Occurrence of emerging contaminants in surface water bodies of a coastal province in Ecuador and possible influence of tourism decline caused by COVID-19 lockdown

In situ synthesis of a UIO-66-NH2@Ti3C2 composite for advanced electrochemical detection of acetaminophen

Acetaminophen (AP) is a widely used analgesic and antipyretic drug, but its excessive use poses health risks and contributes to environmental contamination. In response to the need for rapid, accurate, and cost-effective detection methods, we developed a highly sensitive and selective electrochemical sensor for AP. The sensor was based on a composite of UIO-66-NH2 (UN) and an MXene (Ti3C2). UIO-66-NH2 was in situ synthesized onto the MXene via a one-step hydrothermal process with a varying MXene content, followed by calcination at 300 °C under an argon (Ar) flow. This treatment induced the formation of TiO2 on the MXene surface and increased the interlayer spacing, which enhanced its electrochemical performance. The resulting UN@Ti3C2-C electrode exhibited remarkable electrochemical activity due to the high surface area and excellent conductivity of the MXene. The fabricated sensor demonstrated a simple yet effective approach for the rapid and quantitative detection of AP, with a linear detection range of 0.032-160 μM and a low detection limit of 10 nM. Moreover, the sensor was successfully applied to detect AP in different water samples, validating its potential as a reliable and efficient tool for AP monitoring.

Regional disparities in PPCPs contamination of urban wastewater treatment plants: Unveiling influential factors and ecological effects

This study investigates the discharge of pharmaceuticals and personal care products (PPCPs) from wastewater treatment plants (WWTPs) into natural waters, highlighting a significant correlation with regional human activities. Despite the complexity of assessing factors influencing PPCPs sources, it remains underexplored. By conducting an extensive literature review of seven categories of PPCPs in WWTPs across five typical regions of China, the study reveals both similarities and disparities in PPCPs composition. Correlation analysis and four machine learning algorithms are employed to identify affecting factors for PPCPs emissions. The findings reveal that regional differences in per capita load are affected by treatment scale and population served by WWTPs. Economic indicators, wastewater treatment efficiency, and population age structure correlate with specific PPCPs. The RF algorithms demonstrated reliable predictive capabilities for PPCPs concentrations, identifying significant influencing factors such as service population, treatment capacity, and economic development. Ecological risk assessments indicate that certain PPCPs, such as norfloxacin (NOR) and ofloxacin (OFL), pose high risks to algae. These findings underscore the necessity for region-specific strategies to address PPCPs challenges, considering factors like economic development, urbanization, and demographic characteristics, and provide valuable insights into PPCPs presence and ecological risks.

Co-occurrence and spatial distribution of organic micropollutants in surface waters of the River Aconcagua and Maipo basins in Central Chile

Organic Micropollutants (OMPs) might pose significant risks to aquatic life and have potential toxic effects on humans. These chemicals typically occur as complex mixtures rather than individually. Information on their co-occurrence and their association with land use is largely lacking, even in industrialized countries. Furthermore, data on the presence of OMPs in freshwater ecosystems in South America is insufficient. Consequently, we assessed the co-occurrence and distribution of OMPs, including pharmaceuticals, pesticides, personal care products, surfactants, and other industrial OMPs, in surface waters of two river basins in central Chile. We focused on identifying and ranking quantified chemicals, classifying their mode of actions, as well as correlating their occurrence with distinct land uses. We identified and quantified 311 compounds that occurred at least once in the River Aconcagua and River Maipo basins, encompassing compounds from urban, agricultural, industrial, and pharmaceutical sectors. Pharmaceuticals were the most frequently occurring chemicals, followed by pesticides, personal care and household products. OMPs with neuroactive properties dominated surface waters in Central Chile, along with OMPs known to alter the cardiovascular and endocrine systems of humans and aquatic animals. Finally, we observed positive correlations between agricultural and urban land uses and OMPs. Our findings represent a step forward in extending current knowledge on the co-occurrence patterns of OMPs in aquatic environments, particularly in developing countries of the southern hemisphere.

Occurrence and Environmental Risk Assessment of Contaminants of Emerging Concern in Brazilian Surface Waters

We investigated the occurrence and the environmental risk of eight contaminants of emerging concern (CECs; acetaminophen, naproxen, diclofenac, methylparaben, 17β-estradiol, sulfathiazole, sulfadimethoxine, and sulfamethazine) in three Brazilian water bodies, namely, the Monjolinho River Basin (São Paulo State), the Mogi Guaçu River (São Paulo State), and the Itapecuru River (Maranhão State) in three sampling campaigns. The CECs were only quantified in surface water samples collected at the Monjolinho River Basin. Acetaminophen, naproxen, and methylparaben were detected in the range of <200 to 575.9 ng L-1, <200 to 224.7 ng L-1, and <200 to 303.6 ng L-1, respectively. The detection frequencies of the three measured compounds were between 33% and 67%. The highest concentrations of CECs were associated with intense urbanization and untreated sewage discharge. Furthermore, CEC concentrations were significantly correlated with total organic carbon, electrical conductivity, and dissolved oxygen levels, suggesting that domestic pollution from urban areas is an important source in the distribution of CECs in the Monjolinho River Basin. The environmental risk assessment indicated a high risk for acetaminophen (risk quotient [RQ] values between 2.1 and 5.8), a medium risk for naproxen (RQs between 0.6 and 0.7), and a low risk for methylparaben (RQs < 0.1) to the freshwater biota of the Monjolinho River Basin. Our findings show potential threats of CECs in Brazilian water bodies, especially in vulnerable areas, and reinforce the need for improvements in environmental regulations to include monitoring and control of these compounds in aquatic systems. Environ Toxicol Chem 2024;43:2199-2210. © 2024 SETAC.

Hazardous radical-coupled transformation products of benzophenone-3 formed during manganese dioxide treatment

Radical-coupled transformation products (TPs) have been identified as the byproducts of various transformation processes, including both natural attenuation and artificial treatments, of phenolic micropollutants. Benzophenone-3 (BP-3), an organic UV filter of emerging concern, has been previously reported with ubiquitous occurrence in the natural environment and water bodies. Current research has demonstrated how TPs are formed from BP-3 when it is treated with manganese oxide (MnO2). The ecological and toxicological risks of these TPs have also been assessed. Polymerization of BP-3 through radical coupling was observed as the major pathway by which BP-3 is transformed when treated with MnO2. These radical-coupled TPs haven't shown further degradation after formation, suggesting their potential persistence once occurred in the environment. In silico experiments predict the radical-coupled TPs will increase in mobility, persistence and ecotoxicity. If true, they also represent an ever-increasing threat to the environment, ecosystems and, most immediately, aquatic living organisms. In addition, radical-coupled TPs produced by MnO2 transformation of BP-3 have shown escalated estrogenic activity compared to the parent compound. This suggests that radical coupling amplifies the toxicological impacts of parent compound. These results provide strong evidence that radical-coupled TPs with larger molecular sizes are having potential adverse impacts on the ecosystem and biota.

Application of BiOX Photocatalyst to Activate Peroxydisulfate Ion-Investigation of a Combined Process for the Removal of Organic Pollutants from Water

The persulfate-based advanced oxidation processes employing heterogeneous photocatalysts to generate sulfate radicals (SO4•−) from peroxydisulfate ion (PDS, S2O82−) have been extensively investigated to remove organic pollutants. In this work, BiOX (X = Cl, Br, and I) photocatalysts were investigated to activate PDS and enhance the transformation rate of various organic substances under UV (398 nm) and Vis (400–700 nm) radiation. For BiOCl and BiOBr, in addition to excitability, the light-induced oxygen vacancies are decisive in the activity. Although without organic substances, the BiOI efficiency highly exceeds that of BiOBr and BiOCl for PDS activation (for BiOI, 15–20%, while for BiOBr and BiOCl, only 3–4% of the PDS transformed); each BiOX catalyst showed enhanced activity for 1,4-hydroquinone (HQ) transformation due to the semiquinone radical-initiated PDS activation. For sulfamethoxypyridazine (SMP), the transformation is driven by direct charge transfer, and the effect of PDS was less manifested. BiOI proved efficient for transforming various organic substances even under Vis radiation. The efficiency was enhanced by PDS addition (HQ is wholly transformed within 20 min, and SMP conversion increased from 40% to 90%) without damaging the catalyst; its activity did change over three consecutive cycles. Results related to the well-adsorbed trimethoprim (TRIM) and application of biologically treated domestic wastewater as a matrix highlighted the limiting factors of the method and visible light active photocatalyst, BiOI.