In this study, the occurrence, distribution, and ecological risk of 40 commonly used antibiotics, including 15 sulfonamides (SAs), 9 fluoroquinolones (FQs), 7 macrolides (MCs), 3 tetracyclines (TCs), 2 chloramphenicols (CAPs), and 4 other categories, in the aquatic environment of the karst plateau wetland Caohai of the Yangtze River basin in southwestern China are reported. In total, 27 antibiotics were detected, with the detection rate ranging from 5% to 100%. The total concentration at each site ranged from 21.8 ng/L to 954 ng/L, with the average concentration being 189 ng/L. FQs and MCs were the most predominant categories, contributing 29.3% and 25.0% of the total antibiotic burden. The five most commonly detected antibiotics were ciprofloxacin (CIP), oxytetracycline (OTC), acetyl sulfamethoxazole (ASMZ), norfloxacin (NOR), and florfenicol (FF). The spatial distribution of the total concentration at each site demonstrated a decreasing trend from the southeastern area upstream adjoining the main counties to the northwestern area downstream, indicating that human activities have a great impact. Meanwhile, the natural attenuation rates of different types of antibiotics in the direction of flow ranged from 17.6% to 100%, which implied the natural purification potential of the wetland for antibiotics. The cluster analysis results indicated that domestic sewage and wastewater from agriculture and animal husbandry were the main sources of contamination in the surrounding wetland. Risk quotients (RQs) assessment showed that most of the individuals were at low to medium risk and that the adverse risks posed by mixtures of antibiotics were higher than those posed by the individual antibiotics.

Microplastics (MPs) have become a worldwide concern due to their potential impacts on ecological systems. This study investigated the MPs in sediments of Yushan River, an urban river tributary of the Yangtze River, China. MPs were observed to be present in the sediments with 3.5–53 mg·kg⁻¹ or 30–70 items·kg⁻¹. The average abundance of 44 items kg⁻¹ found in this study was relatively lower compared to other study reports in China. Fourier Infrared Spectrometer analysis shows polyethylene was the major polymer found from the samples, followed by polypropylene and polyester. According to their shapes, MPs had number fractions of 31.8% for fiber, 64.8% for film and 3.4% for fragment, which is coupled with transparent type as the majority (58.0% of the total number) followed by green (14.8%), blue (10.2%) and white (9.1%). As the dominant, transparent film MPs were derived mainly from polyethylene bags and polypropylene woven sacks. Moreover, due to aging processes, the surfaces of MPs were rough and uneven, enhancing their interactions with environmental substances like clay, silicon and iron. Principal Component Analysis indicates that the source of MPs in sediment was the same as that of specific contaminants in water.

The status of organic pollution in groundwater in eastern China along the Grand Canal from Hangzhou to Beijing was evaluated. Forty-two semi-volatile organic contaminants were analyzed, including 16 polycyclic aromatic hydrocarbons (PAHs), seven polychlorinated biphenyls (PCBs), 12 organochlorine pesticides (OCPs) and seven organophosphorus pesticides (OPPs). Among the detected contaminants, PAHs were the most widespread compounds. One PCB and six OCPs were detected in the groundwater samples, but none of the target OPPs was detected. The total concentration of the 16 PAHs ranged from 0.21 to 1006 ng/L, among which phenanthrene (271 ng/L) and fluoranthene (233 ng/L) were present at very high concentrations and naphthalene (32 positive detections in 50 samples) and fluorene (28 detections in 50 samples) were the most frequently detected. Benzo[a]pyrene equivalents indicated a high environmental risk related to PAHs in a few groundwater samples. To identify the possible sources of PAHs, three concentration ratios, low molecular weight PAHs/high molecular weight PAHs, anthracene/(anthracene + phenanthrene) and fluoranthene/(fluoranthene + pyrene), were determined, that indicated that the PAHs mainly originated from mixed sources: pyrolytic and petrogenic sources with different ratios at different sites.

The identification and quantification of organic compounds in leaching basin soil is important for the evaluation of soil pollution. In this study, a non-target screening strategy and a quantitative analytical method were developed based on the accelerated solvent extraction method followed by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry. First, a screening method for potential risk compounds in soil samples was established, and the major compounds were screened under the conditions such as matching similarity, signal-to-noise ratio, and relative area ratio. Second, a quantitative method was further developed by internal calibration curves for 50 main organic pollutants in the soil samples, including 27 polycyclic aromatic hydrocarbons and their derivatives (PAHs), 10 phthalic acid esters, eight phenolic compounds, and five benzene derivatives. The quantitative procedure exhibited good selectivity, accuracy, precision, low limits of detection (0.03–1.02 ng/g), and quantification (0.1–3.0 ng/g) for all target compounds. Finally, the proposed strategy was applied to the soil samples that were collected from a leaching basin and polluted by electroplating wastewater. Abundant PAHs and phenolic compounds were detected in the topsoil sample, which were mainly released from the electroplating wastewater. The application of this multi-dimensional strategy in leaching basin soil samples can also be used for the assessment of organic pollution in other complex soil samples.