Primary aromatic amines
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Date
2007-09-01
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Abstract
3,4-Dichloroaniline (DCA) showed an unusually high bioconcentration factor (BCF) up to
800 in the sediment dweller Lumbriculus variegatus, exceeding BCFs found in fish and other
aquatic organisms by a factor of 8-40. In the scope of the European Risk Assessment process
for different aromatic amines, concern was expressed with regards to biomagnification and
secondary poisoning of man. Although measured BCF data in fish may be not critical, biomagnification
in food chain of sediment, sediment dwelling organisms, fish eating birds or
mammal (including man) can not be excluded. To address this issue, the concentration of
DCA in fish due to dietary uptake via L. variegatus (i. e., the biomagnifications factor, BMF)
was calculated, based on two different assumptions: 1) Either DCA is accumulated in L.
variegatus in the form of a metabolite, but instantaneously released as DCA in fish, or 2) a
DCA metabolite is accumulated in L. variegatus and further accumulated in fish. In the first
case, application of an existing experimental kinetic model showed that the experimental BCF
is likely to increase from 22 to approx. 25 if uptake via food has to be taken into account. In
the second case, use of a physiology-based toxicokinetic model (PBTK) resulted in a BCF of
1.7 to 46 for the DCA metabolite. The daily uptake for a consumer, given in the European
Union Risk Assessment Report for DCA, would rise by 0.6 to 1.3 %. These analyses demonstrate
that biomagnifications via sediment organisms is an exposure route that deserves attention
in environmental risk assessments. However, the bioconcentration factor established in
sediment organisms may overestimate the threat for human beings. The use of PBTK modeling
is proposed as a means of estimating the increased daily uptake for a consumer.
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Keywords
aromatic amines, biomagnification, PBTK modeling, sediment