Understanding the bioaccumulation of pharmaceutical active compounds by clams Ruditapes decussatus exposed to a UWWTP discharge.

Twenty-four pharmaceutical active compounds (PhACs) were evaluated in the soft tissues of clams Ruditappes decussatus exposed along a 1.5-km dispersal gradient of the treated effluent from an urban wastewater treatment plant discharging in Ria Formosa, and compared with those in the marine waters and discharged effluents. The clams were exposed for 1 month, in June-July 2016, 2017 and 2018. PhACs were quantified by high performance liquid chromatography coupled to tandem mass spectrometry after the quick, easy, cheap, effective, rugged and safe (QuEChERS) method (clams) or solid-phase extraction (water samples). The most representative PhACs in the effluents and receiving waters (regardless of the tidal dilution effect) were diclofenac, carbamazepine and caffeine (on average ≤ 2 µg/L) and only caffeine exhibited significant inter-annual differences, with higher values in 2017. In turn, the most bioaccumulated PhACs in clams were caffeine (0.54-27 ng/g wet weight, significantly higher in 2016) and acetaminophen (0.37-3.7 ng/g wet weight, significant lower in 2016). A multivariate principal component analysis showed (i) PhAC bioaccumulation primarily depended on biotic factors (clams length and weight), (ii) PhAC physicochemical properties Log Kow, pKa and water solubility interplaying with water abiotic variables were more relevant for explaining data variability in water than the physical dilution/tidal mixing, (iii) this process, reflected by the salinity gradient, had a tertiary role in data variation, responsible for spatial discrimination of marine waters. This study provides a better understanding of PhACs bioaccumulation by clams Ruditapes decussatus in real environmental conditions, under the influence of urban treated effluent dispersal in Ria Formosa coastal lagoon, a major producer of bivalves, ultimately disentangling key factors of PhAC bioaccumulation.

Screening and Seasonal Behavior of Analgesics, Non-steroidal Anti-inflammatory Drugs, and Antibiotics in Two Urban Wastewater Treatment Plants.

Pharmaceutical active compounds (PhACs) belonging to analgesics, antibiotics, and non-steroidal anti-inflammatory drugs (NSAIDs) therapeutic classes were monitored in wastewater influents and effluents from two Portuguese urban wastewater treatment plants (UWWTPs) for 24 months. Both facilities were chosen due to their effluents are discharged in highly touristic and sensitive areas, Tagus river and Ria Formosa coastal lagoon, respectively. Target PhACs, acetaminophen, diclofenac, ibuprofen, naproxen, sulfadiazine, and sulfamethoxazole were measured using solid-phase extraction (SPE) coupled to liquid chromatography tandem mass spectrometry (LC-MS/MS). PhACs occurrence in the influents was higher than 98%, with acetaminophen presenting the highest concentrations, with values between 16.3 µg/L and 124 µg/L. In the effluents, distinct behavior was observed with diclofenac and sulfamethoxazole showing recalcitrant characteristics, whereas acetaminophen, ibuprofen, and naproxen showed removal efficiencies above 95%. Acetaminophen and ibuprofen amount in influents showed consistently higher concentration levels in autumn (in Beirolas and Faro Nw UWWTPs) and winter (only in Beirolas UWWTP) seasons. These seasonal trends were observed to a greater extent in Beirolas UWWTP than in Faro Nw UWWTP. This study enabled the comprehensive definition of a behavior pattern for these target contaminants, contributing to better characterization and build-up a library of PhACs occurrence. It also allowed a robust seasonal profiling of the target compounds due to the high number of samples analyzed by each season and a longer monitoring campaign, making the obtained results more significant.

Bromate removal by anaerobic bacterial community: mechanism and phylogenetic characterization.

A highly bromate resistant bacterial community and with ability for bromate removal was obtained from a sulphate-reducing bacteria enrichment consortium. This community was able to remove 96% of bromate and 99% of sulphate from an aqueous solution containing 40 µM bromate and 10 mM sulphate. Moreover, 93% of bromate was removed in the absence of sulphate. Under this condition bromate was reduced stoichiometrically to bromide. However, in the presence of sulphate only 88% of bromate was reduced to bromide. Although, bromate removal was not affected by the absence of sulphate, this anion promoted a modification on the structure of the bacterial community. Phylogenetic analysis of 16S rRNA gene showed that the community grown in the presence of bromate and sulphate was mainly composed by bacteria closely to Clostridium and Citrobacter genera, while the community grown in the absence of sulphate was predominantly composed by Clostridium genus. It is the first time that Clostridium and Citrobacter genera are reported as having bromate removal ability. Furthermore, bromate removal by the consortium predominantly composed by Clostridium and Citrobacter genera occurred by enzymatic reduction and by extracellular metabolic products, while the enzymatic process was the only mechanism involved in bromate removal by the consortium mainly composed by Clostridium genus.