AUSTRALIA PESTICIDES, PATHOGENS & CHEMICALS IN SEWAGE SLUDGE POSE RISK TO LIVESTOCK &
HUMANS – UPTAKE BY PLANTS
http://www.eidn.com.au/ukcsirosewagesludge.htm
http://www.eidn.com.au/ukcsirosewagesludge.htm#(iii)%20Toxic%20Organics
"Many pesticides such as dieldrin, heptachlor and chlordane have been found in sewage sludge, along
with a variety of other chlorinated organic compounds such as polychlorinated biphenyls. Such
compounds when ingested by animals tend to accumulate in the body fat where they can persist for many
months or years. Some plants such as lucerne, cowpeas or oats are known to take up organochlorine
pesticides into their tissues, although the route of uptake has not been clearly determined. As such
compounds tend to become more concentrated in each animal group up the food chain, human beings are
at significant risk of having the highest concentrations of these pesticides, which have caused cancer in
laboratory animals."
"There have already been several incidents in Australia (e.g. Werribee) of cattle contaminated with
organochlorine residues after grazing on sludge treated land. A major problem appears to be that close
cropping animals tend to ingest significant quantities of soil as well as plants."
"In sharp contrast to these microtoxins, laundry detergents and surface cleaners are produced in large amounts and
are quantitatively the most important synthetic organic compounds in municipal wastewater. Compounds such as linear
alkylbenzenesulphonates (LAS) and nonylphenolpolyethoxylates (NPnEO), although partially degraded under aerobic
conditions, are lipophilic and not degraded anaerobically. Consequently, they and their degradation products,
such as nonylphenol, become highly enriched in sewage sludge at concentrations in the range 1-10g/kg
total dry solids. This represents a concentration at least 1,000 fold greater than found for the chlorinated
organic micropollutants.
The fate of such material in soil has been examined (Siegrist et al., 1988). The study found that high fluxes of these
materials are present when sludge is applied to agricultural land and even three months after the last application of the
sewage sludge about 10% of the material remained undegraded, resulting in soil concentrations in the mg/kg range. It
was recommended that the long term fate of such compounds in the soil be thoroughly investigated. "
http://www.eidn.com.au/ukcsirosewagesludge.htm#(iii)%20Toxic%20Organics (i) Pathogens
Most pathogens in the raw sewage are concentrated into the sewage sludge and present a considerable hazard
when any handling of the sludge is contemplated. They can be separated into four categories - viruses, bacteria,
protozoans and larger parasites such as human roundworms, tapeworms and liver flukes. Such microorganisms can
cause disease in humans, the transmission occurring in several ways eg by inhaling sludge aerosols or dust, by eating
vegetables or fruit contaminated by sludge, drinking water contaminated by run-off or by eating meat from livestock
infected whilst grazing pastures fertilised with sludge.