Water Treatment Plant Effluent Research Articles

Enhanced adsorption of aqueous perfluorooctanoic acid on iron-functionalized biochar: elucidating the roles of inner-sphere complexation

Perfluorooctanoic acid (PFOA) is ubiquitously detected in various water bodies, which raises the urgent need for developing effective and economic remediation methods in response to its health risks. The adsorptive removal of PFOA by biochar (BC) is regarded as a simple, effective, and economical technique. However, engineered BCs, including FeCl3-activated BC, for PFOA removal and adsorption mechanisms have been ill-studied. In this study, a FeCl3-activated dairy manure-derived biochar (Fe@MBC) was prepared via one-step pyrolysis/activation, and its properties and adsorption characteristics were compared with a pristine manure-derived biochar (P-MBC). The FeCl3 activation largely increased the surface area of Fe@MBC and the deposition of FexOy minerals on surface of Fe@MBC while significantly elevating the surface roughness of Fe@MBC. The maximum adsorption capacity of Fe@MBC for PFOA (233 mg·g−1) was five times higher than that of P-MBC (46 mg·g−1). PFOA adsorption was favorable at low solution pH and was independent on ionic strength, which supported the major contribution by inner-sphere complexation rather than out-sphere complexation. This mechanism was further confirmed by the disappearance of FeO peak on Fourier transform infrared spectrum and the blue-shift of Fe binding energies on X-ray photoelectron Fe 2p spectrum of Fe@MBC after PFOA adsorption. Fe@MBC maintained a near 100% adsorption capacity for PFOA after 4 cycles of chemical regeneration. Fe@MBC also exhibited efficient removal for PFOA and other PFAS compounds at trace levels in the lake water and wastewater treatment plant effluent. Thus, this study highlights a promising insight for selectively eliminating PFASs from water.

The Isotopic Composition of Selected Phosphate Sources (δ18O-PO4) from the Area of the Vistula and Bug Interfluve (Poland)

Phosphorus belongs to the crucial bioelements that cause eutrophication, and phosphates, easily assimilated by organisms, are widespread in the environment. Phosphates can be of natural or anthropogenic origin and can derive from various point or non-point sources. Knowledge about the origin of nutrients is necessary to effectively manage, protect, and revitalize water resources. To recognize various phosphate sources in the study area of our research, i.e., the Vistula and Bug interfluve (SE Poland), we used the oxygen isotopic signature of phosphate ions (δ18O-PO4), which has been successfully used in recent decades as a tracer of phosphorus cycling in water studies. We measured the δ18O-PO4 of dissolved inorganic phosphates (DIPs) extracted from various phosphate sources. The obtained results are as follows: For springs, the δ18O-PO4 value varied from +14.8‰ to +18.5‰; for riverine samples, from +10.3‰ to +18.6‰, which were significantly location-dependent; while waste water treatment plant effluents ranged from +12.4‰ to +15.6‰. Two tested drainage water samples had similar isotopic compositions (+16.7‰ and +17.3‰). In the case of two analyzed bedrock samples, the δ18O-PO4 values, which were similar (+20.5‰ and +21.7‰), are close to the existing data on sedimentary bedrocks derived from similar geological periods. The obtained results can be helpful in future research aimed at identifying phosphate sources and P cycling in the studied area.

Corn stalk decorated with magnetic graphene oxide as an efficient adsorbent for the removal of cationic dye from wastewater

In this study, an in situ immersion loading method is employed to introduce graphene oxide (GO) nanosheets and hollow copper ferrite nanospheres into the ordered porous structure of alkali-activated corn stalk (CS). This approach facilitates the construction of a novel magnetic three-dimensional composite sponge (GO/CS/CuFe2O4) utilized for the efficient removal of methylene blue (MB) and malachite green (MG) dyes from wastewater samples. In this hybrid adsorbent, the stacking of GO nanosheets is inhibited due to the ordered porous structure of CS, based on which GO nanosheets are well immobilized and dispersed. In addition, the hollow CuFe2O4 nanospheres and GO nanosheets support each other, further reducing the accumulation of GO, and increasing the specific surface area of the adsorbent. The engineered morphology of GO/CS/CuFe2O4 sponges supports the maximum exposure of the active adsorption sites to the dye solution, promoting the adsorption process. Microscopy and surface analyses show that GO/CS/CuFe2O4 sponges have a rich pore structure with the specific surface area of 289.85 m2·g−1, more than 17 times higher than that of CS, significantly improving their adsorption performance for MB and MG. The maximum adsorption capacity of GO/CS/CuFe2O4 for MB and MG is as high as 243.65 and 231.53 mg/g, respectively, superior to those of many other biomass-based adsorbents. The dye adsorption performance of GO/CS/CuFe2O4 can be well described by the Langmuir adsorption isotherm and pseudo-second-order kinetic model, suggesting the existence of strong monolayer chemisorption. The FTIR and X-ray photoelectron spectroscopy (XPS) analyses show that the dye removal mechanisms observed mainly includ π-π interactions, hydrogen bonding, electrostatic interactions and pore filling. In addition, GO/CS/CuFe2O4 sponges exhibit an excellent magnetic behavior (Ms = 49.52 emu/g), enabling the adsorbent to be recycled by the application of a magnetic field. The adsorption capacities of the adsorbent for MB and MG remain 88.6 % and 90.2 % of the initial adsorption capacity, respectively, even after 10 regeneration cycles, showing its excellent reusability performance. Finally, GO/CS/CuFe2O4 is applied for the removal of MB and MG from real aqueous environments comprising the seawater, tap water and wastewater treatment plant effluent, and the removal rates are observed to be over 90 % of that achieved in deionized water. This study provides new concepts for the sustainable utilization of agricultural waste and natural structure of plants to purify dye containing wastewater.

Digital One-Step Competitive Detection of a Small Molecule in Synthetic and Environmental Waters.

Optical methods for single-molecule analysis hold the promise of accurate, sensitive, and rapid detection of target molecules. Here, we demonstrate the efficiency of such an approach for the competitive detection of small molecules in water. Our biosensing method is based on a combination of a single-DNA biochip for the parallelization of tethered particle motion real-time measurements with antibodies and modified targets as molecular competitors. The antibodies are coupled to the particles tethered to the surface by a long DNA bearing in its middle the molecular competitor bound to the antibodies. Competitive target binding leads to a detectable conformational change of the DNA tethers from looped to unlooped in proportions related to the target concentration. We thus managed to detect fluorescein, chosen as a model of a target molecule, in freshwater of various qualities, from solutions prepared with ultrapure water to more complex matrices such as river water and wastewater treatment plant effluent samples. Similar dose-response curves were obtained under these various conditions in a wide range of concentrations from nanomolar to micromolar with a limit of detection around 2 nM.

Improving sample preparation by biochar-coated sampling tubes: proof-of-concept extraction of sex hormones from real waters

This work showcases a novel application of biochar for analytical sample treatment. The carbonaceous material, obtained by pyrolysis of orange peel waste (550°C) without any post-synthesis treatment or functionalization, was thoroughly characterized and easily immobilized on the inner wall of sampling tubes in order to perform a sort of “in-vial” solid-phase extraction (SPE). The as-obtained device was tested for the extraction of seven sexual steroids, as probe water pollutants, from tap, lake, river water and wastewater treatment plant effluent samples spiked with 0.2-5 µg L−1 of each compound. The sorption kinetics profiles showed quantitative uptake from the sample (25 mL) in 20 min contact time, followed by complete elution in pure ethanol (2 mL, 15 min), thanks to the proper balance between sorption affinity and ease of elution. Under the selected conditions, recovery was in the range 60-123 %, with good inter-day precision (RSD 10-18 %, n=3). As evidence of the excellent reproducibility, an overall RSD below 15 % was observed from inter-day inter-batch recovery tests on three individually prepared sampling tubes. The procedure, carried out on a roller mixer, allows 10 samples to be extracted simultaneously, improving the sample throughput. Moreover, reusability tests showed that the same device maintains its efficiency for 10 consecutive sorption/desorption cycles. The greenness assessment, carried out by two dedicated software, further supported the sustainability of this biochar-based sample preparation as an alternative SPE.

Traversing the prevalence of microplastics in soil-agro ecosystems: Origin, occurrence, and pollutants synergies

The ubiquity of plastics in modern life has made them a significant environmental concern and a marker of the Anthropocene era. The degradation of plastics results in the formation of microplastics (MPs), which measure 5 mm or less. The coexistence of MPs with other pollutants found in sludge, water treatment plant effluents, surface water, and groundwater, shapes the environmental landscape together. Despite extensive investigation, the long-term implications of MPs in soils remain uncertain, underscoring the importance of delving into their transportation and interactions with soil biota and other contaminants. The present article provides a comprehensive overview of MPs contamination in soil, encompassing its sources, prevalence, features, and interactions with soil flora and fauna, heavy metals, and organic compounds. The sources of MPs in soil agroecosystems are mulching, composting, littering, sewage sludge, irrigation water, and fertilizer application. The concentration of MPs reported in plastic mulch, littering, and sewage sludge is 503 ± 2760 items per kg−1, 4483 ± 2315 MPs/kg, and 11,100 ± 570 per/kg. The transport of MPs in soil agroecosystems is due to their horizontal and vertical migration including biotic and abiotic mobility. The article also highlighted the analytical process, which includes sampling planning, collection, purification, extraction, and identification techniques of MPs in soil agroecosystems. The mechanism in the interaction of MPs and organic pollutants includes surface adsorption or adhesion cation bridging, hydrogen bonding, charge transfer, ligand exchange, van der Waals interactions, and ion exchange.

High enrichment factors in chemical analysis of progestins and in bioassays: insights beyond trace levels.

Concerns are growing about adverse effects of progestins on biota, even at ultra-trace concentrations. The enrichment factor (EF) from extraction of analytes in environmental samples that is needed for sample pre-concentration can affect not only performance of the analytical method but also the matrix effect. Therefore, the present study aimed to assess the influence of high sample EF on performance of the high-performance liquid chromatography with atmospheric pressure chemical ionization and photoionization coupled with high-resolution mass spectrometry (HPLC-APCI/APPI-HRMS) method for analysis of progestins in waste water treatment plant (WWTP) effluents and surface waters and analysis of (anti-)progestogenic activities measured by (anti-)PR-CALUX bioassays. The results showed that HPLC-APCI/APPI-HRMS coupled with solid-phase extraction and a high EF (33,333 Lwater/Lextract) enabled the detection of more compounds compared to samples with lower sample EF (10,000 Lwater/Lextract). The matrix effect did not increase proportionally compared to lower EFs (10,000 and 16,666 Lwater/Lextract), and lower limits of quantification were achieved in WWTP effluents and surface waters. The results of bioassays have shown that relative EF of 25 Lwater/Lbioassay appears high enough to detect progestogenic activity in treated waste water. Our study is one of the first to provide insights into sample pre-concentration in analysis of progestins and progestogenicity in aquatic environments.

Modelling effluent reuse in the pulp and paper industry to predict consequences on conductivity.

The objective of this study was to assess, through simulation, conductivity variations in pulp and paper circuits when recycling waste water treatment plant (WWTP) effluent with a view to reducing fresh water use in a tissue mill. WWTP effluent was recycled in the process for different uses. A PS2000 digital model coupled with the PHREEQC chemical simulation engine was used to identify and quantify the main sources of conductivity: caustic soda, sodium bisulphite and acetate production through anaerobic microbial activity. Recycling WWTP effluent enables fresh water uptake to be reduced by 50% when used for pulp dilution or white water, by 81% when used in paper machine showers, and up to 96% for all uses combined. As fresh water use decreases, circuit closure increases along with, consequently, COD and conductivity. COD build-up can be controlled by best available techniques application. Recycling WWTP effluent has a strong impact on conductivity. However, the impact of high conductivity levels on additives performance is limited in the case of the mill studied. Acetate concentration could be controlled by better agitation of tanks or the introduction of air by pumps. Furthermore, limiting acetate production can reduce the need for caustic soda to control the pH.

Effective removal of iron, nutrients, micropollutants, and faecal bacteria in constructed wetlands cotreating mine water and sewage treatment plant effluent.

Regulators in England and Wales have set new targets under the Environment Act 2021 for freshwater quality by 2038 that include halving the length of rivers polluted by harmful metals from abandoned mines and reducing phosphorus loadings from treated wastewater by 80%. In this context, an intriguing win-win opportunity exists in the removal of iron from abandoned mines and phosphate from small sewage treatment plants by coprecipitation in constructed wetlands (CWs). We investigated such a CW located at Lamesley, Northeast England, which cotreats abandoned coal mine and secondary-treated sewage treatment plant effluents. We assessed the removal of nutrients, heavy metals, organic micropollutants, and faecal coliforms by the CW, and characterized changes in the water bacteriology comprehensively using environmental DNA. The CW effectively removed ammonium-nitrogen, phosphorus, iron, and faecal coliforms by an average of 86, 74, 98, and 75%, respectively, to levels below or insignificantly different from those in the receiving river. The CW also effectively removed micropollutants such as acetaminophen, caffeine, and sulpiride by 70-100%. Molecular microbiology methods showed successful conversion of sewage and mine water microbiomes into a freshwater microbiome. Overall, the CW significantly reduced impacts on the rural water environment with minimal operational requirements.

Analytical Review of Microplastics Occurrence in Bottled Water, Tap Water, and Wastewater Treatment Plants

Currently, water availability and accessibility have become more challenging due to population growth, development of industrial and agricultural activities, and the effects of climate change. Various types of pollutants released by human activities threaten water quality and availability. Microplastics and emerging contaminants are currently affecting water resources and posing a risk to human health. The present study reviews the available studies that analyzed the abundance, shape, and size of microplastics in water, including glass, plastic, reusable, recyclable, and beverage bottled water, tap water, and wastewater treatment plant (WWTP) influent and effluent. Analysis of the collected data allowed comparison of microplastic abundance in different packaging water bottles, tap water, and raw and treated water from WWTPs. The analysis results suggest that microplastics in drinking water are mainly associated with water sources. Therefore, more attention should be paid to water treatment and purification processes and technologies. The type of packaging is also a crucial parameter to consider when quantifying microplastics in drinking water, although the use of glass bottles is recommended to minimize the potential associated risk to humans and ensure safe consumption. Increasing public awareness and knowledge about waste separation, the potential risks of microplastics to human health, and the urgent need for behavioral change in the management of waste, mainly plastic objects, remain the main keys to reducing the number of plastics entering our environment and our bodies.

Efficient removal of toxicity associated to wastewater treatment plant effluents by enhanced Soil Aquifer Treatment

The regeneration of wastewater has been recognized as an effective strategy to counter water scarcity. Nonetheless, Wastewater Treatment Plant (WWTP) effluents still contain a wide range of contaminants of emerging concern (CECs) even after water depuration. Filtration through Soil Aquifer Treatment (SAT) systems has proven efficient for CECs removal although the attenuation of their associated biological effects still remains poorly understood. To evaluate this, three pilot SAT systems were monitored, two of them enhanced with different reactive barriers. SATs were fed with secondary effluents during two consecutive campaigns. Fifteen water samples were collected from the WWTP effluent, below the barriers and 15 m into the aquifer. The potential attenuation of effluent-associated biological effects by SATs was evaluated through toxicogenomic bioassays using zebrafish eleutheroembryos and human hepatic cells. Transcriptomic analyses revealed a wide range of toxic activities exerted by the WWTP effluents that were reduced by more than 70% by SAT. Similar results were observed when HepG2 hepatic cells were tested for cytotoxic and dioxin-like responses. Toxicity reduction appeared partially determined by the barrier composition and/or SAT managing and correlated with CECs removal. SAT appears as a promising approach to efficiently reduce effluent-associated toxicity contributing to environmental and human health preservation.

Simple, fast and eco-friendly micro-solid phase extraction based on thiol and ionic liquid bi-functional nanofibers membrane for the determination of sulfonamides in environmental water

BackgroundSulfonamides (SAs) are a class of synthetic antibacterial agents that are diffusely used in the medical industry and animal husbandry. Their prevalence in the influents and effluents of water treatment plants, as well as in rivers and groundwater, has provoked worldwide concern. Monitoring SAs in environmental water is of great significance for public health. However, most of the available detection techniques for SAs are cumbersome and time-consuming. With the increasing number of actual samples, simple, fast and environmentally friendly analytical methods are always in demand. ResultsHerein, we describe a highly efficient micro-solid phase extraction (μ-SPE) sample preparation technique based on a novel thiol and ionic liquid bi-functional nanofibers membrane (IL-SH-PAN NFsM) for multi-residue detection of sulfonamides (SAs) in water samples. By the synergistic effect of -SH and -IL, the as-prepared IL-SH-PAN NFsM demonstrated high adsorption capacity and excellent selectivity for SAs. The water samples can be directly used for μ-SPE without pH and ionic strength adjustment, and the eluent can be directly collected for HPLC-MS/MS analysis. Compared with other methods reported in the literature, this method required much shorter extraction time (2 min for a batch), much less amount of adsorbent (4.0 mg) and organic solvent (0.5 mL), while providing much higher sensitivity (1.4–3.9 ng L−1), and fine recoveries (88.8%–117.7%) with relative standard deviations less than 4.26%. Significance and noveltyA bi-functional nanofibers membrane was prepared for efficient extraction of SAs. The adsorbent exhibited superior adsorption performance and excellent selectivity. The underlying interaction mechanisms derived from -SH and -IL were proposed, which provide a new idea for preparing versatile adsorbents. Rapid, efficient and sensitive detection of SAs in water was achieved. The novel sample preparation technique can be expected as an efficient method for routine trace SAs residue monitoring in various water samples.

Survey of Appearance and temporal concentrations of polar organic pollutants in Saxon waters

Integrative passive samplers such as the Chemcatcher are often proposed as alternatives for conventional grab sampling of surface waters. So far, their routine application for regulatory monitoring is hampered (among others) by the fact that TWA concentrations may depend significantly on the design and specifics of the samplers employed. The presented study addresses this issue, focusing on the uptake of polar organic pollutants in three different Chemcatcher configurations and polydimethylsiloxane (PDMS) sheets in the field. Covering waste water treatment plant effluents, creeks, and rivers, samplers were deployed for periods of 14–21 days in eight trials over the course of one year. 33 organic pesticides, 14 transformation products and 31 pharmaceuticals could be detected at least once in TWA concentrations ranging from 0.03 ng/L to 16.5 μg/L. We show that through employing generic, i.e. sampler specific, rather than compound specific sampling rates, the variation among results from three integrative passive sampler designs yields linear correlations with an offset of less than 0.1 and correlation coefficients r2 > 0.8. In this way, TWA concentrations enable the identification of low-concentration xenobiotics of concern, which may support regulatory monitoring correspondingly.

Human health risk assessment of Triclosan in water: spatial analysis of a drinking water system.

Triclosan (TCS) has been increased in the water during the COVID-19 pandemic because it cannot remove by conventional water treatment. In addition, it can accumulate in the human body over time through long-term exposure. Therefore, the occurrence of TCS in the water treatment plant (WTP) and tap water, and its human health risk assessment through tap water ingestion, dermal absorption, and inhalation routes in Isfahan, Iran, were investigated. Moreover, spatial regression methods were used for the prediction of water quality parameters, TCS concentration, and total hazard quotient (HQ). The average TCS concentration in the influent and effluent of WTP and tap water was 1.6, 1.4, and 0.4 μg/L, respectively. Conventional WTP has low efficiency in the removal of TCS (12.6%) from water. The average values of total HQ for males were 7.79×10-5, 4.97×10-4, and 4.97×10-5 and for females were 3.31×10-5, 2.11×10-4, and 2.11×10-5 based on RfDEPA, RfDMDH, and RfDRodricks, respectively that were in the low-risk levels (HQ<1). Furthermore, TCS concentration in tap water and the ingestion rate of drinking water had the highest effect on the risk of TCS exposure from tap water. The non-carcinogenic health risk of TCS in water was low. The results of this study may be useful for promoting WTP processes to remove emerging pollutants.

Upgrading of conventional water treatment plant by nanofiltration for enhanced organic matter removal

Natural organic matter (NOM) is responsible for a variety of problems in water, including taste, odor, and color. If NOM is present in treated water, it can also promote microbial growth in water distribution systems. Another problem related with NOM is that it combines with chemicals such as chlorine in water resulting in the formation of disinfection by-products (DBPs). With the DBP regulations becoming more stringent, several advanced treatment methods started to be applied to enhance NOM removal. Pilot-scale advanced treatment tests employing tight nanofiltration (T-NF) membrane with high ion rejection capacity and loose nanofiltration (L-NF) membrane with low ion rejection capacity were conducted in this study in order to remove total organic carbon (TOC) having an average concentration of 2 mg/L at the sand filter effluent of a full-scale drinking water treatment plant and to avoid DBP production. The cost of incorporating membrane processes into the treatment process scheme was also determined during the study, in addition to the experimental studies. At constant 6 bar, the average fluxes for the T-NF and L-NF were determined to be 12.7 and 7.6 L /m2 h, respectively. L-NF had a TOC removal efficiency of 96.0%, which is quite similar to the removal efficiency achieved by T-NF (96.3%). Heavy metals, anions, and cations removal efficiency in T-NF membranes were greater than in L-NF, as expected. The removal efficiencies of Cl-, and Fe on T-NF membrane were determined to be 90.3 ± 2.2% and 69.6 ± 5.6, respectively, which are much greater than those achieved in L-NF membrane The total cost of 400,000 m3/d L-NF membrane system upgrade is calculated as 28,901,262 $/y including capital and operation and maintenance (O&M) costs, while in T-NF is calculated as 28,074,282 $/y. The total cost of NF upgrading is estimated to be around 0.191–0.198 $/m3, which is nearly 50% of the cost of the conventional treatment plant. When upgrading a conventional treatment system with this type of membrane system, additional expenses are typically incurred, resulting in a higher total cost; however, the resultant water quality is significantly improved.

Portable biosensor for the detection of Enrofloxacin and Ciprofloxacin antibiotic residues in food, body fluids, environmental and wastewater samples

Enrofloxacin (ENR) and its metabolite Ciprofloxacin (CIP) are both a class of fluoroquinolone antibiotics effective against a broad-spectrum microbial infection. Recent surge in the consumption of CIP and ENR has been linked to increased cases of drug-resistant pathogens. This is due to the fact that the antibiotic residues remain in milk, meat, soil and environmental water for a prolonged duration. Although gold standard methods such as LC-MS are sensitive, they suffer from expensive operation and maintenance cost, and would need dedicated facilities and tedious sample preparation steps. Such limitations make on site detection impossible for regulatory bodies in developing countries. To address this issue, we developed a portable device that can detect the presence of CIP and ENR antibiotics in the range of parts per billion (ppb) concentrations accurately. It consists of a polyaniline (PAni) coated U-bent optical fiber with anti-ENR/CIP antibody immobilized on the polymer surface. The sensor relies on the principle of evanescent wave absorbance by antigen-antibody complex. The sensor showed limit of detection (LOD) of 1 ppb with a linear range of operation from 1 ppb to 500 ppb (R2 = 0.96-0.99) in lake water, waste water treatment plant effluent, urine, blood serum, milk and meat samples. The recovery of the sensor ranges from 88% to 120% indicating reasonable accuracy. The sensor has excellent selectivity towards CIP and ENR and showed stability for four weeks indicating its field deployability and robustness. The portable sensor is scalable and contract has been given to an industry partner to mass manufacture the device.

Investigation of the effect of water treatment plant effluent on river quality: a case study

Investigation of the effect of water treatment plant effluent on river quality: a case study

Co-occurrence of phthalate esters and perfluoroalkyl substances affected bacterial community and pathogenic bacteria growth in rural drinking water distribution systems

The adverse health effects of phthalate esters (PAEs) and perfluoroalkyl substances (PFAS) in drinking water have attracted considerable attention. Our study investigated the effects of PAEs and PFAS on the bacterial community and the growth of potential human pathogenic bacteria in rural drinking water distribution systems. Our results showed that the total concentration of PAEs and PFAS ranged from 1.02 × 102 to 1.65 × 104 ng/L, from 4.40 to 1.84 × 102 ng/L in rural drinking water of China, respectively. PAEs concentration gradually increased and PFAS slowly decreased along the pipeline distribution, compared to concentrations in the effluents of rural drinking water treatment plants. The co-occurrence of higher concentrations of PAEs and PFAS changed the structure and function of the bacterial communities found within these environments. The bacterial community enhanced their ability to respond to fluctuating environmental conditions through up-regulation of functional genes related to extracellular signaling and interaction, as well as genes related to replication and repair. Under these conditions, co-occurrence of PAEs and PFAS promoted the growth of potential human pathogenic bacteria (HPB), therefore increasing the risk of the development of associated diseases among exposed persons. The main HPB observed in this study included Burkholderia mallei, Mycobacterium tuberculosis, Klebsiella pneumoniae, Acinetobacter calcoaceticus, Escherichia coli, and Pseudomonas aeruginosa. Contaminants including particles, microorganisms, PAEs and PFAS were found to be released from corrosion scales and deposits of pipes and taps, resulting in the increase of the cytotoxicity and microbial risk of rural tap water. These results are important to efforts to improve the safety of rural drinking water.

Monitoring Mixture Effects of Neurotoxicants in Surface Water and Wastewater Treatment Plant Effluents with Neurite Outgrowth Inhibition in SH-SY5Y Cells.

Cell-based assays covering environmentally relevant modes of action are widely used for water quality monitoring. However, no high-throughput assays are available for testing developmental neurotoxicity of water samples. We implemented an assay that quantifies neurite outgrowth, which is one of the neurodevelopmental key events, and cell viability in human neuroblastoma SH-SY5Y cells using imaging techniques. We used this assay for testing of extracts of surface water collected in agricultural areas during rain events and effluents from wastewater treatment plants (WWTPs), where more than 200 chemicals had been quantified. Forty-one chemicals were tested individually that were suspected to contribute to the mixture effects among the detected chemicals in environmental samples. Sample sensitivity distributions indicated higher neurotoxicity for surface water samples than for effluents, and the endpoint of neurite outgrowth inhibition was six times more sensitive than cytotoxicity in the surface water samples and only three times more sensitive in the effluent samples. Eight environmental pollutants showed high specificity, and those ranged from pharmaceuticals (mebendazole and verapamil) to pesticides (methiocarb and clomazone), biocides (1,2-benzisothiazolin-3-one), and industrial chemicals (N-methyl-2-pyrrolidone, 7-diethylamino-4-methylcoumarin, and 2-(4-morpholinyl)benzothiazole). Although neurotoxic effects were newly detected for some of our test chemicals, less than 1% of the measured effects were explained by the detected and toxicologically characterized chemicals. The neurotoxicity assay was benchmarked against other bioassays: activations of the aryl hydrocarbon receptor and the peroxisome proliferator-activated receptor were similar in sensitivity, highly sensitive and did not differ much between the two water types, with surface water having slightly higher effects than the WWTP effluent. Oxidative stress response mirrored neurotoxicity quite well but was caused by different chemicals in the two water types. Overall, the new cell-based neurotoxicity assay is a valuable complement to the existing battery of effect-based monitoring tools.

Micropollutant degradation by UV/H2O2 in drinking water: Facilitated prediction through combination of model simulation and portable measurement

Ultraviolet-based advanced oxidation processes (UV-AOPs) are highly effective for micropollutant degradation. However, it is considerably time and labor consuming to evaluate the practical performance of UV-AOPs. This study developed a novel method, through combination of model simulation with portable measurement (MS-PM), to facilitate prediction of the photon fluence-based rate constant of micropollutant degradation (k′p,MP) by UV/H2O2, a commercially available UV-AOP. Model simulation was performed with photochemical, hydroxyl radical (HO•) concentration steady-state approximation, and quantitative structure-activity relationship models; and portable measurement was conducted on a mini-fluidic photoreaction system to quantify the HO• scavenging capacity (HRSC) of a water matrix. The method was established and further verified experimentally in seven test waters by taking sulfamethazine (SMN) as a model micropollutant. A lower k′p,SMN was predicted in a water matrix with a higher HRSC, for example, 57.5 and 347.8 m2 einstein–1 in the raw water (HRSC = 5.91 × 105 s–1) and sand-filtered effluent (HRSC = 5.25 × 104 s–1) of a drinking water treatment plant at an H2O2 dose of 25 mg L–1, respectively. The predicted values agreed generally well with the experimental ones. The MS-PM method has advantages of high efficiency and convenience, low cost, and acceptable accuracy, which will significantly facilitate the design and field assessment of UV-AOPs for micropollutant removal from drinking water.