Earthworms and TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) in Seveso

Organic Contaminants in Terrestrial Food Chains

“…7 ,8 The relationships between soil and earthworm concentrations were linear when soil concentrations ranged from> 0·1 to 10 ng/g. 8 Earthworms reached a steady state concentration within 7 days exposure in a laboratory study of TCDD uptake by earthworms in soil with TCDD concentrations from 0·05 to 5·0 lLg/g.9 Unlike the Seveso observations, there was a trend for greater relative uptake and retention at the lower soil concentrations. The bioconcentration ratio was about 5 to 1 at the 0·05 lLg/g concentration and less than 1 to 1 at other concentrations.…”

“…41t was concluded from cast production that earthworm activity was more or less normal in the area around Seveso most highly con-taminated by TCDD but there may have been an effect on the ratios of A. caliginosa to A. rosea, which were the most abundant species. 8 Laboratory studies, however, failed to detect adverse effects on A. caliginosa and L. rubel/us at TCDD concentrations as high as 5.0 IJ-g/g. 9 …”

Do natural catastrophic events and exceptional climatic conditions also affect parasites?

“…Collecting earthworms in the contaminated area, it was possible to demonstrate that these worms contributed to moving dioxin from the surface into the soil. Of course, earthworms are not parasites, but excellent intermediated and/or paratenic hosts for many parasites (Martinucci et al ., 1983 ). Unfortunately, to our knowledge, studies targeted to assess dioxin effects on parasites either free-living stages or present in contaminated hosts haven't been conducted.…”