Human Health Risk Assessment Research Articles

Ecological and Human Health Risk Assessment Based on Stream Sediments from Coastal Oecusse (Timor)

Timor Island is located in a geologically complex region strongly affected by the collision of the Australian margin with the Banda volcanic arc. In Oecusse, an enclave of East Timor in the western part of Timor, crop out several lithological units of the Banda Terrane that are associated with the obduction of oceanic crust and upper mantle on the Australian continental crust. This study reports the geochemistry of stream sediments from the coastal region of the Oecusse enclave, where the Banda Terrane is best represented, employing statistical analyses to discern the sources of metal(oid)s and assessing ecological and health risks. Arsenic, Cr, and Ni are the elements with higher potential ecological risk factors. The potential ecological risk index (PERI), which combines single indexes of ecological risk factors for multiple elements, is very high in a stream sourced by the Lolotoi-Mutis Complex. Significant risks for human health were found for As (sourced by the Lolotoi-Multis Metamorphic Complex and basalts of the Barique Formation), Mn (sourced by the Maubisse and Barique formations), and V (sourced by the Manamas Formation). The highest values of hazard index (HI), however, were determined with Cr, in particular for children (HI higher than 10 in 12 sediments sourced by ultramafic units and their covering sedimentary units). This investigation shows that high geogenic concentrations of several elements, particularly those derived from the oceanic crust and the upper mantle, raise significant cancer and non-carcinogenic risks.

Integrated study of hydrochemistry, quality and risk to human health of groundwater in the upper reaches of the Wulong River Basin.

Groundwater, a vital source of water supply, is currently experiencing a pollution crisis that poses a significant risk to human health. To understand the hydrochemical formation mechanisms, quality and risk to human health of groundwater in the upper reaches of the Wulong River basin, 63 sets of groundwater samples were collected and analyzed. A combination of mathematical statistics, correlation analysis, Gibbs diagram, ion ratio, and cation exchange were comprehensively employed for hydrochemical analysis, and further water quality index (WQI) and human health risk assessment were conducted. The results indicate that groundwater is generally neutral to weakly alkaline. The dominant cations in the groundwater are Ca2+ and Mg2+, while the main anions are HCO3- and SO42-. The hydrochemical types of groundwater mainly include HCO3·SO4-Ca, HCO3-Ca and HCO3-Na. The diverse hydrochemical types are mainly due to the fractured and discontinuous nature of the aquifers. The hydrochemical characteristics are influenced by the dissolution of silicate and carbonate minerals, cation exchange processes, and anthropogenic pollution. The presence of NO3- in groundwater is primarily attributed to agricultural activities. The groundwater is mainly categorized as "Good" (36.6%) and "Poor" (60.8%). "Very poor" and "Excellent" categories are rare, accounting for only 1.2% and 1.4%, respectively, and no samples are classified as "Non-drinkable". The Ewi for NO3- is the highest, indicating severe contamination by anthropogenic NO3- pollution. Human health risk assessment reveals that water samples posing exposure risks account for 82.54% for children and 79.37% for adults. This study highlighted that anthropogenic nitrate pollution has deteriorated groundwater quality, posing risks to human health. It also suggests an urgent need to enhance research and protective measures for groundwater in similar regions, such as the Shandong Peninsula.

Human Health Risk Assessment and Source Identification of Toxic Heavy Metals by Multivariate Tools in Groundwater

Human Health Risk Assessment and Source Identification of Toxic Heavy Metals by Multivariate Tools in Groundwater

Spatial distribution, ecological and human health risks of potentially toxic elements (PTEs) in river Ravi, Pakistan: A comprehensive study

Significant quantities of potentially toxic elements have been and are still being discharged into Pakistan's rivers through natural sources and anthropogenic activities. The present study provides a comprehensive study of potentially toxic element contamination in the water and sediment of the Ravi River, Pakistan. The research aims to examine the extent of pollution, its ecological risks, and the potential human health impacts through detailed geospatial analysis and statistical correlation. Water and sediment representative samples were taken and analyzed for potentially toxic elements, including Cobalt (Co), Cadmium (Cd), Zinc (Zn), Nickel (Ni), Arsenic (As), Chromium (Cr), Lead (Pb), Copper (Cu), and Manganese (Mn). Various pollution indices, such as the “Geo-accumulation Index (Igeo), Modified degree of Contamination (mCd), Nemerow comprehensive pollution index (Pt), Contamination factor (CF), Enrichment factor (EF), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI),” were calculated to determine the contamination levels and ecological risks. The results indicated significant spatial variability in metal concentrations, with higher levels observed in industrial and urban areas (near Lahore). Cd and As were identified as the most critical pollutants, exhibiting high Igeo, CF, EF, and PERI values. The PLI revealed that several regions along the river are heavily polluted. Pt shows high comprehensive pollution near Lahore and moderate to high pollution in surrounding areas. According to mCd, most of the study area, especially sampling points near Lahore, ranges between 8 and 16, indicating a high degree of pollution. The Human Health Risk (HHR) assessment, considering ingestion, inhalation, and dermal contact pathways, highlighted that children are particularly vulnerable, showing higher Hazard Quotient (HQ) and Hazard Index (HI) values for several metals. Correlation analysis revealed significant relationships between certain metals, suggesting common sources of contamination, likely from industrial discharges and urban runoff. The comprehensive mapping and statistical analysis underscore the urgent need for implementing effective pollution control measures to mitigate the risks posed by potentially toxic element contamination in the Ravi River. This study provides critical insights for policymakers and environmental managers to prioritize areas for remediation and to develop strategies to protect both ecological and human health in the region.

Evaluation of some anions in groundwater in Riyadh, Saudi Arabia, and human health risk assessment of nitrate and fluoride.

Groundwater is a vital source of water for human and agricultural use in many parts of the world. The purpose of this research was to establish the quality of groundwater in Riyadh, Saudi Arabia, as well as the human health concerns associated with it. We collected and examined groundwater samples for pH, EC, TDS, CaCO3, fluoride (F-), chloride (Cl-), sulfate (SO42-), and nitrate (NO3-). The ion chromatography conductometric detection method was constructed to determine fluoride, chloride, sulfate, and nitrate in groundwater. The suggested method worked well for the anions that were being studied; it had a high coefficient of determination (r2 > 0.998) and average recoveries for all analytes that were between 97.5% and 99.0%, with a range of error of 0.77 to 2.37%. Fluoride concentrations were detected between 0.001 and 0.14mg/L, which are within the acceptable limit by several organizations. Chloride was measured in the range of 17.1 to 966.5mg/L, with some samples above the limits. The influence on sulfate ranged from 2.0 to 1136.0mg/L, with several samples exceeding the limits. In contrast, with nitrate levels ranging from 1.4 to 5.0mg/L, the majority of the samples fall within the acceptable range. The overall intake of fluoride, chloride, sulfate, and nitrate is 0.00605, 138.911, 65.515, and 1.19, respectively, which is lower than the recommended daily consumption except for chloride. The groundwater sample contains fluoride and nitrate with HQ values less than one: 0.000064-0.0641 and 0.033654-0.120192. Humans in Riyadh, Saudi Arabia, do not pose a health risk when digesting or absorbing groundwater fluoride or nitrate.

Environmental assessment of toxic heavy metals and natural radionuclides in irrigation water from Rustenburg, South Africa

Water is a transparent, tasteless and odourless inorganic compound, essential for life and sustainable development. It is important for food and energy production, socio-economic growth, healthy ecosystems and human existence. Global attention is given to water quality monitoring due to the role it plays in human exposure to different kinds of contaminants, including radioactive and toxic contaminants from industrial, agrochemicals, mining and other anthropogenic activities. This work presents the results of measured natural radionuclides and toxic heavy metals in Rustenburg, and their associated non-carcinogenic and carcinogenic risk. The average concentrations of Cd, Cu, Co, Fe, Ni, Mn, Pb and Zn are 0.00007 mg/l, 0.0087 mg/l, 0.0033 mg/l, 0.0636 mg/l, 0.0052 mg/l, 0.0217 mg/l, 0.0003 mg/l and 0.0047 mg/l respectively and are below the safe limit of toxic heavy metals in water. The activity concentration of 40K and 238U ranges from 7.07 Bq/l to 13.2 Bq/l and 1.24 × 10−04 Bq/l to 1.09 × 10−02 Bq/l, with a mean activity concentration of 11.6 Bq/l and 2.78 × 10−03 Bq/l respectively. 232Th was not found in all measured water samples. The estimated average committed effective dose from ingestion of natural radionuclides was observed to be below 170 μSv/yr for 40K, 120 μSv/yr for 232Th and 238U, and a total of 290 μSv/yr reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. The assessment of human health risks resulting from exposure to toxic heavy metals shows negligible carcinogenic and non-carcinogenic health risks to the exposed population, making the water sources from which the sample was collected, safe for agricultural and domestic use. The obtained results will also serve as reference data for future environmental studies.

Tissue distribution, biomagnification, human health risk, and risk mitigation of perfluoroalkyl acids (PFAAs) in the aquatic food web of an urban fringe lake: Insights from urban-rural and seasonal scales

Perfluoroalkyl acids (PFAAs), renowned for their exceptional physical and chemical properties, are ubiquitous in urban and rural environments. Despite their widespread usage, more knowledge is needed concerning their accumulation and transfer mechanisms within the aquatic food webs of urban fringe lakes, especially across rural-urban and seasonal scales. This study investigated the tissue distribution, bioaccumulation, biomagnification, associated human health risks, and potential risk mitigation strategies of 15 PFAAs within the food web of Luoma Lake, a prototypical urban fringe lake. All targeted PFAAs were detected in samples, with ∑PFAA concentrations ranging from 116.97 to 564.26 ng/g dw in muscles and 26.96–1850.95 ng/g dw in viscera. Spatial variations revealed significantly higher ∑PFAA concentrations in the muscles from the urban subregion (∑PFAA: 359.66 ± 76.48 ng/g dw) compared to the rural subregion (∑PFAA: 328.86 ± 87.51 ng/g dw). Seasonal fluctuations impacted PFAA concentrations in fish and crustacean muscles but exhibited negligible effects on bivalve muscles. Spatial variations only influenced PFAA concentrations in specific viscera (gill, liver, kidney), while seasonal changes had minimal effects on viscera. The organisms demonstrated varying bioaccumulation capacities, with crustaceans displaying the highest bioaccumulation potential, followed by crustaceans and fish. Both spatial and seasonal variations modulated the bioaccumulation patterns of PFAA in muscles, whereas bioaccumulation in viscera was only influenced by seasonal factors. Notably, PFAA biomagnification along the food web was exclusively governed by spatial distribution, remaining unaffected by seasonal changes. The human health risk assessment underscored the potential adverse health impacts of PFOS and PFOA, particularly on young children (aged 2 to <6 years). This study further proposed comprehensive recommendations for mitigating PFAA-induced health risks, encompassing source control, selective consumption, pre-cooking treatments, and strategic cooking method selection. This research provides crucial insights into the ecological behaviors and health implications of PFAA in urban fringe lakes.

Human health risk assessment of potentially toxic and essential elements in medicinal plants consumed in Zabol, Iran, using the Monte Carlo simulation method

Medicinal plants (MPs) have long been used for their therapeutic properties in traditional forms of medicine. However, the presence of potentially toxic elements (PTEs) in MPs raises concerns about their safety, efficacy, and potential adverse effects on human health. The current study aimed to determine the level of potentially toxic and essential elements (PTEEs) in commonly consumed MPs in Zabol, Iran, along with their health risk assessments. To conduct the present study, 10 types of MPs widely used in Zabol, Iran, were selected, and 15 samples of each type (150 samples in total) were taken. Each sample was analyzed for the presence of various PTEEs using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) for Lead (Pb), cadmium (Cd), chrome (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), aluminum (Al) and manganese (Mn); and Atomic Absorption Spectrometry (AAS) for arsenic (As) and mercury (Hg). Finally, to better comprehend the scope of exposure and its possible effects, the Monte Carlo simulation method is successfully applied to assess human health risks related to PTEs in MPs. Statistical analysis revealed statistically significant (P < 0.001) variations in PTE averages among MP types. Furthermore, all samples’ overall PTE mean concentration (range: 0.18 to 215.5 µg/kg) was below the World Health Organization’s (WHO) regulatory standards. Probabilistic health risks, including non-carcinogenic-target hazard quotient (THQ) for each element, total target hazard quotient (TTHQ) for all elements, and carcinogenic-incremental lifetime cancer risk (ILCR) for each element, and total carcinogenic risk (TCR) for all elements, were significantly lower than the acceptable limit for children and adults. Accordingly, it can be said that consuming MPs sold in Zabol is safe for children and adults regarding carcinogenic (ILCR/TCR = 10− 4) and non-carcinogenic (THQ/TTHQ = 1) effects. In light of the findings presented here, and to our understanding, the primary factor contributing to lower levels of PTEs in MPs in Zabol City markets is the cultivation of plants in nonindustrialized areas, separate from urban and industrial zones. This practice keeps them from environmental contaminations, including soil quality and water sources. It is recommended that it is essential to regulate the sources that enhance the transfer of PTEs and other harmful pollutants from surroundings to the soil and, consequently, MPs. It is also suggested that, like chemical drugs, MPs should undergo rigorous testing by quality control agencies before being made available to the market.

Bioaccumulation potentials of per-and polyfluoroalkyl substances (PFAS) in recreational fisheries: Occurrence, health risk assessment and oxidative stress biomarkers in coastal Biscayne Bay

Per-and polyfluoroalkyl substances (PFAS) are a group of synthetic, highly fluorinated, and emerging chemicals that are reported to be used for both industrial and domestic applications. Several PFAS have demonstrated persistent, bioaccumulative and toxic tendencies in marine organisms. Therefore, this research aims to characterize and quantify these compounds in both recreational fisheries and surface water samples, including estimating their bioaccumulation potentials. In addition, we assessed the potential contribution of biomonitoring tools such as oxidative stressors and morphological index on fish and ecological health. Finally, human health risk assessment was performed based on available toxicological data on limited PFAS. All PFAS were detected in at least one sample except for N-EtFOSAA in lobster which was below the method detection limit. ƩPFAS body burden ranged from 0.15 to 3.40 ng/g wet weight (ww) in blackfin tuna samples and 0.37–5.15 ng/g ww in lobster samples, respectively. Wilcoxon rank paired test (α = 0.05) shows that there is statistical significance (ρ < 0.05) of ƩPFAS between species. Bioaccumulation factors (BAF) suggest an increasing trend in PFAS classes (PFCAs < PFSAs < FTSs), with higher BAFs observed in tuna compared to lobster. Long-chain PFESAs and FASAA were reported at higher concentrations in lobster compared to Blackfin tuna due to their bioavailability through sediment-sorption interactions. Although Fulton’s condition factor (FCF) indicates healthy fish conditions, oxidative stress biomarkers suggest that tuna and lobster might be under stress, which can weaken their immune system against exposure to emerging contaminants such as PFAS. Hazard risk (HR) suggests a low risk to human health based on the consumption of the studied species; however, the risk of contaminant exposure may be higher than estimated. This study is aimed at improving food safety by providing better understanding of how PFAS infiltrate into human diet and incorporating data on influence of contaminant exposure and environmental stressors on marine health.

Human health risk assessment of potentially toxic metals in fish (Cynoglossus sp.) commonly consumed in Nigeria

In order to determine the concentrations of certain metals that may be hazardous in widely consumed fish species (Cynoglossus sp.) in Nigeria, atomic absorption spectrophotometry was used. The main objectives were to determine the most likely sources of these metals and assess the potential health concerns connected with consuming fish. Fish samples were collected from Sabo market, Ile-Ife, Osun state. They were digested using HNO3 and H2O2 and subjected to elemental analysis (Fe, Zn, Mn, Pb, Cu, Cd, Co, and Cr) using atomic absorption spectrophotometer. The results showed that Lead (Pb) had the lowest mean concentration of 0.56 ± 0.01 mg/kg, while Zinc (Zn) had the highest average concentration of 12.88 ± 0.18 mg/kg. Strong and substantial correlations between the studied metals were shown by the analysis of the correlation matrix and cluster patterns. The study also evaluated a number of health risk parameters, including target hazard quotient, estimated daily intake, and cancer risk, which together suggested that consuming these fish samples posed health concerns for both adults and children. According to relative risk, seafood consumption raises the most alarm about Cd levels. The study came to the conclusion that due to the propensity for these potentially hazardous metals to bioaccumulate, only a moderate amount of these fish samples should be consumed. Additionally, it is strongly advised to discourage the disposal of domestic and industrial wastes into water bodies.

New approach methodologies (NAMs) for the in vitro assessment of cleaning products for respiratory irritation: workshop report.

The use of in vitro new approach methodologies (NAMs) to assess respiratory irritation depends on several factors, including the specifics of exposure methods and cell/tissue-based test systems. This topic was examined in the context of human health risk assessment for cleaning products at a 1-day public workshop held on 2 March 2023, organized by the American Cleaning Institute® (ACI). The goals of this workshop were to (1) review in vitro NAMs for evaluation of respiratory irritation, (2) examine different perspectives on current challenges and suggested solutions, and (3) publish a manuscript of the proceedings. Targeted sessions focused on exposure methods, in vitro cell/tissue test systems, and application to human health risk assessment. The importance of characterization of assays and development of reporting standards was noted throughout the workshop. The exposure methods session emphasized that the appropriate exposure system design depends on the purpose of the assessment. This is particularly important given the many dosimetry and technical considerations affecting relevance and translation of results to human exposure scenarios. Discussion in the in vitro cell/tissue test systems session focused on the wide variety of cell systems with varying suitability for evaluating key mechanistic steps, such as molecular initiating events (MIEs) and key events (KEs) likely present in any putative respiratory irritation adverse outcome pathway (AOP). This suggests the opportunity to further develop guidance around in vitro cell/tissue test system endpoint selection, assay design, characterization and validation, and analytics that provide information about a given assay's utility. The session on applications for human health protection emphasized using mechanistic understanding to inform the choice of test systems and integration of NAMs-derived data with other data sources (e.g., physicochemical properties, exposure information, and existing in vivo data) as the basis for in vitro to in vivo extrapolation. In addition, this group noted a need to develop procedures to align NAMs-based points of departure (PODs) and uncertainty factor selection with current human health risk assessment methods, together with consideration of elements unique to in vitro data. Current approaches are described and priorities for future characterization of in vitro NAMs to assess respiratory irritation are noted.

Phthalate Esters in Water and Surface Sediments of Anambra River in Dry Season: Distribution and Human Health Risks Assessment

This study investigated phthalate ester (PAE) contamination in water and sediment samples due to their persistence and potential health risks as endocrine disruptors. Sediment analysis revealed pH ranged from 5.35 to 6.72, with total organic carbon (TOC) levels varying between 0.74% and 2.56%. Water pH values were within WHO guidelines (5.5–8.5), and turbidity levels ranged from 0.60 to 1.40 NTU. Phthalate concentrations in sediment revealed Monobutyl phthalate (MBP), Diethyl phthalate (DEP), Dipentyl phthalate (DPP), Butyl benzyl phthalate (BBP), Dibutyl phthalate (DBP), and Di(2-ethylhexyl) phthalate (DEHP). Sample SA exhibited the highest levels of MBP (0.40 mg/kg) and DEP (0.93 mg/kg). In water samples, MBP peaked at 0.01 mg/kg, while DEP reached 0.03 mg/kg, with DBP (0.07 mg/kg) and DEHP (0.08 mg/kg) also detected. Phthalate contamination in water remained below harmful thresholds. A health risk assessment calculated Chronic Daily Intake (CDI) and Hazard Quotients (HQ) for both children and adults. CDI results indicated higher risks for children, with DBP (2.20E-06 mg/kg/day) and DEHP (2.46E-06 mg/kg/day) showing the greatest concern. The HQ for children was highest for DBP (0.22), though still below the risk threshold. Adults exhibited lower CDI and HQ values, with minimal non-carcinogenic risk. These findings highlight the need for continued monitoring of phthalate pollution, especially given children’s heightened vulnerability.

Cell line-based in vitro models of normal and chronic bronchitis-like airway mucosa to study the toxic potential of aerosolized palladium nanoparticles.

Physiologically relevant cell line-based models of human airway mucosa are needed to assess nanoparticle-mediated pulmonary toxicity for any xenbiotics expsoure study. Palladium nanoparticles (Pd-NP) originating from catalytic converters in vehicles pose health risks. We aimed to develop in vitro airway models to assess the toxic potential of Pd-NP in normal (Non-CB) and chronic bronchitis-like (CB-like) mucosa models. Bronchial mucosa models were developed using Epithelial cells (16HBE: apical side) co-cultured with fibroblast (basal side) at an air-liquid interface. Furthermore, both Non-CB and CB-like (IL-13 treatment) models with increased numbers of goblet cells were used. The models were exposed to 3 different doses of aerosolized Pd-NP (0.2, 0.3, and 6 μg/cm2) using XposeALI® and clean air as a control. After 24 h of incubation, the expression of inflammatory (IL6, CXCL8, TNFα, and NFKB), oxidative stress (HMOX1, SOD3, GPx, and GSTA1), and tissue injury/repair (MMP9/TIMP1) markers was assessed using qRT-PCR. The secretion of CXCL-8 and the expression of a tissue injury/repair marker (MMP-9) were measured via ELISA. Significantly (p < 0.05) increased expressions of CXCL8, IL6, and NFKB were observed at the highest dose of Pd-NP in CB-like models. However, in Non-CB mucosa models, a maximum effect on TNFα and NFKB expression was observed at a medium Pd-NP dose. In Non-CB mucosa models, SOD3 showed a clear dose-dependent response to Pd-NP exposure, while GSTA1 expression was significantly increased (p < 0.05) only at the lowest dose of Pd-NP. The secretion of CXCL-8 increased in a dose-dependent manner in the Non-CB mucosa models following exposure to Pd-NP. In CB-like models, exposure to high concentrations of Pd-NP significantly increased the release of MMP-9 compared to that in other exposure groups. The combination of our Non-CB and CB-like mucosa models with the XposeALI® system for aerosolized nanoparticle exposure closely mimics in vivo lung environments and cell-particle interactions. Results from these models, utilizing accessible cell lines, will maximize the reliability of in vitro findings in human health risk assessment.

Assessments of hydrogeochemical characteristics, water quality, and health risk of groundwater of Chapi-Nawabganj District of Bangladesh

ABSTRACT A total of 60 groundwater samples were collected over three seasons, aiming to assess hydrochemical characteristics, water quality, pollution level, and health risk. The concentration of Fe, Mn, and Pb exceeded almost 100% of samples in three seasons. The groundwater was found to be highly contaminated with Cd and Cr in the pre-monsoon and Ni in the monsoon. The order of major ion and trace metal concentrations is as follows: Ca2+ &amp;gt; Na+ &amp;gt; Mg2+ &amp;gt; K+; HCO3− &amp;gt; Cl− &amp;gt; SO42− &amp;gt; NO3− &amp;gt; PO43−, and Fe &amp;gt; Mn &amp;gt; Pb &amp;gt; Cd in three seasons. The groundwater was Ca-Mg-HCO3− type. The study suggests that the contamination sources are mostly geogenic as well as slightly anthropogenic. The water–rock interactions are the dissolution of calcite and dolomite, along with silicate weathering, which controls the hydrochemistry of the groundwater. The indices, including the Water Quality Index (WQI), and the Canadian Council of Ministers of the Environment (CCMEWQI), revealed that the groundwater quality in the area was moderately polluted. The Heavy Metal Pollution Index (HMPI), and human health risk assessment (HRA) illustrated that groundwater is a significant health hazard, indicating it is unsuitable for human consumption and suggesting treatment before drinking.

Assessing the distribution and ecotoxicological risks of organochlorine pesticides in a river-wetland system of the Manipur River basin, India

ABSTRACT The present study aims to evaluate the distribution of organochlorine pesticides in the Loktak Lake and its draining rivers over a spatial and seasonal scale. Organochlorine pesticides including α- HCH, β- HCH, γ- HCH, δ- HCH, Aldrin, 4,4-DDE, Endrin, Endosulfan II, 4,4-DDD, Endrin Aldehyde, Endosulfan sulphate and 4,4-DDT were analysed in the water and sediments adopting gas chromatography and mass spectrometric techniques. The concentration of pesticides recorded the highest concentration of 2271 ng/l in the water samples and 5319 ng/g in sediment samples. In water samples, Endosulfan II, Endrin and γ- HCH were present at the higher concentrations, whereas α-BHC was recorded at the lowest at 0.78 ng/l. In sediment samples, 4, 4-DDT recorded the highest concentration, followed by 4,4-DDD and Endosulfan II. Human health risk assessment based on water consumption shows higher risk potential from five pesticides. Pesticides in the region may pose a threat to the wetland comprising vital flora and fauna of the biodiversity hotspot. The bacterial population was more or less related to the pesticide concentration, with a lower population at less contaminated sites.

Groundwater geochemistry using modified integrated water quality index (IWQI) and health indices with special emphasis on nitrates and heavy metals in southern parts of Tirupati, South India.

Groundwater is particularly vulnerable to pollution in places with a high population density and extensive human usage of the land, especially in southern parts of Tirupati, India. To assess this, 60 bore-well samples were obtained and assessed for physical specifications, ion chemistry, and heavy metals during the pre- and post-monsoon seasons 2022. The current investigation employed a modified integrated water quality index (IWQI), conventional graphical and human health risk assessment (HHRA) of nitrates and heavy metals to know the groundwater chemistry and its detrimental health effects on humans. The major ions were analyzed using American public health association (APHA)standards, whereas heavy metals were analyzed using inductively coupled plasma optical emission spectrometry(ICP-OES). Additionally, pH Redox Equilibrium and C (PHREEQC),a geochemical model written in C programming language was employed to determine the saturation indices of mineral facies and ArcGIS 10.3.1 was used for spatial distribution patterns of IWQI. Then, the HHRA of nitrates and heavy metals was performed using United States environmental protection agency (USEPA)guidelines. The noteworthy outcomes include elevated levels of Ca2+, Mg2+, Cl-, NO3-, Cu,Fe, Mn, and Pb, demonstrating rock-water interaction, silicate weathering, Ca-Mg-HCO3 followed by mixed water facies, dissolution/precipitation, reverse exchange, and anthropogenic contamination are the major controlling processes in groundwater of southern Tirupati, India. The modified IWQI reveals that most groundwater samples (38%) fall under the bad quality class, with (47%) in the poor quality class and only (15%) classified as medium qualityclass in pre- and post-monsoon seasons. Elevated IWQI were observed in all directions except in the east, which is suitable for drinking. Moreover, the major hazard quotient (HQ) and hazard index (HI)for nitrates (NO3-) and heavy metals like copper(Cu), iron (Fe), manganese (Mn), lead (Pb) and zinc (Zn) are above the critical value of 1, revealing potential risk to humans, especially infants, followed by children and adults, entailing the instantaneous implementation of proper remedial measures and stringent policies to reduce the risk associated with groundwater pollution in the southern parts of Tirupati.

Accumulation of Heavy Metals in Tissues of Oreochromis Mossambicus from the uMgeni River and Human Health Risk Assessment

Metal enrichment in aquatic ecosystems has compromised the potential of fish to enhance food security. The uMgeni River drains urban and industrialized catchment and flows through economically disadvantaged rural communities that opt for fish to supplement their protein needs. However, there are uncertainties on the safety of consuming fish from the uMgeni River. The present study aims to explore metal distribution between the water, sediment, and tissues of the preferred Oreochromis mossambicus, and evaluate whether concentrations in the muscle are safe for human consumption. The water, sediment, and fish samples were collected from Inanda and Nagle dams, and metal concentrations were analysed using inductively coupled plasma mass spectrometry. Alkaline pH was observed at both dams and metals were below detectable level in the water column. Even though metal concentrations in the water column were below detectable levels, significant concentrations were found in the sediment. No consistent trend in metal concentrations was observed across tissues, but higher levels were generally found in the liver, followed by the gill, and then the muscle. Nickel (Ni) and lead (Pb) exhibited concentrations exceeding the permissible limit for human consumption. Similarly, the target hazard quotient exceeded the threshold of 1 for Pb, chromium (Cr), and antimony (Sb) at both dams with Inanda Dam showing higher indices for Sb and Pb. The carcinogenic risk for the three metals was also found to be higher than 10–6. These findings suggest that consumption of O. mossambicus from the uMgeni River should be limited to no more than 150 g per week.

Harmful Microalgae Exhibit Broad Environmental Adaptability in High-Salinity Area Across the Dafengjiang River Estuary.

Harmful algal blooms (HABs) often occur in estuaries due to their unique environmental heterogeneity, posing significant environmental and human health risks. However, there is limited understanding of the community composition and community-level change points (thresholds) of harmful microalgae in subtropical estuaries. This study explored harmful microalgae community structure and thresholds in the Dafengjiang River estuary using a metabarcoding approach. The results revealed 63 harmful microalgae species, and major species included Guinardia flaccida, Prorocentrum cordatum, Thalassiosira punctigera, Pseudo-nitzschia galaxiae and T. gravida. Nonparametric change-point analysis and threshold indicator taxa analysis (TITAN) showed threshold responses of harmful microalgae community structure to ammonium (57.5-60 μg·L-1), total phosphorus (27.8-28.5 μg·L-1) and dissolved inorganic phosphorus (14.5-28 μg·L-1) along the salinity gradient. Wider environmental thresholds were also found in hypersaline areas. Additionally, Pyrodinium bahamense, Pfiesteria piscicida, Skeletonema tropicum and T. punctigera were sensitive to environmental changes and thus could be used as bioindicators. Overall, our study unveiled diverse abrupt transitions of harmful microalgal communities, providing a risk assessment for human health and ecological safety in subtropical estuary ecosystems.

Legacy and emergent contaminants in glaucous-winged gull eggs from Canada's Pacific coast: Spatial distribution, temporal trends, and risks for human consumers

Using glaucous-winged gull (Larus glaucescens) eggs from Canada's Pacific coast, we investigated spatial and temporal trends (2008–2022) of a suite of legacy and emergent contaminants, including 16 perfluoroalkyl substances (PFAS), 15 polybrominated diphenyl ethers (PBDEs), 7 alternative halogenated flame retardants (AHFRs), total mercury (THg), as well as stable isotopes of carbon (δ13C) and nitrogen (δ15N) to control for diet. Legacy organochlorines (OCs) were also measured in eggs in 2020 for a preliminary human health risk assessment (HHRA). Between 2008 and 2022, glaucous-winged gull eggs from more urban-influenced colonies (Mandarte Island) were up to ∼2x more contaminated with PFAS, PBDEs, AHFRs, and THg than eggs from the offshore colony (Cleland Island), suggesting different source regions and dietary exposures. Concentrations of Σ15PBDEs declined linearly among colonies (p < 0.001), consistent with several North American phase-outs and regulatory restrictions dating back to the early/mid 2000s. Conversely, temporal trends for PFOS, Σ12PFCAs, Σ7AHFRs, and THg were characterized by a combination of second-order declines and non-linear increases in recent years. After correcting THg for dietary shifts using δ15N, THg concentrations followed a U-shaped trend at Mandarte and Cleland Islands, while those at Mitlenatch Island remained relatively constant over time. Increasing trends for some contaminants coincided with both an increase in δ13C and δ15N. For the HHRA, all gull eggs collected in 2020 had hazard quotients (HQs) < 0.2, indicating no foreseeable risk or harm for First Nations consumers for certain contaminants. Our findings indicate that spatio-temporal trends of persistent organic contaminants and THg in Pacific glaucous-winged gull eggs are influenced by a combination of factors, including the impact of regulations on anthropogenic emissions, accompanied by changes in foraging behaviour and food-web structure.

Impact of microplastics pollution on ciprofloxacin bioaccumulation in the edible mussel (Perna viridis): implications for human gut health risks

Antibiotics and microplastics are prevalent pollutants in mariculture. Consuming contaminated bivalves can potentially endanger human health, but the impact of microplastics on antibiotics bioaccumulation in bivalves and the related health risks to consumer health risks is not fully understood. We obtained bivalves from a mariculture farm and set up exposure scenarios with ciprofloxacin (1μg/L) alone, microplastics (0.6mg/L) alone, or their combination on mussels for 2-weeks. We investigated ciprofloxacin accumulation and analyzed the effects of these pollutants on detoxification and intestinal microbiome changes. Furthermore, potential food safety hazards related to ingestion of antibiotic-tainted bivalves were also assessed. We found that the accumulation of the ciprofloxacin in bivalves was significantly aggravated by the presence of microplastics. There was a significant increase in the production of antioxidant substances in the host's haemolymph, and an enhanced synthesis of antioxidants by the predicted metabolic functions of the intestinal microbiome. Concomitantly, microplastics exacerbated intestinal dysfunction, with a reduction in beneficial Spirochaetes and an increase in pathogenic bacteria Treponema, which may lead to deterioration of detoxification in the host. Additionally, an assessment of human gut health risks was conducted on the residual ciprofloxacin in bivalves combined with human consumption habits. The estimated target hazard quotients and cancer risk were below safety thresholds, directly consuming contaminated bivalves poses little toxicity. However, with raw mussels consumption, the dietary exposure doses of ciprofloxacin to human gut microbiome exceeded minimal selective concentrations for resistance. This could promote the growth of potentially resistant bacteria, indicating a risk of antibiotic resistance.