Analyzing a broader spectrum of endocrine active organic contaminants in sewage sludge with high resolution LC-QTOF-MS suspect screening and QSAR toxicity prediction

The behavioral, physiological, and biochemical responses of Lumbriculus variegatus exposed to cannabidiol and its metabolites

Cannabidiol (CBD) is a major non-psychoactive cannabinoid that has been detected in environmental samples, but the ecotoxicological effects remain unknown. In this study, Lumbriculus variegatus were exposed to CBD and its metabolites 7-hydroxy-cannabidiol (7-OH-CBD) and 7-carboxy-cannabidiol (7-COOH-CBD). In this study, toxicity, tactile stimulation to elicit stereotypical behaviors, and locomotor activity were measured after 24-hr exposure of L. variegatus to CBD and its metabolites. We describe the impacts on dorsal blood vessel pulsation and oxygen consumption after 24-hr exposure to CBD and 7-OH-CBD and the effects on regenerative capacity and total energy reserves after 72 hr of exposure to CBD and 7-OH-CBD. We observed that CBD, 7-OH-CBD, and 7-COOH-CBD displayed toxicity in 50% of test populations at 14.12 µM, 11.29 µM, and 15.36 µM, respectively. A 24-hr exposure to CBD decreased tactile stimulation response to elicit body reversal at ≥ 2.5 µM and helical swimming at ≥ 0.5 µM and reduced locomotor activity. Lumbriculus variegatus oxygen consumption was not affected by CBD, but ≥ 2.5 µM significantly reduced dorsal blood vessel pulse rate. We observed that exposure to 7-OH-CBD did not affect the regenerative capacity of L. variegatus whereas CBD was shown to reduce regeneration. Exposure to CBD also resulted in a significant decrease in carbohydrates, increased lipids, and no effect on protein levels in L. variegatus. We determined that CBD can reduce L. variegatus behaviors, decrease pulse rates and regenerative capacity, and disrupt energy reserves. Our findings show that CBD is toxic to this common aquatic organism and the increased availability and use of CBD and related substances warrants further study of their environmental impact.

Characterizing pyrethroid and fipronil concentrations in biosolids

Pesticides are prevalent in wastewater, yet few studies have measured pesticides in biosolids and aqueous media from samples collected concurrently. Seventeen California wastewater treatment plants (WWTPs) were sampled in May 2020. Biosolids samples were analyzed for 27 analytes, and paired aqueous samples (influent and effluent) were analyzed for 23 analytes. Analytes included fipronil and its transformation products (fiproles), pyrethroids, novaluron, and several other pesticides with down-the-drain transport potential. Of the 27 compounds analyzed in biosolids samples, 16 were detected in at least one sample, and 10 had a detection frequency (DF) of at least 25 %. Fipronil sulfone, fipronil sulfide, and fipronil were the most frequently detected fiproles (DF = 100 %, 94 %, and 67 %, respectively); permethrin was the most frequently detected pyrethroid (DF = 100 %), followed by bifenthrin (DF = 94 %), cyhalothrin (DF = 89 %), and etofenprox (DF = 78 %). To elucidate fipronil transformation pathways within the treatment system, data from the three sample types were compared; findings were generally consistent with transformation pathways reported previously (e.g., some fiproles were rarely detected in influent or biosolids, but frequently detected in effluent, indicating their formation during the treatment process). No correlations were found between WWTP characteristics and pesticide concentrations in biosolids. The fraction of organic carbon (fOC) of each biosolids sample was measured, and a statistically significant negative correlation was observed between fOC and some fiproles, but not fipronil; possible explanations are discussed. Additional analysis for two major agricultural pesticides (bifenthrin and permethrin) indicated that estimated mass loads of these pesticides in biosolids applied to land as a soil amendment are minimal (approximately 2 to 3 orders of magnitude lower) compared to inputs from agricultural applications. This study provides insight on the magnitude of pesticides entering the environment via land-applied biosolids; existing regulations surrounding agricultural pesticide applications are expected to also be protective of the relatively low inputs from biosolids.

A Call for Pediatric Clinicians to Address Environmental Health Concerns in Rural Settings

Children in rural communities encounter unique environmental exposures, many of which can result in negative long-term health consequences. Children are particularly at risk from these exposures due to their close interaction with the environment and developing physiology. The authors describe 3 rural environmental hazards: wood stove smoke, well water contaminants, and agricultural pollutants. Contaminants found in these exposures have adverse respiratory, neurodevelopmental, cardiometabolic, and carcinogenic effects, among others. The authors recommend that rural pediatric clinicians screen for these environmental exposures, and they provide tools and resources related to testing, mitigation, and medical monitoring.

Combining Nontargeted Analysis with Computer-Based Hazard Comparison Approaches to Support Prioritization of Unregulated Organic Contaminants in Biosolids

Biosolids are a byproduct of wastewater treatment that can be beneficially applied to agricultural land as a fertilizer. While U.S. regulations limit metals and pathogens in biosolids intended for land applications, no organic contaminants are currently regulated. Novel techniques can aid in detection, evaluation, and prioritization of biosolid-associated organic contaminants (BOCs). For example, nontargeted analysis (NTA) can detect a broad range of chemicals, producing data sets representing thousands of measured analytes that can be combined with computational toxicological tools to support human and ecological hazard assessment and prioritization. We combined NTA with a computer-based tool from the U.S. EPA, the Cheminformatics Hazard Comparison Module (HCM), to identify and prioritize BOCs present in U.S. and Canadian biosolids (n = 16). Four-hundred fifty-one features were detected in at least 80% of samples, with identities of 92 compounds confirmed or assigned probable structures. These compounds were primarily categorized as endogenous compounds, pharmaceuticals, industrial chemicals, and fragrances. Examples of top prioritized compounds were p-cresol and chlorophene, based on human health end points, and fludioxonil and triclocarban, based on ecological health end points. Combining NTA results with hazard comparison data allowed us to prioritize compounds to be included in future studies of the environmental fate and transport of BOCs.

Quantitative Non-targeted Screening to Profile Micropollutants in Sewage Sludge Used for Agricultural Field Amendments

A considerable number of micropollutants from human activities enter the wastewater network for removal. However, at the wastewater treatment plant (WWTP), some proportion of these compounds is retained in the sewage sludge (biosolids), and due to its high content of nutrients, sludge is widely applied as an agricultural fertilizer and becomes a means for the micropollutants to be introduced to the environment. Accordingly, a holistic semiquantitative nontarget screening was performed on sewage sludges from five different WWTPs using nanoflow liquid chromatography coupled to high-resolution Orbitrap mass spectrometry. Sixty-one inorganic elements were measured using inductively coupled plasma mass spectrometry. Across all sludges, the nontarget analysis workflow annotated >21,000 features with chemical structures, and after strict prioritization and filtering, 120 organic micropollutants with diverse chemical structures and applications such as pharmaceuticals, pesticides, flame retardants, and industrial and natural compounds were identified. None of the tested sludges were free from organic micropollutants. Pharmaceuticals contributed the largest share followed by pesticides and natural products. The predicted concentration of identified contaminants ranged between 0.2 and 10,881 ng/g dry matter. Through quantitative nontarget analysis, this study comprehensively demonstrated the occurrence of cocktails of micropollutants in sewage sludges.

Predicting rejection of emerging contaminants through RO membrane filtration based on ANN-QSAR modeling approach: trends in molecular descriptors and structures towards rejections

In this work, a quantitative structure-activity relationship (QSAR) study was performed on a set of emerging contaminants (ECs) to predict their rejections by reverse osmosis membrane (RO). A wide range of molecular descriptors was calculated by Dragon software for 72 ECs. The QSAR data was analyzed by an artificial neural network method (ANN), in which four out of 3000 theoretical molecular descriptors were chosen and their significance was computed based on the Garson method. The significance trends of descriptors were as follows in descending order: ESpm14u > R2e > SIC1 > EEig03d. The selected descriptors were ranked based on their importance and then an explorative study was conducted on the QSAR data to show the trends in molecular descriptors and structures toward the rejections values of ECs. The MLR algorithm was used to make a linear model and the results were compared with those of the nonlinear ANN algorithm. The comparison results revealed it is necessary to apply the ANN model to this data with non-linear properties. For the whole dataset, the correlation coefficient (R2) and residual mean squared error (RMSE) of the ANN and MLR methods were 0.9528, 6.4224; and 0.8753, 11.3400, respectively. The comparison results showed the superiority of ANN modeling in the analysis of ECs' QSAR data.

Endocrine disrupting activity in sewage sludge: Screening method, microbial succession and cost-effective strategy for detoxification

Sewage sludge (SS) presents a high agronomic potential due to high concentrations of organic matter and nutrients, encouraging its recycling as a soil conditioner. However, the presence of toxic substances can preclude this use. To enable the safe disposal of this waste in agriculture, SS requires additional detoxification to decrease the environmental risks of this practice. Although some alternatives have been proposed in this sense, little attention is provided to eliminating endocrine-disrupting chemicals (EDCs). To fill this gap, this study aimed to develop effective and low-cost technology to eliminate EDCs from SS. For this, a detoxification process combining microorganisms and biostimulating agents (soil, sugarcane bagasse, and coffee grounds) was performed for 2, 4, and 6 months with aerobic and anaerobic SSs. The (anti-)estrogenic, (anti-)androgenic, retinoic-like, and dioxin-like activities of SSs samples were verified using yeast-based reporter-gene assays to prove the effectiveness of the treatments. A fractionation procedure of samples, dividing the target sample extract into several fractions according to their polarity, was conducted to decrease the matrix complexity and facilitate the identification of EDCs. A decrease in the abundance and microbial diversity of the SS samples was noted along the biostimulation with the predominance of filamentous fungal species over yeasts and gram-positive bacteria and non-fermenting rods over enterobacteria. Among the 9 EDCs quantified by LC-ESI-MS/MS, triclosan and alkylphenols presented the highest concentrations in both SS. Before detoxification, the studied SSs induced significant agonistic activity, especially at the human estrogen receptor α (hERα) and the human aryl hydrocarbon receptor (AhR). The raw anaerobic sludge also activated the androgen (hAR), retinoic acid (RARα), and retinoid X (RXRα) receptors. However, no significant endocrine-disrupting activities were observed after the SS detoxification, showing that the technology applied here efficiently eliminates receptor-mediated toxicity.

Wide-scope target and suspect screening of emerging contaminants in sewage sludge from Nigerian WWTPs by UPLC-qToF-MS

There is currently a paucity of scientific data in Africa on the analysis and occurrence of emerging contaminants in sewage sludge. In this work, the occurrence of European Union (EU) Water Framework Directive priority substances and wide-range emerging contaminants were investigated and discussed comprehensively in the sewage sludge samples from three different wastewater treatment plants (WWTPs) in Lagos, Nigeria. The identification strategy was implemented by target and suspect screening in liquid chromatography-high resolution mass spectrometry. 250 compounds were identified in the sewage sludge samples from the investigated WWTPs. From 250 detected compounds, 182 compounds were quantified, and 78 compounds significantly show high environmental risk score (calculated from provisional no-effect concentrations values (PNEC) as well as their environmental quality data (EQs)). Most of contaminants detected at high amount belong to pharmaceuticals and are from hospital WWTP. While the highest concentration (72.4 mg kg^-1) was measured for salicylic acid (a non-steroidal anti-inflammatory drug), antibiotics showed high concentrations up to 24.4 and 28.4 mg kg^-1 for ciprofloxacin and ofloxacin, respectively. Three simple factors including frequency of exceedance, frequency of occurrence and extent of exceedance were used to aid prioritization of these substances in future monitoring campaigns. This work presents the first comprehensive and wide-scope screening of a large number of emerging contaminants in sewage sludge from Nigerian WWTPs.

Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Thermal Hydrolysis Pretreatment-Anaerobic Digestion Promotes Plant-Growth Biostimulants Production from Sewage Sludge by Upregulating Aromatic Amino Acids Transformation and Quinones Supply

Micromolecular plant-growth biostimulants (micro-PBs) production from sewage sludge is attracting increasing interest, as it is expected to enhance the fertilizing effect of sludge for land application. This study attempted to promote effective micro-PBs production from sewage sludge through thermal hydrolysis pretreatment-anaerobic digestion (THP-AD) and explore the underpinning regulation mechanisms. Results showed that the highest effective micro-PB production in digested sludge was achieved in THP(160 °C)-AD by day 12, with 80.73 mg/kg volatile solid (VS) of phytohormones and 417.75 mg/kg VS of allelochemicals, and these effective micro-PBs all originated from aromatic amino acids (AAAs). The metabolomic and metagenomic results revealed that, as compared with THP(120 °C)-AD and AD without THP, THP(160°C)-AD uniquely upregulated AAAs biosynthesis and consequently improved AAAs metabolism toward effective micro-PBs production. Further exploration of related microbial pathways and metabolites suggested that the upregulated AAAs biosynthesis in THP(160 °C)-AD in the early stage was partially attributed to the enhanced carbohydrate release. More importantly, the results showed that the amount of quinones, which probably facilitate energy generation via acting as electron-transfer mediators, was significantly positively correlated with the abundance of AAAs biosynthesis genes (R² = 0.93). Hence, the improved initial release and biosynthesis of quinones are critical in enhancing the AAAs biosynthesis in THP(160 °C)-AD. Moreover, the enhanced quinones supply and the consequent active AAAs transformation in THP(160 °C)-AD reinforced the humification process, highly supporting effective micro-PBs stabilization. The important roles of quinones in effective micro-PBs production and stabilization in sludge anaerobic digestion should be considered in technology development for micro-PBs recovery.

A method and its application to determine the amount of cannabinoids in sewage sludge and biosolids

Xenobiotic cannabinoids (phyto and synthetic) are highly lipophilic compounds and have been shown to accumulate within the particulate fraction of wastewater. Limited research has been conducted to investigate the occurrence of cannabinoids in sewage sludge and/or biosolids. The analysis of excreted cannabinoids from sewage sludge or biosolids can provide information about community health, as well as potentially long-term environmental impacts. In this study, a liquid-liquid extraction method was developed for the extraction and detection method for 50 cannabinoids by liquid chromatography-mass spectrometry, including the cannabis urinary biomarker 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH), Δ⁹-tetrahydrocannabinol (THC), cannabidiol (CBD), and a variety of different generation synthetic cannabinoids and their respective metabolites. Method validation assessed criteria including linearity, selectivity, recovery, and matrix effects. The method was applied to samples collected from a conventional activated sludge reactor treatment facility from various stages of the treatment process. Three cannabinoids were abundant in primary sludge including THC, THC-COOH, and CBD, where THC was the most ubiquitous with concentrations up to 3200 μg kg^-1. Only THC and THC-COOH were detectable in aged biosolids. The detection of some cannabinoids in biosolids demonstrated that these compounds are stable throughout the treatment process.

Targeted and suspect screening of contaminants in coastal water and sediment samples in Qatar

In recent years, high resolution mass spectrometry (HRMS) combined with separation techniques has allowed comprehensive analysis of contaminants of emerging concern (CECs) as well as their metabolites and transformation products in various environmental samples via retrospective screening. However, to date, only a few suspect or non-targeted studies on the occurrence of CECs in marine aquatic system are reported. In this study, two methods, based on direct injection for seawater, or ultrasound-assisted extraction for sediments, followed by LC-Q-TOF-MS analysis were developed and applied for the simultaneous targeted and screening of contaminants in coastal samples (seawater, particulates and sediment) from Qatar collected in 2017-2018. Among the twenty-one target analytes (pesticides, PPCPs and a plasticizer), two compounds only were detected in seawater. Caffeine was detected in seawater samples at all sampling sites, and cotinine was detected in seawater samples collected in Umm Bab in 2018 and seawaters receiving stormwater. Traces of trimethoprim and carbamazepine were detected in sediment samples collected at four sites in 2017. These results suggest some inputs of domestic wastewater in the coastal waters in Qatar. In total, twelve molecular features were tentatively identified from suspect screening at concentration levels significantly higher than that in procedure blanks. The presence of four plasticizers and one pesticide were further confirmed using reference standards: diethyl phthalate (DEP), dibutyl phthalate (DBP), and tributyl phosphate (TBP) in seawater samples; bis(2-ethylhexyl) phthalate (DEHP) in sediment and particulate samples; and dinoterb in seawater after storm event and particulate samples. Overall, this study demonstrated the potential of high resolution LC-Q-TOF-MS/MS for combined targeted and non-targeted analyses of trace contaminants in marine systems over a broad range of log P values.

Using Estrogenic Activity and Nontargeted Chemical Analysis to Identify Contaminants in Sewage Sludge

Diverse organic compounds, many derived from consumer products, are found in sewage sludge worldwide. Understanding which of these poses the most significant environmental threat following land application can be investigated through a variety of predictive and cell-based toxicological techniques. Nontargeted analysis using high-resolution mass spectrometry with predictive estrogenic activity modeling was performed on sewage sludge samples from 12 wastewater treatment plants in California. Diisobutyl phthalate and dextrorphan were predicted to exhibit estrogenic activity and identified in >75% of sludge samples, signifying their universal presence and persistence. Additionally, the application of an estrogen-responsive cell bioassay revealed reductions in agonistic activity during mesophilic and thermophilic treatment but significant increases in antagonism during thermophilic treatment, which warrants further research. Ten nontarget features were identified (metoprolol, fenofibric acid, erythrohydrobupropion, oleic acid, mestranol, 4'-chlorobiphenyl-2,3-diol, medrysone, scillarenin, sudan I, and N,O-didesmethyltramadol) in treatment set samples and are considered to have influenced the in vitro estrogenic activity observed. The combination of predictive and in vitro estrogenicity with nontargeted analysis has led to confirmation of 12 estrogen-active contaminants in California sewage sludge and has highlighted the importance of evaluating both agonistic and antagonistic responses when evaluating the bioactivity of complex samples.

A critical review on the detection, occurrence, fate, toxicity, and removal of cannabinoids in the water system and the environment

Cannabinoids are a group of organic compounds found in cannabis. Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD), the two major constituents of cannabinoids, and their metabolites are contaminants of emerging concern due to the limited information on their environmental impacts. As well, their releases to the water systems and environment are expected to increase due to recent legalization. Solid-phase extraction is the most common technique for the extraction and pre-concentration of cannabinoids in water samples as well as a clean-up step after the extraction of cannabinoids from solid samples. Liquid chromatography coupled with mass spectrometry is the most common technique used for the analysis of cannabinoids. THC and its metabolites have been detected in wastewater, surface water, and drinking water. In particular, 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH) has been detected at concentrations up to 2590 and 169 ng L^-1 in untreated and treated wastewater, respectively, 79.9 ng L^-1 in surface water, and 1 ng L^-1 in drinking water. High removal of cannabinoids has been observed in wastewater treatment plants; this is likely a result of adsorption due to the low aqueous solubility of cannabinoids. Based on the estrogenicity and cytotoxicity studies and modelling, it has been predicted that THC and THC-COOH pose moderate risk for adverse impact on the environment. While chlorination and photo-oxidation have been shown to be effective in the removal of THC-COOH, they also produce by-products that are potentially more toxic than regulated disinfection by-products. The potential of indirect exposure to cannabinoids and their metabolites through recreational water is of great interest. As cannabinoids and especially their by-products may have adverse impacts on the environment and public health, more studies on their occurrence in various types of water and environmental systems, as well as on their environmental toxicity, would be required to accurately assess their impact on the environment and public health.

Residuals, sludge, and biosolids: Advancements in the field

Advancements in the field of residuals, sludge, and biosolids have been made in 2019. This review outlines the major contributions of researchers that have been published in peer-reviewed journals and conference proceedings throughout 2019 and includes brief summaries from over 125 articles. The review is organized in sections including life cycle and risk assessments; characteristics, quality, and measurement including micropollutants, nanoparticles, pathogens, and metals; sludge treatment technologies including dewatering, digestion, composting, and wetlands; disposal and reuse including adsorbents, land application and agricultural uses, nutrient recovery, and innovative uses; odor and air emissions; and energy issues.

Developing Unique Nontarget High-Resolution Mass Spectrometry Signatures to Track Contaminant Sources in Urban Waters

Diffuse pollution in urban receiving waters often adversely impacts both humans and ecosystems. Identifying such pollution sources is challenging and limits the effectiveness of management actions intended to reduce risk. Here, we evaluated the use of nontarget analysis via high-resolution mass spectrometry (HRMS) to develop chemical fingerprints/signatures for source tracking. Specifically, we applied nontarget HRMS to characterize and differentiate two urban chemical sources: roadway runoff and wastewater influent. We isolated 112 and 598 nontarget compounds (both known and unidentified chemicals) that co-occurred in all roadway runoff and wastewater influent samples, respectively, and were unique relative to other sampled sources. For example, methamphetamine, often considered wastewater derived, was detected in all samples, implying that individual wastewater indicators may lack sufficient specificity in urban receiving waters impacted by multiple sources. Hierarchical cluster analysis differentiated source types, and normalized abundance profiling prioritized nontarget compounds with consistent relative abundance patterns across field sites for a given source. Hexa(methoxymethyl)melamine, 1,3-diphenylguanidine, and polyethylene glycols co-occurred in roadway runoff across geographic areas and traffic intensities, supporting continued development of a universal roadway runoff fingerprint based on ubiquitous compounds. This study provides a proof-of-concept for isolating nontarget source fingerprints to track diffuse contamination in urban receiving waters.