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Animal manure contains various organic contaminants such as steroids. The fate of these steroids during composting is still unknown. Here we investigated the fate of androgens, progestogens, and glucocorticoids during animal manure composting and evaluated their residues in compost-applied soils. The results showed the presence of 16 steroid hormones in the initial compost with concentrations ranging from 3.26 ng/g dw (Cortisol) to 2520 ng/g dw (5α-dihydroprogesterone). The concentrations of almost all detected hormones increased on the 2nd day of composting, and some of them increased several or even dozens of times. Steroids such as hydroxyprogesterone caproate, melengestrol acetate, and methyltestosterone were not found in the initial compost but later detected during the composting process. After 171 days of composting, only 40.4% of detected steroid hormones was removed, and the total concentration of detected steroids was still as high as 3210 ng/g dw. The removal rates of some target compounds were negative, especially for the natural androgens androsta-1,4-diene-3,17-dione and the synthetic androgen 17β-boldenone whose concentrations significantly increased by the end of composting, indicating conversion from their conjugates or transformation from other steroids. The steroid hormones were mainly eliminated in the first three weeks; prolonged composting time did not obviously promote further removal. The variations in steroid concentration were related to the changes in compost properties such as pH and temperature during the composting process. The dissipation of steroid hormones was also linked to the changes of microbial communities in the compost to some extent. Twelve steroids were detected in the compost-treated soils of a kailyard, while 26 steroid hormones were detected in the roots of Chinese cabbages grown on the soil. The results suggest that the application of manure compost product can lead to soil contamination and plant uptake.

Microplastics (MPs) are ubiquitous in various environment compartments, including food. Here, we collected research reports of MPs in food published during 2010–2020, and summarized the analytical methods developed and utilized by researchers (e.g., digestion, separation and identification, as well as related QA/QC measures implemented), the occurrence, and the characteristics of MPs in six kinds of food. The potential effects on biota from exposure to MPs were also reviewed. The results showed that most researchers digested food samples using chemical solutions such as HNO3, H2O2, KOH, or NaOH. FT-IR and Raman spectroscopy were the main technique for identifying MPs, and microscopes were used to count MP particles. The abundances MPs were in the ranges of 0–5860, 2.00–1100, 0–698, 4.00–18.7, 0–5.68 × 104 and 900–3000 particles/kg in beverages, condiments, honey, meat, seafood and vegetables, respectively. The “maximum” annual human intake of MPs from these foods is approximately 1.42 × 105–1.54 × 105 particles/capita, equivalent to the consumption of 50 plastic bags (size: 0.04 mm × 250 mm × 400 mm, density: 0.98 g/cm3) each year. Blue-colored and fiber-shaped MP particles were the most commonly observed in food, predominated by PA, PE, PES, PET and PP types. Toxicity studies indicated that MPs, additives of MPs and adsorbents or microorganisms on the surfaces of MPs were all somewhat toxic to cells or biota. Exposure to MPs may induce oxidative stress, inflammation, neurotoxicity, and reproductive toxicity, and change the structure of intestinal microflora in cells or biota. Therefore, we call for more investigation into the residual, excretion and bioavailability of MPs or related absorbents/additives in biota and humans.

Anthropogenic activities have inevitably impacted riverine ecosystems, yet their overall contribution to the assemblage of bacterial communities at a large river basin scale remains unclear. In this study, 16S amplicon sequencing was implemented to investigate the bacterial ecosystems in paired water and sediment of North River and West River basins in South China., which contains various anthropogenic environments (e.g., rural/urban area, mining area and livestock area). Subsequently, the links between bacterial community and various types of emerging pollutants in river water were analyzed. The results show that the bacterial assemblage of water and sediment had their own properties that the bacterial community of sediment were mainly affected by seasonal properties, while the bacterial community of water were affected by both seasons and anthropogenic activities. Therein, the aquatic bacterial compositions and abundances were driven by changes in temperature, dissolved oxygen and the emerging pollutants. The dominant phyla Proteobacteria and Firmicutes exhibited adaptability to the mining-affected regions, therein many clades (e.g., Beijerinckiaceae, Acetobacteraceae and Mycobacteriaceae) were also prevalent in the livestock-affected and densely-populated regions. In addition, these two phyla presented associations to the antibiotic resistance in water. The levels of antibiotics, relative antibiotic resistance gens (ARGs) and non-antibiotic pharmaceuticals (NAPs) were closely related to bacterial community composition, diversity and functional diversity, indicating their drive in shifting bacterial communities. Collectively, this work provides a basis for understanding the contribution of anthropogenic activities in shifting bacterial community at a large river basin scale. Further, the results provide new insights for expansion of ecological assessment.

Barbecue (BBQ) is one of the most popular cooking activities with charcoal worldwide and produces abundant polycyclic aromatic hydrocarbons (PAHs) and particulate matter. Size distribution and clothing-air partitioning of particle-bound PAHs are significant for assessing potential health hazards to humans due to exposure to BBQ fumes, but have not been examined adequately. To address this issue, particle and gaseous samples were collected at 2-m and 10-m distances from a cluster of four BBQ stoves. Personal samplers and cotton clothes were carried by volunteers sitting near the BBQ stoves. Particle-bound PAHs (especially 4–6 rings) derived from BBQ fumes were mostly affiliated with fine particles in the size range of 0.18–1.8 μm. High molecular-weight PAHs were mostly unimodal peaking in fine particles and consequently had small geometric mean diameters and standard deviations. Source diagnostics indicated that particle-bound PAHs in BBQ fumes were generated primarily by combustion of charcoal, fat content in food, and oil. The influences of BBQ fumes on the occurrence of particle-bound PAHs decreased with increasing distance from BBQ stoves, due to increased impacts of ambient sources, especially by petrogenic sources and to a lesser extent by wind speed and direction. Octanol-air and clothing-air partition coefficients of PAHs obtained from personal air samples were significantly correlated to each other. High molecular-weight PAHs had higher area-normalized clothing-air partition coefficients in cotton clothes, i.e., cotton fabrics may be a significant reservoir of higher molecular-weight PAHs. Capsule Particle-bound PAHs from barbecue fumes are generated largely from charcoal combustion and food-charred emissions and mainly affiliated with fine particles.

Soil antibiotic resistance due to animal manure application is of great concern in recent years. Little is known about the fate of antibiotic resistance genes (ARGs) in agricultural soils associated with long-term manure application. Here we used soil microcosms to investigate the dissipation of ARGs and the change of bacterial community in agricultural soil originated from a vegetable field which had received 24 years' swine manure application. Soil microcosms were conducted at different soil moistures and with or without biochar over a testing period of two years in lab. Results showed that continuous manure application induced an accumulation of ARGs in soil, wherein the dissipation of ARGs differed from those in non-manure amended soil. ARGs persisted in soils at least two years, although their abundance declined gradually. Meanwhile, soil moisture and biochar had significant impact on the fate of ARGs. ARGs dissipated faster in soil with higher moisture. Biochar amendment contributed to the maintenance of bacterial diversity. Within the two years of simulation experiment, biochar enhanced soil ARG retention as they dissipated slowly in the soil amended with biochar. Succession of microbial community may have sustained the transfer and resilience of ARGs. This study provides insight into the dissipation of antibiotic resistance genes in manure-applied agricultural soil.

Mining activities are known to generate a large amount of mine tailings and acid mine drainage which contain varieties of heavy metals. Heavy metals play an important role in co-selection for bacterial antibiotic resistance. However, the characteristics of antibiotic resistance genes (ARGs) in mining-affected water environments are still unclear. Here we investigated the pollution of metals, profiles of ARGs, mobile genetic elements (MGEs) and microbial community in mining-affected surface water and groundwater. The results showed that in the tested water samples, the concentrations of Zn and Mn were the highest, and Ni was the lowest. Higher abundances of ARGs with great proportion of sulfonamides, chloramphenicols and tetracyclines resistance genes were found in mining-affected water when compared with those without mining activities. Additionally, there were positive correlations between heavy metals (especially Ni, Zn and Mn) and these ARGs. Linear regression analysis suggested that MGEs were positively correlated with ARGs. In addition, total phosphorus was correlated with ARGs (p

The production and usage of polybrominated diphenyl ethers (PBDEs) has been gradually phased out and the application of alternative halogenated flame retardants (AHFRs) has been continuously increased. It is essential to understand how the evolving flame retardants industry has affected the occurrence and flux of legacy and alternative flame retardants so that better pollution control measures can be made accordingly. Air, rainwater, inflowing river water, pond water, pond sediment, fish feed, and fish collected from freshwater cultured fish ponds (FWCFPs) within the Pearl River Delta, South China were analyzed for PBDEs and AHFRs. Concentrations of AHFRs in air (range; median: 7.8–870; 210 pg m−3), rainwater (0.88–65; 4.8 ng L−1), and sediment (19–120; 54 ng g−1 dry weight (d.w.)) were one order of magnitude higher than those of PBDEs in air (12–98; 21 pg m−3), rainwater (0.18–15; 0.70 ng L−1), and sediment (1.5–9.6, 2.9 ng g−1 d.w.) (t-test; p

Rapid industrialization, urbanization, and population growth have led to the common occurrence of black-stinking urban rivers. Assessing regional anthropogenic influences is beneficial to develop effective remediation strategies. This study comprehensively investigated the occurrence and fate of linear alkylbenzenes (LABs) as molecular markers of anthropogenic influences in three media (filtered water, suspended particulate matter (SPM), and sediment) in a highly urbanized river (Baihaimian River) in Guangzhou, South China. The concentrations of LABs ranged from 41 to 215 ng/L in the dissolved phase, from 7122 to 46,640 ng/g dry weight in the SPM phase, and from 73 to 3650 ng/g dry weight in surface sediments (0–10 cm depth). The spatial distribution of LABs was probably affected by the surrounding environment, river flux, and sediment properties. No biotransformation of LABs in water samples and a slight biotransformation in sediments were observed. Significant correlations were found between total nitrogen, ammonia nitrogen, and LABs in river water, indicating the same domestic wastewater sources. The positive correlation between total organic carbon (TOC) and LABs in sediments suggested that TOC worked as the controlling factor for the redistribution of LABs and that local sewage discharge was the dominant TOC input. The total mass inventory of LABs in sediment in Baihaimian River was 21 kg. The total mass of LABs released into Baihaimian River was 183 kg per year, among them, 63% was discharged into the adjacent Liuxi River.

This study aims to investigate the removal of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale constructed wetlands (CWs) with different flow configurations or plant species including the constructed wetland with or without plant. Six mesocosm-scale CWs with three flow types (surface flow, horizontal subsurface flow and vertical subsurface flow) and two plant species (Thaliadealbata Fraser and Iris tectorum Maxim) were set up in the outdoor. 8 antibiotics including erythromycin-H2O (ETM-H2O), monensin (MON), clarithromycin (CTM), leucomycin (LCM), sulfamethoxazole (SMX), trimethoprim (TMP), sulfamethazine (SMZ) and sulfapyridine (SPD) and 12 genes including three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), two chloramphenicol resistance genes (cmlA and floR) and 16S rRNA (bacteria) were determined in different matrices (water, particle, substrate and plant phases) from the mesocosm-scale systems. The aqueous removal efficiencies of total antibiotics ranged from 75.8 to 98.6%, while those of total ARGs varied between 63.9 and 84.0% by the mesocosm-scale CWs. The presence of plants was beneficial to the removal of pollutants, and the subsurface flow CWs had higher pollutant removal than the surface flow CWs, especially for antibiotics. According to the mass balance analysis, the masses of all detected antibiotics during the operation period were 247,000, 4920-10,600, 0.05-0.41 and 3500-60,000μg in influent, substrate, plant and effluent of the mesocosm-scale CWs. In the CWs, biodegradation, substrate adsorption and plant uptake all played certain roles in reducing the loadings of nutrients, antibiotics and ARGs, but biodegradation was the most important process in the removal of these pollutants.

Antibiotics and current-use pesticides are ubiquitous in the environment. It is important to figure out their spatial distribution under the influences of anthropogenic activities and transport from rivers to coastal oceans. To address this knowledge gap, the present study conducted quarterly sampling in eight main runoff outlets of the Pearl River, South China, and obtained total concentrations of antibiotics and current-use pesticides at 24–296 ng L−1. Higher total concentrations of these chemicals occurred in summer, attributed to seasonal consumption patterns and washout by rainfalls, respectively. The spatial distributions of target analytes were not significantly different between the eastern and western outlets with high and moderate urbanization levels, respectively. Approximately 16.4, 17.7, and 12.5 tons of antibiotics, organophosphorus pesticides, and neonicotinoids were discharged annually from the outlets to the South China Sea. These results suggested that usage amount and hydrology exhibited positive effects on the riverine inputs of the target chemicals. In addition, most target chemicals exhibited low risks to green algae, but erythromycin and parathion posed high ecological risks to aquatic organism (Daphnid and fish).

Perfluoroalkyl substances (PFASs) are of particular environmental concern due to their environmental persistence and potential toxicity. Phytoremediation may be used to remove PFASs from wastewater. Here we investigated the uptake mechanism, subcellular distribution, and uptake process of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate acid (PFOS) in the wetland plant Alisma orientale by using a series of hydroponic experiments. Active uptake facilitated by water transporters and anion channels was involved in the uptake of PFASs by plant roots. PFOA and PFOS were mainly distributed in the water-soluble fraction (46.2-70.8%) and in cell walls (45.6-58.4%), respectively. The uptake process was proposed as follows: PFOS and PFOA were first distributed in the soluble fraction; a proportion of PFOS and PFOA were adsorbed gradually by the cell wall, and a proportion of PFOS and PFOA in the cell wall passed through the cell wall and plasmalemma and bind with organelles. PFOS and PFOA were transported from the external solution to the vascular bundle of the plant root through both symplastic and apoplastic routes.

The aim of this study was to investigate the contamination profiles of tetracycline, sulfonamide, and macrolide resistance genes, as well as integrons in sediments of Dongjiang River basin of South China by real time quantitative polymerase chain reaction. sul2 was the most abundant resistance gene, with the average concentration of 6.97×10(8) copies/g and 1.00×10(8) copies/g in the dry and wet seasons, respectively, followed by ermF, sul3, sul1, intI1, tetA, ermB, tetX, tetM, tetQ, tetO, tetW, tetS, ermC, and tetB. The abundance of intI2 gene was the lowest in the sediment samples. Significant correlations existed between the ARGs and sediment properties as well as metals (Cu and Zn) and corresponding antibiotic classes, suggesting that the contamination of ARGs is related to chemical pollution of the sediments in the river basin. Principal component analysis showed distinct groupings of the sampling sites, reflecting that human activities are the key player in the dissemination of ARGs in the catchment environment.