Concentrations Of Organic Micropollutants Research Articles

Trophic fate and biomagnification of organic micropollutants from staple food to a specialized predator

The environmental burden of organic micropollutants has been shown in aquatic ecosystems, while trophic fate of many compounds in terrestrial food chains remains highly elusive. We therefore studied concentrations of 108 organic micropollutants in a common European mammal, the bank vole (Clethrionomys glareolus), and 82 of the compounds in a specialized predator, Tengmalm's owl (Aegolius funereus) relying to >90 % on voles as its prey. We studied compounds in whole voles (n = 19), pools of 4–8 bank voles (npools = 4), owl blood (n = 10) and in owl eggs (n = 10) in two regions in Sweden. For comparison, we also included previously published data on 23 PFAS (per- and polyfluoroalkyl substances) in bank vole liver (npools = 4) from the same regions. In voles, concentrations of the organic micropollutants caffeine (maxIndividual 220 ng/g ww) and DEET (N,N-diethyl-m-toluamide) (maxPool 150 ng/g ww) were 2–200 times higher in voles relative to owl blood and eggs. Conversely, concentrations of nicotine, oxazepam, salicylic acid, and tributyl citrate acetate were 1.3–440 times higher in owls. Several PFAS showed biomagnification in owls as revealed by maximum biomagnification factors (BMFs); PFNA (perfluorononanoate) BMF = 5.6, PFTeDA (perfluorotetradecanoic acid) BMF = 5.9, and PFOS (perfluorooctane sulfonate) BMF = 6.1. Concentrations of organic micropollutants, alongside calculated BMFs, and Tengmalm's owl's heavy reliance on bank vole as staple food, suggest, despite small sample size and potential spatio-temporal mismatch, accumulation of PFAS (especially PFNA, PFTeDA, and PFOS) in owls and biomagnification along the food chain. Concentrations of PFAS in owl eggs (e.g., 21 ng/g ww PFOS) highlight the likely pivotal role of maternal transfer in contaminant exposure for avian embryos. These concentrations are also of concern considering that certain predators frequently consume owl eggs, potentially leading to additional biomagnification of PFAS with yet undetermined consequences for ecosystem health.

Intra-event variations of organic micropollutants in highway runoff and a presedimentation-biofilter treatment facility

The study assessed the quality of highway runoff and a stormwater treatment system, focusing on intra-event variations (IEVs: variations within a runoff/effluent event) of the concentration of organic micropollutants (OMPs) including bisphenol-A, alkylphenols, polycyclic aromatic hydrocarbons (PAHs), and petroleum hydrocarbons (PHCs). IEVs of OMPs varied considerably with no particular recurring pattern in highway runoff and presedimentation effluent, displaying sporadic strong first flushes. IEVs are significantly associated with rainfall intensity variations, especially for particle-bound substances such as PAHs and PHCs. However, phenolic substances showed distinct IEV patterns compared to total suspended solids, PAHs, and PHCs, likely due to their higher solubility and mobility. Downstream sand filter (SF) and vegetated biofilter (BFC) mitigated IEVs, leading to more uniform discharge during outflow events. Although BFC’s IEVs were indiscernible due to low effluent concentrations, SF’s IEVs often peaked at the beginning of events (within the first 100 of ⁓600 m3), exceeding the lowest predicted non-effect concentrations for five PAHs, bisphenol-A, and octylphenol. This study highlights the advantage of IEV analysis over conventional event mean concentration analysis for identifying critical effluent stages, crucial for developing control strategies to protect sensitive water recipients or for reuse applications.

Biodegradation kinetics of organic micropollutants in biofilters for advanced wastewater treatment – Impact of operational conditions and biomass origin on removal

Biofiltration processes are often part of advanced wastewater treatment (aWWT) technologies for the removal of organic micropollutants (OMP) from conventional wastewater treatment plant (WWTP) effluents. Although biological effects are not always the main focus of these technologies (e.g. filtration through granular activated carbon), they have been shown to contribute significantly to total OMP removal. While OMP biodegradation kinetics in conventional biological wastewater treatment are well researched, no systematic comparison to biomass from aWWT is available. This biomass faces different growth conditions and higher OMP concentrations relative to the background organic matter. Adaptation to these conditions could be possible and could lead to faster OMP biodegradation kinetics, which would show in a larger pseudo first-order biodegradation kinetic constant kbiol. In this work, kbiol values for biomass obtained from aWWT biofilters were determined by evaluating OMP removals measured in lab-scale biofilters using a mechanistic model of the experimental setup. A comparison to kbiol values from literature for conventional wastewater treatment (with nutrient removal) revealed similar OMP biodegradation kinetics without any advantages of biomass from aWWT. A conceptual evaluation of influencing factors on OMP removal in biofilters showed that operational parameters (such as the biomass concentration or the empty bed contact time) and the affinity of OMPs to adsorb on biomass have a significant additional effect on biological OMP removal. Therefore, kbiol values alone are not sufficient to estimate biological OMP removal in biofilters and further information about the system is required.

Plant-Wide Models for Optimizing the Operation and Maintenance of BTEX-Contaminated Wastewater Treatment and Reuse

Benzene, toluene, ethylbenzene and xylenes, collectively known as BTEX compounds, are significant emerging contaminants in municipal wastewater. Stricter effluent quality regulations necessitate their removal, especially with concerns about organic micropollutant concentrations. Water scarcity further underscores the need for wastewater treatment to ensure safe agricultural or drinking water supplies. Although biological treatment partially reduces BTEX levels through processes like biodegradation and sorption, additional purification using physico-chemical methods is crucial for substantial reduction. This paper aims to outline plant-wide simulation methods for treating BTEX-contaminated sewage and facilitating reuse, adhering to IWA Good Modelling Practice Guidelines. The model, built upon the MiniSumo process model, incorporates equations detailing BTEX metabolism and removal kinetics, informed by an extensive literature review. Using a variant of the Benchmark Simulation Model with granular activated carbon for water reuse, the study examines strategies for improving effluent quality and minimizing operational costs. These strategies include adjusting the sludge retention time and airflow to enhance BTEX degradation and stripping, respectively, and comparing maintenance approaches for the GAC tower.

Coupling pathway prediction and fluorescence spectroscopy to assess the impact of auxiliary substrates on micropollutant biodegradation.

Some bacteria can degrade organic micropollutants (OMPs) as primary carbon sources. Due to typically low OMP concentrations, these bacteria may benefit from supplemental assimilation of natural substrates present in the pool of dissolved organic matter (DOM). The biodegradability of such auxiliary substrates and the impacts on OMP removal are tightly linked to biotransformation pathways. Here, we aimed to elucidate the biodegradability and effect of different DOM constituents for the carbofuran degrader Novosphingobium sp. KN65.2, using a novel approach that combines pathway prediction, laboratory experiments,and fluorescence spectroscopy. Pathway prediction suggested that ring hydroxylation reactions catalysed by Rieske-type dioxygenases and flavin-dependent monooxygenases determine the transformability of the 11 aromatic compounds used as model DOM constituents. Our approach further identified two groups with distinct transformation mechanisms amongst the four growth-supporting compounds selected for mixed substrate biodegradation experiments with the pesticide carbofuran (Group 1: 4-hydroxybenzoic acid, 4-hydroxybenzaldehyde; Group 2: p-coumaric acid, ferulic acid). Carbofuran biodegradation kinetics were stable in the presence of both Group 1 and Group 2 auxiliary substrates. However, Group 2 substrates would be preferable for bioremediation processes, as they showed constant biodegradation kinetics under different experimental conditions (pre-growing KN65.2 on carbofuran vs. DOM constituent). Furthermore, Group 2 substrates were utilisable by KN65.2 in the presence of a competitor (Pseudomonas fluorescens sp. P17). Our study thus presents a simple and cost-efficient approach that reveals mechanistic insights into OMP-DOM biodegradation.

Performance of a gross pollutant trap-biofilter and sand filter treatment train for the removal of organic micropollutants from highway stormwater (field study)

This field study assessed the occurrence, event mean concentrations (EMCs), and removal of selected organic micro-pollutants (OMPs), namely, polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), nonylphenol (NP), 4-t-octylphenol (OP), and bisphenol A (BPA), in a gross pollutant trap (GPT)-biofilter/sand filter stormwater treatment train in Sundsvall, Sweden. The effects of design features of each treatment unit, including pre-sedimentation (GPT), sand filter medium, vegetation, and chalk amendment, were investigated by comparing the units' removal performances. Overall, the treatment train removed most OMPs from highway runoff effectively. The results showed that although the sand filter provided moderate (<50 % for phenolic substances) to high (50–80 % for PAHs and PHCs) removal of OMPs, adding a vegetated soil layer on top of the sand filter considerably improved the removal performance (by at least 30 %), especially for BPA, OP, and suspended solids. Moreover, GTP did not contribute to the treatment significantly. Uncertainties in the removal efficiencies of PAHs and PHCs by the filter cells increased substantially when the ratio of the influent concentration to the limit of quantification decreased. Thus, accounting for such uncertainties due to the low OMP concentrations should be considered when evaluating the removal performance of biofilters.

Fates of selected pharmaceuticals in a large recirculated mesocosm with a pond and bank filtration

Pharmaceuticals such as carbamazepine (CBZ), sulfamethoxazole (SMX) and diclofenac (DCF) are detected at a high frequency in the aquatic environment. The fates of these compounds in bank filtration (BF), a nature-based water treatment system, have been extensively studied, mainly in batch and laboratory column studies. This study, for the first time, investigated the fates of CBZ, SMX and DCF in a large recirculated mesocosm with a pond and subsequent BF. Changes in dissolved organic carbon (DOC) in the pond and bank filtrate were also observed. The averaged spiking concentration of CBZ, SMX and DCF was 1 μg/L at the pond influent and the hydraulic retention time of surface water in the pond was 15 days to reach at the bank. The infiltrated surface water travelled through two parallel subsurface layers and a combined effluent (from both layers) was collected (35 m from the bank) and recirculated as an influent of the pond. The redox conditions in both layers were significantly different (p < 0.05) and correlated with temperature (R2 = 0.91, p < 0.05). The results revealed that CBZ was persistent in the surface water and groundwater passage, SMX was persistent in surface water and removed entirely through BF within 50 days of operation. DCF was completely removed after infiltration and groundwater passage (within 2 m). The DOC in the surface water showed insignificant variations between the influent and the bank. A significant reduction of DOC was observed within the first 5 m after infiltration, and the reduction was associated with the removal of biopolymers. This work shows that the selected organic micropollutants in surface water were not affected by sunlight intensity, water chemistry and water depth. In addition, recirculation mesocosm BF confirms the potential environmental risk and predictive concentrations of organic micropollutants in the aquatic environment.

Occurrence and concentrations of organic micropollutants (OMPs) in highway stormwater: a comparative field study in Sweden

This study details the occurrence and concentrations of organic micropollutants (OMPs) in stormwater collected from a highway bridge catchment in Sweden. The prioritized OMPs were bisphenol-A (BPA), eight alkylphenols, sixteen polycyclic aromatic hydrocarbons (PAHs), and four fractions of petroleum hydrocarbons (PHCs), along with other global parameters, namely, total organic carbon (TOC), total suspended solids (TSS), turbidity, and conductivity (EC). A Monte Carlo (MC) simulation was applied to estimate the event mean concentrations (EMC) of OMPs based on intra-event subsamples during eight rain events, and analyze the associated uncertainties. Assessing the occurrence of all OMPs in the catchment and comparing the EMC values with corresponding environmental quality standards (EQSs) revealed that BPA, octylphenol (OP), nonylphenol (NP), five carcinogenic and four non-carcinogenic PAHs, and C16-C40 fractions of PHCs can be problematic for freshwater. On the other hand, alkylphenol ethoxylates (OPnEO and NPnEO), six low molecule weight PAHs, and lighter fractions of PHCs (C10-C16) do not occur at levels that are expected to pose an environmental risk. Our data analysis revealed that turbidity has a strong correlation with PAHs, PHCs, and TSS; and TOC and EC highly associated with BPA concentrations. Furthermore, the EMC error analysis showed that high uncertainty in OMP data can influence the final interpretation of EMC values. As such, some of the challenges that were experienced in the presented research yielded suggestions for future monitoring programs to obtain more reliable data acquisition and analysis.

Risk evaluation and prioritization of contaminants of emerging concern and other organic micropollutants in two river basins of central Argentina

A research gap exists in baseline concentrations of organic micropollutants in South American rivers. Identification of areas with different degrees of contamination and risk to the inhabitant biota is needed to improve management of freshwater resources. Here we inform the incidence and ecological risk assessment (ERA) of current used pesticides (CUPs), pharmaceutical and personal care products (PPCPs) and cyanotoxins (CTX) measured in two river basins from central Argentina (South America). Risk Quotients approach was used for ERA differentiating wet and dry seasons. High risk was associated to CUPs in both basins (45 % and 30 % of sites from Suquía and Ctalamochita rivers, respectively), mostly in the basins extremes. Main contributors to risk in water were insecticides and herbicides in Suquía river and insecticides and fungicides in Ctalamochita river. In Suquía river sediments, a very high risk was observed in the lower basin, mainly from AMPA contribution. Additionally, 36 % of the sites showed very high risk of PCPPs in Suquía river water, with the highest risk downstream the wastewater treatment plant of Córdoba city. Main contribution was from a psychiatric drug and analgesics. In sediments medium risk was observed at the same places with antibiotics and psychiatrics as main contributors. Few data of PPCPs are available in the Ctalamochita river. The risk in water was low, with one site (downstream Santa Rosa de Calamuchita town) presenting moderated risk caused by an antibiotic. CTX represented in general medium risk in San Roque reservoir, with San Antonio river mouth and the dam exit showing high risk during the wet season. The main contributor was microcystin-LR. Priority chemicals for monitoring or further management include two CUPs, two PPCPs, and one CTX, demonstrating a significant input of pollutants to water ecosystems from different sources and the need to include organic micropollutants in current and future monitoring.

Monitoring organic micropollutants in stormwater runoff with the method of fingerprinting

The ecological state of receiving water bodies can be significantly influenced by organic micropollutants that are emitted via stormwater runoff. Reported efforts to quantify the emission of micropollutants mainly focus on sampling at combined sewer overflows and storm sewer outfalls, which can be challenging. An alternative method, called fingerprinting, was developed and tested in this study. The fingerprinting method utilizes wastewater treatment plant (WWTP) influent samples and derives the proportion of stormwater in a sample. This is achieved by comparing the wet weather vs dry weather concentrations of substances-tracers which are present only in wastewater. It is then possible to estimate the concentration of organic micropollutants in stormwater runoff from measurements in the influent of a WWTP based on a mass balance. In this research, the fingerprinting method was applied in influent samples obtained in five WWTPs in the Netherlands. In total, 28 DWF and 22 WWF samples were used. The chosen tracers were ibuprofen, 2-hydroxyibuprofen, naproxen and diclofenac. Subsequently, the concentration in stormwater runoff of 403 organic micropollutants was estimated via the WWF samples. The substances that were present and analyzed included glyphosate and AMPA, 24 out of 254 pesticides, 6 out of 28 organochlorine pesticides, 45 out of 63 pharmaceuticals, 15 out of 15 PAHs, 2 of the 7 PCBs, and 20 of 33 other substances (e.g. bisphenol-A). A comparison with findings from other studies suggested that the fingerprinting method yields trustworthy results. It was also noted that a representative and stable dry weather flow reference concentration is a strict requirement for the successful application of the proposed method.

Organic micropollutants measured in roof-harvested rainwater from rural and urban environmental justice communities in Arizona

Due to global water scarcity and population growth, multiple solutions are needed to conserve and collect water, especially in arid and semi-arid regions of the planet. As the practice of harvesting rainwater grows, it is important to assess the quality of roof-harvested rainwater (RHRW). This study measured twelve organic micropollutants (OMPs) in RHRW samples collected between 2017 and 2020 by community scientists, with approximately two hundred RHRW samples and corresponding field blank analyzed annually. The OMPs analyzed were atrazine, pentachlorophenol (PCP), chlorpyrifos, 2,4-dichlorophenoxyacetic acid (2,4-D), prometon, simazine, carbaryl, nonylphenol (NP), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorobutane sulfonic acid (PFBS), and perfluorononanoic acid (PFNA). OMP concentrations measured in RHRW were below the following existing standards: US EPA Primary Drinking Water Standard, Arizona Department of Environmental Quality (ADEQ) Partial Body Contact for Surface Waters, and ADEQ Full Body Contact for Surface Waters for analytes in this study. At the time the study was conducted, 28 % of RHRW samples exceeded the non-enforceable US EPA Lifetime Health Advisory (HA) of 70 ng L−1 for the combined sum of PFOS and PFOA with a mean exceedance concentration of 189 ng L−1. When comparing PFOA and PFOS to the June 15, 2022 interim updated HAs of 0.004 ng L−1 and 0.02 ng L−1, respectively, all samples exceeded these values. No RHRW samples exceeded the final proposed HA of 2000 ng L−1 for PFBS. The limited number of state and federal standards established for the contaminants highlighted in this study indicate potential regulatory gaps and that users need to be aware that OMPs may be present in RHRW. Based on these concentrations, domestic activities and intended uses should be carefully considered.

Characterization of the organic micropollutants behavior during electrochemical ammonia recovery

Nutrient recovery systems can be impacted due to the presence of organic micropollutants (OMPs). TAN (total ammonium nitrogen, sum of ammonium and ammonia) recovery from wastewater can be achieved by combining an electrochemical system with membrane stripping. Essential components of these processes are cation-exchange membranes and a hydrophobic gas-permeable membrane. These membranes are barriers between the OMPs source (wastewater) and recovered products. Despite reports about OMPs – ion exchange membrane interactions, there is limited knowledge about the transport of OMPs in ammonium recovery systems. This work gives a first detailed description of the transport mechanism of a broad group of OMPs with varying properties during electrochemical ammonium recovery supplied with a complex matrix (digested blackwater). Even after continuous exposure to OMPs and consequent system equilibration, OMP concentrations in the effluent were often lower than in the inflow stream. The highest removal and transport towards the concentrate were found for positively charged OMPs. The presence of organic matter contributed to the adsorption and transport of OMPs. Although OMPs were transported over the CEMs, the gas permeable hydrophobic membrane for ammonia recovery retained all OMPs.

Advanced drinking water production by 1 kDa hollow fiber nanofiltration – Biological activated carbon filtration (HFNF – BACF) enhances biological stability and reduces micropollutant levels compared with conventional surface water treatment

This study comprehensively investigates the quality of drinking water produced by novel advanced treatment encompassing 1 kDa hollow fiber nanofiltration (HFNF) – Biological Activated Carbon Filtration (BACF) from (reservoir) surface water, and compares this with drinking water after conventional ‘CSF’ pretreatment (coagulation – flocculation – sedimentation – media filtration – UV-disinfection) – BACF. The objective of HFNF – BACF treatment is to enhance the drinking water's quality in increased biological stability, reduced concentrations of organic micropollutants (OMP), and improvement in other chemical-physical parameters, whilst maintaining sufficient hardness to avoid subsequent remineralization. For this study a large suite of quality parameters was extensively monitored in pilot plants during nearly two years, enabling the incorporation of seasonal effects. HFNF – BACF treatment accomplished a similarly high level of biological stability as regrowth-free drinking waters (total organic carbon (DOC) 0.6 mg/L, assimilable organic carbon (AOC) 4 μg/L Ac–C and <1 μg/L biopolymer-C, total microbial growth potential (MGP) as BPC14 50 ng d/L and as BGP 170 × 103 cells/mL), unlike the conventional treatment (1.9 mg/L, 10 μg/L, 9 μg/L, 130 ng d/L and 170 × 103 cells/mL, respectively) where regrowth occurred in its distribution network. Average OMP removal, including perfluoro-alkyl substances (PFAS), by HFNF – BACF (54%) was higher than conventional treatment (37%). This improvement was mainly attributable to rejection in the HFNF membrane step, indicating that the DOC concentration after HFNF pretreatment was not yet sufficiently low to eliminate competitive adsorption and/or preloading in the BACF (confirmed by laboratory experiments). The advanced treatment also performed better in turbidity, particulates and most trace metals. Importantly, hardness retention by HFNF was only moderate, rendering remineralization unnecessary. Overall, this study demonstrates the superior performance in water quality of advanced HFNF – BACF treatment compared to conventional treatment.

Integration of Photodegradation Process of Organic Micropollutants to a Vertically One-Dimensional Lake Model

Photochemical reactions in the water environments are essential for understanding the fate of organic pollutants, which exist widely in aquatic environments causing potential risks. Therefore, this study aimed to integrate a module of the photodegradation process into a vertically one-dimensional model of the lake to quantify the influence of phytoplankton on the photodegradation process for the first time. After adjusting the code of the APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics), the suite of photochemical reactions was integrated into the pollutant module of MyLake (Multi-year Lake simulation), as MyLake-Photo. This integrated model was then applied to calculate the concentration of four organic micropollutants under the ranges of solar radiation conditions (0–390 W/m2), phytoplankton biomass (0.01–20 mg/m3 of chlorophyll), and water temperature (1–25 °C). These scenario analyses revealed that phytoplankton biomass and pollutant photodegradation are negatively correlated owing to the light absorption by chlorophyll. Thermal stratification also significantly influenced the vertical distribution of organic micropollutants. Then, the model was applied for calculating a temporal distribution of ibuprofen concentration in Lake Giles (PA, USA) with a simple but realistic assumption. The concentration of organic micropollutants varies with seasons, which was mainly affected by the changes in irradiance and water temperature. In this manner, the integrated model is capable of estimating the temporal and vertical shifts of the concentration of organic micropollutants in lakes, allowing us to investigate the fate of organic micropollutants in lakes. The integrated model also allows us to investigate the effect of phytoplankton and CDOM on the photodegradation of organic micropollutants, which should be combined with field surveys and experimental studies for further improvement.

Prevalence of organic micropollutants in the Yamuna River, Delhi, India: seasonal variations and governing factors

This work primarily emphases on evaluating the prevalence of organic micropollutants (OMPs) in the perennial Yamuna River (YR) that flow through the national capital of India, Delhi. Sixteen sampling campaigns (non-monsoon, n = 9; monsoon n = 7) were organized to understand the seasonal variations with special emphasis on monsoon. We have found fifty-five OMPs in the monsoon; while forty-seven were detected in non-monsoon. Fifty-seven screened and quantified OMPs in the most polluted stretch of River Yamuna included the pharmaceutically active compounds, pesticides, endocrine-disrupting chemicals, phthalates, personal care products, fatty acids, food additives, hormones, and trace organics present in hospital wastes. During monsoon months, compounds for which concentrations exceeded 50 μg/L were: adenine (64.6 μg/L), diethyl phthalate (62.9 μg/L), and octamethyltrisiloxane (56.9 μg/L); and the same for non-monsoon months was only for 1-dodecanethiol (52.3 μg/L). The average concentration of OMPs in non-monsoon months indicate PhACs>PCPs>Pesticides>Fatty acids>Hospital waste>Hormones>Pesticides>EDCs. In monsoon months due to surface runoff and high volume of untreated wastewater discharges few more OMPs concentrations were detected which mainly includes PhACs (clofibric acid, diclofenac sodium, gemfibrozil, ketoprofen), pesticides (aldrin, metribuzin, atrazine, simazine). Due to dilution effect in the monsoon months, average concentrations of 3-acetamido-5-bromobenzoic acid (PhACs) was reduced from 45.22 μg/L to 14.07 μg/L, whereas some EDCs such as 2,4- Di-tert-amylphenol, 3,5- di-tert-butyl-4-hydroxybenzyl alcohol, Triphenylphosphine oxide, Benzophenone were found in much higher concentrations in the monsoon months. Octamethyltrisiloxane (PCPs) was detected 50 times higher in concentration in the monsoon months. Interestingly, the concentration of about 50 % of the OMPs was more in the monsoon samples than in non-monsoon samples which is contrary to the general understanding that monsoon-induced dilution lowers the concentrations of OMPs. In RY water higher magnitude of diclofenac sodium, ibuprofen, ketoprofen, and clofibric acid was found than Europe and North America rivers. Hormones such as estriol and estrone in RY water are found 70 to 100 times higher than the maximum reported concentrations in the US streams. Finally, various OMPs responded differently to the monsoon season as evident from multivariate analyses.

Distribution and health risks of organic micropollutants from home dusts in Malaysia

Indoor dust is an important medium to evaluate human exposure to emerging organic contaminants. The principal aim of this study was to determine overall status of organic micropollutants (OMPs) of indoor dust in Kuala Lumpur, Malaysia and assess their corresponding health risks. One hundred thirty-three OMPs, ascribed to 13 chemical groups, were screened by Automated Identification and Quantification System with a GC-MS database. The concentrations of OMPs ranged between 460 and 4000 μg/g, with the median concentration of 719 μg/g. The dominant chemical groups were ascribed to n-alkanes (median: 274 μg/g), plasticizers (151 μg/g), sterols (120 μg/g), and pesticides (42.6 μg/g). Cholestrol was the most abundant compound (median: 115 μg/g). Different sources and usage patterns of OMPs in various houses were expected. Toxicity values of OMPs were obtained from existing databases or predicted by quantitative structure-activity relationship models. Cumulative hazard quotients for OMPs through ingestion route were lower than one for all the dust samples, demonstrating that there was no remarkable non-cancer risk. The cancer risks of these OMPs were greater than 10−4, with cholestrol dominating 99.1% of the carcinogenic risks, which suggested that there was a significant cancer risk. This study might offer a benchmark to ensure the safety of chemical usages in future in Malaysia.

Suspect screening to support source identification and risk assessment of organic micropollutants in the aquatic environment of a Sub-Saharan African urban center

Organic micropollutants (OMPs) are contaminants of global concern and have garnered increasing attention in Africa, particularly in urban and urbanizing areas of Sub-Saharan Africa (SSA). In this work, we coupled suspect screening enabled by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) with multivariate analysis to characterize OMPs in wastewater, surface water, and groundwater samples collected from Kampala, the capital and largest city of Uganda. Suspect screening prioritized and confirmed 157 OMPs in Kampala samples for target quantification. Many OMPs detected in Kampala samples occurred within concentration ranges similar to those documented in previous studies reporting OMP occurrence in SSA, but some have never or rarely been quantified in environmental water samples from SSA. Hierarchical cluster analysis established the source-related co-occurrence profiles of OMPs. Partial least squares regression and multiple linear regression analyses further pinpointed the concentration of nitrate and the content of a fluorescent organic matter component with excitation/emission maxima around 280/330 nm as predictors for the sample-specific cumulative concentrations of OMPs, suggesting the likely contribution of diffuse runoff and wastewater discharges to OMP occurrence in the aquatic environment of Kampala. Parallel calculations of exposure-activity ratios and multi-substance potentially affected fractions provided insights into the potential for biological effects associated with OMPs and highlighted the importance of expanded analytical coverage for screening-level risk assessments. Overall, our study demonstrates a versatile database-driven screening and data analysis methodology for the multipronged characterization of OMP contamination in a representative SSA urban center.

Unraveling competition versus adsorbability of dissolved organic matter against organic micropollutants onto activated carbon

It was widely acknowledged that dissolved organic matter (DOM) in natural water has ubiquitous competitiveness against organic micropollutants (OMPs) during adsorption onto activated carbon. However, some (model) low molecular weight organics have been reported to adsorb onto activated carbon, but were not competitive against co-adsorbates. The objective of this study is to identify which adsorbable DOM fractions in natural water contribute to the DOM competitiveness, and what is the impact of the OMP adsorbability and initial OMP concentration on this competitiveness. We, therefore, disassociated the adsorption of DOM fractions and OMPs (carbamazepine, caffeine and sulfamethoxazole) using a two-stage adsorption procedure, removing various adsorbable DOM fractions with powdered activated carbon pretreatment and then unraveling the competitiveness against OMPs of the remaining DOM. Our results demonstrated that DOM competition was not ubiquitous for all adsorbable fractions in natural water, and ∼ 25% of the adsorbable DOM was not competitive. The poorly adsorbable DOM was shown to be a non-competitive co-adsorbate, and its complexation even elevated the adsorption capacity of one of the OMPs (carbamazepine). The amount of DOM competitors increased for weaker adsorbable OMPs, and at higher initial OMP concentrations. The variability in DOM competition, differentiated by DOM adsorbability, has advanced the understanding of DOM competition, from ubiquitous competition to variable roles (varying competitiveness/complementary adsorption) of differently adsorbable DOM fractions during OMP adsorption.

Risk-based screening for prioritisation of organic micropollutants in Swedish freshwater

Concerns about environmental contamination by organic micropollutants (OMPs) are increasing, due to their potential bioaccumulative and toxic properties. This study evaluated the risk posed by OMPs to aquatic ecosystems in Swedish freshwaters. The assessment was based on measured environmental concentrations (MEC) of OMPs in surface waters upstream and downstream of Swedish wastewater treatment plants (WWTPs). A novel optimised risk quotient (RQf) was used to identify potential high-risk substances in the aquatic environment. A secondary objective was to assess the impact of WWTP effluent on aquatic ecosystems using a novel impact factor (I) based on the risk quotient (RQ). Among the 126 substances investigated, four compounds (metformin, N,N-dimethyltetradecylamine, oxazepam, and venlafaxine) were identified as likely to pose a risk to aquatic ecosystems in Swedish surface waters (RQf>1), and five compounds (clindamycin, gemfibrozil, sertraline, o-desmethylvenlafaxine, and diclofenac) were identified as posing a moderate risk to aquatic ecosystems ( 0.1 <RQf<1). WWTP effluent appeared to pose an environmental risk for all recipient sites, but the impact of calculated RQ was site-specific. These results can be used by authorities to prioritise OMPs and contaminated hotspots, in order to decrease negative impacts on aquatic ecosystems. SynopsisA novel optimised risk assessment approach for identification of high-concern organic micropollutants in aquatic environments.

Occurrence of organic micropollutants and heavy metals in the soil after the application of stabilized sewage sludge.

Stabilized sewage sludge could be used as a fertilizer in the soil because of nitrogen, phosphorus, and other micronutrition material to improve the properties of the soil. In this study, clover and fodder corn plants were planted in the soil to which stabilized sewage sludge was applied. The soil was analyzed and evaluated by collecting samples to determine changes in the application fields before plantation and one year after the harvest. To monitor changes in the soil and after the application of stabilized sludge to the soil, the stabilized sewage sludge was evaluated for the suitability of parameters such as heavy metals, halogenated organic compounds including adsorbable organic halogens (AOX), nonylphenol ethoxylates (NPE), polycyclic aromatic hydrocarbon compounds (PAH), polychlorinated biphenyls (PCB), di(2-ethylhexyl) phthalate (DEHP), linear alkylbenzene sulphonates (LAS), polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/F), and pathogens and other parameters containing organic matter (OM), pH, conductivity (EC), total nitrogen (TN), and total phosphorus (TP). After the sludge application, the heavy metal content increased, except for Zn. The application of stabilized sludge as a soil conditioner and humus caused a significant increase in the TN and TP content since the product increased the harvest that increased soil nutrition. After the sludge application to the soil, the concentration of organic micropollutants in the soil did not change. The concentration of AOX and PCDD/F in the soil increased by 141% and 125%, respectively.