Bioconcentration
Definition
Bioconcentration considers the uptake of substances
from the non-living environment (soil), while the second
stage, i. e. biomagnification, describes the uptake of
such substances through the food chain. Both of these
processes happen simultaneously during bioaccumulation.
Some chemical contaminants have long half-lives,but in other cases derivative chemicals are formed from
decay of primary soil contaminants. Some toxic compounds
may stay in a system for a much longer period
of time, and if the input is greater than the rate of biotransformation
or loss, produce bioaccumulation. For
many fat-soluble and persistent chemicals, biomagnification
is a dominant factor in the risk they pose; examples
include DDT and lipid soluble poisons, including
tetra-ethyl lead compounds (the lead in leaded petrol).
These compounds are stored finally in the body’s fat,
and when the fatty tissues are used for energy, the compounds
are released and cause acute poisoning.Another
important example is the accumulation of Strontium 90,
mistaken by mammalian and human bodies for calcium,
and laid down in the bone tissue, where its radiation can
cause long-term damage.
Tags: accumulation, biotransformation, bone tissue, ddt, decay, derivative chemicals, dominant factor, ethyl, fatty tissues, food chain, half lives, human bodies, leaded petrol, lipid, persistent chemicals, poisons, second stage, soil contaminants, strontium 90, toxic compounds