We analyzed the acute toxicity of the 48% glyphosate (GLY)-based Credit®, the 57.71% dicamba (DIC)-based Kamba®, and the 83.5% 2,4-dichlorophenoxyacetic acid (2,4-D)-based Weedar® Full, alone and as mixtures on the fish Cnesterodon decemmaculatus. Mortality revealed the LC50 96h values of 91.73 mg L−1 (range: 86.80–98.00 mg L−1), 1401.57 mg L−1 (range: 1243.78–1527.35) and 678.04 mg L−1 (range: 639.35–718.04 mg L−1) for GLY, DIC and 2,4-D, respectively. Mean values for the toxic unit (TU) that induced 50% mortality (TU50 96h) of fish exposed to equitoxic mixtures were 1.67 (range: 1.65–1.69) for Credit® and Kamba® and 1.28 (range: 1.20–1.36) for Credit® and Weedar® Full suggesting that both mixtures are antagonic. Non-equitoxic combinations demonstrated an antagonistic interaction of herbicides Credit® and Kamba®, whereas a synergistic effect was observed for Credit® and Weedar® Full formulations. GLY and DIC as a mixture demonstrated lower toxicity on non-target species compared to GLY and 2,4-D in combination, at least for C. decemmaculatus, leading to the conclusion that the former combination could be strongly recommended in further agricultural practices.

Environmental exposure of fish to steroid hormones through wastewater and agricultural runoff may pose a health risk. Thus far, ecotoxicological studies have largely been focused on the disruption of the sex hormone system, but additional effects have been poorly investigated. Here we report on the effects of a series of different natural and synthetic steroid hormones on the locomotor behavior and the transcriptional levels of core clock genes in zebrafish eleuthero-embryos (Danio rerio). Of the 20 steroids analyzed, progestins and corticosteroids, including progesterone and cortisol, significantly decreased the locomotor activities of eleuthero-embryos at concentrations as low as 16 ng/L, while estrogens such as 17β-estradiol led to an increase. Consistently, progestins and corticosteroids displayed similar transcriptional effects on core clock genes, which were remarkably different from those of estrogens. Of these genes, per1a and nr1d2a displayed the most pronounced alterations. They were induced upon exposure to various progestins and corticosteroids and could be recovered using the progesterone receptor/glucocorticoid receptor antagonist mifepristone; this, however, was not the case for estrogens and the estrogen receptor antagonist 4-hydroxy-tamoxifen. Our results suggest that steroid hormones can modulate the circadian molecular network in zebrafish and provide novel insights into their mode of actions and potential environmental risks.

Soil particulate organic matter (POM) has rapid turnover and metal enrichment, but the interactions between organic matter (OM) and metals have not been well studied. The present study aimed to investigate changes in the OM concentration and composition of the POM fraction and their corresponding effects on metal distribution and extractability in long-term polluted paddy soils. Soil 2000–53 μm POM size fractions had higher contents of C–H and C=O bonds, C–H/C=O ratios and concentrations of fulvic acid (FA), humic acid (HA), cadmium (Cd) and zinc (Zn) than the bulk soils. Cadmium and Zn stocks in soil POM fractions were 24.5–27.9% and 7.12–16.7%, respectively, and were more readily EDTA-extractable. Compared with the control soil, the 2000–250 μm POM size fractions had higher organic carbon concentrations and C/N ratios in the polluted soils. However, there were no significant differences in the contents in C–H and C=O bonds or C–H/C=O ratios of POM fractions among the control, slightly and highly polluted soils. In accordance with the lower contents of C=O bonds and FA and HA concentrations, the Cd and Zn concentrations in 250–53 μm POM size fractions were lower than those in 2000–250 μm POM size fractions. Enrichment of Cd in POM fractions increased with increasing soil pollution level. These results support the view that changes in the OM concentration and the size and composition of POM fractions play a key role in determining the distribution of Cd and Zn in paddy soils.

Wind induced flow velocity patterns and associated thermal destratification can drive to hypoxia reduction in large shallow lakes. The effects of wind induced hydrodynamic changes on destratification and hypoxia reduction were investigated at the Meiling bay (N 31° 22′ 56.4″, E 120° 9′ 38.3″) of Lake Taihu, China. Vertical flow velocity profile analysis showed surface flow velocities consistency with the wind field and lower flow velocity profiles were also consistent (but with delay response time) when the wind speed was higher than 6.2 m/s. Wind field and temperature found the control parameters for hypoxia reduction and for water quality conditions at the surface and bottom profiles of lake. The critical temperature for hypoxia reduction at the surface and the bottom profile was ≤24.1C° (below which hypoxic conditions were found reduced). Strong prevailing wind field (onshore wind directions ESE, SE, SSE and E, wind speed ranges of 2.4–9.1 m/s) reduced the temperature (22C° to 24.1C°) caused reduction of hypoxia at the near surface with a rise in water levels whereas, low to medium prevailing wind field did not supported destratification which increased temperature resulting in increased hypoxia. Non-prevailing wind directions (offshore) were not found supportive for the reduction of hypoxia in study area due to less variable wind field. Daytime wind field found more variable (as compared to night time) which increased the thermal destratification during daytime and found supportive for destratification and hypoxia reduction. The second order exponential correlation found between surface temperature and Chlorophyll-a (R²: 0.2858, Adjusted R-square: 0.2144 RMSE: 4.395), Dissolved Oxygen (R²: 0.596, Adjusted R-square: 0.5942, RMSE: 0.3042) concentrations. The findings of the present study reveal the driving mechanism of wind induced thermal destratification and hypoxic conditions, which may further help to evaluate the wind role in eutrophication process and algal blooms formation in shallow water environments.Wind field is the key control factor for thermal destratification and hypoxia reduction. 24.1C° is the critical/threshold temperature for hypoxia, Chlorophyll-a and NH3-N concentrations of the shallow freshwater lake.

Pharmaceutically active compounds (PhACs) are excreted by humans and animals and released into the aquatic environment through wastewater, which can have potential negative impacts on ecological systems. To conduct a nationwide investigation of the occurrence of PhACs in water resources in China, an analytical procedure based on solid-phase extraction (SPE) and LC-MS/MS was used to measure 45 PhACs in surface water samples from a network of 29 rivers across 31 provinces in China in 2014 and 2015. PhACs were prevalent in all sampled streams. The concentrations of commonly detected PhACs were comparable to those detected in other countries. High total concentrations (mean > 1 μg L−1) of all tested PhACs were primarily detected in areas under extreme water stress, specifically northern and eastern coastal areas. Source apportionment based on the profiles of the target compounds found that 54% of the PhACs in China originated from freshly discharged untreated sewage. Metformin (MET) and its biodegradation product, guanylurea (GUL), were used as a pair of indicators to predict PhAC contamination levels and differentiate between biotreated and unbiotreated wastewater. High MET/GUL can be used to indicate untreated wastewater, whereas low MET/GUL values are a strong indicator of treated wastewater. Furthermore, wastewater biotreatment ratios were calculated. We estimated that the biotreatment ratios of most of the provinces in China were less than 50%. We conclude that more attention should be paid to untreated sewage water, especially water in rural areas rather than the existing concentration on urban sewage treatment-oriented management.

With the commercialization of transgenic cotton that expresses Bt (Bacillus thuringiensis) insecticidal proteins, mirid bugs have become key pests in cotton and maize fields in China. Genetically engineered (GE) crops for controlling mirids are unavailable owing to a lack of suitable insecticidal genes. In this study, we developed and validated a dietary exposure assay for screening insecticidal compounds and for assessing the potential effects of insecticidal proteins produced by GE plants on Apolygus lucorum, one of the main mirid pests of Bt cotton and Bt maize. Diets containing potassium arsenate (PA) or the cysteine protease inhibitor E-64 were used as positive controls for validating the efficacy of the dietary exposure assay. The results showed that with increasing concentrations of PA or E-64, A. lucorum larval development time was prolonged and adult weight and fecundity were decreased, suggesting that the dietary exposure assay was useful for detecting the toxicity of insecticidal compounds to A. lucorum. This assay was then used to assess the toxicity of Cry1Ab, Cry1Ac, Cry1F, Cry2Aa, and Cry2Ab proteins, which have been transformed into several crops, against A. lucorum. The results showed that A. lucorum did not show a negative effect by feeding on an artificial diet containing any of the purified Cry proteins. No significant changes in the activities of digestive, detoxifying, or antioxidant enzymes were detected in A. lucorum that fed on a diet containing Cry proteins, but A. lucorum fitness was reduced when the insect fed on a diet containing E-64 or PA. These results demonstrate that A. lucorum is not sensitive to the tested Cry proteins and that the dietary exposure assay is useful for evaluating the toxicity of insecticidal compounds to this species.

Male fertility is progressively declining in many developed countries, but the relationship between male infertility and environmental factors is still unclear.To assess the influence of environmental temperature and air pollution on semen parameters, using a big-data approach.A big data analysis of parameters related to 5131 men, living in a province of Northern Italy and undergoing semen analyses between January 2010 and March 2016 was performed. Ambient temperature was recorded on the day of analysis and the 90 days prior to the analysis and the average value of particulate matter (PM) and NO2 in the year of the test. All data were acquired by geocoding patients residential address. A data warehouse containing 990,904,591 data was generated and analysed by multiple regressions.5573 semen analyses were collected. Both maximum and minimum temperatures registered on the day of collection were inversely related to total sperm number (p < .001), non-progressive motility (NPrM) (p < .005) and normal forms (p < .001). Results were confirmed considering temperature in the 30 and 60 days before collection, but not in the 90 days before collection. Total sperm number was lower in summer/autumn (p < .001) and was inversely related with daylight duration (p < .001). PM10 and PM2.5 were inversely related to PrM (p < .001 and p < .005) and abnormal forms (p < .001).This is the first evaluation of the relationship between male fertility-related parameters and environment using a big-data approach. A seasonal change in semen parameters was found, with a fluctuation related to both temperature and daylight duration. A negative correlation between air pollution and semen quality is suggested. Such seasonal and environmental associations should be considered when assessing changes of male fertility-related parameters over time.

A systematic field measurement was conducted at an island site (Wanshan Island, WSI) over the South China Sea (SCS) in autumn 2013. It was observed that mixing ratios of O₃ and its precursors (such as volatile organic compounds (VOCs), nitrogen oxides (NOₓ = NO + NO₂) and carbon monoxide (CO)) showed significant differences on non-episode days and episode days. Additional knowledge was gained when a photochemical box model incorporating the Master Chemical Mechanism (PBM-MCM) was applied to further investigate the differences/similarities of O₃ photochemistry between non-episode and episode days, in terms of O₃-precursor relationship, atmospheric photochemical reactivity and O₃ production. The simulation results revealed that, from non-O₃ episode days to episode days, 1) O₃ production changed from both VOC and NOₓ-limited (transition regime) to VOC-limited; 2) OH radicals increased and photochemical reaction cycling processes accelerated; and 3) both O₃ production and destruction rates increased significantly, resulting in an elevated net O₃ production over the SCS. The findings indicate the complexity of O₃ pollution over the SCS.

While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil–air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low fₐₙₜᵢ ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (<0.05) than equilibrium value, suggesting that deposition and net transport from air to the soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (KOA) nor black carbon partition coefficient (KBC₋A) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs.

The widespread occurrence of microplastics (MP) in the marine environment is cause of increasing concerns about the safety of the exposed ecosystems. Although the effects associated to the MP uptake have been studied in most marine taxa, the knowledge about their sub-lethal impacts on early life stages of marine species is still limited. Here, we investigated the uptake/retention of 3-μm polystyrene MP by early stages of the Mediterranean mussel Mytilus galloprovincialis, and the related effects on gut clearance, feeding efficiency, morphological and transcriptional parameters involved in embryo-larval development. Uptake measurements were performed on larvae at 48 h, 3, 6 and 9 days post fertilization (pf) after exposure to a range of 50–10,000 particles mL−1. At all tested pf periods, treatments resulted in a significant and linear increase of MP uptake with increasing concentrations, though levels measured at 48 h pf were significantly lower compared to 3–9 d pf. Ingested MP were retained up to 192 h in larvae's gut, suggesting a physical impact on digestive functions. No change was noted between the consumption of microalgae Nannochloropsis oculata by larvae when administered alone or in the presence of an identical concentration (2000 items mL−1) of MP. The exposure to 50–10,000 MP mL−1 did not alter the morphological development of mussel embryos; however, transcriptional alterations were observed at 50 and 500 MP mL−1, including the up-regulation of genes involved in shell biogenesis (extrapallial protein; carbonic anhydrase; chitin synthase) and immunomodulation (myticin C; mytilin B), and the inhibition of those coding for lysosomal enzymes (hexosaminidase; β-glucorinidase; catepsin-L). In conclusion, though not highlighting morphological or feeding abnormalities, data from this study revealed the onset of physical and transcriptional impairments induced by MP in mussel larvae, indicating sub-lethal impacts which could increase their vulnerability toward further environmental stressors.