Toxicity assessment of Fluoranthene, Benz(a)anthracene and its mixed pollution in soil: Studies at the molecular and animal levels

An increasing amount of Fluoranthene (Fla) and Benz(a)anthracene (BaA) is being produced and used, eventually entering the soil sediments. The accumulation of Fla and BaA will cause poisoning to typical enzymes (α-Amylase) and organisms (Eisenia fetida) in soil. However, the studies about exploring and comparing the different effects of Fla, BaA and their joint effect at different levels are rarely reported. In this paper, the different effects of Fla, BaA and their mixed pollutant on α-Amylase were evaluated and compared at the molecular level, and the effect of Fla-BaA to the antioxidant system of earthworm (Eisenia fetida) was investigated from the aspects of concentration and exposure time at the animal level. The results showed that Fla-BaA had the greatest influence on the skeleton structure and the microenvironment of amino acid residue of α-Amylase compared to Fla and BaA, and in the mixed pollutant system, the joint effect mode was additive mode. The inhibitory effect of Fla-BaA on the activity of α-Amylase was also stronger than that of the system alone. The assays at the animal level showed that low concentrations (below 5 mg/kg) of Fla-BaA increased the activity of GSH-Px and SOD while high concentrations inhibited their activity. The POD that was activated throughout the experiment period suggested its key role in the earthworm antioxidant system. Changes in T-AOC and MDA showed that long-term and high-dose of Fla-BaA exposure inhibited the antioxidant capacity of Eisenia fetida, causing lipid peroxidation and damage to cells. [Display omitted] •Fla-BaA had a deeper influence on structure and function of α-Amylase.•Interaction mechanism of α-Amylase with Fla, BaA and Fla-BaA was compared.•Long-term and high-dose of Fla-BaA exposure will inhibit the antioxidant capacity, causing lipid peroxidation.•Fla-BaA had two-phase effects on GSH-Px and SOD.