberculosa, and Larkinia grandis as prospective biomonitors and sentinels, surrogate of Crassostrea rhizophorae for pollution biomonitoring in mangrove-lined coastal systems. Localities were selected along the Nicaraguan coastline in the rainy and dry seasons during 2012-2013: A. tuberculosa and L. grandis were collected in the Pacific, and P. arctata in the Caribbean. The tissue concentration of metals, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) were integrated into pollution indices (chemical pollution index -CPI- and pollution load index -PLI-) and biological endpoints (flesh-condition, reproduction, histopathology and stress-on-stress) were determined as biomarkers of ecosystem health disturbance. In the Caribbean, contaminant tissue concentration was low in P. arctata, with some exceptions. Ag, As, Cd, Hg, Ni and V were mainly recorded during dry season, and PAHs and POPs (HCHs, DDTs, AHTN, PCBs and BDE85) during rainy season. Metals and PAHs were not a major threat in the study area; in contrast, high levels of HCHs and DDTs and low-to-moderate levels of musk fragrances and PBDEs were recorded. Minor differences were found in biological parameters albeit during the rainy season the LT50 values were low and seemingly associated to high PLI and CPI values. In the Pacific, the main pollutants recorded in A. tuberculosa and L. grandis were HCHs, DDTs, AHTN and PDBEs in rainy season and Cd in dry season. Although basic research is needed to understand the general biology, ecology and diseases in these Pacific species, biological endpoints comparable to those used in other sentinel bivalves are seemingly suitable biomarkers of health disturbance. Overall, Caribbean P. arctata and Pacific A. tuberculosa and L. grandis seem to be potential target species for pollution monitoring and ecosystem health disturbance assessment in mangrove-lined Nicaraguan coastal systems. Their use together with C. rhizophorae would provide opportunities for common approaches to be applied in inter-ocean countries of the Mesoamerican region.

Per and polyfluoroalkyl substances (PFAS) blood levels after contamination of a community water supply and comparison with 2013-2014 NHANES.

INTRODUCTION: Per and polyfluoroalkyl substances (PFAS), including perfluorononanoic acid (PFNA) and perfluorooctanoic acid (PFOA), were detected in the community water supply of Paulsboro New Jersey in 2009. METHODS: A cross-sectional study enrolled 192 claimants from a class-action lawsuit, not affiliated with this study, who had been awarded a blood test for 13 PFAS. Study participants provided their blood test results and completed a survey about demographics; 105 participants also completed a health survey. Geometric means, 25th, 50th, 75th, and 95th percentiles of exposure of PFNA blood serum concentrations were compared to that of the 2013-2014 NHANES, adjusted for reporting level. Associations between PFNA, PFOA, PFOS, and PFHxS and self-reported health outcomes were assessed using logistic regression. RESULTS: PFNA serum levels were 285% higher in Paulsboro compared with U.S. residents. PFNA serum levels were higher among older compared with younger, and male compared to female, Paulsboro residents. After adjustment for potential confounding, there was a significant association between increased serum PFNA levels and self-reported high cholesterol (OR: 1.15, 95% CI: 1.02, 1.29). DISCUSSION/CONCLUSION: Further investigation into possible health effects of PFAS exposure in Paulsboro and other community settings is warranted. Since exposure has ceased, toxicokinetics of PFAS elimination should be explored.

Distribution and potential ecological risk assessment of trace elements in the stream water and sediments from Lanmuchang area, southwest Guizhou, China.

Trace elements contamination in sediment is regarded as the global crisis with a large share in developing countries like China. Water and sediment samples were collected during (2016) from Qingshui Stream and analyzed for major physicochemical properties and trace elements by using ICP-MS. Our result of sediments showed that studied trace elements (except Pb, Cd, Co) had a concentration higher than Chinese sediment guideline as well as stream water data for studied trace elements (except Cr, Pb, Cd, Cu, and Zn) had a higher concentration than the maximum permissible safe limit of WHO. Contamination factor (CF) confirmed a moderate to high contamination in the sediment samples due to As and Tl, respectively. The values of pollution load index (PLI) were found above one (> 1), describing the progressive sediment quality decline. Pearson correlation showed that there was a significant positive association between Tl and As (r = 0.725, p < 0.05) in sediment samples. Results revealed that water-rock interaction, weathering of Tl sulfide mineralization, and hydrogeological conditions were major sources of stream water and sediments contamination in the study area. This experimental study contributes to a better understanding of the geochemistry and prevention of trace element contamination in sediments from Lanmuchang area.

From banana fields to the deep blue: Assessment of chlordecone contamination of oceanic cetaceans in the eastern Caribbean.

In the French West Indies (Caribbean), the insecticide Chlordecone (CLD) has been extensively used to reduce banana weevil (Cosmopolites sordidus) infestations in banana plantations. Previous studies have shown high CLD concentrations in freshwater and coastal communities of the region. CLD concentrations, however, have not yet been assessed in marine top predators. We investigated CLD concentrations in cetacean blubber tissues from Guadeloupe, including Physeter macrocephalus, Lagenodelphis hosei, Stenella attenuata and Pseudorca crassidens. Chlordecone was detected in all blubber samples analysed, with the exception of four P. macrocephalus. Concentrations (range: 1 to 329 ng·g-1 of lipid weight) were, however, lower than those found in species from fresh and brackish water. Ecological factors (open ocean habitat), CLD kinetics, and cetacean metabolism (high or specific enzymatic activity) might explain low concentrations found in cetacean blubber. Future analyses that include internal organ sampling would help to confirm CLD levels observed in this study.

Naturalizing pollution: a critical social science view on the link between potash mining and salinization in the Llobregat river basin, northeast Spain.

The scientific literature distinguishes between primary or natural and secondary or human-induced salinization. Assessing this distinction is of vital importance to assign liabilities and responsibilities in pollution cases and for designing the best policy and management actions. In this context, actors interested in downplaying the role of certain drivers of human-induced salinization can attempt to neglect its importance by referring to natural salinization, in a similar fashion to other pollution and health-related cases, from tobacco smoke to climate change. Potash mining, which has experienced continued growth during the last decades and is a significant contributor to salinization, is prone to originate such controversies because natural salinization from the saline geological catch can be mixed with salinization produced by mining waste such as brines and mine tailings, thus obscuring the distinction between causes. By reviewing the long-standing social and environmental conflict caused by potash mining in a region of Mediterranean climate-the Llobregat river basin-in this article, we highlight the importance of the impacts of salinization on human health and provide a critical social science perspective on salinization processes.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.