Ambient Water Quality Research Articles

The interplay of climate change and physical activity: Implications for cardiovascular health

Cardiovascular disease (CVD) is one of the top contributors to global disease burden. Meeting the physical activity guidelines can effectively control and prevent several CVD risk factors, including obesity, hypertension and diabetes mellitus. The effects of climate change are multifactorial and have direct impacts on cardiovascular health. Increasing ambient temperatures, worsening air and water quality and urbanisation and loss of greenspace will also have indirect effects of cardiovascular health by impacting the ability and opportunity to participate in physical activity. A changing climate also has implications for large scale sporting events and policies regarding risk mitigation during exercise in hot climates. This review will discuss the impact of a changing climate on cardiovascular health and physical activity and the implications for the future of organised sport.

One third of African rivers fail to meet the ’good ambient water quality’ nutrient targets

The ambition of Sustainable Development Goal (SDG) target 6.3 is to improve global water quality by 2030. SDG indicator 6.3.2 monitors progress towards this target by assessing water bodies against ‘good’ ambient water quality criteria, with nutrients (nitrogen and phosphorus) as part of the key metrics. However, large data gaps present a fundamental challenge, especially for Africa on how to assess the progress being made with respect to both the current and desired future situations. Here, a continental water quality model for Africa is presented to simulate river sediment load, Total Nitrogen (TN) and Total Phosphorus (TP) loads and concentrations. Furthermore, critical areas and hotspots of TN and TP pollution are mapped for the period 2017 – 2019, in relation to the United Nations Environment Programme (UNEP) target thresholds used for the assessment of SDG indicator 6.3.2. Utilizing the UNEP’s criteria, which designates a water body as having “good ambient water quality” if 80% or more of its monitored values meet their targets, it is estimated that 44 % and 15 % of African rivers fail to meet the set water quality thresholds for simulated TP and TN, respectively. When synthesizing data for both TP and TN, 34 % of the rivers do not qualify as having “good ambient water quality”. Geographically, the most pronounced nutrient pollution hotspots were in North Africa, Niger River Delta, Nile River basin, Congo River basin and specific zones in Southern Africa. These areas correlate with regions characterized by high inputs of fertilizers, manure and wastewater discharge.

Hot and Fresh: Evidence of Climate-Related Suboptimal Water Conditions for Seagrass in a Large Gulf Coast Estuary

Seagrasses have long been a focal point for management efforts aimed at restoring ecosystem health in estuaries worldwide. In Tampa Bay, Florida (USA), seagrass coverage has declined since 2016 by nearly a third (11,518 acres), despite sustained reductions of nitrogen loads supportive of light environments for growth. Changing physical water quality conditions related to climate change may be stressing seagrasses beyond their optimal growth ranges, requiring an assessment to determine if this decline can be linked to climate stress. Three ambient water quality datasets of varying sampling designs and coverage were evaluated to characterize physicochemical environments in Tampa Bay and the potential relationships with seagrass change. Tampa Bay has become hotter and fresher with water temperature increasing by 0.03–0.04 °C per year and salinity decreasing by 0.04–0.06 ppt per year, translating to an increase of 1.3 to 1.7 °C and a decrease of 1.6 to 2.6 ppt over the last 50 years. Additionally, the number of days when temperature was above 30 °C or salinity was below 25 ppt has increased on average across all bay segments by 48 and 37 days, respectively, since 1975. These changes varied spatially and seasonally, with the most dramatic changes observed in the upper bay. Generalized Additive Models provided a weight-of-evidence that recent seagrass declines are somewhat associated with hotter and fresher conditions. Trends in warming and increased precipitation in the region are likely to continue, further creating suboptimal conditions for seagrasses in Tampa Bay. These results should compel resource managers to consider the likelihood that reduced resilience of estuarine resources due to shifting ecological baselines driven by additional climate change drivers will complicate long-standing management paradigms. While conventional management approaches that focus on limiting nutrient loads should be continued, their future effectiveness may be confounded by climate change drivers and warrant additional, complementary interventions and continuous monitoring data to support ecosystem health into the future.

Assessment of Ambient Water Quality Deterioration in Proximity to Municipal Solid Waste Dumpsites in Urban Areas of Chattogram, Bangladesh

This study aims to assess the impact of waste dumping on groundwater quality within the Chattogram City Corporation area. Monitoring eight groundwater sampling points over four years, various physical and chemical parameters were analyzed, utilizing the APHA method. Parameters assessed include pH, temperature, dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS), salinity, biological oxygen demand (BOD), chemical oxygen demand (COD), Turbidity, Total Hardness, Ca-Hardness, Alkalinity, TSS, Chloride, Phosphate, Sulphate, Nitrite, Nitrate, Fluoride, Iron, Arsenic, Zinc, Copper, and Chromium. The findings were compared to the Department of Environment's (DoE) recommended values, as well as the Bangladesh standard and World Health Organization (WHO) values. During sample collection, deep tube wells near the dumping site points were prioritized. According to the investigation CNB, Ananda Bazar Halishahar and Arefin Nagar, deep pump water carries too many irons in their groundwater. Iron levels exceed both WHO and Bangladesh standards across all samples. Specifically, Arefin Nagar and Ananda Bazar Halishahar area sampling points S6, S7, and S8 surpass standards in TDS, Total Hardness, Turbidity, TSS, Chloride, and Iron. Water Quality Index (WQI) calculations suggest unsuitability for drinking purposes in all sampled water, with S5 and S8 demonstrating particularly high values, indicating their unsuitability for human consumption. Heavy Metal Pollution Index (HPI) calculations reveal a decrease at CNB sampling points S1 and S2, where waste dumping ceased in 2017. However, HPI values at other points show an increasing trend, indicating the leaching of heavy metals from solid waste into groundwater. S5 and S8 exhibit notably high HPI values (Average 464.99 and 319.59), suggesting an accumulation of heavy metals in the groundwater. Carcinogenic Risk Analysis of Arsenic highlights the failure of most sampled water to meet Carcinogenic Risk (CR) standards, signalling a potential cancer risk with prolonged use of this water.

Bottom water hypoxia suppresses fish chorusing in estuariesa).

Hypoxia in coastal ecosystems is increasing as a result of water quality declines from nutrient pollution. Hypoxia negatively affects fish populations and marine life, limiting their spawning habitats, population size, and growth. In this study, two approaches were used to understand the effect of hypoxia on the chorusing and reproductive behavior of fishes in estuaries. One approach used a water quality meter integrated with a prototype passive acoustic recorder, developed to monitor dissolved oxygen and fish chorusing simultaneously and continuously at sites with normoxic and hypoxic conditions. In a second approach, passive acoustic recorders were deployed near ambient water quality monitoring stations, monitored by the North Carolina agencies in estuaries where hypoxia occurs periodically. In both approaches, when hypoxia (dissolved oxygen < 4.0 mg/L) occurred, fish chorusing was diminished or ceased. A strong correlation was observed between bottom water dissolved oxygen and the power spectral density in a 100-200 Hz frequency band associated with red drum (Sciaenops ocellatus, Sciaenidae) calling. Passive acoustic monitoring stations and integrated passive acoustic and water quality meters should be used in estuarine hypoxia monitoring efforts to examine the expanding areas of hypoxia and its impact on fish critical spawning habitats.

Impacts of Organic and Non-organic Paddy Farming Practices on Surface Water Quality in Selected Areas

Paddy (Oryza sativa L.) cultivation plays major role in Sri Lanka. Mainly Organic and Non-organic paddy farming methods are conducted. Organic paddy farming method only used organic fertilizers and non-organic paddy farming method used chemical fertilizers which are Urea, Triple Super Phosphates. Therefore, farming practices can be affected to the surface water quality creating various health hazards. The study was conducted from November 2021 to February 2022 (Maha season) to assess the impact of organic and non-organic paddy farming practices on surface water quality in Wallewala, Homagama, and Kottawa paddy agricultural lands by analyzing pH, EC, TDS, DO, BOD, COD, total hardness, nitrate, nitrite, phosphate, sulfate, chloride, potassium, zinc, and chromium. Wallewala is newly created environment sensitive agricultural land in less human influence. Both organic and non-organic paddy lands are in that area. Kottawa paddy lands are cultivated only chemical fertilizers and the Homagama paddy lands are cultivated by organic fertilizers. Randomly, six and nine surface water samples were collected from paddy irrigated systems in Wallewala area represent to organic and non-organic paddy lands respectively. Randomly, five and six surface water samples were collected from paddy irrigated systems in Homagama Organic, and Kottawa non-organic paddy lands respectively. The water from both paddy systems, min pH (5.25±0.04), max EC (315±1.00 μScm-1 ), min DO (6.13±0.06 mgL-1), max BOD5 (2.82±0.06 mgL-1), max sulfate (205.76 ppm), max chloride (45.91 ppm), max K (5.63 ppm), and max Zn (0.12 ppm) were found, while the study revealed that all the water quality parameters were not exceeded the reported ambient water quality standards for inland waters in Sri Lanka for irrigation purposes. Further EC, TDS, COD, total hardness, sulfates, chloride, potassium, and zinc were greater in non-organic paddy lands in both Wallewala and Kottawa areas. According to the obtained data, there was no water pollution from the paddy cultivation in respective areas. But these results indicate that water quality parameters vary with the utilized fertilizers. &#x0D; Keywords: Paddy cultivation, Water quality, Organic paddy farming, Non-organic

Health risk assessment and development of human health ambient water quality criteria for PCBs in Taihu Basin, China

Polychlorinated biphenyls (PCBs) are a class of typical persistent organic pollutants (POPs) with carcinogenicity and extensively found in diverse environmental mediums. The Taihu Basin is one of the most economically developed regions in China, and it has also caused a lot of historical legacy and unconscious emissions of PCBs, posing a threat to the health of people in the region. This study counted the concentrations of PCBs in five environmental media (water, soil, air, dust, and food) in the Taihu Basin from 2000 to 2020 and used Monte Carlo simulation to simulate the multi-channel exposure of PCBs in people of different ages (children, teenagers, and adults), and evaluated their noncarcinogenic and carcinogenic health risks. Finally, the human health ambient water quality standards (AWQC) for PCBs were obtained using regional exposure parameters and bioaccumulation factors. The results showed that the pollution of PCBs in the Taihu Basin was relatively serious in China. The concentration of PCBs in dust is higher than other environmental media. And exposure to water and food is the main exposure pathway for PCBs in the population of the region. Besides, PCBs pose no noncarcinogenic risk to people in this region, but their carcinogenic risk to residents exceeds the safety threshold. Among the three population groups, adults have the highest risk of cancer, and prevention measures need to be taken by controlling the intake of related foods and the concentration of PCBs in water. The following human health AWQC values of the PCBs in Taihu Basin is 3.2 × 10−9 mg/L.

Applying ensemble climate models to predict the fate of marginal coral reefs already existing at thermal and turbidity limits in arid tropical Australia

AbstractMarine fauna, including coral reefs, exist under particular oceanographic and meteorological (metocean) processes that maintain water quality within the range limits to which they have adapted over millennia. Climate‐induced changes to these metocean processes could alter ambient marine water quality to ranges beyond those limits and at rates faster than species can adapt. Extreme (or marginal) coral reefs, such as those in arid tropical regions, already exist at the limits of their ranges for water quality parameters such as temperature and turbidity. Here, we apply projected anomalies from ensemble climate models to the metocean processes that drive turbidity in the Exmouth Gulf region of north Western Australia where habitats of significant environmental value exist. We also apply projected sea surface temperature anomalies to look at how a combined effect of turbidity and temperature might impact important habitats. We find that turbidity is predicted to increase in some parts of the Gulf and decrease in others due to differing metocean drivers of turbidity throughout the region. Temperature anomalies reveal year‐round increases in temperature consistent with current summer marine heat wave events (&gt;2.5°C above mean temperatures). Climate models used in the predictions varied between themselves underscoring the importance of model choice and of using ensembles.

Design of Automated Fish Feeder Using IoT

Abstract: The world's need for seafood is largely met by aquaculture, which calls for improvements in farming practises. In this paper, an Internet of Things (IoT)-powered Automatic Fish Feeder (AFF) system is presented. To collect data in real time, the AFF system makes use of a variety of sensors, such as those that measure ambient factors, fish activity, and water quality. Fish farmers are able to remotely monitor the conditions of the aquatic environment thanks to the processing and wireless transmission of this data by microcontrollers. Farmers may plan and modify feeding schedules, amounts, and feed mixes according to the individual requirements of the fish species using an easy-to-use mobile application. By analysing the gathered data, the system's clever algorithms optimise feeding schedules, guaranteeing that fish get the right nutrition while reducing feed waste. Moreover, by minimising overfeeding—which can result in water contamination and ecological imbalances—the AFF system fosters sustainability. This study shows how IoT technology may be successfully incorporated into aquaculture operations to improve production, save operating costs, and encourage environmental stewardship. The results of this study offer significant insights for the aquaculture sector, opening the door for the global adoption of IoT-based technologies to enhance fish farming methods

An integrated approach for water quality assessment in African catchments based on physico-chemical and biological indicators

Rapid urbanization, industrialization and population growth pose major threats to the ambient water quality, indicator 6.3.2 of the United Nations Sustainable Development Goal (SDG) 6, in African catchments. One example is the catchment of the Akaki Rivers that flow through Ethiopia's capital, Addis Ababa. The objective of this study was to demonstrate a monitoring approach for assessing the physico-chemical and ecological health status of African Rivers using locally available expertise and analytical capabilities. Representative water samples were collected from twenty-three different sampling locations in the Akaki catchment for various physico-chemical measurements. A biological assessment was conducted using the mini-stream assessment scoring system (miniSASS) tool. Principal component analysis (PCA) was applied to assess variations in water quality. The study revealed notable differences in water quality between the Little Akaki River, which flows through the city center of Addis Ababa, and the Big Akaki River, which flows mostly through the peri-urban fringe of Addis Ababa. PCA revealed higher levels of water quality parameters in the Little than in the Big Akaki River. For the Little Akaki River, except for pH, all of the measured parameters had significant seasonal variation. In contrast, for the Big Akaki River, no significant seasonal variation was observed in the measured parameters. Downstream of Addis Ababa, improvement in water quality was observed to most of the measured parameters and during all of the seasons where the Akaki Rivers pass through rural areas. There were no significant correlations between physico-chemical measurements and miniSASS scores. The study thus showed that monitoring physico-chemical parameters alone may be insufficient and biological monitoring should be included. Application of these methods and analysis of the results can help catchment scale monitoring of freshwater quality on the African continent.

Warding off freshwater salinization: Do current criteria measure up?

AbstractSalinization is a global threat to freshwater habitats that has been intensified by climate change. Monitoring, assessment and management of salinity is therefore essential. The first step is to set criteria that are sufficiently stringent to protect ecosystem health. However, many countries have not yet defined criteria, and there are substantial differences between criteria. This has been noted in the EU, where salinity is a required “supporting element” for ecological status in inland waters but also for implementation of UN Sustainable Development Goal (SDG) indicator 6.3.2. for “good ambient water quality” where different approaches and widely different threshold values were reported for salinity criteria. Much of this information has not been published and is difficult to access, hindering further efforts to address the problem. We first discuss the implications of salinization for freshwater ecological health. We go on to discuss the principles and guidelines on how salinity criteria to protect ecology should be established. Next, we review salinity criteria submitted as part of implementation of SDG indicator 6.3.2 and the EU Water Framework Directive. Finally, we discuss setting salinity thresholds in an already‐warming world and the challenges facing anyone trying to develop salinity criteria to protect freshwater ecosystems.This article is categorized under: Water and Life &gt; Stresses and Pressures on Ecosystems Water and Life &gt; Conservation, Management, and Awareness Science of Water &gt; Water Quality

Global microbial water quality data and predictive analytics: Key to health and meeting SDG 6

Microbial water quality is an integral to water security and is directly linked to human health, food safety, and ecosystem services. However, specifically pathogen data and even faecal indicator data (e.g., E. coli), are sparse and scattered, and their availability in different water bodies (e.g., groundwater) and in different socio-economic contexts (e.g., low- and middle-income countries) are inequitable. There is an urgent need to assess and collate microbial data across the world to evaluate the global state of ambient water quality, water treatment, and health risk, as time is running out to meet Sustainable Development Goal (SDG) 6 by 2030. The overall goal of this paper is to illustrate the need and advocate for building a robust and useful microbial water quality database and consortium worldwide that will help achieve SDG 6. We summarize available data and existing databases on microbial water quality, discuss methods for producing new data on microbial water quality, and identify models and analytical tools that utilize microbial data to support decision making. This review identified global datasets (7 databases), and regional datasets for Africa (3 databases), Australia/New Zealand (6 databases), Asia (3 databases), Europe (7 databases), North America (12 databases) and South America (1 database). Data are missing for low- and middle-income countries. Increased laboratory capacity (due to COVID-19 pandemic) and molecular tools can identify potential pollution sources and monitor directly for pathogens. Models and analytical tools can support microbial water quality assessment by making geospatial and temporal inferences where data are lacking. A genomics, information technology (IT), and data revolution is upon us and presents unprecedented opportunities to develop software and devices for real-time logging, automated analysis, standardization, and modelling of microbial data to strengthen knowledge of global water quality. These opportunities should be leveraged for achieving SDG 6 around the world.

Analysis of Ningxia Hui Autonomous District’s Gray Water Footprint from the Perspective of Water Sustainability

Gray water footprint (GWF) is an effective method to evaluate the degree of water pollution and water quality. It is the amount of freshwater needed to dilute water pollutants to meet ambient water quality standards. Accounting and analyzing the GWF will be significant for promoting an improved water environment and sustainable water ecology in Ningxia Autonomous District. We accounted for the GWF of all cities in Ningxia from 2012 to 2020 and evaluated its spatial-temporal variations by the GWF accounting method proposed by Hoekstra. Then, the Logarithmic Mean Divisia Index (LMDI) method was applied to investigate the contributions of four driving factors: the population scale effect, economic development effect, technological effect, and industrial structure effect. And then, the changes in the GWF in the Ningxia region were analyzed. The results showed that the GWF in the Ningxia region changed from 79.21 × 108 to 29.09 × 108 m3/yr during 2012–2020, making a significant decreasing trend. Among all cities, Wuzhong City contributes the most in terms of the GWF. More specifically, economic development and technology structure are the positive and negative drivers of the GWF, respectively. The water pollution levels in Ningxia (0.49–1.3) indicated that the waste assimilation capacity has fallen short of taking up the pollutant load, which had an unfavorable impact on the groundwater according to actual water quality data. NO3-N and NH3-N are detected in the groundwater throughout the Ningxia region, with the highest NH3-N content in the groundwater in Yinchuan, which almost exceeded the groundwater quality standard of category III. Above all, this study reflected the current water pollution situation better by combining the GWF with actual water quality data in Ningxia. The finding of this study is valuable for addressing water quality threats and developing sustainable development.

Freshwater environment risk assessment and derivation of human health ambient water quality criteria for SCCPs in China

Short-chain chlorinated paraffins (SCCPs, CxH2x+2−yCly, where x = 10 to 13 and y = 3 to x) are a complex family of emerging contaminants that have been identified as persistent, bioaccumulative and toxic (PBT) substances. Because of their persistence, high toxicity, bioaccumulation and long-distance mobility, SCCPs were added to the list of controlled POPs in the Stockholm Convention in 2017. China is the largest producer and user of SCCPs all over the world, thus SCCPs have been widely distributed in the freshwater environment. But the ecological risk and human health risk of SCCPs in China were still less evaluated. This study collected and screened the exposure data of SCCPs in freshwater environment in China, and then evaluated the freshwater and sediments ecological risk of SCCPs by risk quotient (RQ) method and the human health risk by margin of exposure (MOE) method. Our results showed that the pollution of SCCPs in the freshwater environment in China was not optimistic. The ecological risks and human health risks had occurred, and even there were high ecological risks occurred in some regions in China. Besides, because of the absence of the concentration threshold of SCCPs to protect human health in freshwater at present, we derived the human health ambient water quality criteria (AWQC) values of SCCPs based on exposure data and bioaccumulation factor (BAF) in China. The human health AWQC values of SCCPs ranged from 14.99 ng L−1 to 154.54 ng L−1 in different regions in China, and the national human health AWQC value was determined as 24.08 ng L−1. This study will provide the scientific references for the management and control of SCCPs in China, especially for the formulation of standard of water environmental quality for SCCPs.

Hydrochemical Delineation of Spring Recharge in an Urbanized Karst Basin, Central Kentucky

ABSTRACT Because of well-integrated surface and subsurface drainage in karst terrains, springs can exhibit relatively rapid hydraulic, chemical, and thermal responses to storms. In urbanized karst basins, impervious cover, stream channelization, and utility infrastructure can alter infiltration, provide alternate pathways for subsurface flow, and affect ambient water quality. We combined continuous logging of electrical conductivity (EC) and water temperature with analyses of stable isotopes (deuterium and oxygen-18) to differentiate focused and diffuse recharge in a karst basin in Lexington, Kentucky, during 2018. Logging occurred at the McConnell Springs Blue Hole and a sinkhole that drains to it; isotopes, specific conductance, and temperature were manually monitored at those sites and along two losing stream reaches. Water temperature at McConnell Springs and stable isotope abundances showed seasonal variability. The Blue Hole responded within hours to stormwater infiltration at the sinkhole (∼2.1 km upgradient), with recharge events marked by colder stormwater in winter and warmer stormwater in spring to early autumn. Stable isotopes indicated that sinkhole infiltration was minimally affected by evaporation during periods of ponding (up to 9 days). Spring discharge appeared to represent a mixture of focused and diffuse, partly evaporated recharge, consistent with a simple hydrologic model of rainfall, runoff, and infiltration in the basin. EC spikes at the spring during January–March were consistent with pulses of road salt or brine in runoff or snowmelt. Despite limited monitoring data, results suggest that restoration of the sinkhole and its inlet stream were effective in stormwater management during an un usually wet year.

Evaluation of locally-available agricultural and industrial waste materials as effective carriers for bacterial inocula in freshwater bioremediation

The pollution of freshwater is a pressing global environmental concern, necessitating effective management strategies for polluted aquatic environments. Bioremediation has emerged as a highly promising environmentally friendly approach. However, the selection of suitable candidates capable of effectively degrading or removing pollutants remains a challenging task. The introduction of live candidates, particularly bacteria, into natural environments also poses its own set of difficulties. To address these challenges, immobilizing bacteria within carrier materials has emerged as a leading option. In this study, we meticulously assessed the suitability of four locally-available and low-cost agricultural and industrial waste materials as carriers to transport bacteria into water bodies. The selection criteria encompassed bacteria immobilization capacity, viability, and the resulting water quality after treatment. In order to facilitate comparison, the widely-used sodium alginate was included as a benchmark, and Escherichia coli was employed as the model bacterial inoculum. Our findings revealed that alkaline pre-treatment of corn husk, rice husk, rice straw, and sugarcane bagasse significantly enhanced the bacteria immobilization capacity of these materials. Notably, the viability of bacteria in carrier materials, including sodium alginate, exhibited remarkable resilience, with a count of 107 CFU/g material even after 49 days of storage at room temperature. Moreover, upon determining the quality parameters of the receiving water, the introduction of rice husk and sodium alginate materials demonstrated no significant adverse impact. The quality parameters were well within the acceptable range defined by the World Health Organization standards for drinking water and the Sri Lankan ambient water quality standards for various purposes. Based on the overall performance evaluation, we advocate for the application of rice husk and sodium alginate as superior carriers for delivering bacterial inocula to aquatic environments, particularly in polluted water bodies targeted for bioremediation efforts. Nonetheless, we recommend the collection of carrier materials only after the establishment of bio inoculum in the receiving water, as a precautionary measure to minimize any potential impact on the chemical oxygen demand of the water.

Hydrochemical Delineation of Spring Recharge in an Urbanized Karst Basin, Central Kentucky

ABSTRACT Because of well-integrated surface and subsurface drainage in karst terrains, springs can exhibit relatively rapid hydraulic, chemical, and thermal responses to storms. In urbanized karst basins, impervious cover, stream channelization, and utility infrastructure can alter infiltration, provide alternate pathways for subsurface flow, and affect ambient water quality. We combined continuous logging of electrical conductivity (EC) and water temperature with analyses of stable isotopes (deuterium and oxygen-18) to differentiate focused and diffuse recharge in a karst basin in Lexington, Kentucky, during 2018. Logging occurred at the McConnell Springs Blue Hole and a sinkhole that drains to it; isotopes, specific conductance, and temperature were manually monitored at those sites and along two losing stream reaches. Water temperature at McConnell Springs and stable isotope abundances showed seasonal variability. The Blue Hole responded within hours to stormwater infiltration at the sinkhole (∼2.1 km upgradient), with recharge events marked by colder stormwater in winter and warmer stormwater in spring to early autumn. Stable isotopes indicated that sinkhole infiltration was minimally affected by evaporation during periods of ponding (up to 9 days). Spring discharge appeared to represent a mixture of focused and diffuse, partly evaporated recharge, consistent with a simple hydrologic model of rainfall, runoff, and infiltration in the basin. EC spikes at the spring during January–March were consistent with pulses of road salt or brine in runoff or snowmelt. Despite limited monitoring data, results suggest that restoration of the sinkhole and its inlet stream were effective in stormwater management during an unusually wet year.

QSAR-QSIIR-based prediction of bioconcentration factor using machine learning and preliminary application

Bioconcentration factor (BCF) is one of the important parameters for developing human health ambient water quality criteria (HHAWQC) for chemical pollutants. Traditional experimental method to obtain BCF is time-consuming and costly. Therefore, prediction of BCF by modeling has attracted much attention. QSAR (Quantitative Structure-Activity Relationship) model based on molecular descriptor is often used to predict BCF, however, in order to improve the accuracy of prediction, previous models are only applicable for prediction for a single category of substance and a single species, and cannot meet the needs of BCF prediction of pollutants lacing toxicity data. In this study, optimized 17 traditional molecular descriptor and five kinds of bioactivity descriptor were selected from more than 200 molecular descriptor and 25 kinds of biological activity descriptors. A QSAR-QSIIR (Quantitative Structure In vitro-In vivo Relationship) model suitable for multiple chemical substances and whole species is constructed by using optimized 4-MLP machine learning algorithm with selected molecular and bioactivity descriptors. The constructed model significantly improves the prediction accuracy of BCF. The R2 of verification set and test set are 0.8575 and 0.7924, respectively, and the difference between predicted BCF and measured BCF is mostly less than 1.5 times. Then, BCF of BTEX in Chinese common aquatic products is predicted using the constructed QSAR-QSIIR model, and the HHAWQC of BTEX in China are derived using the predicted BCF, which provides a valuable reference for establishment of China’s BTEX water quality standards.

Pathways to water sustainability? A global study assessing the benefits of integrated water resources management

Integrated water resources management (IWRM) has been central to water governance and management worldwide since the 1990s. Recognizing the significance of an integrated approach to water management as a way to achieve the Sustainable Development Goals (SDGs), IWRM was formally incorporated as part of the SDG global indicator framework, thus committing the UN and its Member States to achieving high IWRM implementation by 2030 and measuring progress through SDG indicator 6.5.1. This paper examines the extent to which the implementation of IWRM improves the sustainable management of water and the health of water-related ecosystems—a first-of-its-kind in terms of quantitative analysis on a global scale. To achieve this objective, we conducted regression analyses between SDG 6.5.1 (both IWRM (total score) and the dimensions of SDG 6.5.1) and key water-related environmental sustainability indicators: SDG 6.2.1a (access to basic sanitation), 6.3.1 (treated wastewater), 6.4.1 (water-use efficiency), 6.4.2 (water stress), 6.6.1 (freshwater ecosystems, although here the trophic state and turbidity variables were used) and 6.3.2 (ambient water quality). Our analysis covers 124 countries for all these SDGs, with the exception of SDG 6.3.1 and SDG 6.3.2, which cover 112 and 85 countries, respectively. Results show that IWRM—to different degrees—is mainly associated with the good status of water-related sustainability indicators, with the exception of water stress, water quality, and turbidity. We observe a strong impact of control variables such as governance arrangements, economic situation and environmental and geographical conditions. Lagged effects and the scope of the framework may also explain some observed variations in the degree of association. Our study highlights the importance of further uncovering the interlinkages between IWRM implementation and the achievement of water-related environmental sustainability. Overall, the results suggest that although IWRM implementation is primarily linked to sustainable water management and the health of water systems, context-specific factors should be taken into account when evaluating its effectiveness, to enable policy- and decision-makers to make the necessary adjustments to optimize its outcomes.

The Application of Reference Dose Prediction Model to Human Health Water Quality Criteria and Risk Assessment.

Oral reference dose (RfD) is a key parameter for deriving the human health ambient water quality criteria (AWQC) for non-carcinogenic substances. In this study, a non-experimental approach was used to calculate the RfD values, which explore the potential correlation between toxicity and physicochemical characteristics and the chemical structure of pesticides. The molecular descriptors of contaminants were calculated using T.E.S.T software from EPA, and a prediction model was developed using a stepwise multiple linear regression (MLR) approaches. Approximately 95% and 85% of the data points differ by less than 10-fold and 5-fold between predicted values and true values, respectively, which improves the efficiency of RfD calculation. The model prediction values have certain reference values in the absence of experimental data, which is beneficial to the advancement of contaminant health risk assessment. In addition, using the prediction model constructed in this manuscript, the RfD values of two pesticide substances in the list of priority pollutants are calculated to derive human health water quality criteria. Furthermore, an initial assessment of the health risk was performed by the quotient value method based on the human health water quality criteria calculated by the prediction model.