Trivalent chromium [Cr(III)] and tannins serve as necessary substances in leather processing and coexist in tannery site, which lead to the chromium contamination in site soil when disposed improperly. However, coexisting tannins are very likely to complex with Cr(III) and affect its properties, ultimately changing the mobility of chromium in soil. In this study, tannic acid (TA) was selected to investigate the complexation with Cr(III) and the influence on the solubility and sorption of Cr(III) in soils. Then, the transport behavior and mechanism of Cr(III)-TA complexes in soil was clarified. Dialysis results showed that the increase of TA concentration and solution pH promoted the formation of complexed Cr(III). The results of UV–Vis absorption spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations indicated that the adjacent ionized phenolic hydroxyls in TA functioned as the binding sites with Cr(III) to form the Cr–O bonds and the degree of complexation increased with pH. The Cr(III)-TA complexes had higher solubility than free Cr(III) at pH ≥ 6.0. Batch sorption experiments demonstrated that the sorption capacity of Cr(III)-TA to soils with different pH was always lower than that of free Cr(III). These reasons led to the stronger mobility of Cr(III)-TA in soil columns than Cr(III). Our research reveals that the enhanced mobility of Cr(III) in soils coexisting with TA.

Chlorinated paraffins (CPs) are pervasive environmental pollutants which have been reported to be hepatotoxic by laboratory cell and animal studies. However, the related epidemiological reports on their hepatotoxic effects to humans are sparse. In this study, we evaluated the associations between six liver enzymes and serum short-chain CP (SCCP) or medium-chain CP (MCCP) concentrations of 197 residents in Jinan, China. Serum S/MCCPs were detected by quadrupole time-of-flight high-resolution mass spectrometry coupled with atmospheric pressure chemical ionization source (APCI-QTOF-HRMS), and quantified by pattern deconvolution method. The associations between total serum S/MCCP concentrations (ΣS/MCCPs) and continuous liver enzyme levels were assessed by linear regression. Odds ratios (ORs) for the effects of serum ΣS/MCCPs concentrations on liver function biomarkers dichotomized by clinical reference intervals were predicted by logistic regression, either treating ΣS/MCCPs as continuous or categorical dependents. After multivariable adjustment, linear regression results illustrated that 1-ln unit increase in serum ΣSCCPs was negatively associated with male PA levels [-6.08, 95% confidence interval (CI): −11.90, −3.25, p < 0.05], positively associated with male TB levels (1.80, 95% CI: 0.28, 3.31, p < 0.05), and positively associated with female AST levels (1.39, 95% CI: 0.07, 2.70, p < 0.05). One-ln unit increase in serum ΣMCCPs was negatively associated male PA levels (−7.56, 95% CI: −17.15, −4.03, p < 0.05). Logistic regression results suggested that male serum ΣSCCPs were associated with increased prevalence of abnormal PA (OR = 1.47 per 1 ln-unit increase, CI = 1.18, 1.82) and TB (OR = 1.75, 95% CI = 1.12, 2.76) levels, and male serum ΣMCCPs were significantly associated with increased prevalence of abnormal PA (OR = 1.43, 95% CI = 1.03, 1.97) levels. In addition, male participants with concentrations above the median ΣS/MCCPs were associated with increased risk for abnormal PA levels [SCCPs, 2.11-fold (95% CI = 1.15, 3.87); MCCPs, 1.94-fold (95% CI = 1.24, 3.03)]. Male participants with concentrations above the median ΣSCCPs were also associated with increased risk for abnormal TB levels (OR = 1.75, 95% CI = 1.12, 2.76). Conclusively, our results revealed that CP internal exposure was associated with disturbed liver biomarker levels, suggesting the hepatotoxicity of both SCCPs and MCCPs to humans.

The performance of the radon (²²²Rn)-deficit technique has been evaluated at a site in which a complex DNAPL mixture (mostly hexachlorocyclohexanes and chlorobenzenes) has contaminated all four layers (from top to bottom: anthropic backfill, silt, gravel and marl) of the soil profile. Soil gas samples were collected at two depths (0.8 m and 1.7 m) in seven field campaigns and a total of 186 ²²²Rn measurements were performed with a pulse ionization detector. A statistical assessment of the influence of field parameters on the results revealed that sampling depth and atmospheric pressure did not significantly affect the measurements, while the location of the sampling point and ground-level atmospheric temperature did. In order to remove the bias introduced by varying field temperatures and hence to be able to jointly interpret ²²²Rn measurements from different campaigns, ²²²Rn concentrations were rescaled by dividing each individual datum by the mean ²²²Rn concentration of its corresponding field campaign. Rescaled ²²²Rn maps showed a high spatial correlation between ²²²Rn minima and maximum contaminant concentrations in the top two layers of the soil profile, successfully delineating the surface trace of DNAPL accumulation in the anthropic backfill and silt layers. However, no correlation could be established between ²²²Rn concentrations in superficial soil gas and contaminant concentration in the deeper two layers of the soil profile. These results indicate that the ²²²Rn-deficit technique is unable to describe the vertical variation of contamination processes with depth but can be an effective tool for the preliminary characterization of sites in which the distance between the inlet point of the sampling probe and the contaminant accumulation falls within the effective diffusion length of ²²²Rn in the affected soil profile.

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, ROX) is an arsenic-containing compound widely used as a feed additive in poultry industries. ROX excreted in chicken manure can be transformed by microbes to different arsenic species in the environment. To date, most of the studies on microbial transformation of ROX have focused on anaerobic microorganisms. Here, we isolated a pure cultured aerobic ROX-transforming bacterial strain, CZ-1, from an arsenic-contaminated paddy soil. On the basis of 16S rRNA gene sequence, strain CZ-1 was classified as a member of the genus Enterobacter. During ROX biotransformation by strain CZ-1, five metabolites including arsenate (As[V]), arsenite (As[III]), N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA), 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA) and a novel sulfur-containing arsenic species (AsC₉H₁₃N₂O₆S) were detected and identified based on high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), HPLC-ICP-MS/electrospray ionization mass spectrometry (ESI-MS) and HPLC-electrospray ionization hybrid quadrupole time-of-flight mass spectrometry (ESI-qTOF-MS) analyses. N-AHPAA and 3-AHPAA were the main products, and 3-AHPAA could also be transformed to N-AHPAA. Based on the results, we propose a novel ROX biotransformation pathway by Enterobacter. sp CZ-1, in which the nitro group of ROX is first reduced to amino group (3-AHPAA) and then acetylated to N-AHPAA.

With increasing demand for recycled wastewater for irrigation purposes, there is a need to evaluate the potential for manufactured nanomaterials in waste water to impact crop production and agroecosystems. Copper oxide nanoparticles (CuO NPs) have previously been shown to negatively impact the growth of duckweed (Landoltia punctata) a model aquatic plant consumed by water fowl and widely found in agricultural runoff ditches in temperate climates. However, prior studies involving CuO NP toxicity to duckweed have focused on systems without the presence of dissolved organic matter (DOM). In the current study, duckweed growth inhibition was shown to be a function of aqueous Cu²⁺ concentration. Growth inhibition was greatest from aqueous CuCl₂ and, for particles, increased with decreasing CuO particle size. The dissolution of CuO NPs in ½ Hoagland's solution was measured to increase with decreasing particle size and in the presence of Suwannee river humic and fulvic acids (HA; FA). However, the current results suggest that HA, and to a lesser extent, FA, decrease the toxicity of both CuO NPs and free ionized Cu to duckweed, likely by inhibiting Cu availability through Cu-DOM complex formation. Such results are consistent with changes to Cu speciation as predicted by speciation modeling software and suggest that DOM changes Cu speciation and therefore toxicity in natural systems.

High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO2 and H2O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O3). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O3, NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management.

Oxygen vacancy-enriched N/P co-doped cobalt ferrite (NPCFO) was synthesized using ionic liquid as N and P sources, and then the catalytic performance and mechanism of NPCFO upon peroxymonosulfate (PMS) activation for the degradation of organic pollutants were investigated. The as-synthesized NPCFO-700 exhibited excellent catalytic performance in activating PMS, and the degradation rate constant of 4-chlorophenol (4-CP) increased with the increase of OV concentration in NPCFO-x. EPR analysis confirmed the existence of ·OH, SO₄·⁻, and ¹O₂ in the NPCFO-700/PMS system, in which OV could induce the generation of ¹O₂ by PMS adsorption and successive capture, and also served as electronic transfer medium to accelerate the redox cycle of M²⁺/M³⁺ (M denotes Co or Fe) for the generation of radical to synergistically degrade organic pollutants. In addition, the contribution of free radical and nonradical to 4-CP degradation was observed to be strongly dependent on solution pH, and SO₄·⁻ was the major ROS in 4-CP degradation under acid and alkaline condition, while ¹O₂ was involved in the degradation of 4-CP under neutral condition due its selective oxidation capacity, as evidenced by the fact that such organic pollutants with ionization potential (IP) below 9.0 eV were more easily attacked by ¹O₂. The present study provided a novel insight into the development of transition metal-based heterogeneous catalyst containing massive OV for high-efficient PMS activation and degradation of organic pollutants.

The lag effect in the polar organic chemical integrative sampler (POCIS) equipped with a polyethersulfone (PES) membrane (POCIS-PES) is a potential limitation for its application in water environments. In this study, a POCIS with a poly(tetrafluoroethylene) (PTFE) membrane (POCIS-PTFE) was investigated for circumventing membrane sorption in order to provide more reliable concentration measurements of organic contaminants. Sampler characteristics such as sampling rates (RS) and sampler-water partition coefficients (KSW) were similar for POCIS-PES and POCIS-PTFE, indicating that partitioning into Oasis HLB as the receiving phase dominates the overall partitioning from the aqueous phase to the POCIS. Membrane sorption was quantified in both laboratory and field experiments. Although POCIS-PTFE showed minor membrane sorption, the PTFE membranes were not robust enough to prevent changes in the sorption of the pollutants to the inner Oasis HLB sorbent due to biofouling. This was reflected in significant ionization effects in the electrospray ionization (ESI) source during the LC-MS/MS analysis. Despite clear differences in the ionization effects, the two POCISs types provided similar time-weighted average (CTWA) concentrations after a two-week passive sampling campaign in surface water and the outflow of a wastewater treatment plant. This study contributes to a more detailed understanding of POCIS application by providing a quantitative evaluation of membrane sorption and its associated effects in the laboratory and field.

The impacts of microplastic particulates in benthic freshwater organisms have been largely unexplored despite abundant plastic accumulation in the sediments of these systems. We investigated the uptake of plastic particles by benthic filter feeding quagga mussels (Dreissena bugensis) and associated toxicity exhibited through impacts on mortality, filtration rate, reproduction and oxygen consumption. Matrix Assisted Laser Desorption/Ionization Imaging Mass Spectrometry (MALDI-IMS) technology was used to assess the microplastic inclusion. For this purpose, quagga mussels were exposed to four treatments ranging from 0.0 to 0.8 g/L of a high density fluorescent red polyethylene powder in the size range of 10–45 μm for 24-h, and the targeted endpoints were quantified. Identification of several micrograms of microplastics in the digestive tract suggests rapid clearance from the water column by filtering. At the higher concentrations, about 95% of the microplastics ingested remained in the mussels after 24-h. Microplastics were found in the gills which correlated with decreasing filtration rate at higher microplastic concentrations. Despite large-scale ingestion, plastic exposure did not affect survivorship, reproduction rates, or oxygen consumption in the period examined. MALDI-IMS identified unique mass spectra that correlated with microplastic inclusion. This research suggests that microplastics can impair feeding through decreased filtration rates of filter feeding organisms, potentially resulting in a reduction of overall fitness over time and that MALDI-IMS may have the potential to identify microplastics and changes in tissue at the borders of plastic inclusion.

Polycyclic aromatic hydrocarbons containing at least 24 carbon atoms (≥C₂₄-PAH) are often associated with pyrogenic processes such as combustion of fuel, wood or coal, and occur in the environment in diesel particulate matter, black carbon and coal tar. Some of the ≥C₂₄-PAH, particularly the group of dibenzopyrenes (five isomers, six aromatic rings) are known to show high mutagenic and carcinogenic activita.Gas chromatography – mass spectrometry is a well-established method for the analysis of lower molecular weight PAH but is not optimally suited for the analysis of ≥C₂₄-PAH due to their low vapor pressures. Also, hundreds of ≥C₂₄-PAH isomers are possible but only a few compounds are commercially available as reference standards. Therefore, in this study, a combination of multidimensional liquid chromatography, UV–Vis diode array detection, PAH selective and highly sensitive atmospheric pressure laser ionization – mass spectrometry is used to detect and unequivocally identify PAH. For identification of PAH in two bituminous coals and one petrol coke sample, unique and compound specific UV–Vis spectra were acquired. It was possible to identify ten compounds (naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[e,ghi]perylene, dibenzo[cd,lm]perylene, benzo[a]coronene, phenanthrol[5,4,3,2-abcde]perylene, benzo[ghi]naphtho[8,1,2-bcd]perylene, benzo[pqr]naphtho[8,1,2-bcd]perylene, naphtho[8,1,2-abc]coronene and tribenzo[e,ghi,k]perylene) by comparison of acquired spectra with spectra from literature. Additionally, it was possible to detect similar distribution patterns in different samples and signals related to alkylated naphthopyrenes, naphthofluoranthenes or dibenzopyrenes. Subsequent effect-directed analysis of a bituminous coal sample using the microEROD (ethoxyresorufin-O-deethylase) bioassay showed high suitability and revealed lower EROD induction for the ≥C₂₄-PAH (TEQ range 0.67–10.07 ng/g) than for the allover < C₂₄-PAH containing fraction (TEQ 84.00 ng/g). Nevertheless, the toxicity of ≥C₂₄-PAH has a significant impact compared with <C₂₄-PAH and must be considered for risk assessment. The LC-DAD-APLI-MS method, presented in this study, is a powerful tool for the unequivocal identification of these ≥ C₂₄-PAH.