Ecotoxicological effects of polycyclic musks and cadmium on seed germinationand seedling growth of wheat (Triticum aestivum)

Single and joint toxic e ects of polycyclic musks including 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronapthalene (AHTN) and cadmium (Cd) on seedgermination and seedling growth of wheat (Triticum aestivum) were investigated. The results showed that the toxicity sequence ofHHCB toxic to wheat seed germination and seedling growth was similar to that of AHTN, that is, germination rate > shoot elongation> root elongation, while the toxicity of Cd was in the sequence of root elongation > shoot elongation > germination rate, accordingto the LC50 and EC50 values. It is suggested that polycyclic musks and Cd had di erent toxicological mechanisms. Root and shootelongation of wheat might be good bioindicators for the contamination of polycyclic musks and Cd in soil. The mixture of polycyclicmusks and Cd had synergistic e ects on T. aestivum according to the equi-toxic mixture approach when root elongation was selected asthe toxicological endpoint. Thus, the joint toxicity of HHCB and Cd was significantly higher than the single toxicity of HHCB or Cd,which was also confirmed by the EC50 mix value of the mixture (EC50 mix = 0.530 TUmix). The EC50 mix value of the mixture of AHTNand Cd was 0.614 TUmix, which indicated that the mixture toxicity was strengthened when AHTN coexisted with Cd.