Advancements, Challenges, and Future Directions in Aquatic Life Criteria Research in China

Aquatic life criteria (ALC) serve as the scientific foundation for establishing water quality standards, and in China, significant strides have been made in the development of freshwater ALC. This comprehensive review traces the evolution of China's WQC, focusing on the methodological advancements and challenges in priority pollutants selection, test organism screening, and standardized ecotoxicity testing protocols. It also provides a critical evaluation of quality assurance measures, data validation techniques, and minimum data requirements essential for ALC assessments. The paper highlights China's technical guidelines for deriving ALC, and reviews the published values for typical pollutants, assessing their impact on environmental quality standards. Emerging trends and future research avenues are discussed, including the incorporation of molecular toxicology data and the development of predictive models for pollutant toxicity. The review concludes by advocating for a tiered WQC system that accommodates China's diverse ecological regions, thereby offering a robust scientific basis for enhanced water quality management.

Simultaneous Dispersive Liquid-Liquid Microextraction and Determination of Different Polycyclic Aromatic Hydrocarbons in Surface Water

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of water, and their determination at trace levels in the aquatic ecosystems is essential. In this work, an ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) procedure was suggested utilizing a binary dispersive agent for recovery of different molecular weight polycyclic aromatic hydrocarbons (PAHs) from waters. The detection was carried out by gas chromatography-mass spectrometry (GC-MS) as well as high-performance liquid chromatography with fluorescence and diode-array detection (HPLC-FD/PDA). The method was optimized for the extraction of analytes with respect to the mixture composition, ratios of components, ultrasonication time and centrifugation parameters. The analytical schemes for PAHs extraction from water samples using different ratios of extraction and dispersive solvents are reported. The mixture consisting of chloroform and methanol was applied for the extraction of PAHs containing two or three fused aromatic rings; the mixture of chloroform and acetonitrile is suitable for PAHs containing more than four aromatic rings. The mixture of chloroform:acetone + acetonitrile was applied in the universal scheme and allowed for the simultaneous extraction of 20 PAHs with different structures. The developed sample preparation schemes were combined with GC-MS and HPLC-FD/PDA, which allowed us to determine the analytes at low concentrations (from 0.0002 µg/L) with the recoveries exceeding 80% and relative standard deviations of about 8%. The developed methods for the determination of 20 PAHs were applied to the analysis of water samples from the Karasun Lake (Krasnodar), Azov Sea (Temryuk) and Black Sea (Sochi).

Trace-Level Determination of Polycyclic Aromatic Hydrocarbons in Dairy Products Available in Spanish Supermarkets by Semi-Automated Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry Detection

Polycyclic aromatic hydrocarbons (PAHs) have been classified as priority pollutants by the U.S. Environmental Protection Agency (EPA) and the European Commission on the grounds of their carcinogenic, mutagenic and teratogenic properties. Because of their ubiquity in industrial processes and the environment, PAHs can reach milk and dairy products and, eventually, humans. In this work, a new method was developed to detect and quantify sixteen of the EPA’s priority PAHs in commercial milk and dairy products. The method involves liquid−liquid extraction (LLE) followed by semi-automated solid-phase extraction (SPE) to clean up and preconcentrate the analytes prior their detection and quantification by gas chromatography−mass spectrometry (GC−MS). The proposed method provided high precision (relative standard deviation < 11.5%), recoveries of 80−107% and low detection limits (1−200 ng/kg). The method was applied to analyze 30 dairy products, the majority of which contained some PAH at concentrations from 7.1 to 1900 ng/kg. The most-detected analytes were the lighter PAHs (naphthalene, acenaphthylene, fluorene and phenanthrene). None of the samples, however, contained more than four PAHs.

[Screening of Priority Pollutants and Risk Assessment for Surface Water from Shengjin Lake]

Shengjin Lake, which serves as an important National Nature Reserve, is suffering from chemical pollution due to rapid industrial and agricultural development in the circumjacent basin. Therefore, 168 anthropogenic toxic chemicals were determined to examine their spatial distribution and identify priority pollutants using a ranking system based on occurrence(O), persistence(P), bioaccumulation(B), ecological risk(E), and human health risk(H). Ecosystem and human health risks were also assessed. The spatial distribution of pollutants indicated that higher concentrations occur in the upper lake area compared to the middle and lower lake areas because of Jiang Dam. According to the derived priority pollutant list, phthalate esters(PAEs), organochlorine pesticides(OCPs), and heavy metals(HMs) are high-priority pollutants; polychlorinated biphenyls(PCBs), polycyclic aromatic hydrocarbons(PAHs), and volatile organic compounds(VOCs) are medium-priority pollutants; and antibiotics(ANTs) are low-priority pollutants. The ecology risk quotient(RQ) of the high-priority pollutants ranged from 4.3 to 15.9, indicating severe ecology risk to the aquatic organism, and higher risks were found in the upper lake areas. Additionally, the human health risk assessment revealed negligible carcinogenic risks associated with high-priority pollutants. The comprehensive ranking system established in this study can be applied to other lake basins by altering the measured concentrations to screen for priority pollutants, offering a scientific foundation for identifying priority control pollutants for watershed management.

An improved method for assessing environmental impacts caused by chemical pollutants: A case study in textiles production

The use of chemicals in the textile industry has been widely investigated. This study used an improved method with the USEtox model to assess the environmental impacts of chemical pollutants discharged by the textile industry. The environmental impacts attributed to the discharged chemical pollutants were ranked using a quantity analysis method and a toxicity analysis method. The rankings of the two methods were compared by calculating Spearman's correlation coefficients and outliers. The results showed that the human health and ecological hazards potential were mainly caused by heavy metals. The rankings of the environmental impacts calculated with the quantity analysis method were different from those calculated with the toxicity analysis method. Cadmium, hexachlorobenzene and mercury caused severe human and ecological hazards with a small volume of emissions. Zinc and hexavalent chromium were highly toxic chemical pollutants, which could cause severe human health and ecological hazards potential. These five kinds of chemical pollutants should be preferentially controlled to mitigate the environmental impacts caused by chemical pollutants discharged from the textile industry.

Removal of Endocrine Disrupting Chemicals from Water: Adsorption of Bisphenol-A by Biobased Hydrophobic Functionalized Cellulose

The aim of this study is to examine the efficiency of biobased Spanish broom (SB) surface modified cellulose fibers to remove bisphenol A (BPA), a well-known endocrine disruptor, from water. Spanish brooms are flowering plants, which are native and abundant to Mediterranean regions. The functionalized fibers (FF) were found to have the best adsorption efficiency at pH 5, due to the optimal hydrophobic interaction between the FF fiber and BPA. Adsorption kinetics of BPA was found to fit well a pseudo-second order reaction. Equilibrium isotherm data were fitted by Langmuir and Freundlich models. A very fast and simple regeneration method was developed and it was observed that adsorption capacity of the fibers was kept almost unchanged after 3 consecutive uses. Bottled water and synthetic wastewater were also tested to assess the efficiency of the process under more realistic water and wastewater treatment conditions. It was found that BPA removal was slightly decreased from 77% in ultrapure water to 64% in synthetic wastewater matrix, indicating that FF has a high selectivity toward BPA, even in the presence of other organic compounds. Overall, it was observed that SB-modified fibers can be a new promising green biotechnology for water purification.

Sorption of organic pollutants frequently detected in stormwater: evaluation of five potential sorbents

Adsorption filtration is one of the most promising techniques for removal of dissolved, colloidal and particulate pollutants from stormwater. The aim of this study was to compare the capacity of five filter materials - cellulose, chitosan, chitosan-covered bark, pine bark and polypropylene/polyethylene (PP/PE) fibres - to sorb organic pollutants frequently detected in stormwater, including polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates. In batch tests, synthetic stormwater spiked with a mixture of the organic compounds was contacted with the materials for up to 24 h. The compounds were then liquid-liquid extracted and analysed using GC-MS. Cellulose and chitosan showed very low sorption capacity for the organic contaminants, whereas >70% of the initial concentration of most tested compounds was removed using PP/PE fibres, and >80% with pine bark and chitosan-covered bark. The highest adsorption capacity was found for PAHs (up to 44 µg/g) using PP/PE fibres and bark. For all tested compounds, maximum sorption was approached within 30 min using these materials.

[Ozone Formation Potential and Priority Species of VOCs in an Industrial Park]

Ground-level ozone (O₃) pollution is a serious problem in major cities in China. The control of its precursors, volatile organic compounds (VOCs), is a key to limiting ozone production. The ozone formation potential of VOCs in an industrial park in Tianjin was studied by collecting gas samples at the factory boundaries of six representative enterprises. The PTR-TOF-MS was used to analyze VOCs quantitatively. The VOCs/NO_x ratio was used to determine the control strategies. The priority VOCs were selected based on the entropy method. Our results indicated that, the ozone formation potential concentration of enterprise F was the highest with the concentration of 0.4233 mg·m^-3 using the propylene-equivalent concentration (PEC) scale; the highest concentration was obtained at enterprise C with 1.5733 mg·m^-3 using maximum incremental reactivity(MIR) scale. The result of PEC scale is closer to the O₃ concentration, which is applicable to the study of ozone generation in this industrial park. Ozone production is sensitive to both VOCs and NO_x in this industrial park, joint control should be considered. Alkanes contributed most to ozone formation, followed by alkenes & alkynes, alcohols, and aromatics. The prior VOC species that need to be controlled include n-heptane and its isomers, n-nonane, n-octane and its isomers, undecane, pentane, n-decane, and methanol.

Fertirrigation with sugarcane vinasse: Foreseeing potential impacts on soil and water resources through vinasse characterization

This paper reports the characterization of the polluting potential of sugarcane vinasse, the main wastewater from ethanol production. Compositional data from vinasse samples collected from sugarcane biorefineries were used to predict negative effects on the soil, water resources and crops potentially associated with fertirrigation, the primary final destination of vinasse in Brazil. High risks of soil salinization were associated with the land disposal of vinasse, as evidenced by the high levels of total dissolved solids (TDS; >4,000 mg L^-1) and electrical conductivity (>6.7 dS m^-1). The high TDS levels coupled with the high biodegradable organic content of vinasse (>14 g L^-1) also favor organic overloading events, leading to local anaerobiosis conditions. Conversely, soil sodification should not be observed in areas fertirrigated with sugarcane vinasse, given the low Na concentrations (<66 mg L^-1) relative to Mg (>145.1 mg L^-1) and Ca (>458.4 mg L^-1) levels. Priority pollutants (Cu, Cr, Ni, Pb and Zn) and phytotoxic elements (Al and Fe) were also found in the analyzed samples; however, relevant environmental impacts should not be associated with these particular constituents. Overall, the relatively simple methodology used herein could efficiently replace massive field data collection to provide a basic understanding of the fate of vinasse in the environment in order to highlight the priority points to be considered in the management of this effluent. In summary, the prompt implementation of treatment plants in distilleries, in addition to a continuous and broad compositional characterization of vinasse, is essential to guarantee its adequate reuse.