Release kinetics and risk assessment of additives in plastic advertising banners.

Plastic advertising banners (PABs) have been widely used for advertising and publicizing with large usage amount. The PABs are usually added with plenty of chemical additives for improving material performance, and the additives can be released during the lifetime of the PABs. However, limited knowledge is available on the composition and release of the additives in the PABs. In this study, benzenoids were found as the dominant additive categories in PABs. Release kinetics of benzenoid additives with high detection frequency and high abundance from the PABs under indoor and outdoor environments were investigated. During the 150-day release experiment, average release rates of the additives from the PABs under outdoor and indoor environments were 8.3 × 10-10 kg/m2·s and 6.3 × 10-10 kg/m2·s, respectively. The release rates of the additives were negatively related to the thickness of the PAB samples. Health risk assessment indicated that chemicals associated with PABs have potential carcinogenic risks to salesmen in the shopping malls. The risks of chemical exposure associated with PABs to consumers in the shopping malls were acceptable. This study unveils a considerable source of chemical exposure to humans.

Composition and release rates of chemicals in inkjet fabrics determined by non-targeted screening and targeted analysis.

Unveiling composition and release rates of chemicals in chemical-intensive products (CIPs) such as inkjet fabrics that are applied extensively in advertising and publicizing industries, is of importance to sound management of chemicals. This study tentatively identified 212 compounds from 69 inkjet fabric samples using gas chromatograph coupled with quadrupole time-of-flight mass spectrometry (GC-QTOF-MS). Contents of six phthalate esters (PAEs) were quantified to range from 3.0 × 102 mg/kg to 3.1 × 105 mg/kg with GC-MS. Bis(2-ethylhexyl) phthalate was predominantly detected to average 96 g/kg. The inkjet fabrics collected from southern China contained fewer non-intentionally added substances (NIASs) than from northern China. Annual mass release rates (RM) of the 6 PAEs from inkjet fabrics to air were estimated to range from 1.4 × 10-2 kg/year to 2.8 × 104 kg/year in China in 2020, and the mean indoor RM was comparable with the outdoor one. Equilibrium partition coefficients of the compounds between the product and air, ambient temperature, and concentrations of chemicals in the product, are key factors leading to RM with the high variance. The findings indicate that contents of the NIASs in the CIPs should be minimized, and the refining concept should be adopted in design of the CIPs, so as to control the release of chemicals from the CIPs.

Estimation of reduced greenhouse gas emission from municipal solid waste incineration with electricity recovery in prefecture- and county-level cities of China.

Municipal solid waste (MSW) without proper managements could be a significant source of greenhouse gas (GHG) emissions. MSW incineration with electricity recovery (MSW-IER) is recognized as a sustainable way to utilize waste, but its effectiveness on reducing GHG emissions at the city scale in China remain unclear due to limited data of MSW compositions. The aim of the study is to investigate reduction potential of GHG from MSW-IER in China. Based on the MSW compositions covering 106 Chinese prefecture-level cities during the period of 1985 to 2016, random forest models were built to predict MSW compositions in Chinese cities. MSW compositions in 297 cities of China from 2002 to 2017 were predicted using the model trained by a combination of socio-economic, climate and spatiotemporal factors. Spatiotemporal and climatic factors (such as economic development level, precipitation) accounted for 6.5 %-20.7 % and 20.1 %-37.6 % to total contributions on MSW composition, respectively. The GHG emissions from MSW-IER in each Chinese city were further calculated based on the predicted MSW compositions. The plastic is the main GHG emission source, accounting for over 91 % of the total emission during 2002-2017. Compared to baseline (landfill) emission, the GHG emission reduction from MSW-IER was 12.5 × 107 kg CO2-eq in 2002 and 415 × 107 kg CO2-eq in 2017, with an average annual growth rate of 26.3 %. The results provide basic data for estimating GHG emission in MSW management in China.

Development and applications of diffusive gradients in thin films for monitoring pharmaceuticals in surface waters.

Pharmaceutical contaminants in surface water have raised significant concerns because of their potential ecological risks. In particular, coronavirus disease 2019 (COVID-19)-related pharmaceuticals can be released to surface water and reduce environmental water quality. Therefore, reliable and robust sampling tools are required for monitoring pharmaceuticals. In this study, passive sampling devices of diffusive gradients in thin films (DGTs) were developed for sampling 35 pharmaceuticals in surface waters. The results demonstrated that hydrophilic-lipophilic balance (HLB) was more suitable for DGT-based devices compared with XAD18 and XDA1 resins. For most pharmaceuticals, the performance of the HLB-DGT devices were independent of pH (5.0-9.0), ionic strength (0.001-0.5 M), and flow velocity (0-400 rpm). The HLB-DGT devices exhibited linear pharmaceutical accumulation for 7 days, and time-weighted average concentrations provided by the HLB-DGT were comparable to those measured by conventional grab sampling. Compared to previous studies, we extended DGT monitoring to include three antiviral drugs used for COVID-19 treatment, which may inspire further exploration on identifying the effects of COVID-19 on ecological and human health.

Face mask-A potential source of phthalate exposure for human.

Face masks are necessary for fighting against the coronavirus disease 2019 around the world. As the face mask is usually made from polymers and phthalates are widely-used additives into the polymers, the face mask could be a potential source of phthalate exposure to humans. However, limited knowledge is available on the occurrence and risks of the phthalates from the face mask. In this study, twelve phthalates were determined in 56 mask samples collected from different countries. The phthalates were detected in all the samples with total levels ranging from 115 ng/g to 37,700 ng/g. Estimated daily intakes (EDIs) of the phthalates from the masks ranged from 3.71 to 639 ng/kg-bw/day, and the EDIs of the phthalates from masks for toddlers were approximately 4-5 times higher than those for adults. Non-carcinogenic risks in relation to the phthalates in masks were found to be within safe levels, yet 89.3% of the mask samples exhibited potential carcinogenic effects to humans. The extent of the risks for wearing masks located at a moderate level comparing with other skin-contacted products. This study unveiled a potential source of phthalate exposure to human, and indicated necessity of managing types and levels of additives in the face masks.

Occurrence and ecological risks of 156 pharmaceuticals and 296 pesticides in seawater from mariculture areas of Northeast China.

China is the largest mariculture producer in the world. In recent years, pharmaceuticals and pesticides have been widely used in mariculture activities; however, most studies have only focused on the occurrence of limited types of antibiotics and organochlorine pesticides. It is critical to comprehensively investigate the occurrence of pharmaceuticals and pesticides in mariculture areas and assess their potential impacts on ocean ecosystems. In this study, the occurrence, distribution, and ecological risk of 484 compounds, including 296 pesticides, 156 pharmaceuticals, and 32 other substances, in the drainage ditches of culture ponds and raft-culture areas were investigated. A total of 51 compounds were detected in the mariculture area, with total concentrations ranging from 5.4 × 102 to 2.0 × 104 ng/L at each sampling site. Eleven pesticides, three pharmaceuticals, and five other compounds were detected with detection frequencies of 100%. The cluster analysis indicated that mariculture is a source of herbicide pollution in coastal waters. To assess the ecological risks of the detected compounds, toxicity data collected from the database and predicted from quantitative structure activity relationship (QSAR) models were used to calculate the risk quotients and probabilistic risks. According to the risk quotients, five pollutants, including diuron, ametryn, prometryne, simetryn, and terbutryn, were estimated to pose high risks to marine organisms. The results of the probabilistic risk assessment indicated that only diuron, a biocide used in antifouling paint and mariculture, would have an adverse effect on up to 8% of the aquatic species in nearshore areas. These findings could be helpful in determining the aquatic benchmarks of pesticides and pharmaceuticals in mariculture discharge to promote the sustainable development of mariculture and ecological protection in coastal areas.

Development and evaluation of a ceramic diffusive layer based DGT technique for measuring organic micropollutants in seawaters.

Diffusive gradients in thin-films (DGT) technique has been well demonstrated as a robust tool for measuring organic micropollutants (OMPs) in the aquatic environment. However, potential adsorption of the OMPs on organic polymer filters and flow rate of waters can affect the measuring results of the DGT method, hence tedious work should be conducted to reduce these interferences. In the present study, a novel DGT technique coupled with a ceramic diffusive layer was developed to measure the OMPs in seawaters. The ceramic diffusive layer exhibited adsorption inertness to the OMPs with various logKow values. Moreover, the ceramic diffusive layer based DGT technique was proved to be less affected by the flow rate than the traditional DGT with agarose diffusive layer. The developed DGT device exhibited kinetic accumulation for the targets during a 6-d deployment, and measurement of the OMPs by the DGT method was independent with pH and ionic strength. Finally, the developed DGT sampler was applied in coastal waters of Dalian, and eight OMPs were detected with levels ranging from 1.58 to 13.1 ng/L. The development of the ceramic diffusive membrane can lead to simplification of the DGT applications, promoting the progress of the OMPs monitoring technology.

[Concentration Levels and Potential Ecological Risks of Current Use Pesticides in the Surface Seawater of Typical Liaoning Sea Areas].

Fourteen current-use pesticides (CUPs) in the surface seawaters of the typical Liaoning sea areas were analyzed using HPLC-MS/MS. The concentrations, distribution, and ecological risks were studied, as well as their source appointments using principal component analysis (PCA). The results revealed that seven types of CUPs were detected in the surface seawaters of the typical Liaoning sea areas. The total concentrations of these CUPs ranged from 16.7 ng·L-1 to 176.1 ng·L-1. The samples with high concentrations were collected mostly from the estuary, and the concentrations of CUPs in the western Liaodong Bay were generally higher than those in the northeastern Yellow Sea. Atrazine and triadimenol were the predominant CUPs, and their contribution rates accounted for 56.0% and 34.5%, respectively. The PCA results indicated that six types of CUPs might be caused by the runoff from farmlands and the wastewater discharge from the chemical pesticide factory, and fruit planting could be a substantial contributor to the single component acetochlor. Atrazine and acetochlor posed medium-high ecological risks to the microalgae, while all the seven types of CUPs showed relatively lower risks to invertebrates and fish.

Prediction Models on pKa and Base-Catalyzed Hydrolysis Kinetics of Parabens: Experimental and Quantum Chemical Studies.

Parabens for which the molecules contain hydrolytic and ionizable groups, are emerging pollutants due to their ubiquity in the environment. However, lack of pKa and second-order base-catalyzed hydrolysis kinetics (kB) values limits their environmental persistence assessment. Herein, six parabens were selected as reference compounds for which the pKa and kB values were measured experimentally. A semiempirical quantum chemical (QC) method was selected to calculate pKa of the parabens, and density functional theory (DFT) methods were selected to calculate kB for neutral and anionic forms of the parabens, by comparing the QC-calculated and determined values. Combining the QC-calculated and experimental pKa and kB values, quantitative structure-activity relationships with determination coefficients (R2) being 0.947 and 0.842 for the pKa and kB models, respectively, were developed, which were validated and could be employed to efficiently fill the kB and pKa data gaps of parabens within applicability domains. The base-catalyzed hydrolysis half-lives were estimated to range from 6 h to 1.52 × 106 years (pH 7-9, 25 °C), further necessitating the in silico models due to the tedious and onerous experimental determination, and the huge number of hydrolyzable and ionizable chemicals that may be released into the environment.

Occurrence and Health Risks of Organic Micro-Pollutants and Metals in Groundwater of Chinese Rural Areas.

BACKGROUND: Groundwater is a main drinking-water source for Chinese rural residents. The overall pollution status of organic micropollutants (OMPs) and metals in the groundwater and corresponding health risks are unknown. OBJECTIVES: Our objective was to comprehensively screen for and assess the health risks of OMPs and metals in groundwater of rural areas in China where groundwater is used for drinking so as to provide a benchmark for monitoring and improving groundwater quality in future developments. METHODS: One hundred sixty-six groundwater samples were collected in the rural areas of China, and 1,300 OMPs and 25 metals were screened by GC-MS, LC-QTOF/MS, and ICP-MS analysis. To assess the noncarcinogenic and carcinogenic risks of the detected pollutants, missing toxicity threshold values were extrapolated from existing databases or predicted by quantitative structure-activity relationship (QSAR) models. Monte Carlo simulation was performed to account for uncertainties in the exposure parameters and toxicity thresholds. RESULTS: Two hundred thirty-three OMPs and 25 metals were detected from the 166 samples. The concentration summation for the detected OMPs ranged from 2.9 to 1.7×105ng/L among the different sampling sites. Cumulative noncarcinogenic risks for the OMPs were estimated to be negligible. However, high metal risks were calculated in 23% of the sites. Forty-two carcinogens (including 38 OMPs) were identified and the cumulative carcinogenic risks in 34% of the sites were calculated to be >10-4 (i.e., one excess cancer case in a population of 10 thousand people). The carcinogenic risks were estimated to be mainly associated with exposures to the metals, which were calculated to contribute 79% (0-100%) of the cumulative carcinogenic risks. DISCUSSION: The overall status of OMPs and metals pollution in the groundwater and the corresponding health risks were determined preliminarily, which may provide a benchmark for future efforts in China to ensure the safety of drinking water for the local residents in rural areas. The joint application of QSARs and Monte Carlo simulation provided a feasible way to comprehensively assess the health risks of the large and ever-increasing number of pollutants detected in the aquatic environment. https://doi.org/10.1289/EHP6483.

Bioaccumulation, Biotransformation, and Multicompartmental Toxicokinetic Model of Antibiotics in Sea Cucumber (Apostichopus japonicus).

Extensive application of antibiotics leads to their ubiquitous occurrence in coastal aquatic environments. However, it remains largely unknown whether antibiotics can be bioaccumulated and biotransformed in major mariculture organisms such as sea cucumbers and toxicokinetic models for Echinodermata are lacking. In this study, laboratory exposure experiments on juvenile sea cucumber (Apostichopus japonicus) were performed for seven antibiotics (sulfadiazine, sulfamethoxazole, trimethoprim, enrofloxacin, ofloxacin, clarithromycin, and azithromycin). Field sea cucumber and surrounding seawater samples were also analyzed. Results show that the sea cucumbers tend to accumulate high concentrations of the antibiotics with kinetic bioconcentration factors (BCFs) up to 1719.7 L·kg-1 for ofloxacin. The BCFs determined in the laboratory agree well with those estimated from the field measurements. Seven biotransformation products (BTPs) of the antibiotics were identified, four of which were not reported previously in aquatic organisms. The BTPs were mainly found in the digestive tract, indicating its high capacity in the biotransformation. A multicompartmental toxicokinetic model based on the principles of passive diffusion was developed, which can successfully predict time-course concentrations of the antibiotics in different compartments of the juvenile sea cucumbers. The findings may offer a scientific basis for assessing health risks and guiding healthy mariculture of sea cucumbers.

Screening of 484 trace organic contaminants in coastal waters around the Liaodong Peninsula, China: Occurrence, distribution, and ecological risk.

Human activities such as agriculture, aquaculture, and industry can lead to the pollution of coastal waters by trace organic contaminants (TrOCs), and the TrOCs can pose a threat to marine ecosystems. Therefore, it is essential to investigate the occurrence, distribution, and ecological risk of the TrOCs in coastal waters. Previous studies adopting conventional analytical methods have focused on a limited number of targets. Herein, a comprehensive and systematic determination was undertaken to target 484 TrOCs in the waters around the Liaodong Peninsula, China. Eighty-six TrOCs were detected at concentrations of up to 350 ng L-1, and 25 TrOCs were detected at a frequency of >50%. Pesticides were the predominant pollutants, occurring at high concentrations with large detection frequencies. Ecological risks were assessed for single pollutants and mixtures based on the risk quotient and concentration addition modeling, respectively. The detected pesticides posed relatively high risk to aquatic organisms, while pharmaceuticals, consumer products, and other pollutants posed little or no risk. TrOC mixtures posed extremely high risk to aquatic organisms, which represented a significant threat to the marine environment and local communities. The results described here provide useful information that can inform China's "Action Plan for Prevention and Control of Water Pollution".

Concerted Efforts Are Needed to Control and Mitigate Antibiotic Pollution in Coastal Waters of China.

Antibiotics have been applied for decades and antibiotic pollution is of great concern due to the risk for promoting resistant genes. Human activities such as mariculture and land-based discharge can lead to the antibiotic pollution in coastal area and it is of importance to assess the pollution and risks of antibiotics in this area. In this mini-review, the pollution status of antibiotics in Chinese coastal waters is summarized and some perspectives are put forward for future efforts to mitigate the pollution.

Presence and environmental risk assessment of selected antibiotics in coastal water adjacent to mariculture areas in the Bohai Sea.

The presence and concentrations of 25 antibiotics in Dalian coastal water of the Bohai Sea were investigated using solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry. Results showed that antibiotics were widely detected in this region with total concentration ranging from 22.6 to 2402.4 ng/L. Enrofloxacin and trimethoprim were 100% detected followed by sulfamethoxazole with a detection rate of 90.9%. No significant correlations were found between antibiotics concentrations and sample parameters such as dissolved organic carbon, salinity, and distance from the coast, suggesting that concentrations and distributions of the antibiotics in this area were source-dependent. Antibiotic concentration in the sample from an offshore cage-culture area was the highest. Based on composition profiles, mariculture was supposed to be an important source of antibiotics. According to the assessment, individual antibiotic posed low to moderate risk, while the antibiotic mixture presented high risk. Enrofloxacin, clarithromycin and sulfamethoxazole, the top three contributors to the mixture risk quotients for each site, need priority control in this area. Besides, levels of enrofloxacin were high enough to exert a selective pressure on bacteria that may lead to an increase in the prevalence of resistance.

Occurrence, distribution and ecological risks of antibiotics and pesticides in coastal waters around Liaodong Peninsula, China.

Mariculture activities and river inputs can lead to pollution of micropollutants (e.g., antibiotics and pesticides) in coastal seawater which is the base of the most dynamic ecosystems due to its hosting some of the highest biodiversity and biological production in the world. It is thus of importance to investigate the occurrence and risks of organic micropollutants in coastal waters. In this study, 13 antibiotics and 15 pesticides were screened in coastal waters around the Liaodong Peninsula, China. Among the targets, thirteen were detected with concentrations up to 64.8 ng L-1. Simazine, atrazine and triadimenol were found to be the predominant pesticides with detection frequencies of 100%, and sulfamethoxazole was the predominant antibiotic with a detection frequency of 62.5%. The total level of the pollutants in the Bohai Sea was generally higher than that in the Yellow Sea, and a seaward decreasing trend of the pollutants was observed. Terrestrial inputs and mariculture were distinguished as main pollution sources by principal component analysis. Finally, ecological risk quotients were calculated and atrazine and acetochlor showed relatively higher risks to aquatic organisms.

Investigation of antibiotics in sea cucumbers: occurrence, pollution characteristics, and human risk assessment.

Occurrence and distribution of 24 antibiotics from 7 categories were screened in sea cucumbers (Echinodermata: Holothuroidea) collected from different coastal regions of China. The samples were simultaneously extracted and purified using accelerated solvent extraction with in-cell clean-up and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. A total of ten antibiotics were detected in the sea cucumbers with concentrations ranging from not detected to 32.8 µg/kg (dry weight). Sulfonamides are predominant antibiotics with a mean concentration of 11.5 µg/kg (dry weight), followed by macrolides (11.3 µg/kg, dry weight) and fluoroquinolones (11.2 µg/kg, dry weight). High concentrations of the antibiotics were found in the samples from the South China Sea, implying that the antibiotic pollution in sea cucumbers was geographical region-dependent, which was further confirmed by principal component analysis. It was also found that the antibiotic levels are slightly higher in instant sea cucumbers than in the dried ones. Hazard quotient calculation suggested no obvious human health risks associated with the consumption of sea cucumbers regarding antibiotics.

Determination of 21 antibiotics in sea cucumber using accelerated solvent extraction with in-cell clean-up coupled to ultra-performance liquid chromatography-tandem mass spectrometry.

An accelerated solvent extraction (ASE) with in-cell clean-up method coupled to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to determine 21 antibiotics in sea cucumber. The analytes include 10 sulfonamides, 4 fluoroquinolones, 3 amphenicols, 2 beta-lactams, 1 lincosamide and trimethoprim. Optimal parameters of ASE method were obtained at 80 °C, 1 static cycle of 5 min with methanol/acetonitrile (1/1, v/v) using 2 g of C18 as adsorbent. Recoveries at 50.1-129.2% were achieved with RSD under 20%. Method detection limits ranged from 0.03 to 2.9 µg kg-1. Compared to the reported ultrasound-assisted extraction method, the proposed method offered comparable extraction efficiency for sulfonamides from sea cucumber, but higher for other categories of antibiotics. This validated method was then successfully applied to sea cucumber samples and 9 antibiotics were detected with the highest concentration up to 57.7 µg kg-1 for norfloxacin.

Investigation and application of diffusive gradients in thin-films technique for measuring endocrine disrupting chemicals in seawaters.

Endocrine disrupting chemicals (EDCs) can be released to coastal waters and affect the endocrine system of marine organisms. To monitor their levels in seawaters, a simple, robust passive sampling method, the diffusive gradients in thin-films (DGT) technique, was developed with XDA-1 resin as a binding agent. Six EDCs (including three estrogens, two pesticides and bisphenol A) were used to assess the performance of the DGT. The XDA-1 binding gel showed adequate ability for adsorbing EDCs in seawaters. The DGT sampler exhibited linear accumulation for the EDCs during a 15-day deployment and diffusion coefficients and sampling rates were calculated. The DGT measurement was independent of pH in the range 7.0-9.0 and ionic strength in the range 0.4-0.8 M. Field applications of this DGT in a coast of Dalian (China) showed comparable results to those from grab sampling. Five EDCs were detected with concentrations ranging from 0.7 to 19.4 ng L-1. This study is a first attempt to apply DGT sampler for determining EDCs in seawaters.

Modeling photodegradation kinetics of organic micropollutants in water bodies: A case of the Yellow River estuary.

Predicting photodegradation rate constants (k) of pollutants in water bodies is important for assessing their persistence and fate. This prediction used to be based on the k values determined under laboratory conditions that seldom consider underwater downward sunlight attenuation in the field. We studied a procedure to predict k taking the Yellow River estuary and two model chemicals (sulfamethoxazole and acyclovir) as a case. Models were developed for predicting underwater sunlight intensities from optically-active substances. Based on the predicted underwater sunlight intensities, hourly variation of k for the model compounds was predicted as a function of water depth, for a fresh water, an estuarine water and a seawater body in the estuary. Results show that photodegradation half-lives (t1/2) of the two compounds will be underestimated by dozens of times if underwater downward sunlight attenuation and intensity variation are not considered. Outdoor validation experiments show the maximum deviation between the predicted and measured k values is a factor of 2. The developed models can be employed to predict k of environmental chemicals in coastal water bodies once they are locally calibrated.