Dosing the Coast: Leaking Sewage Infrastructure Delivers Large Annual Doses and Dynamic Mixtures of Pharmaceuticals to Urban Rivers

Assessing water quality in the impounded Guana Estuary: A baseline with implications for future management

Assessing water quality is an important undertaking in environmental management, particularly along coasts where human development is concentrated. This study assessed waters of the Guana Estuary, an impounded estuary in Northeast Florida with an urbanized watershed. Discrete monthly samples collected from 2017 to 2023 were analyzed for chlorophyll a, nitrogen species, total phosphorus, fecal indicator bacteria (Enterococcus), and other parameters. Results indicated elevated nutrients and chlorophyll a throughout the entire estuary, but more so in the upper-middle portions. A spatial separation of nutrient sources and peak concentrations suggests that internal processes like sediment recycling and vegetation growth/senescence are important drivers of nutrient availability. A flood control project in the headwaters also introduced a pulse of nutrients and algae to the system. This baseline assessment will inform management strategies to restore water quality in this high value system, and the overall approach can serve as a model for other place-based studies.

Ecotoxicological implications of increased antidepressant concentrations in the Laurentian Great Lakes Basin, 2018-2023

Antidepressants are only partially metabolized and then eliminated in urine and feces. Since waste water treatment plants are not designed to remove pharmaceuticals, antidepressants and their metabolites eventually reach the environment. Antidepressants are among the most prescribed drugs in the world, and their prescription rates increased dramatically following the onset of the COVID-19 pandemic. Our aim was to compare their measured environmental concentrations (MECs) in surface water in the three years before and the three years after the pandemic onset. Nearly 1300 samples were collected from 67 sites in the Laurentian Great Lakes Basin, from streams and rivers. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology to measure the MECs of 7 of the most frequently used antidepressants and 3 of their metabolites. Canadian antidepressant use data was also collected via the IQVIA MIDAS® database of estimated sales data for pharmaceutical drugs (2018-2021). We found that the median MECs for 9 of the 10 substances increased between 1.5- and 7.2-fold (p < 0.05). The greatest median increases corresponded to fluvoxamine (4.8-fold) and 10-hydroxyamitriptyline (4.7-fold). Increases were concurrent with rising use rates post-COVID-onset. The highest concentrations corresponded to the metabolite O-desmethylvenlafaxine (3113.98 ng L-1) and its parent drug venlafaxine (699.59 ng L-1) in 2022. We collected and analyzed antidepressant surface water and ecotoxicological data to provide a comprehensive review to contextualize the LC-MS/MS data. We compared maximal MECs to ecotoxicological reference values and theorize a possible ecotoxicological impact when considering the overlap of maximal levels with ecotoxicological reference values cited in the scientific literature. We offer recommendations for next steps.

Identification of spatiotemporal behavior of organic micropollutants in an agricultural and urban lowland river catchment

Mixed land-use, medium-sized lowland rivers are subject to contamination by various input pathways for organic micropollutants. This study provides a unique long-term (2016-2020) and high-resolution investigation of the Münstersche Aa River (Northwestern Germany) focusing on the thorough characterization of input pathways for pesticides, biocides and pharmaceuticals in the catchment with heterogeneous land-use (62 % agricultural and 26 % urbanized). 468 samples were collected using two automated high-frequency samplers and five catchment-wide sampling campaigns providing a comprehensive data set. While the input of pesticides is the major stressor in the agriculturally dominated upper catchment, input of treated wastewater is dominating the water chemistry of the lower catchment, especially during summer low flows (up to 100 % wastewater fraction). Detected pharmaceuticals in the catchment include carbamazepine, diclofenac, metoprolol, phenazone and sulfamethoxazole. Moreover, caffeine as an indicator substance suggests input through non-conventionally treated wastewater. The pesticides chlortoluron (winter) as well as terbuthylazine and 2-methyl-4-chlorophenoxyacetic acid (MCPA) (summer), occur related to their respective application time. Moreover, a belated, accumulated input of terbuthylazine was observed in winter 2019/2020 after an extremely dry period from 2018 to 2019. Urban runoff adds further pesticides such as mecoprop-P while tebuconazole input from both agricultural and urban land-use was identified. Even though detected concentrations are below thresholds for acute toxicity, mixture toxicity could pose risks in the Münstersche Aa. Ongoing climate change is expected to intensify these seasonal patterns in the catchment. Lake Aasee may however function as a sink for OMPs through degradation processes especially during low-flow conditions. This study enhances the understanding of river pollution dynamics in small, mixed land-use catchments and aids targeting the goals of the Water Framework Directive for the Münstersche Aa and other lowland streams with comparable land use.

Assessing microplastics, per- and polyfluoroalkyl substances (PFAS), and other contaminants of global concern in wadable agricultural streams in Iowa

Microplastics, per- and polyfluoroalkyl substances (PFAS), antibiotic resistance genes (ARGs), pharmaceuticals and personal care products (PPCPs), and pesticides may lead to unintended environmental contamination through many pathways in multiple matrices. This statewide, multi-matrix study of contaminants of global concern (CGCs) in agricultural streams across Iowa (United States) is the first to examine multiple CGCs in water, bed sediment, and fish to understand their occurrence in small streams located in regions of intense agriculture activity. Iowa plays a pivotal role in agriculture, with more than 85% of Iowa's landscape devoted to agriculture, making it an ideal location for determining the prevalence of CGCs to provide critical baseline exposure data. Fifteen sites were sampled across a range of predominant land uses (e.g., poultry, swine); all sites had detections of microplastics in all matrices. Concentrations of PFAS varied but were detected in water and sediment; all fish had detections of perfluorooctanesulfonate (PFOS), a type of PFAS. More than 50% of water and bed sediment samples had detections of ARGs. The most frequently detected PPCP was metformin. No sites had a cumulative exposure activity ratio greater than 1.0 for chemical exposures; 13 sites were above the 0.001 precautionary threshold. Toxicity quotients calculated using Aquatic Life Benchmarks were below the 0.1 moderate risk threshold for chemical exposures for all but one site. For fish, all sites exceeded the moderate and high-risk thresholds proposed for microplastic particles for food dilution (both chronic and acute exposures) and all sites exceeded the microplastic moderate threshold proposed for chronic tissue translocation, and two sites exceeded the threshold for acute tissue translocation.

A multi-marker assessment of sewage contamination in streams using human-associated indicator bacteria, human-specific viruses, and pharmaceuticals

Human sewage contaminates waterways, delivering excess nutrients, pathogens, chemicals, and other toxic contaminants. Contaminants and various sewage indicators are measured to monitor and assess water quality, but these analytes vary in their representation of sewage contamination and the inferences about water quality they support. We measured the occurrence and concentration of multiple microbiological (n = 21) and chemical (n = 106) markers at two urban stream locations in Milwaukee, Wisconsin, USA over two years. Five-day composite water samples (n = 98) were collected biweekly, and sewage influent samples (n = 25) were collected monthly at a Milwaukee, WI water reclamation facility. We found the vast majority of markers were not sensitive enough to detect sewage contamination. To compare analytes for monitoring applications, five consistently detected human sewage indicators were used to evaluate temporal patterns of sewage contamination, including microbiological (pepper mild mottle virus, human Bacteroides, human Lachnospiraceae) and chemical (acetaminophen, metformin) markers. The proportion of human sewage in each stream was estimated using the mean influent concentration from the water reclamation facility and the mean concentration of all stream samples for each sewage indicator marker. Estimates of instream sewage pollution varied by marker, differing by up to two orders of magnitude, but four of the five sewage markers characterized Underwood Creek (mean proportions of human sewage ranged 0.0025 % - 0.075 %) as less polluted than Menomonee River (proportions ranged 0.013 % - 0.14 %) by an order of magnitude more. Chemical markers correlated with each other and yielded higher estimates of sewage pollution than microbial markers, which exhibited greater temporal variability. Transport, attenuation, and degradation processes can influence chemical and microbial markers differently and cause variation in human sewage estimates. Given the range of potential human and ecological health effects of human sewage contamination, robust characterization of sewage contamination that uses multiple lines of evidence supports monitoring and research applications.

Environmental Risks of Pharmaceutical Mixtures in Aquatic Ecosystems: Reflections on a Decade of Research

Pharmaceuticals and personal care products (PPCPs) occur as variable mixtures in surface waters receiving discharges of human and animal wastes. A key question identified a decade ago is how to assess the effects of long-term exposures of these PPCP mixtures on nontarget organisms. We review the recent progress made on assessing the aquatic ecotoxicity of PPCP mixtures-with a focus on active pharmaceutical ingredients-and the challenges and research needs that remain. New knowledge has arisen from the use of whole-mixture testing combined with component-based approaches, and these studies show that mixtures often result in responses that meet the concentration addition model. However, such studies have mainly been done on individual species over shorter time periods, and longer-term, multispecies assessments remain limited. The recent use of targeted and nontargeted gene analyses has improved our understanding of the diverse pathways that are impacted, and there are promising new "read-across" methods that use mammalian data to predict toxicity in wildlife. Risk assessments remain challenging given the paucity of ecotoxicological and exposure data on PPCP mixtures. As such, the assessment of PPCP mixtures in aquatic environments should remain a priority given the potential for additive-as well as nontarget-effects in nontarget organisms. In addition, we need to improve our understanding of which species, life stages, and relevant endpoints are most sensitive to which types of PPCP mixtures and to expand our knowledge of environmental PPCP levels in regions of the globe that have been poorly studied to date. We recommend an increased use of new approach methodologies, in particular "omics," to advance our understanding of the molecular mechanics of mixture effects. Finally, we call for systematic research on the role of PPCP mixtures in the development of antimicrobial resistance. Environ Toxicol Chem 2024;43:549-558. © 2023 SETAC.

Using multilinear regressions developed from excitation-emission matrices to estimate the wastewater content in urban streams impacted by sanitary sewer leaks and overflows

Failing sewer infrastructure introduces unknown quantities of raw wastewater into urban streams, raising human and ecological health concerns. To address this problem, we developed multilinear regressions that relate fluorescent dissolved organic matter to wastewater content. The models were constructed with the area-normalized regional volumes of excitation-emission matrices measured for mixtures of deionized water, surface water from a wastewater-impacted stream, wastewater from a sanitary sewer adjacent to the stream, and Suwannee River natural organic matter. The best performing multilinear regression had a standard error of 0.55 % wastewater. A matrix-matched calibration was used to internally validate the approach and confirm the wastewater content of select samples. The multilinear model was externally validated through (i) comparison to concentrations of contaminants of emerging concern in surface water and wastewater and (ii) extension to samples from previous campaigns that employed alternative wastewater indicators. Using the validated model, we estimated an average wastewater content of 2.4 ± 4.0 % in 165 samples collected from 14 locations in the Gwynns Falls watershed (USA) between April 2019 and April 2023. The maximum wastewater content was 35 % at a site where sanitary sewer leaks and overflows have been previously documented. The reported approach represents a cost-effective and scalable technique to estimate wastewater content in urban streams through analysis of fluorescent dissolved organic matter.

Water, Water Everywhere, but Every Drop Unique: Challenges in the Science to Understand the Role of Contaminants of Emerging Concern in the Management of Drinking Water Supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

Five state factors control progressive stages of freshwater salinization syndrome

Factors driving freshwater salinization syndrome (FSS) influence the severity of impacts and chances for recovery. We hypothesize that spread of FSS across ecosystems is a function of interactions among five state factors: human activities, geology, flowpaths, climate, and time. (1) Human activities drive pulsed or chronic inputs of salt ions and mobilization of chemical contaminants. (2) Geology drives rates of erosion, weathering, ion exchange, and acidification-alkalinization. (3) Flowpaths drive salinization and contaminant mobilization along hydrologic cycles. (4) Climate drives rising water temperatures, salt stress, and evaporative concentration of ions and saltwater intrusion. (5) Time influences consequences, thresholds, and potentials for ecosystem recovery. We hypothesize that state factors advance FSS in distinct stages, which eventually contribute to failures in systems-level functions (supporting drinking water, crops, biodiversity, infrastructure, etc.). We present future research directions for protecting freshwaters at risk based on five state factors and stages from diagnosis to prognosis to cure.

Neuroactive pharmaceuticals in estuaries: Occurrence and tissue-specific bioaccumulation in multiple fish species

Contamination of surface waters by pharmaceuticals is an emerging problem globally. This is because the increased access and use of pharmaceuticals by a growing world population lead to environmental contamination, threatening non-target species in their natural environment. Of particular concern are neuroactive pharmaceuticals, which are known to bioaccumulate in fish and impact a variety of individual processes such as fish reproduction or behaviour, which can have ecological impacts and compromise fish populations. In this work, we investigate the occurrence and bioaccumulation of 33 neuroactive pharmaceuticals in brain, muscle and liver tissues of multiple fish species collected in four different estuaries (Douro, Tejo, Sado and Mira). In total, 28 neuroactive pharmaceuticals were detected in water and 13 in fish tissues, with individual pharmaceuticals reaching maximum concentrations of 1590 ng/L and 207 ng/g ww, respectively. The neuroactive pharmaceuticals with the highest levels and highest frequency of detection in the water samples were psychostimulants, antidepressants, opioids and anxiolytics, whereas in fish tissues, antiepileptics, psychostimulants, anxiolytics and antidepressants showed highest concentrations. Bioaccumulation was ubiquitous, occurring in all seven estuarine and marine fish species. Notably, neuroactive compounds were detected in every water and fish brain samples, and in 95% of fish liver and muscle tissues. Despite variations in pharmaceutical occurrence among estuaries, bioaccumulation patterns were consistent among estuarine systems, with generally higher bioaccumulation in fish brain followed by liver and muscle. Moreover, no link between bioaccumulation and compounds' lipophilicity, species habitat use patterns or trophic levels was observed. Overall, this work highlights the occurrence of a highly diverse suite of neuroactive pharmaceuticals and their pervasiveness in waters and fish from estuarine systems with contrasting hydromorphology and urban development and emphasizes the urgent need for toxicity assessment of these compounds in natural ecosystems, linked to internalized body concentration in non-target species.

Non-point source fecal contamination from aging wastewater infrastructure is a primary driver of antibiotic resistance in surface waters

Antibiotic resistance is a global threat to human health. Many surface water resources are environmental hotspots of antibiotic resistant gene (ARG) transfer, with agricultural runoff and human waste highlighted as common sources of ARGs to aquatic systems. Here we quantified fecal marker genes and ARGs in 992 stream water samples collected seasonally during a 5-year period from 115 sites across the Upper Oconee watershed (Georgia, USA), an area characterized by gradients of agricultural and urban development. Widespread fecal contamination was found from humans (48% of samples), ruminants (55%), and poultry (19%), and 73% of samples tested positive for at least one of the six targeted ARGs (ermB, tet(B), bla_CTX-M-1, bla_KPC, bla_SHV, and qnrS). While ARGs were strongly correlated with human fecal markers, many highly contaminated samples were not associated with sewage outfalls, an expected source of fecal and ARG pollution. To determine sources of contamination, we synthesized ARG and fecal marker data with geospatial data on land use/land cover and wastewater infrastructure across the watershed. This novel analysis found strong correlations between ARGs and measures of sewer density, sewer length, and septic system age within sample watersheds, indicating non-point sources of fecal contamination from aging wastewater infrastructure can be critical disseminators of anthropogenic ARGs in the environment.

Pharmaceuticals in water and sediment of small streams under the pressure of urbanization: Concentrations, interactions, and risks

Small streams are crucial but vulnerable elements of ecological networks. To better understand the occurrence of pharmaceutically active compounds (PhACs) in streams, this study focused on the occurrence, distribution, and environmental risk of 111 PhACs and 7 trace elements based on a total of 141 water and sediment samples from small streams located in the urbanizing region of Budapest, Hungary. Eighty-one PhACs were detected in the aqueous phase, whereas sixty-two compounds were detected in the sediment. Carbamazepine (CBZ) was the most frequently identified PhAC in water, and was found in 91.5% of all samples. However, the highest concentrations were measured for lamotrigine (344.8 μg·L^-1) and caffeine (221.4 μg·L^-1). Lidocaine was the most frequently occurring PhAC in sediment (73.8%), but the maximum concentrations were detected for CBZ (395.9 ng·g^-1) and tiapride (187.7 ng·g^-1). In both water and sediment, more PhACs were found downstream of the wastewater treatment plants (WWTPs) than in the samples not affected by treated wastewater, even though no relationship was observed between the total amount of treated wastewater and the number of detected PhACs. The PhAC concentrations were also independent of the distance from the WWTP effluents. PhAC-polluted samples were detected upstream of the WWTPs, thereby suggesting the relevance of diffuse emissions in addition to WWTP outlets. The most frequently detected PhACs in the sediment were usually also present in the water samples collected at the same place and time. The varying concentrations of PhACs and the fluctuating water-sediment properties resulted in a lack of correlation between the general chemical properties and the concentrations of PhACs, which makes it difficult to predict PhAC contamination and risks in urbanized small streams. The environmental risk assessment indicated that diclofenac had the highest risk in the sampling area.