Environmental Protection Agency Research Articles

Spatio-temporal variation of microbial indicators of river water and treatment efficiencies of drinking water treatment plants along the upper Mahaweli river segment of Sri Lanka.

The microbial pollution status of river surface water is important to ensure a river-based quality drinking water supply for the public. The present study aimed to investigate bacterial contamination status in the upper Mahaweli River, the main drinking water supplier to the hill country of Sri Lanka. Both the raw surface water and treated water, taken at 14 drinking water treatment plants (DWTPs) along the river segment of 60km between Kotmale and Victoria reservoirs, were tested for total bacterial counts (TBC), total coliform counts (TCC) and faecal coliform counts (FCC). Irrespective of the flow, the selected river segment showed significant contamination variations of TBCs, TCCs and FCCs between dry and wet seasons due to point source discharges and drains of septic waste. The level of pollution was enhanced in the wet season due to the diffusion of pollutants with the runoff. Locations of DWTPs could be clustered into 3 categories according to microbial contamination as very low (Kotagala, Thalawakelle-Galkanda, Kandy South, Pundaluoya, Ulapane, Greater Kandy), moderate (Nawalapitiya, Paradeka, Elpitiya, Nillambe, Balagolla, Haragama, University Plant, Polgolla) and high (Thalawakelle-Nanuoya). Although the bacterial reduction efficiencies of many DWTPs (10 out of 14) were higher than 77.9%, treated water samples from 10 DWTPs exceeded the maximum TBC recommended by the US Environmental Protection Agency (2.70 log10CFU/mL) for drinking water, during wet season due to high bacterial load in the surface water. Isolates from treated water were Gram-positives with Staphylococci (74.3%) and Micrococci (25.7%). Total coliforms and faecal coliforms were absent in treated water satisfying the SLS 614:2013 guidelines for drinking water. The disinfection process of DWTPs should be improved to ensure the safety of drinking water, particularly during the wet season. Incorporation of more microbiological parameters into routine testing practices is important in understanding bacterial load and diversity to improve treatment strategies.

Chemical mixtures of mercury, PCBs, PFAS/PFOS, and pesticides in freshwater fish in the US and the risks they pose for fish consumption

Freshwater fish are important food sources that also pose risks to human and wildlife health because of the bioaccumulation of environmental chemicals in their tissues. Although most studies, fish consumption advisories, and regulations focus on individual contaminants, fish consumers are exposed to mixtures of chemicals, including legacy contaminants and contaminants of emerging concern, that can have combined effects. Chemicals of emerging concern represent one source of hazard, but legacy contaminants can still pose threats to fish consumers due to their persistence in the environment. We investigate the following questions: 1) Do different chemicals correlate with one another in fish tissue, and if so, how? 2) How do levels of different chemicals in fish tissue vary by time and location? and 3) How do observed chemical levels compare with risk-based screening levels? Using several national data sources established and maintained by the US Environmental Protection Agency (NRSA, NCCA-GL, GLENDA, and NLFTS), this study examines the co-occurrence of chemicals in freshwater fish in lakes, ponds, streams, and rivers in the US. We determine that organic contaminants correlate with one another, but generally not with mercury; organic chemicals have declined over time, but mercury has not; and fish concentrations of legacy contaminants-even those banned for decades-continue to exceed risk-based screening levels. Despite some successes in curtailing release of pollutants, some contaminants in fish tissue have not declined and legacy and emerging pollutants continue to pose risks to fish consumers in the US. Correlations between chemicals in fish tissue suggest that exposures to mixtures is prevalent in the US but that organic contaminants do not generally correlate with mercury-noteworthy particularly since fish consumption advisories in the US are frequently driven by the level of mercury, and do not account for exposure to multiple contaminants. While programs such as the National Aquatic Resource Surveys (NARS) Program seek to systematically monitor contaminants in fish tissue and other environmental indicators, continuous support from the US federal government is required to sustain this monitoring. Moreover, greater legislative and regulatory efforts are required at both the state and federal levels to reduce continuing sources and ongoing contamination.

Screening for Endocrine Bioactivity Potential of Tobacco Product Chemicals Including Flavor Chemicals.

Adolescence and pregnancy involve elevated levels of hormones (e.g., estrogen, androgen) during which exposure to endocrine disruptors could have long-term developmental and reproductive toxicity (DART) effects. Therefore, the use prevalence and abuse liability of electronic nicotine delivery systems (ENDS) among adolescents and youth, and during pregnancy, raises concerns about possible exposure to endocrine disruptors. In addition, endocrine disruptors have adverse effects on wildlife and environmental health. While many studies focus on carcinogenicity and mutagenicity of tobacco products, research efforts screening chemicals in tobacco products for endocrine disruption potential are few. In this study, we curated 5179 chemicals in tobacco and tobacco smoke, 2803 flavor chemicals, and 156 e-liquid chemicals from literature or openly available databases. We screened the chemicals for endocrine bioactivity using new approach methodologies (NAMs) developed through US Environmental Protection Agency's Endocrine Disruptor Screening Program. The specific NAMs, estrogenic and androgenic pathway models, identified 137 tobacco chemicals, 34 flavor chemicals, and three e-liquid chemicals (Veratraldehyde, (2E)-3-Phenylprop-2-enal, and 2'-Acetonaphthone) as "active," indicating potential endocrine bioactivity. Further, among the tobacco chemicals with endocrine bioactivity potential, 48 were environmentally persistent, 29 bioaccumulative, and 19 both persistent and bioaccumulative. Our findings document many chemicals in tobacco products with potential endocrine bioactivity, which raises concerns for both human and environmental health. These results also underscore the importance of DART potential of tobacco products and flavors. Overall, our study characterizes the endocrine bioactivity potential of tobacco and flavor chemicals and provides a list of chemicals to consider in future ecological and health risk assessments.

How does the water flow? And does data follow it?

Climate adaptation and effective flood management require accurate and accessible data on water levels and water flow. In consultation with the Danish Geological Survey (GEUS), the Danish municipalities association (KL), and the Danish Environmental Protection Agency as well as the private companies WatsonC, DRYP, and WSP, Denmark's Environmental Portal (DMP) has developed an IT system for water levels, water flow and groundwater level measurements. The system makes it possible to compile data from different loggers in near real time. The system supports authorities such as the Danish Meteorological Institute (DMI) and municipalities in their work to prepare flood warnings and implement climate adaptation plans. It also enables a broader use of data that was originally collected for specific purposes, such as mass transport calculations and crop cutting, and it opens up new solutions at the societal level. As groundwater rises and climate adaptation problems grow, it is essential to have access to integrated data on both watercourses and groundwater level measurements. The new system supports the work of municipalities and utilities on these challenges, and makes it possible to share data effectively across public authorities. In addition, the system opens up the development of commercial IT solutions that can help tackle future climate adaptation challenges.

An investigation into the influence of climate extreme on groundwater regimes and human health in the Periyar Basin: a fast growing urban centre in India

ABSTRACT A total of 212 groundwater samples were collected during North East Monsoon (NEM), South West Monsoon (SWM), Pre-Monsoon (PREM), and Post-Monsoon (POM) seasons of 2020–2021 from the Periyar River Basin, draining the south western flanks of Western Ghats. The analytical results revealed the order of abundance of cations as Ca2+ > Na+ > Mg2+ > K+ and anions in the order of HCO3− > Cl− > SO42− > NO3− for all seasons. The major hydrochemical facies identified were CaHCO3 and mixed Ca–Mg–Cl in all the seasons with rock–water interaction as the key process regulating water chemistry. Ionic ratios of Ca2+ + Mg2+/Na+ + K+ and Ca2+/Mg2+ suggested significant effect of silicate minerals and other sources. The Water Quality Index (WQI) shows that the majority of the samples, namely, 98% in NEM, 86% in POM, 82% in PREM, and 95% in MON, fall in the categories ranging from excellent to good for drinking purposes. Furthermore, the health risk assessment based on carcinogenic and non-carcinogenic risk of the United States Environmental Protection Agency (US EPA) during monsoon and non-monsoon seasons for adults and children revealed the potential risk posed by Pb via oral exposure in the study area suggesting children are more susceptible to the damaging effects than adults.

Miniaturisation of the Daphnia magna immobilisation assay for the reliable testing of low volume samples

International standard test guidelines for the ecotoxicological characterisation of various substances use organisms such as algae, daphnids and fish embryos. These guidelines recommend or use relatively high volumes of water for the process of testing, for example, 200 mL for a complete dose–response relationship in a daphnia assay. However, for various samples such as concentrated extracts from environmental monitoring or leachates from microplastic ageing experiments, the amount of available sample volume is limited, that is, rather in the range of 10–50 mL/biotest. Using the exposure volumes as recommended in test guidelines would not allow to test a range of different concentrations or to repeat tests or use multiple different organismic bioassays. Lower media volumes would allow the testing of more samples (more concentrations per sample, more test repetitions for statistical robustness, etc.) but it may also decrease the possible number of organisms tested in the same volume. Here, we aimed at reducing the test volumes in the acute daphnia assay (using a maximum of 30 mL for a complete dose–response relationship) without impacting animals’ sensitivity towards toxicants. A literature review on existing miniaturisation approaches was used as a starting point. Subsequently, assays employing conventional as well as reduced test volumes were compared for 16 selected test substances with a diverse spectrum of lipophilicity. Results showed that there are differences in EC50 between the two approaches, but that these differences were overall only within a range of a factor of two to three. Further, by retrieving EC50 values for the genus Daphnia and 16 test substances from the United States Environmental Protection Agency database, we demonstrated that our results are well in line with the general differences in sensitivities.

How Much Room is there for Negotiations between Upper and Lower Governments in an Authoritarian System? A Case Study from the Reform of China's Environmental Protection Agencies

China restructured its environmental protection agencies in 2019 to address environmental governance challenges. The restructuring aimed to reorganize the bureaucracy by transferring local environmental monitoring responsibilities to provincial departments, thereby breaking the traditional governance structure in which local governments are both "athletes" and "referees". Since the reform involved functional reorganization, realignment of interests, and redistribution of institutional authority, local governmental departments and reassigned personnel actively participated in the negotiation process, to safeguard their own interests. A case study in G City, southern China, this paper explored limited negotiation between the municipal Environmental Protection Bureau and the Provincial Department of Ecology and Environmental Protection. Within China's authoritarian system, constrained negotiation showed distinct operational logic and characteristics. Key negotiation strategies included "weapons of the weak," "threat withdrawal," and "collusion" to advance reform. However, in order to maintain the authority of their superiors and respect the legal relationship of the bureaucratic structure, the subordinates ultimately use the ambiguity of the central documents as the dividing line for the limited negotiation space between the two parties.

Navigating Rough Waters After Sackett v. EPA

The Clean Water Act is the primary federal law regulating impacts to water resources and water quality in the United States. Congress asserted the focus of the Act in the first section: to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters. Federal jurisdiction to implement this focus for many of the Act’s water protection programs turns on whether a waterbody is classified as a “Water of the United States” (WOTUS). The definition of WOTUS has been contested since the ink dried on the Act, with proponents of greater water protections arguing for more expansive boundaries of federal jurisdiction. Most recently, the Supreme Court re-interpreted WOTUS in Sackett v. Environmental Protection Agency (2023), in which the Court held that wetlands 300 feet from Priest Lake would no longer be considered adjacent wetlands protected as WOTUS. Upending forty-five years of agency and judicial interpretation, the Court narrowed the definition of WOTUS to only those wetlands that have a continuous surface connection to a traditionally navigable body of water, such as a river or lake. This places many wetlands and ephemeral and intermittent streams outside of federal jurisdiction, and thus, the protections of the CWA. Yet, wetlands and nonperennial streams are vital to the chemical, physical, and biological integrity of the Nation’s waters. Wetlands filter pollutants from water, retain and absorb flood waters, and provide habitats for wildlife. Ephemeral and intermittent streams are ubiquitous and important pathways that drain water and pollutants into traditional navigable waters. Removing federal protections means these areas are vulnerable to ruin by human alterations, and it increases flood risks to downstream communities. Decreasing federal jurisdiction over the majority of wetlands and nonperennial streams across the U.S. places a greater emphasis on the role of states and tribes in water protection. Lacking a consistent federal approach results in a patchwork of protections for waters that are now considered nonfederal, even when those waters impact large regional shared waters, such as the Great Lakes, the Mississippi River, the Colorado River, and Rio Grande, to name a few. This Article starts with a grounding in the scientific literature to explore the importance and vital functions of the waters that have lost federal jurisdiction. Using that as a springboard, we explain the most important legal decisions defining WOTUS to place Sackett v. EPA in context. We then discuss the divergent responses to the loss of federal jurisdiction by surveying responses at federal, tribal, and state levels of government. We show that many tribes opposed reducing federal protections leading up to Sackett, and after the decision, at the federal and state level, the battle continues over removing versus restoring regulatory protections. We observe that even in states where reducing regulatory control is favored, agreements have been forged around non-regulatory programs that fund wetland protections. We conclude that tribes and states have the power to shape protections for these vital waters regardless of federal jurisdiction, but with no federal regulatory backstop, the integrity of the Nation’s waters is threatened by this piecemeal approach.

Hydrological Parametric Investigation of Water Distribution Network for Sawale Village, Raigad District (Maharashtra): A GIS Approach

The water distribution network (WDN) is considered one of the most important infrastructural requirements for future cities worldwide. In order to meet the growing water demand of the developing population, it is essential to design a sustainable WDN. In recent decades, numerous researches have been conducted in this field considering various parameters, but poor WDN layout design leads to increasing project cost in terms of execution, maintenance, etc. Hence, the objective of this research work was to overcome the above drawbacks by designing a real time network for a rural emerging village near Rasayani, Maharashtra with the help of Geographical Information System (GIS) and hydraulic simulation using Environmental Protection Agency Network (EPANET). The area of Sawale village is surveyed both physically and using the software. The basic objective of this research is to determine the best possible way in which a given WDS can be optimized to meet the current water demand in Sawale village. EPANET is hydraulic simulation software that can be efficiently used for such purposes. The results show that hydraulic simulation together with the application of GIS helps to create a less time consuming, sustainable and optimized WDN.

A National Synthetic Populations Dataset for the United States

Geospatially explicit and statistically accurate person and household data allow researchers to study community-and neighborhood-level effects and design and test hypotheses that would otherwise not be possible without the generation of synthetic data. In this article, we demonstrate the workflow for generating spatially explicit household- and individual-level synthetic populations for the United States representing the year 2019. We use publicly available U.S. Census American Community Survey (ACS) 5-year estimates from the 2015–2019 ACS. We use Iterative Proportional Fitting (IPF) to create our synthetic population and use the resulting joint counts to sample representative households and people directly from microdata. Our dataset contains records for 120,754,708 households and 303,128,287 individuals across the United States. We spatially allocate households using the Environmental Protection Agency (EPA) Integrated Climate and Land Use Scenarios (ICLUS) project household distribution estimates to create a spatially explicit dataset. Our validation shows strong correlation with original census variables, with many categories reporting a greater than 0.99 Pearson’s r correlation coefficient.

Copper-Induced Enhancement of Glioblastoma Tumorigenicity via Cytochrome C Oxidase

Copper is an essential trace element, yet chronic copper exposure can lead to toxicity in humans, and high levels of copper have been found in the blood or tumors of patients with various forms of cancer and may affect cancer severity and response to treatment. Copper is required for the activation of cytochrome c oxidase (CcO), the mitochondrial complex that facilitates oxidative phosphorylation (OXPHOS)-mediated ATP production. We recently reported that the increased activation of CcO underlies the acquisition of treatment resistance in glioblastoma (GBM) cells. However, the potential role of copper in GBM progression or treatment resistance has not been investigated. Here, we present evidence that exposure to 20 µM copper, the maximum allowable limit for public water supplies set by the U.S. Environmental Protection Agency, promotes GBM tumor growth and reduces overall survival in vivo and increases GBM cell resistance to radiation and chemotherapy in vitro. In vitro exposure to 20 µM copper substantially increased the activity of CcO, elevated the rate and level of ATP production, and triggered a metabolic shift to an OXPHOS phenotype in GBM cells. Furthermore, copper exposure led to a substantial increase in the accumulation of glutathione and glutathione precursors in these cells. These findings establish copper as a tumor promoter in GBM and suggest that copper mediates these effects through the upregulation of CcO activity, which enhances OXPHOS metabolism and glutathione production.

Good Intention, Bad Result? Government Subsidies for Green Consumerism in the Remanufacturing Industry

The green ecological property is increasingly recognized as a sustainable option in remanufacturing. In practice, despite the environmental concerns expressed by consumers, the growth of the remanufacturing industry falls short of expectations, largely due to the fact that, although remanufacturing conserves costs and is beneficial to our environment, it may not be a profitable option for OEMs, a major barrier in its appearance to green consumers. Many researchers have proposed that environmental groups and similar entities should provide necessary subsidies to encourage green consumerism and improve the profitability of the remanufacturing industry. In this paper, we intend to address how the subsidy policy on green consumerism impacts an OEM’s incentives in remanufacturing; more specifically, we develop two theoretical models: Model N, in which the OEM does not undertake remanufacturing, and Model R, in which the OEM does undertake remanufacturing under the subsidy policy for encouraging green consumerism. In addition to confirming the traditional wisdom that the subsidy policy encourages the remanufacturing industry, our analysis surprisingly reveals that, if a few consumers characterize green consumerism, the aggressive subsidy policy may potentially result in a cannibalization problem, in which remanufacturing hurts the OEM’s overall profits. Therefore, the government and environmental protection agencies need to fully consider the characteristics of the industry to avoid a “good intention, bad result” situation.

Industrial air emissions and breast cancer incidence in a United States-wide prospective cohort.

We evaluated air emissions of industrial compounds, many of which have carcinogenic or endocrine disrupting properties, in relation to breast cancer incidence. Using the United States Environmental Protection Agency's Toxics Release Inventory, we quantified air emissions of 28 compounds near Sister Study participants' residences during the 10 years leading up to study enrollment (2003-2006; n=46,150). We used Cox proportional hazards regression to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for associations of residential emission levels of single pollutants with incident breast cancer. We assessed pollutant mixtures using an Exposure Continuum Mapping (ECM) framework and characterized associations using a joint-exposure response function. During follow-up (median=13.4 years), we identified 4,155 breast cancer cases. We observed non-monotonic but elevated associations with breast cancer for emissions within 3km of the residence for nickel compounds (HRquintile5vs.none = 1.3; 95% CI 1.0, 1.6) and trichloroethylene (HRquintile5vs.none = 1.3; 95% CI 1.0, 1.6). ECM identified 25 mixture profiles that explained 72% of the variance in emissions patterns, with most participants experiencing relatively low emissions profiles. The joint-exposure response function suggested that higher incidence of breast cancer occurred among individuals with relatively rare, high emissions profiles; however, the overall trend was not associated with breast cancer (p=0.09). In our study, breast cancer incidence was associated with air emissions of certain industrial carcinogens. Although the overall emissions mixture did not show a trend related to breast cancer, this may not reflect the importance of individual compounds or specific emissions sources.

Assessing riparian functioning condition for improved ecosystem services: A case study of the Back Creek watershed (Virginia, USA).

Riparian functioning condition refers to a rating and description of the current ecological status of a reach of a riparian ecosystem in consideration of its potential hydrology, vegetation, and geomorphology. Reach rating options are Proper Functioning Condition (PFC), Functional-At-Risk (FAR), Non-Functional, and apparent or monitored trends. We assessed the functioning condition of flowing riverbank areas of Back Creek located in Virginia (USA) following a PFC protocol developed by the U.S. Department of the Interior and the U.S. Department of Agriculture. The PFC protocol involves 17 qualitative assessment items that address three categories of attributes (hydrology, vegetation, and geomorphology); each is answered as "yes", "no," or "not applicable" with an explanation. We discussed key PFC items driving stream water quality contextualizing the previously modeled riparian buffer zones and ecosystem services tradeoffs in the Back Creek watershed published by U.S. Environmental Protection Agency. Using the remote sensing data in the Geographic Information System, we delineated and characterized 26 Back Creek reaches of 41.1km length. We also analyzed the 38-year (1981-2018) daily datasets of the precipitation, surface runoff, temperature, soil moisture pattern, and vegetation types for the watershed. Then, we conducted the PFC assessments using field reconnaissance of 10 reaches, 19.3km of the Back Creek. The field assessments concluded that 52% of the assessed length of Back Creek was in PFC, attributed to diverse vegetation, maintained channel characteristics, floodplain accessibility (where appropriate), and balanced water and sediment loading supplied by individual headwater streams to the Back Creek. 48% of the assessed length was in FAR condition due to land use changes and urban road network. This study provides an exemplar of nonpoint source (diffused pollution generated by land runoff) methodology for identifying key riparian functioning issues and assessing effectiveness of the non-point source best management practice programs.

A global review on perfluoroalkyl acids (PFAAs) in the riverine systems: Environmental behaviours and risks implications.

This review provides a comprehensive global overview of the occurrences, distribution, emissions, and associated risks of perfluoroalkyl acids (PFAAs) in riverine systems across both developed and developing countries including the United States (US), Spain, France, Netherlands, Germany, Pakistan, China, Korea, Vietnam, Italy, and Japan. Data for this review were systematically gathered through a comprehensive and structured search process using various databases, search engines, and academic repositories to identify relevant literature and studies. Human health risks were assessed using recommended United States Environmental Protection Agency (USEPA) models, including estimated daily intake (EDI), hazard risk (HR), and hazard index (HI) for each reported PFAA compound in the studied countries. The overall results revealed significant variability in PFAAs contamination from the 1950s to 2023, reflecting extensive industrial usage and increasing environmental concerns, with levels often exceeding the permissible limits set by environmental quality standards established by national or international regulatory authorities, agencies, and organizations. Among the studied countries, Italy exhibited the highest average sum of PFAA compounds (∑PFAAs) concentration in riverine water, ranging from 4.07 to 140.61ng/L, with an average of 41.37ng/L, followed by the Netherlands, China, Japan, the US, Pakistan, Spain, France, Germany, Korea, and Vietnam. Similarly, Germany showed the highest average ∑PFAAs concentration in riverine sediments, ranging from 40.25 to 213.00ng/g, with an average of 126.63ng/g, followed by China, Spain, the US, Pakistan, Vietnam, and Korea. Whereas, in riverine fish, Spain had the highest average ∑PFAAs concentration, ranging from 0.05 to 144.97ng/g, with a mean of 15.94ng/g, followed by Korea, Vietnam, and the US. From a human risk perspective, the highest average EDI of ∑PFAAs via riverine water consumption was observed in the dependent population of Italy (2.02×10-3ng/L/day), followed by the Netherlands (8.24×10-4ng/L/day), the US (5.56×10-4ng/L/day), Pakistan (3.99×10-4ng/L/day), Japan (3.69×10-4ng/L/day), France (3.42×10-4ng/L/day), China (2.58×10-4ng/L/day), Spain (2.43×10-4ng/L/day), Germany (1.17×10-4ng/L/day), Korea (6.01×10-5ng/L/day), and Vietnam (1.28×10-5ng/L/day). For fish consumption, Spain recorded the highest average EDI of ∑PFAAs (9.92×100ng/g/day) in its dependent population, followed by the US (3.44×100ng/g/day), Korea (8.13×10-1ng/g/day), and Vietnam (4.99×10-1ng/g/day). The non-carcinogenic HR values for individual PFAA compounds via riverine water intake in the dependent populations of both developed and developing countries were within acceptable limits (<1). However, the HI values for ∑PFAAs intake via riverine fish consumption in the dependent population exceeded the threshold (>1) in the developed countries, the US and Spain, indicating higher potential risks associated with fish consumption in these countries. Given the inadequate wastewater treatment facilities in many regions, coupled with untreated runoff from urban areas and agricultural fields draining directly into rivers, this study underscores the urgent need for integrated prevention and control measures to mitigate PFAAs contamination in riverine systems and reduce associated risks. Ultimately, stricter regulations, improved monitoring, and enhanced water treatment technologies are crucial to reducing PFAAs contamination and safeguarding public health.

Bioactivity of the ubiquitous tire preservative 6PPD and degradant, 6PPD-quinone in fish and mammalian-based assays.

6PPD-quinone (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone), a transformation product of the antiozonant 6PPD (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) is a likely causative agent of coho salmon (Oncorhynchus kisutch) pre-spawn mortality. Stormwater runoff transports 6PPD-quinone into freshwater streams, rapidly leading to neurobehavioral, respiratory distress, and rapid mortality in laboratory exposed coho salmon, but causing no mortality in many laboratory-tested species. Given this identified hazard, and potential for environmental exposure, we evaluated a set of U.S. Environmental Protection Agency's high throughput assays for their capability to detect the large potency difference between 6PPD and 6PPD-quinone observed in coho salmon and screen for bioactivities of concern. Assays included transcriptomics in larval fathead minnow (FHM), developmental and behavioral toxicity in larval zebrafish, phenotypic profiling in a rainbow trout gill cell line, acute and developmental neurotoxicity in mammalian cells, and reporter transcription factor activity in HepG2 cells. 6PPD was more consistently bioactive across assays, with distinct activity in the developmental neurotoxicity assay (mean 50th centile activity concentration = 0.91 µM). While 6PPD-quinone was less potent in FHM and zebrafish, and displayed minimal neurotoxic activity in mammalian cells, it was highly potent in altering organelle morphology in RTgill-W1 cells (phenotype altering concentration = 0.024 µM compared to 0.96 µM for 6PPD). Although in vitro sensitivity of RTgill-W1 cells may not be as sensitive as intact Coho salmon, the assay may be a promising approach to test chemicals for 6PPD-quinone-like activities. The other assays each identified unique bioactivities of 6PPD, with neurobehavioral and developmental neurotoxicity being most affected, indicating a need for further assessment of this chemical.

Biomonitoring potential of trace metal accumulation and bioavailability in coral skeletons and reef sediments of Persian Gulf: A comparative study.

Nayband Marine National Park in the northern Persian Gulf is an important ecological areas, significantly impacted by industrial activites that poses risk of trace metal pollution to living organisms. In this study, we investigated the bioaccumulation of trace metals in scleractinian corals using annual growth bands and biota-sediment accumulation factor to assess their potential as biomonitoring organisms. Furthermore, to assess the sediment quality, sediment pollution indices and international guidelines was employed. To achieve this, three Faviidae coral and sixteen sediment samples were collected in March 2023 from three sites: an industrial zone (site I), a rural fishing zone (site II), and a marine protected area (site III). In first step, coral samples washed, sun-dried, sliced into 1-cm slabs, X-rayed to reveal annual growth bands, and powder was prepared from each growth band. Then freeze-dried sediments and coral powder were ground, sieved (63 μm), digested (using United States Environmental Protection Agency - Method 3050b) and filtered (Whatman No. 42). Finally, trace metals were analyzed using Inductively Coupled Plasma Mass Spectrometry instrument. The results show severe anthropogenic pollution at sites I and II compared to site III and significant differences between their sampling stations. Mg and Sr concentrations were highest in sediments and corals, respectively, while, Co is lowest in both. According to the sediment pollution indices, Site I showed the highest potential toxicity to biota, followed by Site II and then Site III. The results also suggest that the Faviidae corals are effective bio-indicators for Pb, Li, Cu, and Ni contamination.

Determination of the zebrafish embryo developmental toxicity assessment (ZEDTA) as an alternative non-mammalian approach for the safety assessment of agrochemicals.

With the US Environment Protection Agency reducing requests for (and funding of) mammalian studies alongside the proposed elimination of requests by 2035, there is an urgent need for fully validated New Approach Methods (NAMs) to fill the resultant gap for safety assessment of agrochemicals. One promising NAM for assessing the potential for human prenatal developmental toxicity potential is the Zebrafish Embryo Developmental Toxicity Assessment, a bioassay that has been used by the pharmaceutical industry for more than a decade in early-stage drug safety assessment. Despite its promise, little data has been generated to assess the validity of ZEDTA for assessing Developmental and Reproductive Toxicity of new agrochemical products. Addressing this knowledge gap, we tested 67 compounds (insecticides, herbicides and fungicides) spanning multiple different chemical groupings and mechanisms of action. ZEDTA assay results were compared with the European Chemicals Agency (ECHA) Classification and Labelling (C&L) for mammalian hazard classification and with publicly available data to determine the ZEDTA's translation power. Overall, the ZEDTA assay had an effective detection capability of 65 % for sensitivity and 64 % for specificity as compared with the ECHA-C&L classification and publicly available data. Comparing the ZEDTA data there were both strengths and weaknesses in alignments for across the different chemical classes and chemical mechanisms of action. Overall, the data generated, show the performance of the ZEDTA assay was comparable with other bioassays highlighted as alternatives for mammalian assessment and holds good promise as a NAM for screening agrochemical prenatal developmental toxicity during new product human safety assessment.

A hybrid Harris Hawks Optimization with Support Vector Regression for air quality forecasting

This paper proposes a hybridized model for air quality forecasting that combines the Support Vector Regression (SVR) method with Harris Hawks Optimization (HHO) called (HHO-SVR). The proposed HHO-SVR model utilizes five datasets from the environmental protection agency’s Downscaler Model (DS) to predict Particulate Matter () levels. In order to assess the efficacy of the suggested HHO-SVR forecasting model, we employ metrics such as Mean Absolute Percentage Error (MAPE), Average, Standard Deviation (SD), Best Fit, Worst Fit, and CPU time. Additionally, we contrast our methodology with recently created models that have been published in the literature, such as the Grey Wolf Optimizer (GWO), Salp Swarm Algorithm (SSA), Henry Gas Solubility Optimization (HGSO), Barnacles Mating Optimizer (BMO), Whale Optimization Algorithm (WOA), and Manta Ray Foraging Optimization (MRFO). In particular, the proposed HHO-SVR model outperforms other approaches, establishing it as the optimal model based on its superior results.

Satellite monitoring of annual US landfill methane emissions and trends

Abstract We use satellite observations of atmospheric methane from the TROPOMI instrument to estimate total annual methane emissions for 2019–2023 from four large Southeast US landfills with gas collection and control systems. The emissions are on average 6× higher than the values reported by the landfills to the US Greenhouse Gas Reporting Program (GHGRP) which are used by the US Environmental Protection Agency for its national Greenhouse Gas Inventory (GHGI). We find increasing emissions over the 2019–2023 period whereas the GHGRP reports a decrease. The GHGRP requires gas-collecting landfills to estimate their annual emissions either with a recovery-first model (estimating emissions as a function of methane recovered) or a generation-first model (estimating emissions from a first-order decay applied to waste-in-place). All four landfills choose to use the recovery-first model, which yields emissions that are one-quarter of those from the generation-first model and decreasing over 2019–2023, in contrast with the TROPOMI observations. Our TROPOMI estimates for two of the landfills agree with the generation-first model, with increasing emissions over 2019–2023 due to increasing waste-in-place or decreasing methane recovery, and are still higher than the generation-first model for the other two landfills. Further examination of the GHGRP emissions from all reporting landfills in the US shows that the 19% decrease in landfill emissions reported by the GHGI over 2005–2022 reflects an increasing preference for the recovery-first model by the reporting landfills, rather than an actual emission decrease. The generation-first model would imply an increase in landfill emissions over 2013–2022, and this is more consistent with atmospheric observations.