Once one of the largest saline lakes, the Aral Sea, was recognized as a significant environmental disaster as the water level decreased dramatically. Water level decrease increases water salinity, affecting biodiversity. Exposed lake beds become the source for fine dust picked up by the dust storms and spread across a long distance, affecting people’s health in surrounding areas. This review paper attempts to evaluate the potential links between the Aral Sea shrinking and the existing health issues in the case of Kazakhstan. The literature-based research revealed that the population of the Aral Sea basin region has been suffering from exposure to various pollutant residues for a long time. There is an apparent increase in morbidity and mortality rates in the region, especially in people suffering from chronic illness. Furthermore, the catastrophic desiccation of the Aral Sea has led to the sharp deterioration in living conditions and negative trends in the socio-economic situation of the region’s population. While the dust storms spread the polluted salts from the exposed bottom across the Aral Sea region, specific contaminants define the relevance and importance of public health problems linked to the basin rather than the Aral Sea drying process. There is, however, no clear evidence that associated dust storms are the only primary source of the deterioration of people’s health. Moreover, One Health approach seems to play a crucial role in achieving better outcomes in the health of people and the health of the environment.

While slow sand filters (SSFs) have produced drinking water for more than a hundred years, understanding of their associated microbial communities is limited. In this study, bacteria in influent and effluent water from full-scale SSFs were explored using flow cytometry (FCM) with cytometric histogram image comparison (CHIC) analysis; and routine microbial counts for heterotrophs, total coliforms and Escherichia coli. To assess if FCM can monitor biofilm function, SSFs differing in age and sand composition were compared. FCM profiles from two established filters were indistinguishable. To examine biofilm in the deep sand bed, SSFs were monitored during a scraping event, when the top layer of sand and the schmutzdecke are removed to restore flow through the filter. The performance of an established SSF was stable: total organic carbon (TOC), pH, numbers of heterotrophs, coliforms, E. coli, and FCM bacterial profile were unaffected by scraping. However, the performance of two newly-built SSFs containing new and mixed sand was compromised: breakthrough of both microbial indicators and TOC occurred following scraping. The compromised performance of the new SSFs was reflected in distinct effluent bacterial communities; and, the presence of microbial indicators correlated to influent bacterial communities. This demonstrated that FCM can monitor SSF performance. Removal of the top layer of sand did not alter the effluent water from the established SSF, but did affect that of the SSFs containing new sand. This suggests that the impact of the surface biofilm on effluent water is greater when the deep sand bed biofilm is not established.

Contamination of the water and sediment with per- and polyfluoroalkyl substances (PFAS) was studied for the lake impacted by the release of PFAS-containing aqueous film forming foam (AFFF). PFAS concentrations were analyzed in lake water and sediment core samples. ΣPFAS concentrations were in the range of 95–100 ng L⁻¹ in the lake water and 3.0–61 µg kg⁻¹ dry weight (dw) in sediment core samples, both dominated by perfluorohexane sulfonate, perfluorooctane sulfonate; 6:2 fluortelomer sulfonate was inconsistently present in water and sediment core samples. The sediment–water partitioning coefficients (log K_d) were estimated and ranged 0.6–2.3 L kg⁻¹ for individual perfluoroalkyl carboxylates (PFCAs) and 0.9–5.6 L kg⁻¹ for individual perfluoroalkane sulfonates (PFSAs). The influence of the sediment inorganic content and organic matter on PFAS distribution was investigated. In studied sediments, the mineral content (corresponding to <5% of the bulk media mass) was mainly represented by sulfur, iron and calcium. The PFAS distribution was found strongly connected to the sediment mineral content (i.e., Fe, Pb, Rb and As), whereas the sediment organic carbon content did not to have a direct influence on the PFAS distribution. The aim of this study was to improve our understanding of the PFAS distribution in the natural heterogeneous media.

Groundwater contamination caused by the use of the aqueous film-forming foam (AFFF) containing per- and polyfluoroalkyl substances (PFAS) was investigated in southern Sweden. ΣPFAS concentrations in groundwater ranged between 20 and 20,000 ng L⁻¹; PFAS composition was primarily represented by PFOS and PFHxS. The PFAS chain length was suggested to have an impact on the contaminant distribution and transport in the groundwater. PFAS profiling showed that the use of PFSAs- and PFCAs/FTSAs-based PFAS-AFFF can be a contributor to PFAS contamination of the drinking water source (groundwater). PFAS emission was connected to PFAS-AFFF use during the fire-training and fire-fighting equipment tests at the studied location. PFAS emission per individual fire training was (semi-quantitatively) estimated as [1.4 < 11.5 ± 5.7 < 43.7 kg] (n = 20,000). The annual emission estimates varied as [11 < 401 ± 233 < 1125 kg yr⁻¹] (n = 1005) considering possible [2 < 35 ± 20 < 96] individual fire-training sessions per year.

Control of nutrients, mainly nitrogen (N) and phosphorus (P), plays a significant role in preventing cyanobacterial blooms (harmful algal blooms (HABs)). This study aims at evaluating changes in the risk of the occurrence of cyanobacterial blooms and advancing the understanding of how nitrogen and phosphorus affect the growth of cyanobacteria in a eutrophic lake, Lake Vombsjön, in southern Sweden. Our results show that TP (total phosphorus) has stronger positive correlation with cyanobacteria biomass than DIP (dissolved inorganic phosphorus); DIN (dissolved inorganic nitrogen) has a stronger negative correlation with cyanobacteria biomass than TN (total nitrogen); and DIN:TP has a stronger negative correlation with cyanobacteria biomass than TN:TP. The highest amount of cyanobacteria biomass, above WHO (World Health Organization) Alert Level 2 (10 mm³/L) for drinking water correspond to the DIP/TP ratio below 10. To diminish the growth of cyanobacteria in Lake Vombsjön, TP and DIN control should be in focus, preferably a TP below 20 µg/L, and the DIN:TP ratio should be maintained at a level of at least above 10, but preferably above 50, thereby reducing the likelihood for a nitrogen limiting situation which may favor cyanobacteria dominating blooms.