The effect of environmental parameters on growth, cholinesterase activity and glutathione S-transferase activity in the earthworm (Apporectodea caliginosa)

The effect of age and environmental parameters on growth, cholinesterase (C hE), and glutathione S-transferase (GST) activities were assessed in juveni le Apporectodea caliginosa earthworms. Earthworms were maintained in three types of soil - loam, sandy, and clay - at a range of moisture contents (15 -30%), and temperatures (5-20 degrees C). Earthworm age (1-3 months) had no significant affect on ChE activity. Growth rates were influenced by all en vironmental parameters tested and these effects were interrelated. Optimum conditions for growth appeared to be in loam or sandy soil with 25-30% mois ture at 10-15 degrees C. The GST activity was influenced by soil temperatur e and activity was significantly higher at 15 degrees C than at 5 degrees C and 10 degrees C. Soil type also influenced GST activity and this influenc e was dependent on moisture content. In sandy soil GST activity was signifi cantly lower at 30% moisture than at lower moisture contents, in loam soil GST activity was significantly higher at 15% moisture than at higher moistu re contents, while in clay soil GST activity was not affected by moisture c ontent. These results indicate that in field experiments when evaluating GS T activity soil temperature and soil type need to be consistent between con trol and 'contaminated sites'. ChE activity was only affected by temperatur e, so this should be considered when comparing control and treated areas.