Three-dimensional numericalmodel of polychlorobiphenyls dynamics in the Black Sea
| Autor: | Andrei Bagaev, Vladimir Zalesny, S. P. Lyubartseva, V. A. Ivanov, S. G. Demyshev |
|---|---|
| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Russian Journal of Numerical Analysis and Mathematical Modelling. 27 |
| ISSN: | 1569-3988 0927-6467 |
| DOI: | 10.1515/rnam-2012-0004 |
| Popis: | A three-dimensional numerical model of the pollution of the water column and bottom sediments of the Black Sea by polychlorobiphenyls (PCBs) is developed. The model consists of a physically complete hydrodynamic block and also the transport and transformation modules for the detritus and PCB. The PCB transfer module calculates three functions: the concentration of dissolved PCB,the PCBon sinking detritus particlesand inthe upper layer of thebottom sediments. Wetake into account the processes of adsorption-desorption of PCB on sinking detritus particles, the alternating- sign flow of the substance on the water-sediment boundary, and destruction of the detritus. A model spin-up calculation is performed for the scenario of an instantaneous PCB emission from the Sfantu Gheorghe branch of the Danube. It is shown that the PCB transport on detritus is a natural buffer mechanism damping the spread of a steady organochlorine pollution. The method of mathematical modelling is an efficient approach to ecological stud- ies of the marine environment. The construction of numerical models and the study of biogeochemical cycles of the group of stable organochlorine pollutants damag- ing the marine ecosystem are urgent problems. Such compounds possess a series of specific features. These are their global prevalence, extreme resistance to physical, chemical, and biological transformations, their bioaccumulation caused by their low water solubility and high solubility in lipids, and their toxic impact on living organ- isms in extremely small doses. PCBs, which are some of the most widely-spread and toxic synthetic substances, belong to the class of aromatic compounds. When PCBs are included into bio- logical food chains, due to their selective biotransformation a progressive loss of low-chlorinated components occurs. Therefore, human and animal organisms accu- mulate the most dangerous high-chlorinated PCBs (21). Polychlorinated biphenyls were massively produced beginning with 1929. The synthesis and extensive use of PCBs is explained by their physical and chemical properties: exceptional ther- mal and electrical insulating characteristics, heat resistance, etc. Until the end of their industrial production in 1986, approximately 2 million tons of PCBs had been produced in the world. Polychlorobiphenyls get into the sea via river runoff, at- mospheric precipitation, and also with industrial and municipal drainage effluent. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|