The antimicrobial agent triclosan (TCS) has attracted much attention worldwide because of its pervasive existence in the human body and environment. TCS exposure has been reported to be associated with decreased male reproductive function. However, few studies have investigated these associations in humans. To examine the relationship between TCS in urine and male semen quality. A total of 406 men from a reproductive clinic were enrolled in this study. Urinary TCS concentrations were determined by ultra-high performance liquid chromatography–electrospray ionization tandem mass spectrometry. Sixteen semen parameters were assessed according to the guidelines of World Health Organization (WHO), including parameters for volume, count, motility, and motion. We used multivariate linear regression models and restricted cubic splines to estimate the linear and non-linear associations between TCS exposure and semen parameters, respectively. Logistical regression models were further applied to explore the associations with abnormal semen quality. TCS was detected in 74.6% of urine specimens. The monotonous trend of TCS tertiles and continuous TCS levels with all semen quality parameters were not observed in multivariate linear regression models (p > 0.05). However, compared with those in the lowest tertile, subjects in the second tertile showed significantly higher linearity and wobble (p < 0.05), indicating potential effects on sperm motion. In the models using restricted cubic splines with 3–5 knots, there were no significant non-linear associations between TCS exposure and any semen quality parameter. In addition, TCS tertiles were not associated with the risk of abnormal semen quality (i.e., count and motility) in the logistical regression models. Our results revealed that low-level TCS exposure may have limited (none or modest) effects on male semen quality, potentially inducing some fluctuations. Further mechanistic studies on low levels of exposure are needed.

Exposure to endocrine disruptors such as bisphenols, can lead to and be the explanation for idiopathic infertility. In our study, we assessed the effect of exposure to bisphenol S (BPS) via breast milk on the testicular tissue health of adult male mice. Milking dams were exposed to BPS through drinking water (0.216 ng g bw/day and 21.6 ng g bw/day) from post-natal day 0–15. Although there was no significant difference in testicular histopathology between the control and experimental groups, we observed an increase in the number of tight and gap junctions in the blood-testis barrier (BTB) of adult mice after nursing BPS exposure. Moreover, there was an increase in oxidative stress markers in adult testicular tissue of mice exposed during nursing. Our nursing model indicates that breast milk is a route of exposure to an endocrine disruptor that can be responsible for idiopathic male infertility through the damage of the BTB and weakening of oxidative stress resistance in adulthood.

Municipal sewage treatment plants (STPs) have been regarded as an important source of organic contaminants in aquatic environment. To assess the impact of STPs on occurrence and toxicity of STP-associated contaminants in receiving waterways, a novel passive sampler modified from polar organic chemical integrative sampler (m-POCIS) was deployed at the inlet and outlet of a STP and several upstream and downstream sites along a river receiving STP effluent in Guangzhou, China. Eighty-seven contaminants were analyzed in m-POCIS extracts, along with toxicity evaluation using zebrafish embryos. Polycyclic musks were the predominant contaminants in both STP and urban waterways, and antibiotics and current-use pesticides (e.g., neonicotinoids, fiproles) were also ubiquitous. The m-POCIS extracts from downstream sites caused significant deformity in embryos, yet the toxicity could not be explained by the measured contaminants, implying the presence of nontarget stressors. Sewage treatment process substantially reduced embryo deformity, chemical oxygen demand, and contamination levels of some contaminants; however, concentrations of neonicotinoids and fiproles increased after STP treatment, possibly due to the release of chemicals from perturbed sludge. Source identification showed that most of the contaminants found in urban waterways were originated from nonpoint runoff, while cosmetics factories and hospitals were likely point sources for musks and antibiotics, respectively. Although the observed embryo toxicity could not be well explained by target contaminants, the present study showed a promising future of using passive samplers to evaluate chemical occurrence and aquatic toxicity concurrently. Zebrafish embryo toxicity significantly decreased after sewage treatment, but higher toxicity was observed for downstream samples, demonstrating that urban runoff may produce detrimental effects to aquatic life, particularly in rainy season. These results highlight the relevance of monitoring nonpoint source pollution along with boosting municipal sewage treatment infrastructure.

Phosphorus (P) is an essential element in the ecosystem and the cause of the eutrophication of rivers and lakes. The river-lake ecotone is the ecological buffer zone between rivers and lakes, which can transfer energy and material between terrestrial and aquatic ecosystems. Vegetation restoration of degraded river-lake ecotone can improve the interception capacity of P pollution. However, the effects of different vegetation restoration types on sediment P cycling and its mechanism remain unclear. Therefore, we seasonally measured the P fractions and physicochemical properties of sediments from different restored vegetation (three native species and one invasive species). The results found that vegetation restoration significantly increased the sediment total P and bioavailable P content, which increased the sediment tolerance to P pollution in river-lake ecotone. In addition, the total P content in sediments was highest in summer and autumn, but lower in spring and winter. The total P and bioavailable P contents in surface sediments were the highest. They decreased with increasing depth, suggesting that sediment P assimilation by vegetation restoration and the resulting litter leads to redistribution of P in different seasons and sediment depths. Microbial biomass-P (MBP), total nitrogen (TN), and sediment organic matter (SOM) are the main factors affecting the change of sediment phosphorus fractions. All four plants’ maximum biomass and P storage appeared in the autumn. Although the biomass and P storage of the invasive species Alternanthera philoxeroides were lower, the higher bioavailable P content and MBP values of the surface sediments indicated the utilization efficiency of sediment resources. These results suggest that vegetation restoration affects the distribution and circulation of P in river and lake ecosystems, which further enhances the ecological function of the river-lake ecotone and prevents the eutrophication and erosion of water and sediment in the river-lake ecotone.

The objective of this study was to demonstrate the feasibility and the relevance of combining biochar with the Fenton process for the simultaneous improvement of polycyclic aromatic hydrocarbons (PAHs) degradation and immobilization of heavy metals (HMs) in real soil remediation processes at circumneutral pH. The evaluation of PAHs degradation results was performed through multivariate statistical tools, including principal component analysis (PCA) and partial least squares (PLS). PCA showed that the level of biochar amendment decisively affected the degree of degradation of total PAHs, highlighting the role of biochar in catalyzing the Fenton reaction. Moreover, the PLS model was used to interpret the important features of each PAH's physico-chemical properties and its correlation to degradation efficiency. The electron affinity of PAHs correlated positively with the degradation efficiency only if the level of biochar amendment sat at 5%, explained by the ability of biochar to transfer the electrons to PAHs, improving the Fenton-like degradation. Moreover, the addition of biochar reduced the mobilization of HMs by their fixation on their surface, reducing the Fenton-induced metal leaching from the destruction of metal-organic complexes. In overall, these results on the high immobilization rate of HMs accompanied with additional moderate PAHs degradation highlighted the advantages of using a biochar-assisted Fenton-like reaction for sustainable remediation of technogenic soil.

The excessive proliferation of Microcystis aeruginosa can lead to ecological damage, economic losses, and threaten animal and human health. For controlling Microcystis blooms, microorganism-based methods have attracted much attention from researchers because of their eco-friendliness and species-specificity. Herein, we first found that a Paucibacter strain exhibits algicidal activity against M. aeruginosa and microcystin degradation capability. The algicidal activity of DH15 (2.1 × 10⁴ CFU/ml) against M. aeruginosa (2 × 10⁶ cells/ml) was 94.9% within 36 h of exposure. DH15 also degraded microcystin (1.6 mg/L) up to 62.5% after 72 h. We demonstrated that the algicidal activity of DH15 against M. aeruginosa can be mediated by physical attachment and indirect attack: (1) Both washed cells and cell-free supernatant could kill M. aeruginosa efficiently; (2) Treatment with DH15 cell-free supernatants caused oxidative stress, altered the fatty acid profile, and damaged photosynthetic system, carbohydrate, and protein metabolism in M. aeruginosa. The combination of direct and indirect attacks supported that strain DH15 exerts high algicidal activity against M. aeruginosa. The expression of most key genes responsible for photosynthesis, antioxidant activity, microcystin synthesis, and other metabolic pathways in M. aeruginosa was downregulated. Strain DH15, with its microcystin degradation capacity, can overcome the trade-off between controlling Microcystis blooms and increasing microcystin concentration. Our findings suggest that strain DH15 possesses great potential to control outbreaks of Microcystis blooms.

Globally, arsenic (As) contamination is widespread in hydrological systems and the link between As enrichment and regional tectonic and climatic factors is still not well understood in orogenic environments. This work provides new insights on the relationship between As, tectonics, and climate by assessing the hydrochemistry of Chile, an active subduction zone with highly diverse natural settings. Selected study sites include fluvial courses along four regional transects connecting the Chilean coast to the Andes Cordillera in the northern, central, and southern areas of the country. The results indicate that As concentrations in surface water and fluvial sediments show a general positive correlation to crustal thickness and they tend to decrease progressively from northern to southern Chile. In contrast, As concentrations are negatively correlated to average annual precipitation which shows a significant increase toward southern Chile. From a regional tectonic perspective, northern Chile presents greater Andes shortening and higher crustal thicknesses, which induces increased crustal contamination and As content at the surface. Extremely low precipitation rates are also tied to local As enrichment and a sediment-starved trench that might favor higher plate coupling and shortening. On the contrary, decreased shortening of the Andes in southern Chile and related lower crustal thickness induces lower crustal contamination, thus acting as an As-poor provenance for surficial sediments and surface water. High precipitation rates further induce dilution of surface water, potential mobilization from the solid phase, and a significant amount of trench sediments that could induce lower plate coupling and lower shortening. At the local scale, a low potential for As mobilization was found in northern Chile where a greater distribution of As-bearing minerals was observed in sediments, mostly as finer particles (<63 μm). The abundance of Fe-oxides potentially acts as a secondary surficial sink of As under the encountered physicochemical conditions.

Plastic pollution has become one of the most pressing environmental issues. Recycling is a potential means of reducing plastic pollution in the environment. However, plastic fragments are still likely released to the aquatic environment during mechanical recycling processes. Here, we examined the plastic inputs and effluent outputs of three mechanical recycling facilities in Vietnam dealing with electronic, bottle, and household plastic waste, and we found that large quantities of microplastics (plastics <5 mm in length) are generated and released to the aquatic environment during mechanical recycling without proper treatment. Comparisons with literature data for microplastics in wastewater treatment plant effluents and surface water indicated that mechanical recycling of plastic waste is likely a major point source of microplastics pollution. Although there is a mismatch between the size of the microplastics examined in the present study and the predicted no-effect concentration reported, it is still possible that microplastics generated at facilities pose risks to the aquatic environment because there might be many plastic particulates smaller than 315 μm, as suggested by our obtained size distributions. With mechanical recycling likely to increase as we move to a circular plastics economy, greater microplastics emissions can be expected. It is therefore an urgent need to fully understand not only the scale of microplastic generation and release from plastic mechanical recycling but also the environmental risk posed by microplastics in the aquatic environment.

The excessive arsenic (As) accumulation in plant tissues enforced toxic impacts on growth indices. So, the utilization of As-contaminated food leads to risks associated with human health. For the reduction of As concentrations in foods, it is obligatory to fully apprehend the take up, accretion, transportation and toxicity mechanisms of As within plant parts. This metalloid impairs the plant functions by disturbing the metabolic pathways at physio-biochemical, cellular and molecular levels. Though several approaches were utilized to reduce the As-accumulation and toxicity in soil-plant systems. Recently, engineered nanoparticles (ENPs) such a zinc oxide (ZnO), silicon dioxide or silica (SiO₂), iron oxide (FeO) and copper oxide (CuO) have emerged new technology to reduce the As-accumulation or phytotoxicity. But, the mechanistic approaches with systematic explanation are missing. By knowing these facts, our prime focus was to disclose the mechanisms behind the As toxicity and its mitigation by ENPs in higher plants. ENPs relives As toxicity and its oxidative damages by regulating the transporter or defense genes, modifying the cell wall composition, stimulating the antioxidants defense, phytochelatins biosynthesis, nutrients uptake, regulating the metabolic processes, growth improvement, and thus reduction in As-accumulation or toxicity. Yet, As-detoxification by ENPs depends upon the type and dose of ENPs or As, exposure method, plant species and experimental conditions. We have discussed the recent advances and highlight the knowledge or research gaps in earlier studies along with recommendations. This review may help scientific community to develop strategies such as applications of nano-based fertilizers to limit the As-accumulation and toxicity, thus healthy food production. These outcomes may govern sustainable application of ENPs in agriculture.

Quinolone antibiotics (QNs) pollution in lake environments is increasingly raising public concern due to their potential combined toxicity and associated risks. However, the spatiotemporal distribution and trophodynamics of QNs in transit-station lakes for water diversion are not well documented or understood. In this study, a comprehensive investigation of QNs in water, sediment, and aquatic fauna, including norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), and ofloxacin (OFL), was conducted in Luoma Lake, a major transit station for the eastern route of the South-to-North Water Diversion Project in China. The target QNs were widely distributed in the water (∑QNs: 70.12 ± 62.79 ng/L) and sediment samples (∑QNs: 13.35 ± 10.78 ng/g dw) in both the non-diversion period (NDP) and the diversion period (DP), where NOR and ENR were predominant. All the QNs were detected in all biotic samples in DP (∑QNs: 80.04 ± 20.59 ng/g dw). The concentration of ∑QNs in the water in NDP was significantly higher than those in DP, whereas the concentration in the sediments in NDP was comparable to those in DP. ∑QNs in the water-sediment system exhibited decreasing trends from northwest (NW) to southeast (SE) in both periods; however, the Kₒc (organic carbon normalized partition coefficients) of individual QNs in DP sharply rose compared with those in NDP, which indicated that water diversion would alter the environmental fate of QNs in Luoma Lake. In DP, all QNs, excluding NOR, were all biodiluted across the food web; whereas their bioaccumulation potentials in the SE subregion were higher than those in the NW subregion, which was in contrast to the spatial distribution of their exposure concentrations. The estimated daily QN intakes via drinking water and aquatic products suggested that residents in the SE side were exposed to greater health risks, despite less aquatic pollution in the region.