A Fugacity Based Model for the Assessment of Pollutant Dynamic Evolution of VOCS and BTEX in the Olt River Basin (Romania)

doi:10.37358/rc.19.10.3456

Abstract

An important tributary of the Danube River, the Olt River, was characterized in its middle and lower catchment in terms of volatile organic compounds (1,2 -dichloroethane and perchlorethylene) and volatile aromatic hydrocarbons (benzene, toluene and xylene isomers) to better assess their transfer in the environmental compartments (air, water, sediment and biota). A fugacity based calculation model was applied to establish the bio-concentration factors (BCFs) that relates the compounds concentration from sediment-, water- or air- to the biota based on experimental data. Thus, conclusive suggestions can be achieved for a rapid preliminary risk assessment as support tool for the preventive measures in the contaminated areas resulting from accidental chemical discharges or continuous pollution. For thus, water and sediment samples were collected and analyzed by gas chromatography for the selected compounds, the results being applied as input data for the model. The modeling revealed the tendency of the investigated compounds to transfer from water section to air. Simulated values obtained for section sediment as validation tool, are comparable and compatible with the values obtained by analytical measurements, and thus a rapid estimation of the pollution level in the environmental compartment of interest can be achieved based on a limited number of analytical measurements. Thus, by applying the fugacity model to estimate a pollution footprint, conclusive indications for a rapid environmental risk assessment can be achieved. Keywords: volatile organochlorine substances, volatile aromatic hydrocarbons (BTEXs), MacKay model, fugacity, ecosystem

Highlights

Environmental pollution with hazardous substances occur mainly due to wastewater discharges from point sources and diffuse emission sources containing nonsynthetic pollutants and/or synthetic pollutants
In previous studies [16,17,18] we described an updated state of the science EQuilibrium Criterion (EQC) model that is used to provide a screening level evaluation of the likely fate of a chemical that is introduced into a multimedia environment by various modes of entry
The values of physicochemical properties of volatile organic compounds (1,2 dicloethane and perchlorethylene) and volatile aromatic hydrocarbons used here were the mean values derived from previous studies [21] or most frequently used in the model calculation

Summary

Introduction

Environmental pollution with hazardous substances occur mainly due to wastewater discharges from point sources and diffuse emission sources containing nonsynthetic pollutants (heavy metals) and/or synthetic pollutants (organic micro-pollutants). The level of contamination resulting from accidental or continuous chemical discharges was usually assessed using the transfer models on environmental compartments. The chemicals that are released into the environment, succeed through various compartments of the environment as a result of complex processes physico- chemical and biological [5,6,7,8] One such model is the MacKay model [9, 10], which uses patterned backgrounds to explore the possible behaviour of the chemical and may estimate the level of pollution with hazardous chemicals to environmental water, sediment, and biota. Environmental models are important tools in understanding the behavior of contaminants in complex environments They are used to simulate chemical transport with focus on a single medium and multimedia fate models, allowing to calculate the chemical behavior in various environmental compartments. It provides equilibrium concentrations of the chemical in each compartment of the model environment and shows the media where concentrations are likely to be highest (i.e. the fugacity capacity, Z, is largest) and where the masses are highest (i.e. VZ is largest, where V is the compartment volume and Z is the corresponding Z value)

Methods

Results

Conclusion