title: Influences of humic acid on the bioavailability of phenanthrene and alkyl phenanthrenes to early life stages of marine medaka (Oryzias melastigma).
abstract: The influences of humic acid (HA) on the environmental behavior and bioavailability of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs were investigated and compared using the early life stages of marine medaka (Oryzias melastigma, O. melastigma). It was demonstrated that the binding affinity of parent phenanthrene (PHE) with HA was smaller than that of 3-methyl phenanthrene (3-MP) and 9-ethyl phenanthrene (9-EP). Furthermore, the bioaccumulation of the three PAHs and the levels of lipid peroxidation (LPO) were calculated to study the changes in bioavailability of PAHs in presence of HA. The results indicated that the addition of HA significantly decreased the bioaccumulation and toxicity of PAHs by decreasing free PAHs concentrations. The bioavailable fractions of HA-bound PAHs in bioaccumulation (α) and toxicity (β) were evaluated, indicating that the HA-bound 3-MP and 9-EP show higher bioavailability in bioaccumulation and lower bioavailability in toxicity relative to those of PHE. The β/α values were less than 1 for all PAH treatment groups containing HA, suggesting that the fraction of HA-bound PAHs contributing to bioaccumulation was higher than that of HA-bound PAHs inducing toxic effect. In addition, we proposed that the free PAHs generated by desorption from HA in the cell were toxic by showing that the β/α ratio values are correlated with the log KOW values (p = 0.007 and R(2) = 0.8355). Thus, oil spill risk assessments should consider both alkyl PAHs and the factors that influence the bioavailability and toxicity of PAHs in the natural aquatic environments.
authors.affiliation: State Key Laboratory of Marine Environmental Science of China, College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
authors.forename: Yangzhi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Marine Environmental Science of China, College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
authors.forename: Chenghu
authors.initials: C
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Marine Environmental Science of China, College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
authors.forename: Pakkin
authors.initials: P
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Marine Environmental Science of China, College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Yaxian
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Marine Environmental Science of China, College of the Environment and Ecology, Xiamen University, Xiamen 361102, PR China; Zhangzhou Institute of Technology, Zhangzhou 363000, PR China. Electronic address: yzhang@xmu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001682:Biological Availability; D006812:Humic Substances / Q000032:analysis*; D009990:Oryzias / Q000378:metabolism*; D059392:Petroleum Pollution; D010616:Phenanthrenes / Q000737:chemistry* / Q000493:pharmacokinetics*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D006812:Humic Substances; D010616:Phenanthrenes; D014874:Water Pollutants, Chemical
keywords: Alkyl polycyclic aromatic hydrocarbons; Bioavailability; Humic acid; Marine medaka; Phenanthrene