Lokugama Hewage Panchamee Dharmadasa

Doctor of Philosophy, (Health Science)
Study Completed: 2020
College of Health


Thesis Title
Investigations into the Uptake and Effects of Long-term Cadmium and Arsenic Exposure on the Earthworm Eisenia fetida

Cadmium and arsenic are common soil contaminants that are highly toxic in trace amounts. They could have adverse impacts on soil-dwelling organisms and food crops. Ms Dharmadasa investigated the uptake of cadmium and arsenic by the earthworm Eisenia fetida. She examined the effects of the uptake (for up to three generations) and the potential for recovery when exposure ceases. Both elements accumulated in worm tissue as level and time of exposure increased. This accumulation changed gene expression and had a negative impact on growth and reproduction. Depending on exposure levels, the effects of cadmium could be reversed when worms were returned to clean soil. Arsenic could stimulate first-generation growth and cocoon production. However, effects were negative for subsequent generations. Her results have implications for how we might manage the impact of these toxic elements as environmental contaminants.

Dr Nick Kim
Dr Yan Li
Professor Murray Cox
Dr Michelle Thunders
Dr Barry Palmer