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Abstract Many toxic and/or noxious cyanobacteria appear in nature with a filamentous, stacked cell arrangement called trichomes. Although water treatment can be optimized to keep cyanobacterial cells intact and avoid the release of toxic and/or noxious compounds, many physical and chemical stresses encountered during the treatment process may result in trichome truncation, decreasing treatment efficiency by allowing single cells or short trichomes to reach the product water. This makes it possible for harmful/noxious compounds as well as organic matter to enter the distribution system. Investigations in a pilot and three full-scale water treatment plants were carried out in order to elucidate the degree of trichome truncation across different unit processes. It was found that genera (Pseudanabaena , Planktolyngbya) with short trichomes (<10–12 cells per trichome), are hardly affected by the unit processes (loss of one to four cells respectively), while genera (Planktothrix , Geitlerinema , Dolichospermum) with longer trichomes (30+ cells per trichome) suffer from high degrees of truncation (up to 63, 30, and 56 cells per trichome respectively). The presence of a rigid sheath and/or mucilaginous layer appears to offer some protection from truncation. It was observed that certain unit processes alter the sensitivity or resilience of trichomes to disruption by physical stress. Some genera (Planktothrix , Geitlerinema) were sensitive to pre-oxidation making them more susceptible to shear stress, while Dolichospermum sp. appears more robust after pre-oxidation. While the potential of toxicogenic genera breaking through into the product water is a real danger, in the current study no toxicogenic cyanobacteria were observed. This work stresses the need for plant operators to study the incoming cyanobacterial composition in the raw water in order to adjust treatment parameters and thus limit the potential of toxic/noxious compound breakthrough. Graphical abstract Unlabelled Image Highlights • Pilot and full-scale treatment plant water samples were examined under a microscope to evaluate trichome integrity; • Treatment train breaks cyanobacterial trichomes leading to smaller trichomes and single cells; • Morphological factors affect trichome truncation resulting in single cells in product water; • Filtration step was the most damaging unit process for most cyanobacterial genera; • Trichome integrity should be considered when designing and operating treatment processes. [ABSTRACT FROM AUTHOR]

Abstract In this study, 20 groundwater samples and 7 surface water samples were collected and analyzed by HRGC-HRMS to evaluate the levels, congener distributions, and dissolved/solid partitioning of polybrominated diphenyl ethers (PBDEs) in water matrix as well as the removal efficiency of a typical water treatment plant (WTP). The results indicated that the level of PBDEs concentrations ranging from 18.51 to 4212 pg/L and 30.24 to 1021 pg/L were found in groundwater and surface water, respectively. BDE-209 predominated and contributed over 90% of total PBDEs concentrations for all samples analyzed. In addition, the dissolved/solid distribution indicated that 60–80% of PBDEs were measured in solid phase. 97% of total PBDEs was removed in a WTP. Positive matrix factorization (PMF) analysis was conducted for groundwater samples and the results indicated that 3% and 41% of PBDEs were attributed to octa and deca-BDEs commercial mixtures, respectively, while 56% resulted from anaerobic microorganism debromination process. Understanding the PBDEs occurrences, distribution and debromination process as well as their removal efficiency of water treatment plant could provide valuable information on the fate of those compounds in environment. Graphical abstract Unlabelled Image Highlights • PBDEs levels measured in some groundwater samples reflected significant contamination. • PBDEs predominated in solid phase in groundwater and surface water. • Deca-BDE (BDE-209) was predominant congener. • PBDEs levels in surface water were higher in wintertime compared with summertime. • Sources and possible debromination of PBDEs in groundwater were identified. [ABSTRACT FROM AUTHOR]

The presence of Enterobacteriaceae producing extended spectrum beta-lactamases (ESBL) or transferable AmpC beta-lactamases (pAmpC) is increasingly being reported in humans, food-producing animals and food world-wide. However, the occurrence and impact of these so-called extended spectrum cephalosporinase (ESC)-producing Enterobacteriaceae in aquatic environments are poorly documented. This study investigated the occurrence, concentrations and characteristics of ESC-producing E. coli (ESC-Ec) in samples of surface water collected at five Swedish water treatment plants that normally have relatively high prevalence and concentration of E. coli in surface water. ESC-Ec was found in 27 of 98 surface water samples analysed. All but two positive samples were collected at two of the water treatment plants studied. The ESC-Ec concentration, 1–3 cfu/100 mL, represented approximately 4% of the total amount of E. coli in the respective surface water sample. In total, 74% of the isolates were multi-resistant, but no isolate was resistant to carbapenems. Six types of ESBL/pAmpC genes were found in the 27 E. coli isolates obtained from the positive samples, of which four ( bla CTX-M-15 , bla CMY-2 , bla CTX-M-1 and bla CTX-M-14 ) were found during the whole sampling period, in samples taken at more than one water treatment plant. In addition, the genes were situated on various types of plasmids and most E. coli isolates were not closely related with regard to MLST types. The combinations of ESBL/pAmpC genes, plasmids and E. coli isolates were generally similar to those found previously in healthy and sick individuals in Sweden. In conclusion, the occurrence of ESC-Ec in Swedish surface water shows that resistant bacteria of clinical concern are present in aquatic environments even in a low-prevalence country such as Sweden. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the emergy-based evaluation (EME) of the ecological performance of four water treatment plants (WTPs) using three different approaches. The results obtained using the emergy calculation software SCALE (EMESCALE) are compared with those achieved through a conventional emergy evaluation procedure (EMECONV), as well as through the application of the Solar Energy Demand (SED) method. SCALE's results are based on a detailed representation of the chain of technological processes provided by the lifecycle inventory database ecoinvent®. They benefit from a higher level of details in the description of the technological network as compared to the ones calculated with a conventional EME and, unlike the SED results, are computed according to the emergy algebra rules. The analysis delves into the quantitative comparison of unit emergy values (UEVs) for individual technospheric inputs provided by each method, demonstrating the added value of SCALE to enhance reproducibility, accurateness and completeness of an EME. However, SCALE cannot presently include non-technospheric inputs in emergy accounting, like e.g. human labor and ecosystem services. Moreover, SCALE is limited by the approach used to build the dataset of UEVs for natural resources. Recommendations on the scope and accuracy of SCALE-based emergy accounting are suggested for further steps in software development, as well as preliminary quantitative methods to account for ecosystem services and human labor. [Copyright &y& Elsevier]

Disinfection By-products (DBPs) are formed during the chemical treatment of water for human consumption, by the reaction of raw water with chemical agents used in the different steps of the process. Disinfection is one of the most important steps, inactivating pathogens and preventing their regrowth during water distribution. However, it is also involved in DBPs formation due to the use of disinfectant agents, such as chlorine, which reacts with dissolved precursors, such as pharmaceuticals, toxins, pesticides, among others. Given their widespread occurrence, potential human health and (eco) toxicological impacts are of particular interest due to their potential carcinogenicity and various non-carcinogenic effects, such as endocrine disruption. In this study, the developmental toxicity of chemically- different unregulated DBPs was evaluated using zebrafish embryo bioassay. Embryos were exposed to different concentrations of the target DBPs and multiple endpoints, including, mortality, morphological abnormalities and locomotor behavior were assessed at specific developmental stages (24, 48, 72 and 96 hpf). The different families of DBPs tested included nitrosamines, aldehydes, alcohols and ketones. The results show that the effects were compound dependent, with EC10 values varying between 0.04 mg/L (2-ethyl-1-hexanal) to 9.2 mg/L (hexachloroacetone). Globally, several of the tested unregulated DBPs displayed higher toxicity when compared with the available data for some already regulated, such as trihalomethanes (THMs), which highlights the importance of screening the toxicity of still untested and poorly characterized DBPs. Unlabelled Image • Disinfection By-products (DBPs) in water for human consumption • Toxicity testing of unregulated DBPs using zebrafish embryo bioassay • Unregulated DBPs tested included nitrosamines, aldehydes, alcohols and ketones. • Several of the tested unregulated DBPs displayed higher toxicity then regulated. [ABSTRACT FROM AUTHOR]