Objective To investigate the chemical speciation of metals in particulate matter from diesel exhaust, and to analyze the biological effectiveness of metals.

Methods The particulate matter from diesel engine exhaust was extracted by BCR three step sequential extraction method and digested by microwave digestion method. The chemical speciation of main metals Ti, Ba and Zn in particulate matters was analyzed, the biological effective coefficient of each element was calculated by a formula, and the biological effectiveness of each metal was evaluated by the coefficient.

Results The chemical speciation of Ba and Zn was mainly in organic binding state, and Ti was mainly in residue state. Through calculation, the biological effective coefficient of Zn and Ba was 0.2 < k < 0.8, they were in a certain degree of biological effectiveness. The biological effective coefficient of Ti was k < 0.2, which was in low biological effectiveness.

Conclusions The content of metals Zn, Ba and Ti in particulate matter from diesel exhausts was high, and the chemical speciation of Ti was mainly in residue form, Zn and Ba were mainly in organic form. Based on biological effective coefficient, the biological effectiveness of Ti was low, Ba and Zn have had some biological effectiveness.