BIOACCUMULATION OF LIPID – SOLUBLE POLLUTANTS IN AQUATIC SYSTEMS

Autor: N. Topić Popović, I. Strunjak-Perović
Jazyk: angličtina
Rok vydání: 1999
Předmět:
Zdroj: Croatian Journal of Fisheries : Ribarstvo
Volume 57
Issue 1
ISSN: 1848-0586
1330-061X
Popis: One of the major problems of water pollution is the capability of pollutants to concentrate in aquatic organisms. Bioaccumulation and bioconcentration of such chemicals in fish render it unsuitable for human consumption. Bioconcentration of water pollutants through algae, zooplankton and other organisms, can lead to their accumulation through food.chain, with the fish at the top of the pelagic food web. The occurrence of elevated residue levels of various xenobiotics with increasing trophic level has been demonstrated in a variety of aquatic environments and organisms. The increased bioconcentration occurs with increasing trophic level. The tendency of a chemical to bioconcentrate has been shown to be strongly related to its lipophilicity. Trophic.level differences in bioconcentration are due largely to increased lipid content and decreased chemical elimination efficiency of organisms occupying increasing trophic levels. The accumulation of pollutant is expressed as the bioconcentration factor (BCF), which is determined as the rate of its uptake to the organism and its elimination from it plus the organism growth rate. Chemical uptake efficiency from water, excretion rate, and chemical assimilation efficiency are variable as a function of the octanol.water partition coefficient (Kow).
Jedan od najvećih problema onečišćenja vode raznim onečišćivačima jest u tome što se oni mogu koncentrirati u vodenim organizmima. Bioakumulacija i biokoncentracija onečišćivača u ribi čine takvu ribu nepogodnom za ljudsku prehranu. Biokoncentracija onečišćivača iz vode preko algi, zooplanktona i drugih organizama može dovesti do njihove akumulacije preko prehrambenog lanca, s ribom na vrhu pelagičkoga prehrambenog niza. Pojava povišene razine ksenobiotika uz povišenje trofične razine prisutna je u brojnim vodenim sustavima i organizmima koji žive u vodi. Tendencija neke kemijske tvari prema biokoncentraciji vrlo je usko vezana s njezinom lipofilnošću. Razlike trofičnih razina u biokoncentraciji posljedica su povećanog sadržaja lipida i smanjene sposobnosti kemijske eliminacije organizama viših trofičnih razina. Mogućnost nakupljanja polutanata u organizmu može se odrediti biokoncentracijskim faktorom (BCF), koji je odnos stupnja unosa i stupnja eliminacije određenoga spoja zbrojen sa stupnjem rasta organizma. Djelotvornost unosa kemijske supstancije iz vode, stupanj izlučivanja, te učinkovitost kemijske asimilacije ovise o kemijskom koeficijentu odnosa oktanola i vode (Kow).
Databáze: OpenAIRE
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