Recently polymer inclusion membranes (PIMs) have been proposed as materials for passive sampling, nonetheless a theoretical base to describe the mass transfer process through those materials, under such conditions of monitoring, has not been elucidated. Under the assumption that: (i) the transport of the metal ion occurs at steady state conditions, (ii) the concentration gradients are linear, and (iii) the kinetics of the chemical reactions in the extraction process on the membrane are elemental; an equation for the passive sampling of copper (II) using a PIM system containing Kelex-100 as carrier is derived. The prediction capacity of this sampler under different conditions of temperature, metal concentration, flow velocity, ionic strength and pH is analyzed as well. Among the dependencies of the PIM on the physicochemical conditions, effects of concentration, temperature and flow velocity tend to increment copper (II) flux across the membrane, being the parameter temperature the one with the most pronounced effect at T ≥ 30 °C. Ionic strength had no great effect on passive sampler response, however the sampler is dependent on the acidity of the medium. The comparable metal ion concentrations estimated from the PIM sampler to those obtained by direct measurements of the sampling medium suggest that PIMs can be robust materials when used as passive sampler devices.

Although livestock manure, such as from swine (Sus scrofa domestica), have high capacity to introduce endocrine-disrupting free estrogens into the environment, the frequency of estrogen detections from reconnaissance studies suggest that these compounds are ubiquitous in the environment, perhaps resulting from historic manure inputs (e.g. cattle grazing residues, undocumented historic manure applications) or uncontrolled natural sources. Compared to free estrogens, conjugates of estrogens are innocuous but have greater mobility in the environment. Estrogen conjugates can also hydrolyze to re-form the potent free estrogens. The objective of this study was to identify the transport of free and conjugated estrogens to subsurface tile drains and groundwater beneath fields treated with swine manure slurry. Three field treatments were established, two receiving swine lagoon manure slurry and one with none. Manure slurry was injected into soils at a shallow depth (∼8 cm) and water samples from tile drains and shallow wells were sampled periodically for three years. Glucuronide and sulfate conjugates of 17β-estradiol (E2) and estrone (E1) were the only estrogen compounds detected in the tile drains (total detects = 31; 5% detection frequency; conc. range = 3.9–23.1 ng L(−1)), indicating the important role conjugates played in the mobility of estrogens. Free estrogens and estrogen conjugates were more frequently detected in the wells compared to the tile drains (total detects = 70; 11% detection frequency; conc. range = 4.0–1.6 × 103 ng L(−1)). No correlations were found between estrogen compound detections and dissolved or colloidal organic carbon (OC) fractions or other water quality parameters. Estrogenic compounds were detected beneath both manure treated and non-treated plots; furthermore, the total potential estrogenic equivalents (i.e. estrogenicity of hydrolyzed conjugates + free estrogens) were similar between treated and non-treated plots.

Polycyclic aromatic hydrocarbons (PAHs) are prone to post-emission transformation and degradation to yield transformed PAH products (TPPs) that are potentially more hazardous than parent PAHs. This review provides a comprehensive evaluation of the potential environmental processes of PAHs such as sorption, volatilisation, photo- and bio-transformation and degradation on road surfaces, a significant accumulation point of PAHs. The review primarily evaluates key influential factors, toxicity implications, PAHs and TPPs fate and viable options for mitigating environmental and human health impacts. Photolysis was identified as the most significant transformation and degradation process due to the light absorption capacity of most PAHs. Climate conditions, physicochemical properties of road dust (sorbent), PAHs and TPPs and the existence of heavy metals such as Fe (III) are notable underlying factors for photolysis. Available data points to the predominance of carbonyl TPPs than other products such as nitro and hydroxyl TPPs with decreasing concentration trend of 9-fluorenone > 9,10-anthraquinone > benzo[a]fluorenone on road surfaces. The review recommends conducting future investigations targeting the influential factors pertaining to the fate of road deposited PAHs and TPPs. Furthermore, development of cost and time effective modern analytical methods is needed to quantify PAHs and TPPs present in minute quantities of samples. The review also identified that the unavailability of toxicity equivalency factors (TEF) for the most critical TPPs can be addressed using quantitative structure-activity relationship (QSAR) models and bioassays simultaneously. The content of this review is significant to the future work of researchers across various fields including analytical and environmental chemistry, stormwater pollution and toxicology.

The atmospheric concentrations of 14 organophosphate esters (OPEs) were monitored by passive air sampling at 33 sites to determine their spatial distributions, and seasonal variations (summer and winter) in Tianjin, North China. The total concentrations of the OPEs (∑₉OPEs) in the summer ranged from 0.08 to 1113 ng/sample with a median of 98.4 ng/sample, which was non-statistically different from the concentrations obtained in the winter (which ranged from 1.93 to 548 ng/sample with a median of 46.2 ng/sample). Among the observed OPEs, the concentrations of TnBP and TCiPP were statistically higher in the summer compared with the winter (p < 0.05). For grouped OPEs, only a significantly higher level of chlorinated OPEs was found in summer than that in winter. In the winter, spatial differences were found to be significantly different between the concentrations of TnBP, TiBP, TCEP, and TEHP in the suburban and rural areas (p < 0.05). Considering the possible point-sources, in the summer, the concentrations of TDCPP, TCiPP, DPEHP, TEHP, and the total concentration of TCPs (denoted as ∑₃TCP, comprised of the concentrations of TCP, TmCP, and ToCP) in an electronic-waste (e-waste) dismantling area were higher than those obtained at the other sampling sites. ∑₉OPEs at the e-waste site and another site located near a manufacturing plant of organophosphate flame retardants (OFRs) were both higher than the median concentrations obtained at the other sampling sites, and TCiPP was the most abundant pollutant. In the winter, the concentrations of ∑₉OPEs at the e-waste site were still higher than their median concentrations at the other sites. Because OPEs are used in aircraft lubricating oils and hydraulic fluids, an airport was thought to be another important source of TiBP and TPhP in the present study. Therefore, the e-waste site, airport, and OFR manufacturing plant may be the major sources of OPEs in the environment.

Heavy metal contamination in protected-field vegetable production has aroused widespread concern and manure is considered to be one of the contamination sources. Little is known about its long-term effects on heavy metal pollution in uncontaminated soils. A 15-year protected-field vegetable production experiment was carried out with three manure treatments (chicken manure: cattle manure = 3:1) with high (HMAR), medium (MMAR) and low (LMAR) application rates to evaluate the long-term risks of heavy metal pollution. It was found that continuous and high manure application rates significantly increased the total concentrations of soil Cd, Zn, Cr, and Cu rather than Pb, Ni or As. The high application rate of manure also increased soil available heavy metals although the soil organic matter was increased as well. Though total soil Cd under the HMAR exceeded the threshold of national soil standard, Cd content in tomato and fennel still complied with the food safety requirements of vegetables. Generally, the accumulation rates of soil Zn, Cu, and Cr with 1 t⋅ha⁻¹ of manure application in three treatments were ranked by HMAR < MMAR < LMAR. Based on the results of the ratio of heavy metal accumulation risk (RAR), Zn, Cu, and Cr under HMAR and Cd and Zn under MMAR would exceed their soil threshold values within 100 years and RAR could be a useful indicator for monitoring the long-term risk of soil heavy metal pollution. Recommended manure application rates to guarantee a 100-year period of clean production were 44, 74, and 63 t⋅ha⁻¹⋅yr⁻¹ for Zn, Cu, and Cr, respectively. Measurements should be taken to minimize the risk of heavy metals (Cd, Zn, Cr, and Cu) pollution sourced from manure to ensure food safety and ‘cleaner’ protected-field vegetable production.

Cadmium cations (Cd²⁺) are extremely toxic to organisms, which limits the remediation of Cd by microorganisms. This study investigated the feasibility of applying biochar to protect bacteria from extreme Cd²⁺ stress (1000 mg/L). An alkaline biochar (RB) and a slightly acidic biochar (SB) were selected. SB revealed a higher Cd²⁺ removal than RB (15.5% vs. 4.8%) due to its high surface area. Addition of Enterobacter sp. induced formation of Cd phosphate and carbonate on both SB and RB surface. However, Cd²⁺ removal by RB enhanced more evidently than SB (78.9% vs. 30.2%) due to the substantial microbial regulation and surficial alkalinity. Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and geochemical modeling (GWB) all confirmed that the formation of stable Cd phosphate on RB was superior to that in SB. These biomineralization, together with biochar pore structure, protect bacterial cells from Cd stress. Moreover, the alkalinity of biochar promoted the formation of carbonate, which strengthened the decline of Cd²⁺ toxicity. The protection by RB was also confirmed by the intense microbial respiration and biomass (PLFA). Furthermore, this protection induced a positive feedback between P-abundant biochar and Enterobacter sp.: biochar provides P source (the most common limiting nutrient) to support microbial growth; bacteria secrete more organic acids to drive P release. This study therefore elucidated the protection of bacteria by P-enriched biochar based on both physic-chemical and microbial insights.

Total concentrations of hydrophobic organic contaminants (HOCs) in sediment present a poor quality assessment parameter for aquatic organism exposure and environmental risk because they do not reflect contaminant bioavailability. The bioavailability issue of HOCs in sediments can be addressed by application of multi-ratio equilibrium passive sampling (EPS). In this study, riverbed sediment samples were collected during the Joint Danube Survey at 9 locations along the Danube River in 2013. Samples were ex-situ equilibrated with silicone passive samplers. Desorption isotherms were constructed, yielding two endpoints: pore water (CW:₀) and accessible (CAS:₀) concentration of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers in sediment. CW:₀ concentrations of DDT and its breakdown products exhibited elevated levels in the low Danube, with the maximum in the river delta. Other investigated HOCs did not show any clear spatial trends along the river, and only a moderate CW:₀ variability. CAS:₀ in sediment ranged from 10 to 90% of the total concentration in sediment. CW:₀ was compared with freely dissolved concentration in the overlaying surface water, measured likewise by passive sampling. The comparison indicated potential compound release from sediment to the water phase for PAHs with less than four aromatic rings, and for remaining HOCs either equilibrium between sediment and water, or potential compound deposition in sediment. Sorption partition coefficients of HOC to organic carbon correlated well with octanol-water partition coefficients (KOW), showing stronger sorption of PAHs to sediment than that of PCBs and OCPs having equal logKOW. Comparison of CW:₀ values with European environmental quality standards indicated potential exceedance for hexachlorobenzene, fluoranthene and benzo[a]pyrene at several sites. The study demonstrates the utility of passive sampling as an innovative approach for risk-oriented monitoring of HOCs in river catchments.

Occupational exposure to hexavalent chromium (Cr(VI)) can cause cytotoxicity and carcinogenicity. In this study, we established a liver injury model in rats via intraperitoneal injection of potassium dichromate (0, 2, 4, and 6 mg/kg body weight) for 35 d to investigate the mechanism of Cr(VI)-induced liver injury. We found that Cr(VI) induced hepatic histopathological lesions, oxidative stress, and apoptosis and reduced the expression of mitochondrial-related regulatory factors such as adenosine 5′-monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in a dose-dependent manner. Furthermore, Cr(VI) promoted mitochondrial division and inhibited fusion, leading to increased expression of caspase-3 and production of mitochondrial reactive oxygen species. Our study demonstrates that long-term exposure to Cr(VI) induces mitochondrial dynamics disorder by inhibiting AMPK/PGC-1α signaling pathway in rat liver.

Due to the abusive usage of antibiotics in animal husbandry, a large amount of residual antibiotics has been released into the environment, therein posing great threat against both environment security and public health. Therefore, it is of great significance to investigate the toxicity of antibiotics on the widely-applied bioindicator-earthworm. In this work, the physiological parameters and the intestinal bacteria community of Metaphire guillelmi were monitored simultaneously to evaluate their sensitivity to the tetracycline (TC) exposure. As expected, the antioxidant enzyme activity and coelomocyte apoptosis acted fairly well as biomarkers for the TC toxicity. In contrast, the intestinal bacteria of Metaphire guillelmi responded varyingly to different TC doses. When TC concentration increased from 0 to 35.7 μg cm⁻², the percentage of the Proteobacteria phylum declined significantly from 85.5% to 34.4%, while the proportions of the Firmicutes, Planctomycetes and Atinomycete phyla clearly increased (p < 0.05). Meanwhile, the levels of TC resistance genes tetA, tetC, and tetW increased with the increasing TC concentration, in contrast to the declined abundance in denitrifying genes nirS and nosZ (p < 0.05). By analyzing the correlation between the antioxidant enzyme activity and the dominant intestinal bacteria in the worm gut, it is interesting to found that the four dominant bacteria genera Mesorhizobium, Aliihoeflea, Romboutsia, and Nitrospira are the promising bioindicator of TC stress due to their sensitive response. This work shed novel light on evaluating the ecotoxicological risks posed by residual TC in environment by using a combination of physiological parameters and intestinal bacterial activity in earthworms.

The new-generation geostationary satellites feature higher radiometric, spectral, and spatial resolutions, thereby making richer data available for the improvement of PM₂.₅ predictions. Various aerosol optical depth (AOD) data assimilation methods have been developed, but the accurate representation of the AOD-PM₂.₅ relationship remains challenging. Empirical statistical methods are effective in retrieving ground-level PM₂.₅, but few have been evaluated in terms of whether and to what extent they can help improve PM₂.₅ predictions. Therefore, an empirical and statistics-based scheme was developed for optimizing the estimation of the initial conditions (ICs) of aerosol in WRF-Chem (Weather Research and Forecasting/Chemistry) and for improving the PM₂.₅ predictions by integrating Himawari-8 data and ground observations. The proposed method was evaluated via two one-year experiments that were conducted in parallel over eastern China. The contribution of the satellite data to the model performance was evaluated via a 2-week control experiment. The results demonstrate that the proposed method improved the PM₂.₅ predictions throughout the year and mitigated the underestimation during pollution episodes. Spatially, the performance was highly correlated with the amount of valid data.