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Location-specific patterns of regulated and non-regulated disinfection byproducts (DBPs) were detected in tap water samples of the Barcelona Metropolitan Area. However, it remains unclear if the detected DBPs together with undetected DPBs and organic micropollutants can lead to mixture effects in drinking water.

A wide range of chemicals was measured in different types of drinking water and urine samples through target and non-target screening (NTS) to estimate human exposure. Tap water samples collected from 42 locations in Barcelona (August–October/2020, May/2021), tap water filtered with domestic activated carbon filters (AC, N = 6) and reverse osmosis (RO, N = 5), commercial bottled water (N = 10), and urine (N = 39) samples were included. 35 per- and polyfluoroalkyl substances (PFAS), bisphenol A, and nonylphenol were analyzed using LC–MS/MS and GC–MS/MS, and NTS using LC–HRMS. 9 PFAS were detected in unfiltered tap water of first sampling (79% samples, median = 30 ng/L), 6 in the second (69%, median = 9.8 ng/L), and 5 in 13% urine samples. NTS tentatively identified pharmaceuticals and other industrial chemicals in drinking water. PFAS were removed by RO and not by AC filters. Findings provide valuable information for exposure science and water quality monitoring of emerging drinking water contaminants.

Dissolved organic matter (DOM) remineralization is limited to a greater or lesser degree at different layers in the ocean. In order to investigate the key abiotic and biotic factors that may enhance DOC remineralization in the deep ocean, we studied the changes in function and structure of deep prokaryotic communities after additions of the same amount of dissolved organic compounds with different quality. We performed experiments with deep sea prokaryotic assemblages subjected to four different treatments: CL (addition of labile DOC), CM (addition of a mix of organic compounds with different lability) and CR (addition of recalcitrant humic acids) and K (control). Prokaryotic biomass markedly increased when the labile compounds or the diverse chemical mixture were added (CL and CM treatments), whereas the prokaryotic response was lower under either the control K or CR treatments. Accordingly, we found lower activity and similar patterns of extracellular enzymatic activities in CR and K compared to CL and CM treatments. In all treatments a decrease in prokaryotic richness consistently occurred along the incubations, but interestingly, the decrease was lower in the control and in the CR treatments. Our results indicate that the chemical diversity of organic matter is a key factor determining microbial structure and activity in the deep ocean

Microbial biofilms communities in mineral waters and hot springs have a particular composition with species belonging to different groups such as epsilonproteobacteria and gammaproteobacteria or different siderobacteria and other chymoautrophic organisms, in addition to certain bacillaryophytes, chlorophytes and especially cyanobacteria. Balneotherapy can cause adverse reactions to the usual doses of application of treatments, that consists of a non-specific clinical picture, the so-called "thermal crisis” or “balneointoxication". Despite its clinical similarity (gastric discomfort, hepatic congestive outbreaks, cutaneous reactions, etc.) with that observed in acute cyanotoxin poisonings, thermal crisis has never been associated with the abundant growth of potentially toxic cyanobacteria in the mineral water sources. The aim of this work was to verify the hypothetical involvement of cyanotoxins in this clinical picture. Samples from mostly sulphurous water sources, with thermal characteristics ranging from cold to hyperthermal waters were analysed. ELISA (both in solution and in cellular matrix samples), LC-ESI-HRMS (in cellular matrix samples), and analysis of potential toxicity by means of a standardized bioassay were carried out. The toxic effect observed in the toxicity bioassays in one third of the sources may be related to the existence of microcystins and nodularins and even with other cyanobacterial peptides detected. In addition, several responses observed in the toxicity analyses reflect a pattern, probably linked to a type of hormetic response (hormesis is an adaptive response to low levels of stress, characterized by a biphasic dose-response curve)

Knowledge about human exposure and health effects associated with non-routinely monitored disinfection by-products (DBPs) in drinking water is sparse.

Microbial biofilms communities in mineral waters and hot springs have a particular composition with species belonging to different groups such as epsilonproteobacteria and gammaproteobacteria or different siderobacteria and other chymoautrophic organisms, in addition to certain bacillaryophytes, chlorophytes and especially cyanobacteria. Balneotherapy can cause adverse reactions to the usual doses of application of treatments, that consists of a non-specific clinical picture, the so-called "thermal crisis” or “balneointoxication". Despite its clinical similarity (gastric discomfort, hepatic congestive outbreaks, cutaneous reactions, etc.) with that observed in acute cyanotoxin poisonings, thermal crisis has never been associated with the abundant growth of potentially toxic cyanobacteria in the mineral water sources. The aim of this work was to verify the hypothetical involvement of cyanotoxins in this clinical picture. Samples from mostly sulphurous water sources, with thermal characteristics ranging from cold to hyperthermal waters were analysed. ELISA (both in solution and in cellular matrix samples), LC-ESI-HRMS (in cellular matrix samples), and analysis of potential toxicity by means of a standardized bioassay were carried out. The toxic effect observed in the toxicity bioassays in one third of the sources may be related to the existence of microcystins and nodularins and even with other cyanobacterial peptides detected. In addition, several responses observed in the toxicity analyses reflect a pattern, probably linked to a type of hormetic response (hormesis is an adaptive response to low levels of stress, characterized by a biphasic dose-response curve).

Ciguatera Poisoning (CP) is caused by consumption of fish or invertebrates contaminated with ciguatoxins (CTXs). Presently CP is a public concern in some temperate regions, such as Macaronesia (North-Eastern Atlantic Ocean). Toxicity analysis was performed to characterize the fish species that can accumulate CTXs and improve understanding of the ciguatera risk in this area. For that, seventeen fish specimens comprising nine species were captured from coastal waters inMadeira and Selvagens Archipelagos. Toxicity was analysed by screening CTX-like toxicity with the neuroblastoma cell-based assay (neuro-2a CBA). Afterwards, the four most toxic samples were analysed with liquid chromatography-high resolution mass spectrometry (LC-HRMS). Thirteen fish specimens presented CTX-like toxicity in their liver, but only four of these in their muscle. The liver of one specimen of Muraena augusti presented the highest CTX-like toxicity (0.270 ± 0.121 µg of CTX1B equiv·kg-1). Moreover, CTX analogues were detected with LC-HRMS, for M. augusti and Gymnothorax unicolor. The presence of three CTX analogues was identified: C-CTX1, which had been previously described in the area; dihydro-CTX2, which is reported in the area for the first time; a putative new CTX m/z 1127.6023 ([M+NH4]+) named as putative C-CTX-1109, and gambieric acid A.