A stable and efficient Fe₂O₃/expanded perlite (Fe₂O₃-Ep) composite catalyst was synthesized by a simple hydrothermal method for degradation of refractory contaminants in heterogeneous photo-Fenton system. X-ray diffraction and FT-IR analyses confirmed the presence of the Fe₂O₃ in the synthesized catalyst. The catalytic activity of the Fe₂O₃-Ep catalyst was evaluated by the degradation of rhodamine B (RhB, 5 mg/L) and metronidazole (MET, 5 mg/L) in the presence of H₂O₂ under visible light irradiation. The Fe₂O₃-Ep catalyst exhibited high efficiency for degradation of RhB at a wide pH range from 2 to 10 and showed excellent catalytic property for decomposition of MET as well. The degradation ratio of RhB was achieved 99%, and the removal ratio of COD was 62% within 90 min at the best experimental conditions (0.5 g/L of Fe₂O₃-Ep catalyst, 2 mL/L of H₂O₂). Furthermore, iron leaching of the Fe₂O₃-Ep catalyst during the catalytic degradation reaction was negligible and the catalyst still exhibited high catalytic activity and stability after five cycles. These results show that the catalyst can be used as a highly efficient heterogeneous photo-Fenton catalyst for the degradation of non-biodegradable refractory pollutants in water.

Soil texture and soil organic carbon (OC) influence the bacterial microenvironment and also control herbicide sorption. A field-scale exploratory study was conducted to investigate the potential interaction between soil texture parameters, herbicides, and soil bacterial richness and diversity. Glyphosate and bentazon were used to evaluate the herbicidal effect on bacterial community under different conditions created by clay and OC gradients in a loamy field. Metabarcoding by high-throughput sequencing of bacterial rDNA was used to estimate bacterial richness and diversity using OTUs, abundance-based coverage (ACE), Shannon diversity index, and phylogenetic diversity. In general, bacterial richness and diversity increased after bentazon application and decreased after glyphosate application. There was no significant effect for field locations with Dexter n (the ratio between clay and OC) values below 4.04 (the median of the values in the field study). The correlation coefficient (r) between bacterial richness and clay decreased after bentazon application, but increased after glyphosate application. Correlations between Dexter n and bacterial indices followed the same pattern, decreasing after bentazon application and increasing after glyphosate application. This indicated that the specific chemical nature of individual herbicides affected bacterial communities. This study reinforced the importance of including soil physical and chemical characteristics to explain the influence of pesticides on the variation in soil bacterial communities in agroecosystems.

Dairy cattle manure has been implicated as a major source of fecal contamination in non-point source agricultural runoff in watersheds. Four different dairy farms in central Texas, each utilizing a different dairy manure management practice, in the Leon River watershed were sampled for E. coli using EPA Method 1603, with a percentage of isolates genotyped and phylotyped using the Clermont quadruplex PCR method. E. coli concentration was reduced as manure moved through the management process with tiered management systems lowering concentration the most. E. coli genotypes showed no correlation with sampling season or management practice. The highest percentage of unique genotypes was observed in dairy 2, which consisted of a settling basin then lagoon. One genotype was seen across all dairies and composed 15% of all genotypes characterized. E. coli phylotypes showed no seasonal or management practice trend. B1 was the most common phylotype isolated from all dairies and time periods, which was expected. Potentially pathogenic phylotypes were rarely observed, which could indicate isolation from pathogenic E. coli introduction. Dairy manure management practices that separate solid from liquid waste reduced E. coli concentrations the most based on these results.

The incidence of Legionella and Acanthamoeba spp. was correlated to microbial indicator analysis and physico-chemical characteristics of rainwater harvested from catchment areas constructed from galvanized zinc, Chromadek®, and asbestos, respectively. Quantitative PCR (qPCR) analysis indicated that no significant difference (p > 0.05) in copy numbers of Legionella spp. and Acanthamoeba spp. was recorded in tank water samples collected from the respective roofing materials. However, significant positive Spearman (ρ) correlations were recorded between the occurrences of Legionella spp. gene copies vs. nitrites and nitrates (p = 0.05) in all tank water samples. Significant positive correlations were also established between Acanthamoeba spp. vs. barium (p = 0.03), magnesium (p = 0.02), sodium (p = 0.02), silicon (p = 0.05), arsenic (p = 0.03), and phosphate (p = 0.01), respectively. Additionally, while no significant correlations were observed between Legionella spp. vs. the indicator bacteria (p > 0.05), positive correlations were observed between Acanthamoeba spp. vs. total coliforms (p = 0.01) and Acanthamoeba spp. vs. Escherichia coli (p = 0.02), respectively. Results obtained in the current study thus indicate that the incidence of Acanthamoeba and Legionella spp. in harvested rainwater was not influenced by the roofing material utilized. Moreover, it is essential that the microbial quality of rainwater be assessed before this water source is implemented for potable and domestic uses as untreated harvested rainwater may lead to legionellosis and amoebae infections.

Bioretention systems are of immense importance as they serve as small “sponges” for cities, cutting stormwater runoff, removing pollution, and using precipitation resources. However, performance data for these facilities are generally lacking, particularly at the field scale. This study investigated the runoff quantity regulation and pollutant removal performance of bioswale and rain garden systems from 2014 to 2017. A performance assessment of these facilities demonstrated that anti-seepage rain garden, bioswale-A, and bioswale-B effectively retained inflow volumes by the filter media, reducing runoff volumes by 54.08, 98.25, and 77.65%, respectively, on average, with only two events of overflowing. According to the water quality data in 24 rainfall events, the main pollutant indexes for the new city include total nitrogen and chemical oxygen demand, and the median values for their respective effluent event median concentrations were 1.29 and 40.13 mg/L for anti-seepage rain garden and 1.68 and 74.00 mg/L for bioswale-B systems. The mean values of pollutant removal of the three bioretention systems, except for infiltration rain garden, were 39.8–59.73% (median = 54.32%), 61.06–72.66% (median = 73.47%), and 76.67%–88.16% (median = 80.64%). Meanwhile, outflow volume of water was found to be most influenced by inflow volumes for the bioswales and anti-seepage rain garden. Mass removals were higher than concentrations owing to water volume attenuation. Based on the data of monitored pollution loads, this study estimated the annual pollutant load removal as 75.45 and 90.7% for anti-seepage rain garden and bioswale-B according to the percent of monitoring rainfall depth in total annual precipitation. This study also established the target pollutant service life model on the basis of accumulated annual load and media adsorption capacity. The results of this study will contribute to a greater understanding of the treatment performance of bioretention systems, assisting in the design, operation, and maintenance of them.

Air pollution represents a significant fraction of the total mortality estimated by the World Health Organization (WHO) global burden of disease project (GBD). The present paper discusses the characteristics of trace gases (O₃, NO, NO₂, and CO) and particulate matter (PM₁₀ and PM₂.₅) in two Asian megacities, Delhi (India) and Beijing (China). A continuous measurement of trace gases and particulate matter are considered from 12 measuring sites in Beijing and 8 sites in Delhi. Over Beijing, the annual average of PM₂.₅, PM₁₀, O₃, NO₂, and CO is, respectively, 85.3, 112.8, 58.7, and 53.4 μg/m³ and 1.4 mg/m³, and, respectively, over Delhi 146.5, 264.3, 24.7,and 19.8 μg/m³ and 1.73 mg/m³. From the spatial variations of pollutants, the concentrations of particulate matter and trace gases are observed to be much higher in the urban areas compared to the suburban areas. The higher average concentrations of PM₁₀ and PM₂.₅ over Delhi and Beijing are observed during winter season compared with other seasons. The maximum diurnal variation of PM₁₀ concentration is observed during winter season over Beijing and Delhi. The comparison of trace gases shows that the O₃ concentrations during daytime are obviously higher compared with nighttime, and the highest diurnal variation of O₃ is observed during summer. The concentrations of CO are highest during winter season, and higher concentrations are observed during nighttime compared to daytime. The O₃ and CO show negative correlation over Beijing and Delhi. The negative correlation between O₃ and NO₂ is merely observed over Beijing, while CO and NO₂ concentrations, in contrast, show positive correlation over Beijing.

Advanced nitrogen (N)-removal onsite wastewater treatment systems (OWTS) are installed in coastal areas throughout the USA to reduce N loading to groundwater and marine waters. However, final effluent total nitrogen (TN) concentration from these systems is not always routinely monitored, making it difficult to determine the extent to which they contribute to N loads. We monitored the final effluent TN concentration of 42 advanced N-removal OWTS within the Greater Narragansett Bay Watershed, Rhode Island between March 2015 and August 2016. The compliance rate with the State of Rhode Island final effluent standard (TN ≤ 19 mg N/L) was 64.3, 70.6, and 75.0% for FAST, Advantex, and SeptiTech systems, respectively. The median (range) final effluent TN concentration (mg N/L) was 11.3 (0.1–41.6) for SeptiTech, 14.9 (0.6–61.6) for Advantex, and 17.1 (0.6–104.9) for FAST systems. Variation in final effluent TN concentration was not driven by temperature; TN concentrations plotted against effluent temperature values resulted in R ² values of 0.001 for FAST, 0.007 for Advantex, and 0.040 for SeptiTech systems. The median effluent TN concentration for all the systems in our study (16.7 mg N/L) was greater than reported for Barnstable County, MA systems (13.3 mg N/L), which are monitored quarterly. Depending on technology type, ammonium (NH₄⁺), nitrate (NO₃⁻), alkalinity, forward flow, biochemical oxygen demand (BOD), and effluent temperature best predicted effluent TN concentrations. Service providers made adjustments to seven underperforming systems, but TN was reduced to 19 mg N/L in only two of the seven systems. Advanced N-removal OWTS can reduce TN to meet regulations, and monitoring of these systems can enable service providers to proactively manage systems. However, improvement of performance may require recursive adjustments and long-term monitoring.

Two soil amendments, KH₂PO₄ and sodium tetraethylenepentamine–multi dithiocarbamate (TEPA/CSSNa), were applied to heavy metal-contaminated sites, and their corresponding stabilization effects were compared. Three kinds of procedures, namely, sequential extraction procedure (SEP), toxicity characteristic leaching procedure (TCLP), and diethylenetriaminepentaacetic acid (DTPA) extraction procedure, were adopted to examine the potential of using TEPA/CSSNa to stabilize Cd and Pb in polluted sites. Simplified bioaccessibility extraction test (SBET) was used to investigate the bioaccessibility of Cd and Pb. TCLP and DTPA results showed that TEPA/CSSNa was more efficient than KH₂PO₄ in reducing the mobility of Cd and Pb. SBET results indicated that the bioaccessibility of Cd and Pb decreased with increasing dose of TEPA/CSSNa. The mobility rates of Cd and Pb decreased to 0.26 and 0 %, respectively, when using 3 % TEPA/CSSNa. The exchangeable and carbonate fractions of Cd and Pb were gradually converted into organic matter–sulfate compounds. After 1 year, natural aging tests revealed that organic matter–sulfate fractions of Cd and Pb increased and the labile fractions (exchangeable and carbonate fractions) decreased in the treated soil.

In this study, an iron oxide-coated zeolite (IOCZ) nanocomposite was synthesized and used for the removal of U(VI) and As(III) from aqueous solutions using a batch system. Parameters such as various contact times, pH, competing ions (Cd²⁺, Co²⁺, and Cr³⁺), temperature, and initial concentrations of uranium(VI) and arsenic(III) were investigated. The experimental results were fitted to the Langmuir, Freundlich, and Dubinin–Radushkevich isotherms to obtain the characteristic parameters of each model. Results suggested that adsorption of U(VI) and As(III) by IOCZ was best modeled with the Freundlich isotherm. The kinetic experimental data fitted the pseudo second-order model better than the pseudo first-order model for both elements. Using the thermodynamic equilibrium constants obtained at different temperatures, various thermodynamic parameters, such as ΔG ᵒ, ΔH ᵒ, and ΔS ᵒ, were calculated. These parameters indicated that the process is spontaneous and exothermic in nature. It was noted that an increase in temperature resulted in a decrease of 8.5 and 27.5% for U and As removal, respectively. An increase in initial concentrations of U(VI) and As(III) from 10 to 100 mg L⁻¹ at pH 3 resulted in increased adsorption capacities (q ₑ) for both elements. The increases were from 1.247 to 20.10 mg g⁻¹ for U(VI) and from 3.115 to 54.18 mg g⁻¹ for As(V). The presence of competing ions such as Cd²⁺, Co²⁺, and Cr³⁺ enhanced the removal of As by 9.2% whereas the adsorption capacity of uranium decreased by 13.8%. This research demonstrated that IOCZ is a potential adsorbent for the removal of U(VI) and As(III) from aqueous solutions.

Bisphenol A (BPA), a well-known endocrine-disrupting chemical, is receiving increasing concerns regarding its adverse effects on the endocrine system in wildlife and humans. This study was designed to investigate BPA pollution in environmental media in plastics industry areas and to explore the relationship between BPA pollution and the characteristic of different plastics industry. A total of 66 river water samples, 6 aquatic animal samples, and 64 surface soil samples were collected from three cities with different characteristics of plastics industry in southeast China. BPA concentrations in river water (240–5680 ng L⁻¹), aquatic animals (116.13–477.42 ng g⁻¹), and surface soil (38.70–2960.86 ng g⁻¹) were highest in Yuyao City where the plastics industry mainly involved in the production of plastic raw materials. BPA concentrations in Taizhou City were modest and comparable to those reported elsewhere though Taizhou is characterized by its massive production of plastic products. BPA concentrations in Wenzhou City were the lowest where relatively low activities are involved in the plastics industry. Our data indicate that the plastics industry involved the use of BPA as an intermediate in production of raw plastics such as polycarbonate plastics and epoxy resins was the dominant cause of BPA pollution in the surrounding environments. Graphical Abstract Production of raw plastic is the dominant cause of BPA pollution in the environment