STUDY OF BIOMARKERS SELECTION OF THE SCALLOP CHLAMYS FARRERI EXPOSED TO B[A]P

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants derived from incomplete combustion of carbon. As a pollutant, they are of concern because some compounds have been identified as carcinogenic, mutagenic and teratogenic. Benzopyrene (B[a]P) is a five-ring polycyclic aromatic hydrocarbon whose metabolites are mutagenic and highly carcinogenic. It is listed as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). B[a]P is the most studied high molecular mass PAH and usually used as the model of PAHs. In China, environmental PAHs concentrations have been increasing day after day, particularly in aquatic environment. Therefore, more and more researchers pay attention to the toxic effects of PAHs/B[a]P on organisms and human health. Biomarkers are important tools for measuring of exposure to and effects of stressors that may arise at the molecular, cellular, physiological or behavioral level of an individual organism. Recently, they have been widely used to assess the effects of pollutants on aquatic animals. In present study, the effects of B[a]P on activities of detoxification metabolism parameters in gills and digestive glands of scallop Chlamys farreri were studied. At first, the clams were exposed to different concentrations of B[a]P (0.05, 0.5, 5 and 10 μg/L) for 15 days, and then they were cultured in normal seawater without B[a]P for 30 days. At last, the clams were treated with B[a]P for 15 days again. The experiment lasted for 60 days and the gills and digestive glands of the clams in control and different treatments were sampled at 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 day respectively. The activities of aryl hydrocarbon hydroxylase (AHH) and Glutathione S-transferase (GST), the content of Glutathione (GSH), DNA damaged and DNA-protein crosslinks (DPC) were tested by Spectrophotometry. The results indicated that the activity of AHH was significantly induced (Pa]P, while GST activity and GSH content decreased with the increase of B[a]P concentration and the prolong of experimental period. DNA damage and DNA-protein crosslinks were increased with the increase of concentration of B[a]P. All parameters were returned to control level during the clearance stage except the 5 and 10 μg/L groups DPC which were still significant higher than control. When the clams were treated with different concentration of B[a]P again, the change trends of all the parameters were similar to the first stage of B[a]P treatment. The correlation analysis showed that there was a good relativity between the indexes and the concentration of B[a]P. It supposed that all the parameters in the study can be the potential biomarkers for the PAHs contamination assessment. In addition, AHH, GST and DPC value were much more suitable for biological monitoring as the biomarkers because of their stability. They can form the combined biomarkers and used for pollution monitoring sensitively and effectively. In a word, the resulting data in this study may provide basic information of PAHs pollution assessment and the useful monitoring strategy of biomarkers for related departments. What is more, the scientific data must be useful for the assessment of food security in the ocean and estimate the hazard of pollutants to the aquatic products.