Remediation of hexavalent chromium [Cr(VI)] has been widely studied for its high mobility and toxicity. As Cr(VI) migrates in natural environment, both soils and groundwater are contaminated simultaneously. In the present study, a novel reactor combining adsorption and microbial fuel cell (A-MFC) using Platanus acerifolia leaves was developed for removing Cr(VI) from groundwater and soils. When initial Cr(VI) concentration was 50 mg/L, the adsorption efficiency of A-MFC achieved 98% after 16 h. Afterwards, the leaves were used for fabricating an MFC-integrated leaching reactor. The A-MFC significantly improved the overall Cr(VI) removal efficiency through leaching and 40% of Cr(VI) in the soil column was removed. The electrical voltage and current of A-MFC reactor achieved averagely 343 mV and 141 μA to maintain the system operation without extra energy supply. This novel A-MFC reactor is an environmentally friendly technology which achieved efficient Cr(VI) removal from groundwater and soils using natural materials, proving the concept that integrated self-remediation of Cr(VI) in contaminated soil and groundwater with natural material and energy.

While wastewater treatment plants have been identified as the most prominent source of emerging micropollutants in surface waters, prediction of their ambient concentrations remains a challenge. This is due to the variability of loads entering individual treatment plants and of the elimination capacity by the latter as well as potential attenuation in the river network. Although geospatially detailed models exist, they suffer from the same data input uncertainties. Here, we investigated the concentration profiles of 20 emerging pollutants in different river stretches in Luxembourg with variable sanitary pressures. Using carbamazepine as a recalcitrant wastewater indicator, the correlation of the compounds to the latter revealed source and fate variability as well as specific emitters. Relating carbamazepine to sanitary pressure, expressed as the sum of population equivalents in a catchment divided by its surface [PE ha⁻¹] allowed predicting the impact of emerging pollutants on the entire river network. The limited variability of the pollutant profiles allowed for prioritization of impacted stretches depending on the different sanitary pressures at risk quotient exceedance. The main drivers of impact were triclosan, diclofenac, clarithromycine and diuron.

We analyzed paired serum, urine, and hair samples from 94 Korean children and adults to investigate levels of 11 perfluoroalkyl acids (PFAAs). The effects of demographic factors and dietary habits on PFAA exposure were also assessed based on the paired samples. The total PFAA concentrations were 2.4–31 ng/mL in serum, not detected–9.5 ng/mL in urine, and 0.48–15 ng/g in hair. Levels of perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), which have short carbon chains, were 1.5–5 fold higher in urine and hair than in serum. The PFAA concentrations in serum exhibited a decreasing trend with age from young childhood to adolescence, followed by an increasing trend after adolescence. For most PFAA species, concentrations in serum were higher in adult males than in adult females (p < 0.01). No sex difference was evident in the urine and hair samples. In addition, there was no age difference in the urine samples, but in the hair samples, we observed higher concentrations of PFAAs in children than in the other age groups (p < 0.01). The consumption rates of fish and water showed significant correlations with serum (positive correlation) and hair (negative) concentrations, respectively. No relationships between serum and hair/urine levels for most PFAAs were observed, except between serum and hair levels for perfluorooctanoic acid (PFOA).

Denitrification is considered as the dominant nitrogen (N) removing pathway, however, anaerobic oxidation of ammonium (anammox) also plays a significant part in N loss in agricultural ecosystems. Large N inputs into agricultural soils may stimulate the growth of anammox bacteria, resulting in high activity and diversity of anammox bacteria and subsequent more N loss. In some specific niches, like oxic-anoxic interface, three processes, nitrification, anammox and denitrification couple with each other, and significant anammox reaction could be observed. Soil parameters like pH, dissolved oxygen, salinity, oxidation-reduction potential (ORP), and substrate concentrations impact the anammox process. Here we summarize the current knowledge on anammox activity and contribution to N loss, abundance and diversity of anammox bacteria, factors affecting anammox, and the relationship between anammox and other N loss pathways in agricultural soils. We propose that more investigations are required for (1) the role of anammox to N loss with different agricultural management strategies; (2) microscale research on the coupling of nitrification-anammox-denitrification, that might be a very complex process but ideal model for further studies responsible for N cycling in terrestrial ecosystems; and (3) new methods to estimate differential contributions of anammox, codenitrification and denitrification in total N loss in agricultural ecosystems. New research will provide much needed information to quantify the contribution of anammox in N loss from soils at landscape, ecosystem and global scales.

Eggs from mature Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) salmon were collected between 2004 and 2014 from the Salmon River fish hatchery in Altmar, New York. The egg samples were analyzed for seventeen polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), as well as four dioxin-like polychlorinated biphenyls (DL-PCBs) using USEPA methods 1613 and 1668. Salmonid eggs were chosen as a tissue of interest since salmon feed at all trophic levels of the food web as they grow, and spawn in a narrow range of ages providing consistent, representative, and temporal samples of contaminant exposure. First-order decay models indicate decreasing trends for all select contaminants in both species, expressed by a toxic equivalence (TEQ) half-life (t₁/₂) of 11 years in Chinook and Coho eggs. No significant statistical difference in contaminant elimination rates were noted between species. TEQ elimination rates for Coho and Chinook eggs were not significantly different (p > 0.05) when compared with published Lake Ontario whole-fish lake trout elimination rates. Our research demonstrates that salmonid eggs are an effective means to assess PCDD, PCDF, and DL-PCB exposures and long-term trends in the Great Lakes.

In this study, a proposed integrated high-gravity technology for air pollution control, CO2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO2), nitrogen oxides (NOx), total suspended particulates (TSP)) and CO2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO2, SO2, NOx, and TSP removal efficiencies of 96.3 ± 2.1%, 99.4 ± 0.3%, 95.9 ± 2.1%, and 83.4 ± 2.6% were respectively achieved. Moreover, a 112 kWh/t-CO2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO2 and 0.468 kg NOx per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO2 capture, and waste utilization.

Concentrations of atmospheric carbon dioxide have been continuously increasing, and more investigations are needed in regard to the responses of various plants to the corresponding climatic conditions. In particular, potential variations in phytoremediation efficiency induced by global warming have rarely been investigated. Objective of this research was to evaluate the changes in phytoremediation efficiency of Noccaea caerulescens exposed to different concentrations of CO2. The concentrations of CO2 in the elevated CO2 treatments were adjusted to 550 ± 50 ppm to match the level of atmospheric CO2 predicted in 2050–2070. Compared to ambient controls (400 ppm), biomass yields and metal concentrations of N. caerulescens increased under elevated CO2 conditions, thus indicating that the phytoremediation efficiency of the species could increase in higher CO2 environment. In addition, water soluble and exchangeable Pb and Cu concentrations in soils decreased under elevated CO2 conditions, which reduced the leaching risks of the metals. The concentrations of malondialdehyde (MDA) of N. caerulescens decreased to different degrees with the increased CO2 concentrations. The overall findings suggested that elevations in CO2 can reduce the oxidative damage caused by metals in this species. The phytoremediation efficiency of N. caerulescens grown in multiple metal-enriched soils could be enhanced with global warming.

The ground-level ozone (O₃) concentration in the urban regions of China has become an increasingly noticeable environmental problem in recent years. Many epidemiological studies have reported the association between O₃ pollution and mortality, only a few studies have focused on the O₃-related mortality and corresponding economic effects at the Chinese city and province level. This study reports the seasonal variation of ground-level O₃ in 338 cities of China during the year 2016 and evaluates its effect on premature mortality and economic loss. It further illustrates the differences in cause-specific mortality outcomes of the log-linear and linear model, two of the prominently used methods for estimating health effects. In 2016, the annual average daily maximum 8-h O₃ concentration in China ranged between 74 and 201 μg/m³ (138 ± 24.7 μg/m³). 30% of the total population was exposed to >160 μg/m³ O₃ concentration (Chinese national ambient air quality standard) and about 67.2% urban population lived in exposure above the WHO recommended O₃ concentrations (100 μg/m³). The estimated national O₃-attributable mortality was 74.2 × 10³ (95% CI: 16.7×10³–127×10³) in the log-linear model, whereas, the total O₃-related mortality using the linear model was 69.6 × 10³ (95% CI: 16.2 × 10³–115 × 10³). The exposure to O₃ caused a nationwide economic loss of about 7.6 billion US$ (range: 1.7–12.9) in 2016. This study uniquely provides most comprehensive coverage of the Chinese cities for O₃ associated mortality utilizing ground level measurement data for 2016 and presents a measurable assessment to the policymakers of China for streamlining their efforts on air quality improvement and O₃ containment.

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in environmental media and biological samples. However, knowledge of its adverse health consequences is limited. In the current study, Caenorhabditis elegans (C. elegans, L1 larvae) were exposed to TDCPP at environmentally relevant concentrations (control, 0.1, 1, 100 and 1000 μg L⁻¹) for 72 h to explore any association between TDCPP and the aging process. Some of the degenerative age-related indicators were observed, including locomotion behaviors and lifespan. As crucial biomarkers of aging, the accumulation of lipofuscin, and lipid peroxidation (LPO) products exemplified by 4-hydroxynon-2-enal (4-HNE) were detected. This product forms as a result of oxidative stress, as confirmed by an N-acetyl-L-cysteine (NAC) pharmacological assay. Moreover, a significant increase in reactive oxide species (ROS) production in a dose-dependent manner using a fluorescent probe was observed. For the underlying molecular mechanism of the above aging phenotypes, significantly upregulated transcription of genes related to antioxidant systems, especially a subset of glutathione S-transferase (gst-5, gst-6, gst-9, gst-10, gst-19, gst-24, gst-26, gst-29, gst-33, and gst-38), was found by RNA-Seq and further confirmed by RT-qPCR. The elevated glutathione S-transferase (GST) was attributed to the significant increase in 4-HNE because mutations in gst-5 and gst-24 inhibited the conjugation of GSTs with 4-HNE. Therefore, GST play an indispensable role in the detoxification process of TDCPP exposure and further confirmed LPO accumulation at the molecular mechanism level. In conclusion, TDCPP accelerated the aging process induced by the LPO products, 4-HNE, response to reactive oxidative species in C. elegans.

Despite the endeavour to eradicate informal e-waste recycling, remediation of polluted sites is not mandatory in many developing countries and thus the hazard of pollutants remaining in soil is often overlooked. It is noteworthy that a majority of previous studies only analysed a few pollutants in e-waste to reflect the impact of informal e-waste recycling. However, the actual impact may have been largely underestimated since e-waste contains various groups of pollutants and the effect of some emerging pollutants in e-waste remains unexplored. Thus, this study examined the contamination of metals, PBDEs and AHFRs in the vicinity of an abandoned e-waste recycling site. The accumulation and translocation of these pollutants in rice plants cultivated at the nearby paddy field were measured to estimate the health risk through rice consumption. We revealed that the former e-waste burning site was still seriously contaminated with some metals (e.g. Sn, Sb and Ag, Igₑₒ > 5), PBDEs (Igₑₒ > 3) and AHFRs (Igₑₒ > 3), which can disperse to the nearby paddy field and stream. The rice plants can effectively absorb some metals (e.g. Mo, Cr and Mn, BCF > 1), but not PBDEs and AHFRs (BCF < 0.15), from soil and translocate them to the leaves. Alarmingly, the health risk through rice consumption was high primarily due to Sb and Sn (HQ > 20), whereas PBDEs and AHFRs had limited contribution (HQ < 0.08). Our results imply that abandoned e-waste recycling sites still act as the pollution source, jeopardising the surrounding environment and human health. Since some trace metals (e.g. Sb and Sn) are seldom monitored, the impact of informal e-waste recycling would be more notorious than previously thought. Remediation work should be conducted promptly in abandoned e-waste recycling sites to protect the environment and human health.