An integrated multimedia fate modeling framework for identifying mitigation strategy of antibiotic ecological risks: A case study in a peri-urban river.

Antibiotics have been heavily used over the past decades, resulting in their frequent detections in rivers and increasing ecological risks. Recognizing characteristics of antibiotic ecological risks (AERs) and making effective strategies to mitigate the AERs are essential to ensure the safety of aquatic ecosystem and public health. In this study, an integrated technological framework has been proposed toward identifying management options for reducing AERs by jointly utilizing multimedia fugacity modelling and ecotoxicological risk assessment, and applied to characterize the AERs in a peri-urban river in Beijing. Specifically, a level III fugacity model has been successfully established to simulate the fate of antibiotics in the environment, and the manageable parameters have been screened out via sensitivity analysis of the model. Then the validated fugacity model has been used for scenario modellings to optimize mitigation strategies of AERs. Results show most of the antibiotics considered are frequently detected in the river, and pose medium or high risks to aquatic organisms. Relatively, the macrolides and fluoroquinolones present higher ecotoxicological risks than sulfonamides and tetracyclines. Furthermore, the mixture risk quotient and predictive equation of concentration addition suggest joint and synergistic/antagonistic effects of AERs for multiple or binary antibiotics in the environment. Largely, the concentrations of antibiotics in the river are determined by the source emissions into water and soil. Scenario modellings show the improvement of antibiotic removal rates would be considered preferentially to mitigate the AERs. Also, controlling human consumption is conducive to reducing the risks posed by tetracyclines, macrolides and trimethoprim, while controlling animal consumption would benefit the reduction for sulfonamides. Overall, the joint strategy presents the greatest reduction of AERs by reducing antibiotic consumption and together improving sewage treatment rate and antibiotic removal rate. The study provides us a useful guideline to make ecological risk-based mitigation strategy for reducing AERs in environment.

Application of the multimedia fugacity model in predicting the environmental behaviors of PCBs: Based on field measurements and level III fugacity model simulation.

The comprehensive understanding of PCBs' fate has been impeded by the lack of simultaneous monitoring of PCBs in multiple environmental media in the background areas, which were considered long-term sinks for highly chlorinated PCBs. To address this gap, this study analyzed soils, willow tree barks, water, suspended particulate matter (SPM), and sediment samples collected from the middle reach of the Huaihe River in China for 27 PCBs. The results showed that the levels of ∑27PCBs in the soils were comparable to or lower than the background values worldwide. There were no significant correlations between organic matter and ∑27PCB concentrations in the soils and sediments. Additionally, the contamination of dioxin-like PCBs in the aquatic environment of the study area deserves more attention than in the soils. Applying the level III fugacity model to PCB 52, 77, 101, and 114 revealed that the soil was the primary reservoir, and air-soil exchange was the dominant intermedia transfer process, followed by air-water exchange. Furthermore, simulated results of air-soil and air-water diffusion were compared with those calculated from the field concentrations to predict the potential environmental behaviors of PCBs. Results indicated that the studied river would be a "secondary source" for PCB 52, 77, and 101. However, PCB 52, 77, 101, and 114 would continue to transfer from the air to the soil. This study combines multimedia field measurements and the fugacity model, providing a novel approach to predicting the potential environmental behaviors of PCBs.

Source, occurrence and risks of twenty antibiotics in vegetables and soils from facility agriculture through fixed-point monitoring and numerical simulation.

In this study, a universal method that combined fixed-point monitoring and numerical simulation was used to understand the source, fate and risks of antibiotics in environment. Results showed that the antibiotic concentration in vegetables, soil and manure from 53 fixed-point monitoring sampling sites were ND-18.47, ND-1438.50 and ND-24710.00 µg kg-1, respectively. There were positive correlations between the antibiotic concentrations of vegetables and soil as well as between soil and manure. The average Amountsoil/manure values were 1.48-46.02, indicating that antibiotics built up pseudo persistent residues in soil due to repeated fertilization. The modified level-III fugacity model showed that tetracyclines and fluoroquinolones tend to remain in soil given their sorption and mobility, while sulfonamides were highly distributed in plants, especially in leaves. Norfloxacin, ofloxacin, sulfadiazine, sulfamethoxazole and sulfisoxazole were found to be risk factors in facility agriculture and should be continuously monitored during agricultural production. Most importantly, we used the inversion method to determine the recommended maximum residue limits of antibiotics in soil. This will not only allow for better control of the amount of the antibiotics in the environment, but also act as a potential method to assess the risks of pollutants without maximum residue limits in the environment.

Developing and applying a site-specific multimedia fate model to address ecological risk of oxytetracycline discharged with aquaculture effluent in coastal waters off Jangheung, Korea.

The overuse of oxytetracycline (OTC) in aquaculture has become a problem because of its chronic toxic effects on marine ecosystems. The present study assessed the ecological risk of OTC in the coastal waters near the Jangheung Flatfish Farm using a site-specific multimedia fate model to analyze exposure. Before the model was applied, its performance was validated by comparing it with field data. The coastal waters in the testbed were sampled and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by solid-phase extraction (SPE). The concentrations of OTC measured varied from 7.05 to 95.39ng/L. The results of validating the models showed that the site-specific multimedia fate model performed better (root mean square error (RMSE): 24.217, index of agreement (IOA): 0.739) than conventional fugacity approaches. This result demonstrated the utility of this model in supporting effective future management of aquaculture effluent. The results of probabilistic risk assessment indicated that OTC from aquaculture effluent did not cause adverse effects, even in a maximum-use scenario.

A multimedia fugacity model to estimate the fate and transport of polycyclic aromatic hydrocarbons (PAHs) in a largely urbanized area, Shanghai, China.

Increasing PAHs pollution is creating more complex urban pollution system. However, the availability of sufficient monitoring activities for PAHs in multicompartment and corresponding multi-interface migration processes is still not well understood. In this study, a Level III steady state fugacity model was validated to evaluate the detailed local variations, and mass fluxes of PAHs in various environmental compartments (i.e., air, soil, sediment, water, vegetation and organic film). This model was applied to a region of Shanghai in 2012 based on a large number of measured data and brings model predictions in 2020. The model results indicate that most of the simulated concentrations agreed with the observed values within one order of magnitude with a tendency of underestimation for vegetation. Direct emission is the main input pathway of PAHs entering the atmosphere, whereas advection is the main outward flow from Shanghai. Organic film was achieved the highest concentration of PAHs compared to other compartments up to 58.17 g/m3. The soil and sediment served as the greatest sinks of PAHs and have the longest retention time (2421.95-78642.09 h). Importantly, a decreasing trend of PAHs was observed in multimedia from 2012 to 2020 and the transfer flux from the air to vegetation to soil was the dominant pathways of BaP intermedia circulation processes. A sensitivity analysis showed that temperature was the most influential parameter, especially for Phe. A Monte Carlo simulation emphasized heavier PAHs were overpredicted in film and sediment, but lighter PAHs in air and water were generally underestimated.

Quantitative assessment of human health risks induced by vehicle exhaust polycyclic aromatic hydrocarbons at Zhengzhou via multimedia fugacity models with cancer risk assessment.

Traffic-related pollution released a large amount of atmospheric polycyclic aromatic hydrocarbons (PAHs) which have severely influenced environmental safety and human health until now. However, the important issue of polycyclic aromatic hydrocarbon (PAH) emission from vehicle exhaust in urban populated areas has not been sufficiently investigated yet. This study focused on environmental behavior of vehicle exhaust PAHs (VEPAHs) and resultant health risk on local residents in urban populated areas. This study combined the multimedia fugacity models (Level III and Level IV) and the incremental lifetime cancer risk (ILCR) model, for analyzing the VEPAHs' environmental fate and related health risk on local residents in Zhengzhou of the central China. Regression models were applied to explore correlation between atmospheric concentration of VEPAHs and local pulmonary disease mortality rate. Our results demonstrate that the majority of VEPAH was sunk into the soil compartment in 2013, but the calculated BaP-equivalent concentrations of total VEPAHs in the air compartment exceeded the annual average standard limit of China (1ng/m3) yet. The human exposure routes of VEPAHs caused cancer risk in the following order: inhalation>dermal contact>ingestion.

[Simulating the Fate of Typical Organochlorine Pesticides in the Multimedia Environment of the Pearl River Delta].

A level Ⅳ multimedia fugacity model was established to simulate the fate of p,p'-DDT and γ-HCH in special climatic conditions, such as in the high temperature and humidity environment of the Pearl River Delta, China. The law of migration and transformation of p,p'-DDT and γ-HCH were approached by the Ⅳ multimedia fugacity model, corrected for time and temperature change during 1952-2030. The simulation results showed a better response of the variation of pollutant concentrations to the changes in the pesticide application policy; the concentrations of these two targets in air, water, soil, and sediment were found continuing to increase with the growth of application rates, and decreased with the prohibition in the use of pesticide. We predicted that concentrations will decrease to 6.1×10-12, 3.2×10-9, 6.07×10-7, and 8.72×10-7 mol·m-3 for p,p'-DDT, and to 3.37×10-11, 1.14×10-8, 1.21×10-6, and 4.18×10-7 mol·m-3 for γ-HCH, in air, water, soil, and sediment, respectively, by 2030. The output values of the Ⅳ multimedia fugacity model corrected by designating temperature as a variable parameter, was closer to the survey results than the simulation results obtained by using the model with a constant temperature parameter. The results also showed the pattern of organochlorine pesticides transformation in the whole environmental media in the study area as follow:the pollutants transferred from air to soil, air to water, soil to water, and from water to sediment, and were lastly stored in the soil and sediment. The results of sensitivity analysis indicated that the emission rate, degradation rate, temperature, and lgKow had significant influences on the concentrations of p,p'-DDT and γ-HCH in all the above-mentioned environmental medias. Uncertainty analysis showed that changes in the whole parameter sets had great impact on air concentrations. There were seasonal variations in the distribution of organochlorine pesticide concentrations, and temperature change had influence on its partition in the environment.

[Transfer and Fate of Polybrominated Diphenyl Ethers in an Electrical Equipment Dismantling Area Using a Multimedia Fugacity Model].

The multimedia fugacity model (Ⅲ) was used to simulate the distribution, transfer and fate of typical polybrominated diphenyl ethers (PBDEs) in air, water, soil and sediment in an electrical equipment dismantling area in eastern China. The modeling data were compared with monitored values in air, soil and sediment for validation purpose. Moreover, the transfer fluxes between different compartments were analyzed in order to infer the main transfer process. Parameters of the model were tested and the key parameters were identified using sensitivity analysis method for BDE47 and BDE209.The results of sensitivity analysis indicated that vapor pressure, the lgKow value and half-life had significant influence on concentrations of PBDEs in different media. The results showed that when the system reached equilibrium, most of the PBDEs would be accumulated in soil and sediment. The air advection outflow and soil degradation were the major routes for PBDEs to disappear in the area. The results will provide the basis for the risk management of PBDEs contamination.