Phytotoxicity of chlorinated aliphatics to hybrid poplar ( Populus deltoides × nigra DN34)

Abstract Effects of a series of chlorinated ethenes and ethanes on hybrid poplar ( Populus deltoides × nigra DN34) were assessed in laboratory experiments. Poplar cuttings were grown in sealed reactors with hydroponic solutions and were exposed to a chlorinated solvent for a period of two weeks. Exposure concentrations ranged from 0 to 0.4 mM for perchloroethylene to 0 to 8.4 mM for 1,1‐dichloroethane. Effects were assessed by gravimetrically monitoring transpiration and measuring change in cutting mass. The zero‐growth concentrations of the chemicals tested were 0.3 mM perchloroethylene, 0.9 mM trichloroethylene, 0.9 mM 1,1,2,2‐tetrachloroethane, 2.0 mM 1,1,1‐trichloroethane, 2.3 mM 1,1,2‐trichloroethane, 4.8 mM trans ‐dichloroethylene, 5.6 mM 1,1‐dichlor‐oethylene, 6.0 mM cis ‐dichloroethylene, and 10.7 mM 1,1‐dichloroethane. Adverse effects were found to increase with increasing number of chlorine atoms within a homologous series of ethenes or ethanes. Ethenes were more toxic than similarly chlorinated ethanes.