Screening of organic chemicals in surface water of the North River by high resolution mass spectrometry

Endocrine disrupting chemicals in children's and their parents' urine: Is the exposure related to the Chinese and Western lifestyle?

Children are known to be more vulnerable to exposure to endocrine-disrupting chemicals (EDCs) compared to adults, but evaluating the exposure pathways can be challenging. This research employed target and non-target analysis (NTA) to examine the exposure characteristics of EDCs in spot urine samples collected from 46 children's (aged 3-12 years) and their parents in Hong Kong (Chinese/Western lifestyle) and Guangzhou (mainly Chinese lifestyle). The results revealed that the geometric mean concentrations of phthalate esters metabolites (mPAEs) and bisphenols (BPs) in children's urine were 127.3 μg/gcrea and 2.5 μg/gcrea in Guangzhou, and 93.7 μg/gcrea and 2.9 μg/gcrea in Hong Kong, respectively, which were consistent with global levels. NTA identified a total of 1069 compounds, including 106 EDCs, commonly detected in food, cosmetics, and drugs. Notable regional differences were observed between Guangzhou and Hong Kong with potential sources of EDCs including dietary and cosmetic additives, toys, flooring and dust, as well as differences in lifestyles, diet, and living environment. However, age was found to significantly impact EDC exposure. The quantified EDCs (mPAEs and BPs) posed possible health risks to 60% of the children. Moreover, the presence of caffeine in children's urine, which exhibited higher detection rates in children from Hong Kong (95.6%) and Guangzhou (44.4%), warrants further attention. The sources of EDCs exposure in these regions need to be fully confirmed.

Electrochemical oxidation of azo dyes degradation by RuO2-IrO2-TiO2 electrode with biodegradation Aeromonas hydrophila AR1 and its degradation pathway: An integrated approach

Azo dyes are the most varied class of synthetic chemicals with non-degradable characteristics. They are complex compounds made up of many different parts. It was primarily utilized for various application procedures in the dyeing industry. Therefore, it's crucial to develop an economical and environmentally friendly approach to treating azo dyes. Our present investigation is an integrated approach to the electrooxidation (EO) process of azo dyes using RuO2-IrO2-TiO2 (anode) and titanium mesh (cathode) electrodes, followed by the biodegradation process (BD) of the treated EO dyes. Chemical oxygen demand (COD) removal efficiency as follows MB (55%) ≥ MR (45%) ≥ TB (38%) ≥ CR (37%) correspondingly. The fragment generated during the degradation process which was identified with high-resolution mass spectrometry (HRMS) and its degradation mechanism pathway was proposed as demethylation reaction and N-N and C-N/C-S cleavage reaction occurs during EO. In biodegradation studies by Aeromonas hydrophila AR1, the EO treated dyes were completely mineralized aerobically which was evident by the COD removal efficiency as MB (98%) ≥ MR (92.9%) ≥ TB (88%) ≥ CR (87%) respectively. The EO process of dyes produced intermediate components with lower molecular weights, which was effectively utilized by the Aeromonas hydrophila AR1 and resulted in higher degradation efficiency 98%. We reported the significance of the enhanced approach of electrochemical oxidation with biodegradation studies in the effective removal of the pollutants in dye industrial effluent contaminated water environment.

Comprehensive discovery and migration evaluation of antimicrobial drugs and their transformation products in a swine farm by target, suspect, and nontarget screening

Swine farms contaminated the surrounding environment through manure application and biogas slurry irrigation, hence causing the wide residual of multiple antimicrobial drugs (ADs) and their transformation products (TPs). This study performed target, suspect, and nontarget screening methods to comprehensively investigate the pollution profiles of ADs in a typical swine farm, and characterize the potential transformed pathway of TPs and distinguish specific reactions of different catalog of ADs. Samples of fresh feces, compost, biogas slurry, topsoil, column soil, groundwater and plants were analyzed using the database containing 98 target analytes, 679 suspected parent ADs, and ∼ 107 TPs. In total, 29 ADs were quantitively detected, and tetracyclines (TCs) were mostly frequently detected ADs with the concentrations up to 4251 ng/g in topsoil. Soil column investigation revealed that doxycycline (DOX) and tetracycline (TC) in soil could migrate to depths of approximately 1 m in soil. Suspect screening identified 75 parent ADs, with 10 being reported for the first time in environmental media. Semi-quantification of ADs revealed that one of the less-concerned ADs, clinafloxacin, was detected to exceed 5000 ng/L in biogas slurry, suggesting that significant attentions should be paid to these less-concerned ADs. Moreover, 314 TPs was identified, and most of them were found to undergo microbial/enzymatic metabolism pathways. Overall, our study displays a comprehensive overview of ADs and their TPs in swine farming environments, and provides an inventory of crucial list that worthy of concern. The results emphasize the need to quantify the levels and distribution of previously overlooked ADs and their TPs in livestock farms.

Screening and prioritization of organic chemicals in a large river basin by suspect and non-target analysis

Many organic chemicals are present in aquatic environments, but how to screen and prioritize these chemicals has always been a difficult task. Here we investigated organic chemicals in the West River Basin by using a developed non-target identification workflow. A total of 957 chemicals were tentatively identified, with 96 assigned as high confidence levels by matching with reference standards, MassBank spectral library, and using CompTox Chemistry Dashboard database as the compound library for MetFrag. More pesticides and their transformation products (e.g., metolachlor ESA, acetochlor ESA, deethylatrazine, and hydroxyatrazine) were detected in the wet season due to the increasing usage. High detection of pharmaceutical and personal care products and their transformation products in the tributaries was linked to rural farming and human activities. Irbesartan that is used to treat high blood pressure was recognized in the river and positive correlations between some detected chemicals and irbesartan were observed, indicating a domestic wastewater source. Ecological risks of the identified chemicals were calculated by toxicological prioritization ranking schemes, and 24 chemicals showed high ToxPi scores in the river. The results from this study show the presence of a large number of emerging organic chemicals in our waterways, and demonstrated conceptual schemes for integrating risk assessment into a non-target screening workflow.

Direct Z-scheme P-TiO2/g-C3N4 heterojunction for the photocatalytic degradation of sulfa antibiotics

The construction of direct Z-scheme heterojunctions with high photocatalytic degradation ability is important for wastewater treatment, but there are still many unsolved challenges. In this article, we report the fabrication of a Z-scheme P-TiO₂/g-C₃N₄ (CNPT-X) heterostructure by the calcination method. Under simulated sunlight, CNPT-X composites are found to show excellent degradation performance against sulfonamide antibiotics sulfadiazine (SD), sulfamethazine (SM2), sulfamonomethoxine (SMM), and sulfamethoxazole (SMZ). CNPT-3 (400 mg L^-1) can be used to degrade four sulfa antibiotics within 90 min, with a degradation rate as high as 99%, which is higher than that for P-TiO₂ and g-C₃N₄ alone. The internal electron transfer paths and mechanisms for the composites are revealed by ESR radical detection experiments, XPS energy spectrum shifts, valence band positions and active material quenching experiments. Furthermore, the degradation products are analyzed by GC-MS, and four possible degradation pathways for sulfonamide pollutants are proposed. This photocatalyst provides new insights into the fundamental aspects of the photocatalytic degradation mechanism for composite pollutants, as well as new ideas for practical environmental applications.

Non-target, suspect and target screening of chemicals of emerging concern in landfill leachates and groundwater in Guangzhou, South China

Landfill sites have been regarded as a significant source of chemicals of emerging concern (CECs) in groundwater. However, our understanding about the compositions of CECs in landfill leachate and adjacent groundwater is still very limited. Here we investigated the CECs in landfill leachates and groundwater of Guangzhou in South China by target, suspect and non-target analysis using high-resolution mass spectrometry (HRMS). A variety of CECs (n = 242), including pharmaceuticals (n = 64), pharmaceutical intermediates (n = 18), personal care products (n = 9), food additives (n = 18), industrial chemicals (n = 82, e.g., flame retardants, plasticizers, antioxidants and catalysts), pesticides (n = 26), transformation products (n = 8) and other organic compounds (n = 17) were (tentatively) identified by non-target and suspect screening. 142 CECs were quantitated with target analysis, and among them 37, 24 and 27 CECs were detected respectively in the raw leachate (272-1780 μg/L), treated leachate (0.25-0.81 μg/L) and groundwater (0.10-53.7 μg/L). The CECs in the raw leachates were efficiently removed with the removal efficiencies greater than 88.7%. Acesulfame, bisphenol F and ketoprofen were the most abundant compounds in both treated leachate and groundwater. The CECs in groundwater was found most likely to be originated from the landfill sites. Our results highlight the importance of non-target screening in identifying CECs, and reveal the contamination risk of groundwater by landfill leachate.

Per- and polyfluoralkyl substances (PFAS) in drinking water system: Target and non-target screening and removal assessment

The massive use and the persistence of per- and polyfluoroalkyl substances (PFAS) have led to their frequent detection in aquatic environments, which may further threaten drinking water safety. So far, our knowledge about the occurrence of PFAS in drinking water system is still very limited. Here we investigated the occurrence and removal of PFAS in a drinking water system using non-target, suspect and target screening strategies. Sampling was performed in three seasons in the drinking water system including a water source, two drinking water treatment plants, and tap water in five households. The results showed detection of 17 homologous series with 51 homologues in non-target screening and 50 potential PFAS detected in suspect screening. Probable structures were proposed for 15 PFAS with high confidence levels (the first three of the five levels), with seven of them being reported for the first time in drinking water system. Semi-quantification was performed on seven homologous series based on target PFAS, the estimated total concentrations for non-target PFAS ranged between 4.10 and 17.6 ng/L. Nine out of 50 target PFAS were found and precisely quantified (<LOQ-13.4 ng/L) with predominance of perfluorocarboxylic acids (PFCA) and perfluorosulfonic acids (PFSA). All target and non-target PFAS were detected in tap water with similar concentrations in all three seasons. Removal efficiency for the detected PFAS in each processing unit was almost zero, indicating the recalcitrance of these chemicals to the conventional treatment process. The findings from this study clearly show the wide presence of PFAS in the whole drinking water treatment process, and suggest an urgent need for effective removal technology for this group of chemicals.