Health risks of typical benzene series and halocarbons (BSHs) in a densely populated area near a large-scale chemical industrial park were investigated. Ambient and indoor air and tap water samples were collected in summer and winter; and the concentration characteristics, sources, and exposure risks of typical BSH species, including five benzene series (benzene, toluene, ethylbenzene, o-xylene, m,p-xylene) and five halocarbons (dichloromethane, trichloromethane, trichloroethylene, tetrachloromethane, and tetrachloroethylene), were analysed. The total mean concentrations of BSHs were 53.32 μg m⁻³, 36.29 μg m⁻³, and 26.88 μg L⁻¹ in indoor air, ambient air, and tap water, respectively. Halocarbons dominated the total BSHs with concentrations relatively higher than those in many other industrial areas. Industrial solvent use, industrial processes, and vehicle exhaust emissions were the principal sources of BSHs in ambient air. The use of household products (e.g., detergents and pesticides) was the principal source of indoor BSHs. Inhalation is the primary human exposure route. Ingestion of drinking water was also an important exposure route but had less impact than inhalation. Lifetime non-cancer risks of individual and cumulative BSHs were below the threshold (HQ = 1), indicating no significant lifetime non-cancer risks in the study area. However, tetrachloromethane, benzene, trichloromethane, ethylbenzene, and trichloroethylene showed potential lifetime cancer risk. The cumulative lifetime cancer risks exceeded the tolerable benchmark (1 × 10⁻⁴), indicating a lifetime cancer risk of BSHs to residents near the chemical industry park. This study provides valuable information for the management of public health in chemical industrial parks.

Although hexachlorobutadiene (HCBD) has been listed as a persistent organic pollutant (POP) under Annexes A and C of the Stockholm Convention, information about its unintentional production and emission is still very limited. We estimated the historical unintentional production and emission of HCBD during 1992–2016 in China based on aggregated activity data and emission functions. The unintentional production of HCBD increased from 60.8 (95% confidence interval, 38.2–88.5) MT/yr to 2871.5 (2234.2–3530.0) MT/yr during 1992–2016, representing an average annual growth rate of 17.4%. The main unintentional source of HCBD changed from carbon tetrachloride to trichloroethylene production during this period. We estimated that China's cumulative emissions of HCBD were 8211.3 (6131.5–10,579.5) MT during the same period. HCBD consumption and the chlorinated hydrocarbon production sector were the major contributors to total HCBD emissions. Owing to the long-range transport capability of HCBD (8784 km), such high emissions in China may cause adverse effects in other regions.

A total of 152 groundwater samples were collected around a contaminated site to evaluate the carcinogenic and noncarcinogenic risks of exposure to twelve volatile chlorinated hydrocarbons (VCHs) by oral ingestion, dermal contact and inhalation absorption during showering. Although toxicity data of some VCHs are fragmentary, the results showed that the carcinogenic and noncarcinogenic risks of exposure to VCHs in contaminated drinking groundwater for local residents needs immediate attention. The main risk contributors for the carcinogenic and noncarcinogenic risks are carbon tetrachloride and 1,1,2-trichloroethane through inhalation exposure pathway, respectively. The health risk contribution rates associated with three exposure pathways for a specific VCH were intrinsic to the compound, and the dermal contact corresponded to a negligible contribution for almost every VCH species. Although most of the evaluated VCHs had a higher risk contribution by inhalation than by oral ingestion pathway, the integrated multi-VCH health risk contributions of the three exposure pathways were mainly dependent on the VCH compositions. Drinking boiled water not only decreased the exposure risk but also affected the risk contribution rates of three exposure pathways, which indicates that it is feasible to reduce the risk of VCH exposure during daily activities based on the risk contribution of the exposure pathways. In addition to the VCHs included in the drinking water standards, species such as 1,1,2,2-tetrachloroethane and hexachloroethane also showed a remarkable exposure health risk according to the standardized health risk calculation, which implied that improved drinking water standards are urgently required.

PURPOSE OF REVIEW: The purpose of this review is to summarize the current understandings of atmospheric VOC characteristics in China and put forward the methodological drawbacks of the VOC measurement that need to be resolved and the research gaps that need to be filled. RECENT FINDINGS: Whereas in recent investigations in the North China Plain (NCP) a reduction (20–66%) in total VOC concentration is noticed compared with the ones published before 2015, an increase (13–127%) is observed for the Yangtze River Delta (YRD) region. Aromatics and oxygenated VOCs are frequently appearing as the most abundant VOC group in recent investigations. Industry-related VOC sources are more dominant in the YRD regions while vehicle-related sources are more influential in the NCP, Central China, and Pearl River Delta regions. Benzene, 1,3,5-trimethylbenzene, ethylbenzene, naphthalene, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, chloroform, carbon tetrachloride, and 1,2-dibromoethane pose carcinogenic risk to exposed population in China and the most risk-prone areas are affected by the petrochemical industry, biomass burning, waste management, and vehicle emissions. Formaldehyde and toluene have relatively high concentrations among the different indoor VOCs observed and their concentrations noticed to be exceeded the national air quality standard. More investigations have to be performed on rarely studied health risk assessment of VOCs and characterization of indoor VOCs. BVOC studies are rarely conducted in China, which has to be performed on common plant species, different forest, and agricultural crops. VOC characterization in forest fire smokes and more process-specific emission characteristics in common industries need to be conducted.

Airborne volatile organic compounds (VOCs) concentration data from monitoring stations in industrial and urban (Bangkok) area of Thailand were analyzed using Positive Matrix Factorization (PMF) to identify and elaborate on their source profiles. Analyzed data were obtained from those measured from January 2009 to December 2013 in the study area. The PMF was performed to estimate the contribution of specific source types to ambient concentrations. The most suitable number of factors for a dataset in this study was found to be eleven factors for compositions and characteristics of VOCs. Emission sources of VOCs in industrial area were classified into three to five groups based on their contribution. In industrial area, 42 to 57% of total VOC concentrations were contributed from mobile sources. Contribution to total VOCs concentration from industrial processes and household chemical usage were about 15 to 44% and 3 to 10%, respectively. Moreover, some species of VOCs particularly the ozone depleting substances such as Freon 11, Freon 114 and carbon tetrachloride were found as background concentration in ambient air. As for Bangkok, it was found that most of total VOC concentrations were contributed from mobile source emissions.

Six volatile halogenated organic compounds (VHOC), namely, chloroform, carbon tetrachloride, trichloroethylene, bromodichloromethane, dibromochloromethane, and bromoform, were studied in the Yellow Sea and East China Sea from April to May, 2009. The spatial variability of these VHOC was influenced by various factors, including anthropogenic inputs, biogenic production and complicated hydrographic features such as Changjiang Diluted Water, Yellow Sea Cold Water Mass, and Kuroshio Current. Diurnal study results showed that factors such as solar irradiation, biological activity, and tide affected the abundance of these VHOC. Correlation analyses revealed that bromodichloromethane was positively correlated with chlorophyll a in surface seawater. Principal component analysis suggested that chlorinated compounds like carbon tetrachloride originated from anthropogenic sources whereas brominated compounds such as bromodichloromethane originated from biogenic sources. Sources of other chlorinated and brominated compounds may not be governed by biological processes in the marine environment.

Physicochemical properties are essential characteristics of organic compounds, which not only impact the fate of organic pollutants but also determine their application in biological processes. Here, we first found that the dielectric constants (ɛ) of organic pollutants negatively correlated to their strength for enhancing microbial Fe(III) reduction. Those with lower ɛ values than 2.61 potentially promoted the above process following the sequence carbon tetrachloride (CT) > benzene > toluene > tetrachloroethylene (PCE) due to their different ability to deprotonate the phosphorus-related groups on the outer cell membrane of iron-reducing bacteria Shewanella oneidensis MR-1 (MR-1). The stronger deprotonation of phosphorus-related groups induced more negative charge of cell surface and more strongly increased cell membrane permeability and consequently stimulated faster release of flavin mononucleotide (FMN) as an electron shuttle/cofactor for Fe(III) reduction. These findings are significant for understanding the biogeochemistry in multi-organic contaminated subsurface and providing knowledge for remediation strategies and current production.

A simple, rapid, sensitive, and inexpensive dispersive liquid–liquid microextraction method was developed for the determination of trace amounts of copper by flame atomic absorption spectrometry (FAAS). N,N′-bis-(2-hydroxy-5-bromobenzyl)-2-hydroxy-1,3-diiminopropane was used as the chelating ligand. Several analytical parameters affecting the microextraction efficiency such as, sample pH, volume of extraction solvent (carbon tetrachloride), concentrations of the chelating ligand and NaCl, and sample volume were investigated and optimized. The effect of the interfering ions on the recovery of copper was also examined. Under the optimum conditions, the detection limit (3σ) was 0.75 μg L⁻¹for copper with a sample volume of 10 mL, and a preconcentration factor of 20 was achieved. The relative standard deviation (R.S.D) for ten independent determinations of a 10 μg L⁻¹solution of Cu(II) was 2.3 %. In order to verify the accuracy of the developed method, different certified reference materials (SLRS-5, QCS-19, Rice flour unpolished high level of Cd NIES 10c) were analyzed and the results obtained were in good agreement with the certified values. The proposed method was applied to tap water, river water, seawater, rice flour, and wheat flour samples. The percentage recovery values for spiked water samples were between 95.4 and 108.4.

Background, aim and scope The use of sodium hypochlorite (HYP) in viticulture results in effluents which are contaminated with halogenated substances. These disinfection by-products (DBPs) can be quantified as group parameter 'adsorbable organic halogens' (AOX) and have not been determined in effluents of viticulture yet. The substances that are detected as AOX are unknown. The AOX can be composed of harmless substances, but even toxic contaminants. Thus, it is impossible to assess ecological impacts. The aim of this study is to determine the quantification of AOX and DBPs after the use of HYP. This will be helpful to reduce environmental pollution by AOX. Materials and methods The potential of HYP to generate AOX was determined in laboratory-scale experiments. Different model solutions were treated with HYP according to disinfection processes in viticulture and conditions of AOX formation in effluents were simulated. AOX were quantified using the flask-shaking method and identified DBPs were investigated by gas chromatography-mass spectrometry. Results Treatment with HYP resulted in the formation of AOX. The percentage conversion of HYP to AOX was up to 11%. Most important identified DBPs in viticulture are chloroform, dichloroacetic acid and trichloroacetaldehyde. In addition, the formation of carbon tetrachloride (CT), 1,1,1-trichloropropanone, 2,4-dichlorobenzoic acid and 2-chloro-/2,4-dichlorophenylacetic acid was investigated. It was demonstrated that reaction temperature, concentration of HYP and type of organic matter have important influence on the formation of chlorinated DBPs. Discussion The percentage conversion of HYP to AOX was similar to other published studies. Although a correlation of single compounds and AOX is difficult, chloroform was the predominant AOX. Generation of the volatile chloroform should be avoided due to possible adverse effects. The generation of dichloroacetic acid is of minor importance on account of biodegradation. Trichloroacetaldehyde and 1,1,1-trichloropropanone are weak mutagens and their formation should be avoided. Conclusions The generation of AOX and chlorinated DBPs can be minimised by reducing the concentrations of the organic materials in the effluents. The removal of organic matter before disinfection results in a decreased formation of AOX. HYP is an effective disinfectant; therefore, it should be used at low temperatures and concentrations to reduce the amount of AOX. If possible, disinfection should be accomplished by the use of no chlorine-containing agents. By this means, negative influences of HYP on the quality of wine can also be avoided. Recommendations and perspectives Our results indicate that HYP has a high potential to form AOX in effluents of viticulture. The predominant by-products are chloroform, dichloroacetic acid and trichloroacetaldehyde. In further research, wastewaters from a winery and the in- and outflows of two sewage treatment plants were sampled during vintage and analysed. These results will be discussed in a following paper.

The current study was designed to assess the in vivo hepatoprotective properties of trans-Anethole, which is a principal aromatic component of star anise. The hepatoprotective effects of trans-Anethole were evaluated at three doses [40, 80, and 160 mg/kg body weight (b.wt.)] against carbon tetrachloride (CCl₄)-induced hepatic damage in male Wistar rats for 4 weeks. Forty-two male Wistar rats were equally divided into seven groups; the control (group I) received only distilled water. Rats of group II received CCl₄ (1 ml/kg b.wt.) in a 1:1 ratio of CCl₄ and olive oil via intraperitoneal doses, while rats of group III received silymarin (50 mg/kg b.wt.), followed by CCl₄ intraperitoneal doses, 3 days in a week. Rats of group IV received trans-anethole (160 mg/kg b.wt.) for 28 days as a negative control. Trans-anethole at the doses of 40, 80, and 160 mg/kg b.wt. was administered to groups V, VI, and VII, respectively, for 28 days, followed by CCl₄ (i.p). Results showed that CCl₄ treatment (group II) elevated the levels of different serum markers like aspartate aminotransferase (AST) by 4.74 fold, alanine aminotransferase (ALT) by 3.47 fold, aspartate alkaline phosphatase (ALP) by 3.55 fold, direct bilirubin by 3.48 fold, and total bilirubin by 2.38 fold in contrast to control. Furthermore, it was found that the decreased levels of liver antioxidant enzymes viz. catalase (CAT) and glutathione reductase (GR) were significantly modulated by the pre-administration of rats with different doses (40, 80, and 160 mg/kg b.wt.) of trans-anethole. Furthermore, pre-treatment of trans-anethole reduced the level of phase I enzymes and elevated the level of phase II detoxifying enzymes. Histopathological investigations showed that the treatment with trans-anethole was effective in ameliorating CCl₄-induced liver injury and restored the normal hepatic architecture. Moreover, trans-anethole restored p53 and cyclin D levels in liver tissue relative to group II. Western blot analysis revealed that the trans-anethole treatment downregulated the expression of Bax and caspase-3 while upregulated the expression of Bcl-xL. Collectively, the findings of the study showed the strong efficacy of trans-anethole in ameliorating the hepatic damage caused by CCl₄ through the modulation of antioxidants and xenobiotic-metabolizing enzymes.