Subject: Dioxin proliferation through sludge -Reply
Date: Thu, 12 Mar 1998 14:36:53 -0500
From: DAVID CLEVERLY <CLEVERLY.DAVID@EPAMAIL.EPA.GOV>
To: Carl@websida.com
CC: TUXEN.LINDA@EPAMAIL.EPA.GOV
Carl: Hi, I am responding to your e-mail to Linda Tuxen. Fist, the dioxins will not behave exactly the same way as PCBs when incorporated into soil from the land application of sludge. Although the low molecular weight PCBs, i.e., PCB 118, may readily volatilize from soils, CDDs and CDFs will not. These compounds evidently bond more tightly to the carbon fraction of the soils. Plant uptake is also expected to be nil. Since these compounds are insoluble in water, they cannot be conducted through the roots, up the stem and into the leaves. The major concern, however, is that foraging farm animals may graze on this land and consume soils that have become contaminated with CDDs/Fs. If this occurs, then there is a high likelihood on ingesting soils, and bioaccumulating dioxins in the fat of animal. Humans who consume beef and milk from these animals could be potentially exposed. Another concern is of an ecological nature. There have been studies of the land application of paper mill sludge in forested areas that suggests this material leads to an increase in the insect population. When this occurs, it attract greater numbers of song birds. The song birds may eat the contaminated earth worms, for example, and acquire a body burden of the 2,3,7,8-substituted Ds and Fs. This may lead to reproductive toxicity within certain avian species and a subsequent decline in the local song bird population. I hope this addresses your major questions.
David Cleverly
>>> "Carl R. Lindstrom" <Carl@websida.com> 03/13/98 06:34am >>>
Thank you David for your response - very interesting and complex isn't it?. So earthworms could be a collector and moving mechanism of the soil contained dioxins? Do you know if anyone has studied if the worms accumulate and concentrate dioxins as they pass a lot of soil through their digestive system? Also. I have heard about the grazing ingestion of soil by cows - apparently up to a couple of pounds of soil per day... what about wildlife ... deer and moose are more leaf and upper growth eaters but badgers, moles and wood chucks who are predominantly soil inhabitors ...any data/thoughts about that?
Carl
Carl:
A couple of years ago, EPA evaluated the ecological risks associated with spreading dioxin-contaminated paper mill sludge on land. Certain avian species were found to exceed the reference dose for reproductive toxicity by a factor of 3-10 fold. I do not have a copy of this assessment. But the bioaccumulation route of interest was: dioxin-sludge to soil to earthworm to bird. You many contact Maurice Zeeman at 202-260-1240 and Bob Morcick at 202-260-1265 for further information on this assessment.
Dave
>>> "Carl R. Lindstrom" <Carl@websida.com> 03/11/98 10:45pm >>>
Dear Linda Tuxen:
Any estimate of the impact and further proliferation of dioxins as they
are spreadwith sludge directly onto farm land. Any path similar to PCB
evaporating from top-soil layer and adsorbed in plant tissue? Anything
on the spreading and concentrating processes?
Thoughts and leads would be most appreciated.
Carl Lindstrom