Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of insect pests. To assess potential risks from this compound to non-target aquatic organisms, an outdoor mesocosm study was performed. Mesocosms (1300 L) were treated once with a formulated product with the active substance (a.s.) thiamethoxam at nominal concentrations of 1 (n = 3), 3 (n = 3), 10 (n = 4), 30 (n = 4), and 100 (n = 2) μg a.s./L, plus untreated controls (n = 4). Primary producers (phytoplankton), zooplankton, and macroinvertebrates were monitored for up to 93 days following treatment. Thiamethoxam was observed to have a water column dissipation half-life (DT50) of ≤1.6–5.2 days in the mesocosms. Community-based principal response curve analysis detected no treatment effects for phytoplankton, zooplankton, emergent insects, and macroinvertebrates, indicating a lack of direct and indirect effects. A number of statistically significant differences from controls were detected for individual phytoplankton and zooplankton species abundances, but these were not considered to be treatment-related due to their transient nature and lack of concentration-response. After application of 30 μg a.s./L, slight temporary effects on Asellus aquaticus could not be excluded. At 100 μg a.s./L, there was an effect with no clear recovery of Asellus observed, likely due to their inability to recolonize these isolated test systems. A statistically significant but transient reduction in the emergence of chironomids by day 23 at the 100 μg a.s./L treatment was observed and possibly related to direct toxicity from thiamethoxam on larval stages. Therefore, a conservative study specific No Observed Ecological Adverse Effect Concentration (NOEAEC) is proposed to be 30 μg a.s./L. Overall, based on current concentrations of thiamethoxam detected in North American surface waters (typically <0.4 μg/L), there is low likelihood of direct or indirect effects from a pulsed exposure on primary producers, zooplankton, and macroinvertebrates, including insects, as monitored in this study.

Pollution of agricultural soils by pesticides, such as organochlorine pesticides (OCPs), can be a significant issue since high detection rates of these compounds were reported in our previous studies. However, more uncertain kinds, quantities and density of pollutants remained in soil samples were unidentified. In this study, the total hormonal activities of complex mixtures of both known and unknown contaminants in agricultural soils in mainland China were measured by applying highly sensitive reporter gene assays for detecting agonists/antagonists for estrogen receptor (ER), androgen receptor (AR), progesterone receptor (PR), glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). High detection rates of estrogenic activities and anti-progestogenic activities were observed among the 123 soil samples, reaching 79% and 73%, respectively. More than half of the soil samples showed obvious antagonistic effects against AR and GR. Approximately a third of tested samples exhibited androgenic, progestogenic and glucocorticoidic effects. A total of 72% and 78% soil extracts had mineralocorticoid-like and anti-mineralocorticoid activities, respectively. Significant positive correlations were observed between estrogenic activity and the concentrations of Σdichlorodiphenyltrichloroethanes (DDTs), Σendosulfans, Σchlordanes, heptachlor and Σdrins, respectively, but not other receptors. As a rapid and convenient pre-caution method, determination of endocrine-disrupting potencies of contaminated soils via bioassay could help to identify and define sites that required further attention for ecological risk assessments.

Inflammation may play an important role in the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and atherosclerotic cardiovascular disease (ASCVD) risk. However, the underlying mechanisms remain unclear.To investigate the association of PAHs exposure with ASCVD risk and effects of mean platelet volume (MPV) or Club cell secretory protein (CC16) on the association.A total of 2022 subjects (689 men and 1333 women) were drawn from the baseline Wuhan residents of the Wuhan-Zhuhai Cohort study. Data on demography and the physical examination were obtained from each participant. Urinary monohydroxy PAH metabolites (OH-PAHs) levels were measured by a gas chromatography-mass spectrometry. We estimated the association between each OH-PAHs and the 10-year ASCVD risk or coronary heart disease (CHD) risk using logistic regression models, and further analyze the mediating effect of MPV or plasma CC16 on the association by using structural equation modeling.The results of multiple logistic regression models showed that some OH-PAHs were positively associated with ASCVD risk but not CHD risk, including 2-hydroxyfluoren (β = 1.761; 95% CI: 1.194–2.597), 9-hydroxyfluoren (β = 1.470; 95% CI: 1.139–1.898), 1-hydroxyphenanthrene (β = 1.480; 95% CI: 1.008–2.175) and ΣOH-PAHs levels (β = 1.699; 95% CI: 1.151–2.507). The analysis of structural equation modeling shows that increased MPV and increased plasma CC16 levels contributed 13.6% and 15.1%, respectively, to the association between PAHs exposure and the 10-year ASCVD risk (p < 0.05).Exposure to PAHs may increase the risk of atherosclerosis, which was partially mediated by MPV or CC16.

Environment pollution often occurs as an obvious combined effect involving two (or more) elements, and this effect changes with the concentrations of the different elements. The effects on barley root elongation were studied in hydroponic systems to investigate the toxicity of Cu–Ni combined at low doses and at a fixed concentration ratio. For low doses of Cu–Ni, the addition of Ni (<0.5 μM) to Cu significantly decreased Cu toxicity for barley, but the addition of Cu (<0.25 μM) had no significant effect on Ni toxicity. At a fixed concentration ratio, according to the single effective concentration (EC) (barley root elongation inhibitory concentration) values of Cu and Ni, five sets of Cu–Ni fixed ratios were used: ECn(Cu)+ECm(Ni) (n + m = 100) (ECn and ECₘ indicate toxicity unit value for n% and m% inhibition of barley root length, respectively). The calculated toxicity unit value for 50% inhibition of root length ranged from 0.44 to 0.98 (i.e., <1), indicating a synergistic effect. To consider the interactions between the metal ions, the extended concentration addition model (e-CA) was established by integrating the Cu–Ni interaction into the concentration addition model (CA), and the data of two groups (the low doses of Cu–Ni and at a fixed concentration ratio) were respectively fitted. The e-CA accurately predicted the root length of barley under the Cu–Ni combined action. The correlation coefficient (r) and the root-mean-square error (RMSE) between predicted and observed values were 0.97 and 6.6 (low-dose group) and 0.96 and 8.12 (fixed-ratio group), respectively, and e-CA significantly improved the prediction accuracy compared to the traditional CA model without consideration of the Cu–Ni competition (r = 0.89, RMSE = 14.16). The results provided a theoretical basis for evaluation and remediation of soil contaminated with heavy metal composites.

Surfactants are high production volume chemicals used in numerous domestic and industrial applications and, after use, the most abundant organic contaminants in wastewater. Their discharge might jeopardize the receiving aquatic ecosystems, including sediments, where they tend to accumulate. This is the first comprehensive study on their distribution and fate in this environmental compartment as we performed simultaneous analysis of the three main classes of surfactants (anionic: LAS; nonionic: NPEO and AEO; cationic: DTDMAC, DADMAC, BAC, and ATMAC) and some of their transformation products (SPC, NP, NPEC, and PEG). To account for spatial and time trends, surface sediments and dated cores were collected from Jamaica Bay, a heavily sewage-impacted estuary in New York City. The concentrations of surfactants in surface sediments were between 18 and > 200 μg g⁻¹ and showed slight variation (<10%) over different sampling years (1998, 2003 and 2008). Cationic surfactants were found at the highest concentrations, with DTDMAC accounting for between 52 and 90% of the total sum of target compounds. Vertical concentration profiles in dated cores from the most contaminated station, in the vicinity of the biggest local sewage treatment plant (STP), indicated two sub-surface surfactant peaks in the mid-1960s (469 μg g⁻¹) and late 1980s (572 μg g⁻¹) coinciding with known STP upgrades. This trend was observed for most target compounds, except for DADMAC, C22ATMAC, and PEG, which showed a continuous increase towards the top of the cores. In-situ degradation was studied by comparing sediment core samples taken 12 years apart (1996 and 2008) and revealed a net decrease in PEG and specific surfactants (BAC, ATMAC, NPEO, and AEO) accompanied by growing concentrations of metabolites (SPC, NP, and NPEC). DTDMAC, DADMAC, and LAS, however, remained stable over this period, suggesting recalcitrant behavior under the anaerobic conditions in Jamaica Bay sediments.Chronology of major synthetic surfactants are illustrated in the dated sediment cores, as well as their different diagenetic fates.

Narragansett Bay is a temperate estuary on the Atlantic coast of Rhode Island in the north-eastern United States, which receives organic pollutants from urban and industrial activities in its watershed, though detailed knowledge on sources and fluxes is missing. Twenty-four polyethylene passive samplers were deployed in the surface water of the watershed around Narragansett Bay during June–July of 2014, to examine the spatial variability and possible sources of priority pollutants, namely dissolved polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Dissolved ∑22PAH concentrations ranged from 3.6 to 340 ng L−1, and from 2.9 to 220 pg L−1 for ∑12PBDE. The spatial variability of the concentrations was correlated to land use pattern and population distribution, in particular with human activities within 2 km of sampling sites. River discharges derived from the concentrations of PAHs and PBDEs measured here were 10–20 times greater than their previously measured concentrations in the open waters of Narragansett Bay. These results imply that river waters are the main source of PAHs and PDBEs to the Bay and that major sink terms (e.g., sedimentation, degradation) affect their concentrations in the estuary. Predicted PAH and PBDE toxicity based on dissolved concentrations did not exceed 1 toxic unit, suggested that no toxicity occurred at the sampling sites.

Elevated atmospheric nitrogen (N) deposition has exerted profound influences on ecosystems. Understanding the effects of N deposition on the dynamics of soil organic carbon (SOC) is important in the studies of global carbon cycle. Although many studies have examined the effects of N deposition on SOC turnover using N addition experiments, the effects were reported to be different across studies. Thus, we lack a predictive understanding of how SOC turnover respond to atmospheric N deposition. The inconsistent results could be associated with ecosystem types and N addition rates. This study mainly wants to confirm the argument that the response of SOC turnover to N deposition is related with N input rates. We conducted a field experiment with multiple N addition levels (0, 3, 6, 12, and 24 g N m−2·yr−1) in Inner Mongolia Grassland, China. To better reveal the responses of SOC turnover to N enrichment, this study measured the soil 14C contents, because it can indicate SOC turnover directly. Compared with the control treatment (0 g N m−2·yr−1), N addition inhibits SOC turnover at the addition rate of 3 g N m−2·yr−1, whereas SOC turnover is not affected when N addition rate was 6, 12, and 24 g N m−2·yr−1. Our results suggest that N input rates affect the responses of SOC turnover to N enrichment. Thus, this study can confirm the argument mentioned above. Based on this study, it should be considered in the climate prediction model that varied atmospheric N deposition levels across regions may have different impacts on local SOC turnover. In addition, we also carried out a soil incubation to compare between the results obtained in incubation and that in 14C measurements. Two results are found to be inconsistent with each other. This indicates that soil respiration from incubation experiments could not comprehensively assess the effects of N deposition on SOC turnover.

Arsenic (As) behavior in paddy soils couples with the redox process of iron (Fe) minerals. When soil is flooded, Fe oxides are transformed to soluble ferrous ions by accepting the electrons from Fe reducers. This process can significantly affect the fate of As in paddy fields. In this study, we show a novel technique to manipulate the Fe redox processes in paddy soils by deploying soil microbial fuel cells (sMFC). The results showed that the sMFC bioanode can significantly decrease the release of Fe and As into soil porewater. Iron and As contents around sMFC anode were 65.0% and 47.0% of the control respectively at day 50. The observed phenomenon would be explained by a competition for organic substrate between sMFC bioanode and the iron- and arsenic-reducing bacteria in the soils. In the vicinity of bioanode, organic matter removal efficiencies were 10.3% and 14.0% higher than the control for lost on ignition carbon and total organic carbon respectively. Sequencing of the 16S rRNA genes suggested that the influence of bioanodes on bulk soil bacterial community structure was minimal. Moreover, during the experiment a maximum current and power density of 0.31 mA and 12.0 mWm−2 were obtained, respectively. This study shows a novel way to limit the release of Fe and As in soils porewater and simultaneously generate electricity.

Organophosphate flame retardants (OPFRs), as alternatives to polybrominated biphenyl ethers (PBDEs), are frequently detected in various environmental matrices. Owing to urbanization and industrial pollution, co-contamination of OPFRs and heavy metals is ubiquitous in the environment. The toxicity of OPFRs in aqueous phase is a significant concern, but uncertainty still exists regarding the co-toxicity to benthic organisms of OPFRs and metals in sediments. Hence, we explored the physiological response of Corbicula fluminea to OPFRs and Cd in sediments. The results indicated that the antioxidant system in the clams was stimulated in the presence of OPFRs and Cd, and the oxidative stress increased with increasing concentrations of OPFRs. In contrast, the cytochrome P450 (CYP450) content and acetylcholinesterase (AChE) activity were reduced by exposure to both OPFRs and Cd. The cytochrome P450 4 family (CYP4) mRNA expression and OPFR toxicity were lower than those in previously reported experiments conducted in the water phase. Moreover, the expression levels of metallothionein (MT) and AChE mRNA decreased when OPFRs and Cd were present together. The highest integrated biomarker response (IBR) index (IBR = 15.41) was observed in the presence of 45 mg kg⁻¹ Cd + 200 mg kg⁻¹ OPFRs, rather than the 45 mg kg⁻¹ Cd + 400 mg kg⁻¹ OPFRs treatment (IBR = 9.48). In addition, CYP450 and AChE in the digestive glands of C. fluminea exhibited significant correlations with the concentration of the OPFR/Cd mixture (p < 0.01) and could be effective biomarkers for OPFR and Cd co-contamination. The results potentially contribute to more realistic predictions and evaluations of the environmental risks posed by OPFRs in aquatic sediments contaminated with heavy metals, particularly with respect to the risk to benthic organisms.

Particulate matter with a diameter of 10 μm or less (PM10) using receptor modelling was determined at an urban (La Linea, LL) and an industrial area (Puente Mayorga, PMY) in Southern Spain with samples collected during 2005–2014. The concentrations of PM10 had been decreasing at both sites in three distinctive periods: 1) the initial PM10 levels approached or exceeded the Spain and EU PM10 annual guidelines of 40 μg/m3 during 2005–2007 at LL and 2005–2009 at PMY; 2) then PM10 dropped by 25%–∼30 μg/m3 during 2008–2011 at LL and during 2010–2011 at PMY; 3) since 2012, the PM10 concentrations gradually decreased to <30 μg/m3. Chemical compositions of PM10 revealed the important contributions of water soluble ions (sulfate, nitrate, ammonium, and chloride), carbonaceous aerosols, and other major elements. These PM components generally showed a decrease trend, in accord with the trend of PM10 reduction. A PMF model identified seven sources to PM10 contributions. Secondary sulfate, soil/urban/construction dust, and secondary nitrate showed significantly decreasing trends with reduction of 40–60% comparing to the initial levels. The road traffic contribution decreased by 14% from the first to third period. However, sea salt, oil combustion, and industrial metallurgical process had relative stable contributions. These source contribution changes are reasonably governed by the PM emission abatement actions implemented during the past decade, as well as the financial crisis, that accounted for a significant decrease of PM pollution in Southern Spain.We identified that the mitigation efforts on industry, fossil fuel combustion, and urban transportation during the past decade were successful for air quality improvement in a highly industrialized area in Southern Spain.