The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this transnational study, we developed, validated, and tested a low-cost surveillance and easy to implement approach to evaluate antibiotic resistance in wastewater treatment plants (WWTPs) by targeting cefotaxime-resistant (CTX-R) coliforms as indicators. The rationale for this approach was: i) coliform quantification methods are internationally accepted as indicators of fecal contamination in recreational waters and are therefore routinely applied in analytical labs; ii) CTX-R coliforms are clinically relevant, associated with extended-spectrum β-lactamases (ESBLs), and are rare in pristine environments. We analyzed 57 WWTPs in 22 countries across Europe, Asia, Africa, Australia, and North America. CTX-R coliforms were ubiquitous in raw sewage and their relative abundance varied significantly (<0.1% to 38.3%), being positively correlated (p < 0.001) with regional atmospheric temperatures. Although most WWTPs removed large proportions of CTX-R coliforms, loads over 103 colony-forming units per mL were occasionally observed in final effluents. We demonstrate that CTX-R coliform monitoring is a feasible and affordable approach to assess wastewater antibiotic resistance status.

Chemical pollution poses a threat to the aquatic environment and to human health. Wastewater treatment plants are the last defensive line between the aquatic environment and emissions of pollutants. This study focuses on identification of most relevant hazardous substances in Estonian municipal wastewater and their fate in the treatment process. During this study, seasonal wastewater and sewage sludge samples were collected from nine municipal wastewater treatment plants and analyzed for 282 hazardous substances, including EU (n = 45) and Estonian (n = 31) priority substances. Results of this study show that several substances that are subject to international restrictions (e.g. Stockholm Convention) are still present in untreated sewage. Wastewater treatment systems that had a greater level of complexity (TEC >5) were more successful in removing hazardous substances. Statistical analyses showed that removal efficiency of organic hazardous substances had significant (p-value <0.05) linear correlation with removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS), but a monotonic relationship with operators' competency. This study showed that operators' competency had a strong influence on the stability of the wastewater treatment efficiency and removal of organic hazardous substances.

Internationally agreed long-term monitoring indicators do not consider the risks of new synthetic substances

POCIS passive samplers were deployed at differently polluted marine sites in the cities of Helsinki and Tallinn and in an open part of the Gulf of Finland. The aim was to determine baseline concentration levels for pharmaceuticals in water monitored with passive sampling techniques, which could also be applied to regulatory monitoring. That baseline concentration data method could then be applied to other sites in the Tallinn and Helsinki area to assess whether the pharmaceutical concentration is elevated or at the baseline level. Altogether, 150 pharmaceuticals were analysed from passive and grab water samples, and 30 substances were discovered. The number of pharmaceuticals detected in passive samplers (27) was higher than in grab samples (20). However, the study revealed the presence of several pharmaceuticals even from expected background sites, such as the open sea site in Gulf of Finland, implying their ubiquitous presence in the study area. The passive sampling results have been converted to TWAC with sampling rate, which is characteristic of the sampler type and studied compound. We assessed the suitability and differences of sampling rates collected from the literature, calculated from LogK _OW values and estimated from field deployment results. The selection of sampling rate is essential, as it can cause 86 to 99% differences in determined TWACs. The TWAC was compared with PNEC was calculated to evaluate the potential environmental risk. There are still open questions regarding how to reconcile the passive sampling results with regulatory monitoring obligations based on grab water sampling and existing limit concentrations.