Routine Water Quality Monitoring Research Articles

Autonomous Underwater Robot for Water Quality Measurement of Northwest Pennsylvania Lakes

The Northwestern Pennsylvania Region, notably affected by toxic algae blooms like those in Lake Erie, suffers from a lack of adequate water quality monitoring tools. This project aims to bridge this gap through the development of cost-effective underwater robots designed to gather critical water quality data. The software developed for this project facilitates the generation of analytics essential for assessing the health of aquatic environments. The robots engineered through this project are set to be deployed by the local Conservation District for routine water quality monitoring activities.

Multi-element analysis of unfiltered samples in river water monitoring—digestion and single-run analyses of 67 elements

Routine analysis of inorganic analytes in whole water samples from rivers (unfiltered river water) is rarely reported in scientific publications. However, this sample type is valuable and often used in long-term monitoring, regulation, and catchment element budgets, as it includes the dissolved, colloidal, and particulate fraction in one sample type. Preservation measures are not needed and solid–liquid partitioning can be disregarded, which simplifies automated sampling and storage procedures. In this study, we provide several digestion protocols for whole water samples from rivers and the subsequent multi-element analysis of 67 major, minor, and trace elements: Li, Be, B, Na, Mg, Al, Si, P, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Ru, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Ir, Pt, Au, Hg, Tl, Pb, Bi, Th, U. In the absence of whole water reference materials for inorganic analytes, we introduce simulated whole water samples by suspending sediment reference materials as quality control measures. The applicability for improved routine water quality monitoring was successfully tested on samples from different rivers revealing variations of the element fingerprints over time.Graphical abstract

Environmental factors associated with Escherichia coli concentration at freshwater beaches on Lake Winnipeg, Manitoba, Canada

At many public beaches, routine monitoring of beach water quality using fecal indicator bacteria is conducted to evaluate the risk of recreational water illness. Results from water sample analysis can take over 24-hr, which may no longer accurately reflect current water quality conditions. This study aimed to assess which combination of environmental factors best predicts fecal contamination (E. coli) levels at two of the most popular beaches on Lake Winnipeg, Manitoba (Gimli and Grand Beach), by linking water quality data and publicly available environmental data from 2007 to 2021. We developed separate mixed effects models for each beach for two outcomes, linear (continuous log-transformed E. coli concentration) and categorical (200 CFU/100 ml threshold), to explore differences in the predictors of E. coli concentrations and exceedances of the provincial health risk threshold, respectively. We used a Directed Acyclic Graph to choose which predictor variables to include in the models. For both beaches, we identified clustering of the E. coli outcomes by year, suggesting year-specific variation. We also determined that extreme weather days, with higher levels of rainfall in the preceding 48-hr, previous day average air temperature, and previous day E. coli concentration could result in a higher probability of E. coli threshold exceedances or higher concentrations in the water bodies. In Grand Beach, we identified that days with lower average UV levels in the previous 24-hr and antecedent dry days could result in a higher probability of E. coli threshold exceedances or higher concentrations. The findings can inform possible trends in other freshwater settings and be used to help develop real-time recreational water quality predictive models to allow more accurate beach management decisions and warrant enhancement of beach monitoring programs for extreme weather events as part of the climate change preparedness efforts.

What, How, When, and Where: Spatiotemporal Water Quality Hazards of Cyanotoxins in Subtropical Eutrophic Reservoirs.

Though toxins produced during harmful blooms of cyanobacteria present diverse risks to public health and the environment, surface water quality surveillance of cyanobacterial toxins is inconsistent, spatiotemporally limited, and routinely relies on ELISA kits to estimate total microcystins (MCs) in surface waters. Here, we employed liquid chromatography tandem mass spectrometry to examine common cyanotoxins, including five microcystins, three anatoxins, nodularin, cylindrospermopsin, and saxitoxin in 20 subtropical reservoirs spatially distributed across a pronounced annual rainfall gradient. Probabilistic environmental hazard analyses identified whether water quality values for cyanotoxins were exceeded and if these exceedances varied spatiotemporally. MC-LR was the most common congener detected, but it was not consistently observed with other toxins, including MC-YR, which was detected at the highest concentrations during spring with many observations above the California human recreation guideline (800 ng/L). Cylindrospermopsin was also quantitated in 40% of eutrophic reservoirs; these detections did not exceed a US Environmental Protection Agency swimming/advisory level (15,000 ng/L). Our observations have implications for routine water quality monitoring practices, which traditionally use ELISA kits to estimate MC levels and often limit collection of surface samples during summer months near reservoir impoundments, and further indicate that spatiotemporal surveillance efforts are necessary to understand cyanotoxins risks when harmful cyanobacteria blooms occur throughout the year.

Efficient extraction of heavy metals from aqueous environments using magnetic effervescent Tablet-Assisted ionic Liquid-Based dispersive Solid-Phase microextraction

In this study, we successfully developed an effervescent tablet-assisted dispersive solid-phase microextraction approach using sulfanilic acid-modified magnetic graphene oxide (MGO@SA-DSPM) for the efficient removal of heavy metals (Pb(II), Cd(II), Zn(II), and Cr(II)). The study systematically investigated the impact of different variables on the extraction efficiency of heavy metals. Results demonstrated that the MGO@SA nanocomposite exhibited superior extraction yields for all four metals, with recovery rates of 100.6 % for Cd(II), 103.6 % for Zn(II), 99.39 % for Cr(III), and 87.08 % for Pb(II), surpassing those of the MGO composite (81.08 % for Cd(II), 101.5 % for Zn(II), 54.35 % for Cr(III), and 80.48 % for Pb(II)). The enhanced extraction efficiencies due to the introduction of additional functional moieties, such as sulphonyl (-SO3-) and amid (NH-CO) moieties, onto the surface of MGO through its modification with SA. This led to a significantly improved extraction process. Under optimized conditions, the MGO@SA-DSPM method achieved low limits of detection (LOD) ranging from 0.204 to 299 μg/L, and limits of quantification (LOQ) between 0.68 and 0.99 μg/L, along with satisfactory extraction recoveries (87.08 % − 103.6 %) and relative standard deviations of 1.36–1.99 % for all four heavy metals. In summary, the proposed MGO@SA-DSPM approach demonstrates promising potential for routine water quality monitoring.

Comprehensive evaluation of heavy metals in surface water of the upper Banar River, Bangladesh

The main focus of the research was to examine the dispersion of elements and evaluate the possible ecological impact of heavy metals in the water of the Upper Banar River. To achieve this, water samples were obtained from ten different locations along the river, and the concentrations of Cr, Ni, Cu, Cd, Pb, and As were analyzed using an atomic absorption spectrophotometer (AAS). Results exhibited that the abundance of Cr, Ni, Cu, Cd, Pb, and As in water varied from 1.10 to 3.20, 0.11 to 1.30, 1.30 to 13.50, 1.14 to 1.91, 0.39 to 0.75 and 1.44 to 2.56 µgL-1, respectively. Mean (±SD) concentrations of considered metals declined with the following downward direction: Cu (5.07±4.11) > As (1.94±1.15) > Cr (1.81±0.63) > Cd (1.42±0.23) Pb (0.55±0.12) > Ni (0.54±0.41), indicated that concentrations were reasonably assorted throughout the observed region. Moreover, the Upper Banar River water was contaminated with heavy metals, but the pollution level was not significant based on HPI analysis. Based on the computed HEI values, water quality is deemed low hazard and lower degrees of contamination. Overall, the river's water was still in good condition and had low levels of contamination, as per PI and CD ratings. Upper Banar River water's computed ERI ranged from 7.24 to 12.16, which showed a low-risk level. The study concluded that the Upper Banar River experienced some metallic pollution because of anthropogenic disturbances. Thus, responsible authorities should immediately implement appropriate management strategies and conduct routine water quality monitoring. Int. J. Agril. Res. Innov. Tech. 13(1): 110-122, June 2023

WASH and drinking water quality considerations in schools in reflection of the sustainable development goals – a review

Abstract Poor drinking water quality has been linked to negative health outcomes across the world. Drinking water quality is an essential part of safe water, sanitation, and hygiene (WASH). Safe WASH in schools is linked with the achievement of sustainable development goals (SGDs), specifically, SDG 6. It is unclear whether water quality is always assessed as part of WASH in schools. This study focused on determining the consideration of water quality aspects during WASH assessment in schools by examining published studies. A systematic online review of the literature was conducted to identify studies that reported on the assessment of WASH facilities in schools. Titles, abstracts, and full text of retrieved articles were screened. Seventy-five studies were identified. Thirty-two studies considered drinking water quality analysis as part of WASH in schools. Chemical (66%), microbial (59%), and physical (38%) parameters were included in drinking water quality analysis, with lead (Pb), and Escherichia coli being mostly included. This study reveals that some studies did not include an evaluation of drinking water quality, though it reflects an important exposure pathway between WASH services and health outcomes. It is, therefore, recommended that routine water quality monitoring be included in school WASH to ensure learner's health is protected.

Recreational water exposures and illness outcomes at a freshwater beach in Toronto, Canada: A prospective cohort pilot study.

Swimming and other recreational water activities in surface waters are popular in Canada during the summer. However, these activities can also increase the risk of recreational water illness. While routine monitoring of beach water quality is conducted by local authorities each summer, little research is available in Canada about beach exposures and illness risks. We conducted a pilot of a prospective cohort study at a popular beach in Toronto, Ontario, Canada, in 2022 to determine characteristics of beachgoers, common water and sand exposures, the incidence of recreational water illness, and the feasibility for a larger, national cohort study. We enrolled beachgoers on-site and surveyed about their exposures at the beach and conducted a follow-up survey 7 days following their beach visit to ascertain acute gastrointestinal, respiratory, skin, ear, and eye illness outcomes. We descriptively tabulated and summarized the collected data. We enrolled 649 households, consisting of 831 beachgoers. Water contact activities were reported by 56% of beachgoers, with swimming being the most common activity (44% of participants). Similarly, 56% of beachgoers reported digging in the sand or burying themselves in the sand. Children (≤14 years) and teenagers (15-19 years) were most likely to report engaging in water contact activities and swallowing water, while children were most likely to report sand contact activities and getting sand in their mouth. Boys and men were more likely than women and girls to report swallowing water (15.2% vs. 9.4%). Water and sand exposures also differed by household education level and participant ethno-racial identity. E. coli levels in beach water were consistently low (median = 20 CFU/100 mL, range = 10-58). The incidence of illness outcomes was very low (0.3-2.8%) among the 287 participants that completed the follow-up survey. The identified beach exposure patterns can inform future risk assessments and communication strategies. Excellent water quality was observed at the studied beach, likely contributing to the low incidence of illnesses. A larger, national cohort study is needed in Canada to examine risks of illness at beaches at higher risk of fecal contamination.

Routine Estimation of Dissolved Organic Matter Sources Using Fluorescence Data and Linear Least Squares

Dissolved organic matter (DOM) is an important component of the biogeochemistry and ecosystem function of streams and rivers. Unlike inorganic nitrogen nutrients, organic nitrogen (DON) nutrients can vary considerably depending on the contributions of various sources. The properties of DOM in natural waters have been measured using fluorescence spectroscopy, which is inexpensive compared to more sophisticated chemical analysis and is fast enough to enable its use in routine water quality monitoring. However, estimating the contributions of DOM sources to surface waters from fluorescence data in a similarly efficient manner remains an area of active research. In this study, we develop a simple linear regression method for estimating the relative amounts of DOM sources in a stream or river sample. The regression estimates are more accurate than those of previous approaches and are orders of magnitude faster to compute. Codes and data to implement the method are provided for a variety of computing environments to facilitate use for water quality and research applications.

Spatio-temporal analysis of the Brantas river water quality status by using principal component weighted index (PCWI)

River, as one of the surface water resources, has faced many contaminations due to domestic and industrial activities in its surrounding, and thus routine water quality monitoring is required. This activity yields a large number of water quality characteristics that can be very useful to evaluate the status of river quality status. In this study, we integrated a statistical multivariate analysis such as Principal Component Analysis (PCA) and conventional Water Quality Index (WQI) measure to produce a data-driven composite index for water quality assessment. We implemented this technique to evaluate the status of Brantas River, the largest river in East Java Province-Indonesia, using a long-term dataset collected from 2012 to 2021. The study area was divided into three classes: upstream, midstream, and downstream. Results of the study suggested that the pollution level in the Brantas River fluctuates yearly. Meanwhile, the degree of contamination increased from upstream to downstream.

QMRA of beach water by Nanopore sequencing-based viability-metagenomics absolute quantification

The majority of the current regulatory practices for routine monitoring of beach water quality rely on the culture-based enumeration of faecal indicator bacteria (FIB) to develop criteria for promoting the general public's health. To address the limitations of culture methods and the arguable reliability of FIB in indicating health risks, we developed a Nanopore metagenomic sequencing-based viable cell absolute quantification workflow to rapidly and accurately estimate a broad range of microbes in beach waters by a combination of propidium monoazide (PMA) and cellular spike-ins. Using the simple synthetic bacterial communities mixed with viable and heat-killed cells, we observed near-complete relic DNA removal by PMA with minimal disturbance to the composition of viable cells, demonstrating the feasibility of PMA treatment in profiling viable cells by Nanopore sequencing. On a simple mock community comprised of 15 prokaryotic species, our results showed high accordance between the expected and estimated concentrations, suggesting the accuracy of our method in absolute quantification. We then further assessed the accuracy of our method for counting viable Escherichia coli and Vibrio spp. in beach waters by comparing to culture-based method, which were also in high agreement. Furthermore, we demonstrated that 1 Gb sequences obtained within 2 h would be sufficient to quantify a species having a concentration of ≥ 10 cells/mL in beach waters. Using our viability-resolved quantification workflow to assess the microbial risk of the beach water, we conducted (1) screening-level quantitative microbial risk assessment (QMRA) to investigate human illness risk and site-specific risk patterns that might guide risk management efforts and (2) metagenomics-based resistome risk assessment to evaluate another layer of risk caused by difficult illness treatment due to antimicrobial resistance (AMR). In summary, our metagenomic workflow for the rapid absolute quantification of viable bacteria demonstrated its great potential in paving new avenues toward holistic microbial risk assessment.

Effect-Based Trigger Values Are Essential for the Uptake of Effect-Based Methods in Water Safety Planning.

Effect-based methods (EBMs) using in vitro bioassays and well plate-based in vivo assays are recommended for water quality monitoring because they can capture the mixture effects of the many chemicals present in water. Many in vitro bioassays are highly sensitive, so an effect in a bioassay does not necessarily indicate poor chemical water quality. Consequently, effect-based trigger values (EBTs) have been introduced to differentiate between acceptable and unacceptable chemical water quality and are required for the wider acceptance of EBMs by the water sector and regulatory bodies. These EBTs have been derived for both drinking water and surface water to protect human and ecological health, respectively, and are available for assays indicative of specific receptor-mediated effects, as well as assays indicative of adaptive stress responses, apical effects, and receptor-mediated effects triggered by many chemicals. An overview of currently available EBTs is provided, and a simple approach is proposed to predict interim EBTs for assays currently without an EBT based on the effect concentration of the assay reference compound. There was good agreement between EBTs predicted using this simplistic approach and EBTs from the literature derived using more robust methods. Finally, an interpretation framework that outlines the steps to take if the effect of a sample exceeds the EBT was developed to help facilitate the uptake of EBMs in routine water quality monitoring and water safety planning for drinking water production. Environ Toxicol Chem 2023;42:714-726. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Water quality monitoring based on chemometric analysis of high-resolution phytoplankton data measured with flow cytometry

River water is an important source of Dutch drinking water. For this reason, continuous monitoring of river water quality is needed. However, comprehensive chemical analyses with high-resolution gas chromatography [GC]-mass spectrometry [MS]/liquid chromatography [LC]-MS are quite tedious and time consuming; this makes them poorly fit for routine water quality monitoring and, therefore, many pollution events are missed. Phytoplankton are highly sensitive and responsive to toxicity, which makes them highly usable for effect-based water quality monitoring. Flow cytometry can measure the optical properties of phytoplankton every hour, generating a large amount of information-rich data in one year. However, this requires chemometrics, as the resulting fingerprints need to be processed into information about abnormal phytoplankton behaviour. We developed Discriminant Analysis of Multi-Aspect CYtometry (DAMACY) to model the “normal condition” of the phytoplankton community imposed by diurnal, meteorological, and other exogenous influences. DAMACY first describes the cellular variability and distribution of phytoplankton in each measurement using principal component analysis, and then aims to find subtle differences in these phytoplankton distributions that predict normal environmental conditions. Deviations from these normal environmental conditions indicated abnormal phytoplankton behaviour that happened alongside pollution events measured with the GC/MS and LC/MS systems. Thus, our results demonstrate that flow cytometry in combination with chemometrics may be used for an automated hourly assessment of river water quality and as a near real-time early warning for detecting harmful known or unknown contaminants. Finally, both the flow cytometer and the DAMACY algorithm run completely autonomous and only requires maintenance once or twice per year. The warning system results may be uploaded automatically, so that drinking water companies may temporary stop pumping water whenever abnormal phytoplankton behaviour is detected. In the case of prolonged abnormal phytoplankton behaviour, comprehensive analysis may still be used to identify the chemical compound, its origin, and toxicity.

Statistical process control in assessing water quality in the Doce river basin after the collapse of the Fundão dam (Mariana, Brazil).

The process of extracting information from data generated in environmental monitoring programs is often carried out using statistical tools, with Statistical Process Control (SPC) showing great potential for application in environmental monitoring. In November 2015, millions of cubic metres of tailings were dumped into the basin of the River Doce with the collapse of the Fundão dam. A study of the impact of this incident requires new approaches in data monitoring and processing, so it was sought to evaluate, using SPC tools, changes in water quality in the basin of the River Doce following the collapse of the dam. Using process charts and the process capability index (PCI), water quality parameters in the Doce and Carmo rivers were evaluated between 2009 and 2020. There, turbidity has improved since 2018, and Mn since 2016. Control charts showed that by December 2020 dissolved Fe was still not within normal pre-event fluctuation patterns. The PCI value showed that the situation worsened after the event for each of the parameters, with the lowest values for Mn and E. coli. By using a reference period, SPC makes it possible to infer the permanence of the impact of extreme pollution on the waterbody, which can be used in the routine monitoring of water quality in such events.

Remotely sensed data for estimating chlorophyll-a concentration in wetlands located in the Limpopo Transboundary River Basin, South Africa

Wetlands in semi-arid regions are highly productive and biologically diverse ecosystems that contribute significantly to livelihood and economic development and play a substantial role in sustaining rural livelihoods. These ecosystems are not only rich in biodiversity, but also predominantly valuable in terms of the services they provide to people, including water security, hydrological regulation, and other services. Chlorophyll-a concentrations and associated dynamics in two tropical wetland systems were estimated in the Makuleke and Nylsvlei wetlands. The Makuleke and Nylsvlei wetlands are in the Limpopo Transboundary River Basin, South Africa. Moderate-resolution Landsat 8 images for September 2018 and June 2019 and in situ field measurements were used to estimate and map chlorophyll-a concentration from the two wetlands. Landsat-derived chlorophyll-a concentrations were validated using field-derived chlorophyll-a measurements. Validation was implemented to assess the consistency of the remotely sensed chlorophyll-a estimates. The relationship between field-measured chlorophyll estimates and Landsat-derived chlorophyll estimates was determined using the coefficient of determination (r-square: R2) and the root mean square error (RMSE). The results showed that the Makuleke wetland had low estimates of Chl-a during September 2018. The variation of Chl-a concentration in Makuleke ranged from 0 to 1.15 μg/L, whereas for Nylsvlei the wetland range varied between 0 and 1.42 μg/L, for the period under study. The spatial characterization of Chl-a concentration varied significantly between the two wetlands, with much of it concentrated along the wetland shorelines. The finding of this study underscores the relevance of remotely detected data in the evaluation and routine monitoring of wetland water quality, a previously challenging task within situ measurements.

Contribution of the reservoir backflow to the eutrophication of its tributary: a case study of the Xiangxi River, China

Abstract Based on the routine water quality monitoring data of the Xiangxi River and its main monitoring section from January 2014 to May 2016, the monthly dynamics of nutrient concentrations and fluxes were analyzed, and the relationship between the water exchange between the reservoir and the tributaries and the changes of nutrient fluxes in the river was established. The results showed that the nutrient flux in the Xiangxi bay estuary was negatively correlated with the reservoir reflux intensity, and the overall correlation coefficient was −0.52. Four nutrient indexes, total nitrogen, total phosphorus, ammonia nitrogen (), and soluble phosphorus, all showed the same regularity and characteristics, among which was particularly prominent. It can be concluded that the variation of nutrient salts in the water body of the tributary bay is mainly determined by the water exchange between the reservoir and the tributary. In addition, the change of chemical oxygen demand and chlorophyll a flux in the Xiangxi Bay and water exchange in the reservoir area were analyzed. We found that changes in the hydraulic conditions of the return flow in the reservoir area can destroy the suitable flow environment necessary for the survival of algae, thus preventing the proliferation of harmful algae. Therefore, by controlling the hydrodynamic conditions between the reservoir area and the tributaries and changing the degree of water exchange between them, the objective of improving the water environment in the Xiangxi Bay can be achieved to a large extent.

Assessing the drinking water quality of educational institutions at selected locations of district Swat, Pakistan

Water pollution is a primary environmental concern in Pakistan due to its serious health effects. Over more than 1.25 million people in the Swat district rely on surface and groundwater sources for drinking, agricultural purposes. Hence, the need to ascertain the drinking water quality and associated human health risks were considered highly significant. In this study, eighty water samples (40 for chemical parameters and 40 for biological parameters) were randomly collected from schools and colleges at Mingora city, district Swat. The mean values of physico-chemical water quality parameters such as pH (6.3), TDS (410.7 mg/l), EC (709.7), temperature (25.83 °C), turbidity (0.47 NTU), alkalinity (104.8 mg/l), salinity (910.0 mg/l), total hardness (348.15 mg/l), dissolved oxygen (DO) (2.35 ppm), chlorine (5.4 mg/l), fluoride (1.12 mg/l), nitrate (NO3) (44.52 mg/l) and nitrite (NO2) (4.05 mg/l) were measured using standard methods recommended by World Health Organization and the American Public Health Association. Besides, the mean value of total coliform bacteria, including fecal coliform, was found; (0.32) with standard deviation; (0.572) whereas, the mean value of Escherichia coli was found (0.3) with a standard deviation of (0.564). This study also finds the drinking water sources highly contaminated by fecal coliform bacteria, including Escherichia coli, which is the main reason for many waterborne diseases such as gastroenteritis, dysentery, and diarrhea. Additionally, residents of the area also reported some instances of viral hepatitis. Moreover, the significant variations among various water quality parameters were attributed to growing urbanization trends, nearby agricultural runoffs, lack of proper sewerage/solid waste disposal systems, and direct discharge of waste effluents containing human and animal fecal material. Hence, the need for adequate education on health hygiene and water treatment practices was highly recommended. Similarly, the execution of routine drinking water quality monitoring by relevant organizations was considered indispensable.

Iron operates as an important factor promoting year-round diazotrophic cyanobacteria blooms in eutrophic reservoirs in the tropics

We hypothesize that iron availability plays an important role in driving phytoplankton structure and dynamics in tropical reservoir. This role has often been neglected in routine monitoring of water quality since the main focus has been addressed on macronutrients such phosphorus and nitrogen. To elucidate the potential regulation exerted by iron availability on phytoplankton, a limnological investigation was carried out in two neighboring eutrophic reservoirs in tropical China. Traditional physical and chemical variables were measured along with total and dissolved iron concentrations to explore how they could influence phytoplankton structure. Statistical analyses showed that dissolved iron (DFe) as well as dissolved nitrogen (DIN) and soluble reactive phosphorus (SRP) significantly explained the variance of phytoplankton assemblages in both reservoirs. We could also find that diazotrophic cyanobacteria blooms generally developed when DFe concentrations were above 0.025 mg/L. Moreover, the DFe availability in the water columns was modulated by the effects exerted by the stratification/circulation patterns on redox conditions and pH values. Anaerobic conditions favored the release of iron and phosphorus from sediments, and likely favored an enhanced nitrogen assimilation and a decrease of DIN in the epilimnion. Our results highlighted that iron functions as an important factor promoting diazotrophic cyanobacteria and driving seasonal phytoplankton succession in tropical eutrophic reservoirs, not only with a direct effect on phytoplankton growth but also indirect effect by modifying the availability of nitrogen and phosphorus.

Development of a framework to derive effect-based trigger values to interpret CALUX data for drinking water quality

Bioassays are increasingly being implemented for water quality monitoring as targeted chemical analyses are not always sufficient for the detection of all emerging chemicals or transformation products. However, the interpretation of bioassay results remains challenging, in particular because a positive response does not necessarily indicate that there may be an increased risk. For this purpose, effect-based trigger (EBT) values have been introduced as thresholds above which action needs to be undertaken to determine the cause of the response. The goals of this study were to (i) evaluate various approaches used to determine EBT values and (ii) based on the findings, derive human health EBT values for Chemical Activated LUciferase gene eXpression (CALUX) in vitro bioassays used for routine monitoring of water quality in the Netherlands. Finally, (iii) an uncertainty analysis was carried out to determine the protective power of the derived EBT values and the chance that potentially harmful substances might not be detected. EBT values that can be implemented in routine monitoring could be determined for four of eight selected bioassays. These EBT were compared to bioassay results from routine water quality monitoring carried out in the Netherlands. Furthermore, a framework for the calculation and evaluation of derived EBT values for routine application to monitor drinking water and its sources is proposed.

Variable fecal source prioritization in recreational waters routinely monitored with viral and bacterial general indicators

Somatic and F+ coliphage methods are under consideration as potential routine surface water quality monitoring tools to identify unsafe levels of fecal pollution in recreational waters. However, little is known about the cooccurrence of these virus-based fecal indicators and host-associated genetic markers used to prioritize key pollution sources for remediation. In this study, paired measurements of cultivated coliphage (somatic and F+) and bacterial (E. coli and enterococci) general fecal indicators and genetic markers indicative of human (HF183/BacR287 and HumM2), ruminant (Rum2Bac), canine (DG3), and avian (GFD) fecal pollution sources were assessed in 365 water samples collected from six Great Lakes Basin beach and river sites over a 15-week recreational season. Water samples were organized into groups based on defined viral and bacterial fecal indicator water quality thresholds and average log10 host-associated genetic marker fecal score ratios were estimated to compare pollutant source inferences based on variable routine water quality monitoring practices. Eligible log10 fecal score ratios ranged from -0.051 (F+ coliphage, GFD) to 2.08 (enterococci, Rum2Bac). Using a fecal score ratio approach, findings suggest that general fecal indicator selection for routine water quality monitoring can influence the interpretation of host-associated genetic marker measurements, in some cases, prioritizing different pollutant sources for remediation. Variable trends were also observed between Great Lake beach and river sites suggesting disparate management practices may be useful for each water type.