title: Mechanism of concentration addition toxicity: they are different for nonpolar narcotic chemicals, polar narcotic chemicals and reactive chemicals.
abstract: According to the toxicity mechanism of the individual chemicals, the concentration addition toxicity mechanism is revealed for nonpolar-narcotic-chemical mixtures, polar-narcotic-chemical mixtures and reactive-chemical mixtures, respectively. For nonpolar-narcotic-chemical mixtures, the partitioning of individual chemicals from water to biophase was determined, and the result shows that their concentration additive effect results from no competitive partitioning among individual chemicals. For polar-narcotic-chemical mixtures, their toxicity are contributed by two factors (the total baseline toxicity and the hydrogen bond donor activity of individual chemicals), and it is the concentration additive effect for either of these two factors that leads to their concentration addition toxicity. In addition, the interactions between the reactive chemicals and the biological macromolecules are discussed thoroughly. The results suggest that the net effect of these interactions is zero, and it is this zero net effect that leads to the concentration addition toxicity mechanism for reactive-chemical mixtures.
authors.affiliation: Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China. lzhifen@yahoo.com
authors.forename: Zhifen
authors.initials: Z
authors.lastname: Lin
authors.forename: Jianwei
authors.initials: J
authors.lastname: Du
authors.forename: Kedong
authors.initials: K
authors.lastname: Yin
authors.forename: Liansheng
authors.initials: L
authors.lastname: Wang
authors.forename: Hongxia
authors.initials: H
authors.lastname: Yu
mesh_terms: D064420:Drug-Related Side Effects and Adverse Reactions / Q000378:metabolism*; D015386:Hazardous Substances / Q000032:analysis / Q000494:pharmacology*; D008956:Models, Chemical; D010776:Photobacterium / Q000187:drug effects* / Q000378:metabolism; D023382:Toxicity Tests, Acute
chemical_list: D015386:Hazardous Substances