Effects of humic acids on the sorption and bioavailability of pyrene and 1,2-dihydroxynaphthalene

AbstractSorption of organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is an important process that controls their mobility and toxicity in soil. The relationship between the chemical properties of various types of humic acids (HAs) and their pyrene (4-ring PAH) sorption ability was investigated in batch experiments. Commercial HAs as well as those obtained from Umbric Andosol, Dystric Cambisol and cow manure compost were used. Additionally, fractionated Aldrich humic acid (AHA), which was obtained by fractional precipitation with ethanol, was evaluated to better understand how its chemical characteristics affect pyrene sorption. The value of the carbon-normalized partition coefficient (Kdoc ×105 L kg-C−1) for pyrene in all commercial HAs was within the expected range in the two soil HAs (0.43–2.69). Correlation analysis indicated that Kdoc values for fractionated AHA series tended to increase with increasing aromaticity (r = 0.82). Subsequently, the effects of various HAs on the toxicit...