Plants can take up and transform brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) from soil, water and the atmosphere, which is of considerable significance to the geochemical cycle of BFRs and OPFRs and their human exposure. However, the current understanding of the plant uptake, translocation, accumulation, and metabolism of BFRs and OPFRs in the environment remains very limited. In this review, recent studies on the accumulation and transformation of BFRs and OPFRs in plants are summarized, the main factors affecting plant accumulation from the aspects of root uptake, foliar uptake, and plant translocation are presented, and the metabolites and metabolic pathways of BFRs and OPFRs in plants are analyzed. It was found that BFRs and OPFRs can be taken up by plants through partitioning to root lipids, as well as through gaseous and particle-bound deposition to the leaves. Their microscopic distribution in roots and leaves is important for understanding their accumulation behaviors. BFRs and OPFRs can be translocated in the xylem and phloem, but the specific transport pathways and mechanisms need to be further studied. BFRs and OPFRs can undergo phase I and phase II metabolism in plants. The identification, quantification and environmental fate of their metabolites will affect the assessment of their ecological and human exposure risks. Based on the issues mentioned above, some key directions worth studying in the future are proposed.

Mining activities in the world's largest platinum mining area in South Africa have resulted in environmental contamination with Pt (e.g., the Hex River's vicinity). The present study compared a Pt mining area with a non-mining area along this river in terms of (1) metal concentrations in different grain size fractions from soils and aquatic sediments; (2) the toxicological potential of aquatic sediments based on the Consensus-Based Sediment Quality Guideline (CBSQG); and (3) the chronic toxicity of aqueous eluates from soils and sediments to Caenorhabditis elegans. Platinum concentrations were higher in the mining area than in the non-mining area. For most metals, the sediment silt and clay fraction contained the highest metal concentrations. Based on the CBSQG, most sampling sites exhibited a high toxicological potential, driven by Cr and Ni. Eluate toxicity testing revealed that C. elegans growth, fertility, and reproduction inhibition were not dependent on mining activities or the CBSQG predictions. Toxicity was instead likely due to Cd, Fe, Mn, Ni, Pt, and Pb. In conclusion, the investigated region is loaded with a high geogenic background resulting in high reproduction inhibition. The mining activities lead to additional environmental metal contamination (particularly Pt), contributing to environmental soil and sediment toxicity.

Tropospheric ozone (O₃) affects isoprenoid emissions, and floral emissions in particular, which may result in potential impacts on the interactions of plants with other organisms. The effects of ozone (O₃) on isoprenoid emissions have been investigated for many years, while knowledge on O₃ effects on floral emissions is still scarce and the relevant mechanism has not been clarified so far. We investigated the effects of O₃ on floral and foliar isoprenoid emissions (mainly isoprene, monoterpenes and sesquiterpenes) and their synthase substrates from three rose varieties (CH, Rosa chinensis Jacq. var. chinensis; SA, R. hybrida ‘Saiun’; MO, R. hybrida ‘Monica Bellucci’) at different exposure durations. Results indicated that the O₃-induced stimulation after short-term exposure (35 days after the beginning of O₃ exposure) was significant only for sesquiterpene emissions from flowers, while long-term O₃ exposure (90 days after the beginning of O₃ exposure) significantly decreased both foliar and floral monoterpene and sesquiterpene emissions. In addition, the observed decline of emissions under long-term O₃ exposure resulted from the limitation of synthase substrates, and the responses of emissions and substrates varied among varieties, with the greatest variation in the O₃-sensitive variety. These findings provide important insights on plant isoprenoid emissions and species selection for landscaping, especially in areas with high O₃ concentration.

Effective and fair mitigation measures hinge on the identification of hotspots and tracking provenance on reactive nitrogen (Nr) loss at a high spatial resolution. We assessed the Nr loss intensity in China at 1 km spatial resolution from 1980 to 2015. The total Nr loss increased from 20.2 to 54.5 Tg N yr⁻¹, with hotspots (>100 kg N ha⁻¹ yr⁻¹) concentrated in the North China Plain, the Middle and Lower Yangtze River and the Sichuan Basin. The Nr loss hotspots covered less than 20% of the Chinese territory but contributed more than 90% of total Nr loss since 1990. Geographical disparity in Nr loss has increased and calls for a fair regional policy synergy. Compared to managing Nr loss based only on production, we demonstrate that the estimation of Nr loss responsibility driven by consumption has greater potential to allocate a fair share of responsibility for reducing Nr loss.

Studies have shown that the mixture toxicity of compounds with similar modes of action (MOAs) is usually predicted by the concentration addition (CA) model. However, due to the lack of toxicological information on compounds, more evidence is needed to determine whether the above conclusion is generally applicable. In general, the same type of compounds with similar chemical structures have similar MOAs, so whether the toxicities of the mixture of these compounds are additive needs to be further studied. In this paper, three types of pesticides with similar chemical structures (three organophosphoruses, two carbamates and two neonicotinoids) that may have similar MOAs were selected and five binary mixture systems were constructed. For each system, five mixture rays with different concentration ratios were designed by the direct equipartition ray design (EquRay) method. The mortality of Caenorhabditis elegans was regarded as the endpoint for the toxicity exposure to single pesticides and binary mixtures. The combined toxicities were evaluated simultaneously using the CA model, isobologram and combination index. The structural similarity of the same type of pesticides was quantitatively analyzed according to the MACCS molecular fingerprint and the slope of dose-response curve at pEC₅₀. The results show that the toxicities of neonicotinoid mixtures and carbamate mixtures are almost antagonistic. The entire mixture system of dichlorvos and dimethoate produced synergism, and four of the five mixture rays of dimethoate and methamidophos induced antagonism, while among the mixture rays of dichlorvos and methamidophos, different concentrations showed different interaction types. The results of structural similarity analysis show that the size of structural similarity showed a certain quantitative relationship with the toxicity interaction of mixtures, that is, the structural similarity of the same type of pesticides may show an additive action in a certain range.

A native strain of Bacillus paramycoides isolated from the leachate of coal mine overburden rocks was investigated for its potential to produce selenium nanoparticles (SeNPs) by biogenic reduction of selenite, one of the most toxic forms of selenium. 16S rDNA sequencing was used to identify the bacterial strain (SP3). The SeNPs were characterized using spectroscopic (UV–Vis absorbance, dynamic light scattering, X-ray diffraction, and Raman), surface charge measurement (zeta potential), and ultramicroscopic (FESEM, EDX, FETEM) analyses. SP3 exhibited extremely high selenite tolerance (1000 mM) and reduced 10 mM selenite under 72 h to produce spherical monodisperse SeNPs with an average size of 149.1 ± 29 nm. FTIR analyses indicated exopolysaccharides coating the surface of SeNPs, which imparted a charge of −29.9 mV (zeta potential). The XRD and Raman spectra revealed the SeNPs to be amorphous. Furthermore, biochemical assays and microscopic studies suggest that selenite was reduced by membrane reductases. This study reports, for the first time, the reduction of selenite and biosynthesis of SeNPs by B. paramycoides, a recently discovered bacterium. The results suggest that B. paramycoides SP3 could be exploited for eco-friendly removal of selenite from contaminated sites with the concomitant biosynthesis of SeNPs.

In the present study, produced water sample collected from the Indian crude oil reservoir is used to enrich the bacterial communities. The impact of these enriched bacterial communities on the biodegradation of crude oil, biofilm formation, and biocorrosion process are elucidated. A crude oil degradation study is carried out with the minimal salt medium and 94% of crude oil was utilized by enriched bacterial communities. During the crude oil degradation many enzymes including alkane hydroxylase, alcohol dehydrogenase, and lipase are playing a key role in the biodegradation processes. The role of enriched bacterial biofilm on biocorrosion reactions are monitored by weight loss studies and electrochemical analysis. Weight loss study revealed that the biotic system has vigorous corrosion attacks compared to the abiotic system. Both AC-Impedance and Tafel analysis confirmed that the nature of the corrosion reaction take place in the biotic system. Very less charge transfer resistance and higher corrosion current are observed in the biotic system than in the abiotic system. Scanning electron microscope confirms that the dense biofilm formation favoured the pitting type of corrosion. X-ray diffraction analysis confirms that the metal oxides formed in the corrosion systems (biotic). From the metagenomic analysis of the V3–V4 region revealed that presence of diverse bacterial communities in the biofilm, and most of them are uncultured/unknown. Among the known genus, Bacillus, Halomonas, etc are dominant in the enriched bacterial biofilm sample. From this study, we conclude that the uncultured bacterial strains are found to be playing a key role in the pitting type of corrosion and they can utilize crude oil hydrocarbons, which make them succeeded in extreme oil reservoir environments.

As ubiquitous, persistent organic pollutants, polycyclic aromatic hydrocarbons (PAHs) have adverse impacts on human health. Phenanthrene (Phe) is one of the most abundant PAHs in the environment. However, the long-term effects of exposure to environmental level of Phe on the kidneys and the potential mechanisms are unclear. T helper (Th) cells, a subtype of CD4⁺ T cells that play a central role in the renal immune microenvironment. In this study, male mice were chronically exposed to 5, 50, and 500 ng/kg bw Phe every other day for total 210 days. Those results indicated that environmental Phe exposure caused kidney hypertrophy, injury and fibrosis in the mice. Chronic, long-term environmental level of Phe exposure did not significantly alter the innate immune response but induced adaptive immune response changes (Th1/Th2 related cytokines release), causing a type 1 immune response in the 5 ng/kg bw Phe group and a type 2 immune response in the high dose groups (50 and 500 ng/kg bw). This study provides novel insights into the roles of adaptive immune response in long-term PAH exposure-induced chronic kidney injury and fibrosis, which is beneficial for further understanding the potential health hazards of PAHs and providing new avenues for immune intervention strategies to alleviate PAHs toxicity.

Seabirds are widely used as indicators of marine pollution, including mercury (Hg), because they track contaminant levels across space and time. However, many seabirds are migratory, and it is difficult to understand the timing and location of their Hg accumulation. Seabirds may obtain Hg thousands of kilometers away, during their non-breeding period, and deposit that Hg into their terrestrial breeding colonies. We predicted that Hg concentration in rectrices reflects exposure during the previous breeding season, in body feathers reflects non-breeding exposure, and in blood collected during breeding reflects exposure during current breeding. To test this hypothesis, we measured total Hg concentration in these three tissues, which reflect different timepoints during the annual cycle of rhinoceros auklets (Cerorhinca monocerata) breeding on both sides of the North Pacific (Middleton Island in Alaska and Teuri Island in Hokkaido), and tracked their wintering movement patterns with biologging devices. We (i) identify the wintering patterns of both populations, (ii) examine Hg levels in different tissues representing exposure at different time periods, (iii) test how environmental Hg exposure during the non-breeding season affects bird contamination, and (iv) assess whether variation in Hg levels during the non-breeding season influences levels accumulated in terrestrial plants. Individuals from both populations followed a figure-eight looping migration pattern. We confirm the existence of a pathway from environmental Hg to plant roots via avian tissues, as Hg concentrations were higher in plants within the auklet colonies than at control sites. Hg concentrations of breast feathers were higher in Alaskan than in Japanese auklets, but Hg concentrations in rectrices and blood were similar. Moreover, we found evidence that tissues with different turnover rates could record local anthropogenic Hg emission rates of areas visited during winter. In conclusion, Hg was transported across thousands of kilometers by seabirds and transferred to local plants.

Understanding the distribution and persistence of the fumigant dimethyl disulfide (DMDS) under different soil conditions would contribute to a more environmentally sustainable use of this gas. We determined the effects of soil type, soil moisture content and soil organic amendment rate on DMDS distribution and persistency using soil columns in the laboratory. The peak concentrations of DMDS at 60 cm soil depth in sandy loam soil, black soil and red loam soil were 1.9 μg cm⁻³, 0.77 μg cm⁻³, 0.22 μg cm⁻³, respectively. The total soil residues of DMDS in sandy loam soil, black soil and red loam soil were 0.4, 1.3 and 1.3%, respectively. The peak concentrations of DMDS at 60 cm soil depth and the total soil residues of DMDS applied decreased from 3.2 μg cm⁻³ to 0.9 μg cm⁻³ and 3.3 to 0.5% when soil moisture content increased from 6 to 18%, respectively. Incremental increases (0–5%) in organic amendment rates decreased DMDS distribution through the soils and increased soil residues. Wait periods were required of 7, 21 and 21 days after polyethylene (PE) film was removed to reduce residues sufficiently for cucumber seed germination in sandy loam soil, black soil and red loam soil with 12% moisture content and 0% organic amendment rate, respectively. However, no wait period was required for successful cucumber seed germination in sandy loam soils (Beijing) with 6, 12 or 18% moisture content or organic amendment rates of 1 or 5%, respectively, but in commercial practice 7 days delay would be prudent. Our results indicated that soil type, soil moisture content and organic amendment rates significantly affected DMDS distribution, persistency and residues in soil. Those factors should be taken into consideration by farmers when determining the appropriate dose of DMDS that will control soil pests and diseases in commercially-produced crops.