Biomagnification factors of chlorobenzenes in predator-prey systems

Abstract

Chlorobenzenes (CBs) are widely used as industrial chemicals, agricultural pesticides, and domestic use of chemicals. The CBs are released into the environment and accumulated in aquatic and terrestrial biota. The concentrations of CBs generally increase with trophic levels of biota. Biomagnification factor (BMF), the ratio between the concentration of CBs in predators to those in preys, is influenced by dynamic predator-prey relationships in the natural environment. A study analyzing variabilities of the BMFs of CBs is important to understand the behavior of CBs in the environment. This study evaluated BMFs of CBs in predator-prey systems, consisting of mammals, birds, and fish as predators. This study also analyzed factors influencing the BMFs of CBs such as octanol-water partition coefficients (KOW), octanol-air partition coefficients (KOA), lipid contents, age, trophic level (TL), and gut contents of predators. The BMFs of hexachlorobenzene ranged approximately 2.5 log units with maximum value was 2.02 while BMFs of the other CBs were between 1 to 1.5 in log units. In general, moderate to high variabilities were found for the relationships between the BMFs and physical-chemical characteristics (KOW and KOA) as well as with biological parameters (age, lipid contents, trophic levels) of CBs. Using gut contents of predators in determining BMF values resulted in highly variable BMFs.