Media Advisory
U.S. Department of the Interior
U.S. Geological Survey
For release: February 20, 2008
Contact: Edward T. Furlong, 303-236-3941, efurlong@xxxxxxxx
Jennifer LaVista, 703-648-4432, jlavista@xxxxxxxx
Earthworms Found to Contain Chemicals from Households and Animal Manure
Earthworms studied in agricultural
fields have been found to contain organic chemicals from household products
and manure, indicating that such substances are entering the food chain.
Manure and biosolids, the solid
byproduct of wastewater treatment, were applied to the fields as fertilizer.
Earthworms continuously ingest soils for nourishment and can accumulate
the chemicals present in the soil.
The chemicals investigated are
considered indicators of human and animal waste sources and include a range
of active ingredients in common household products such as detergents,
antibacterial soaps, fragrances, and pharmaceuticals. Some of the detected
chemicals are naturally occurring such as plant and fecal sterols and fragrances.
All of these chemicals tend to be concentrated in the municipal waste distribution
and disposal process and are referred to as anthropogenic waste indicators
(AWI).
U.S. Geological Survey Scientists
and their colleague from Colorado State University at Pueblo published
their new findings today in Environmental Science and Technology.
The results demonstrate that organic chemicals introduced to the environment
via land application of biosolids and manure are transferred to earthworms
and enter the food chain.
Scientists found 28 AWIs in biosolids
being applied at a soybean field for the first time and 20 AWIs in earthworms
from the same field. Similar results were found for the field where swine
manure was applied. Several compounds were detected in earthworms collected
both from the biosolids- and manure-applied fields, including phenol (disinfectant),
tributylphosphate (antifoaming agent and flame retardant), benzophenone
(fixative), trimethoprim (antibiotic), and the synthetic fragrances galaxolide,
and tonalide. Detergent metabolites and the disinfectant triclosan were
found in earthworms from the biosolids-applied field, but not the manure-applied
field.
Biosolids are made from the sludge
generated by the treatment of sewage at wastewater treatment plants. Biosolids
are used as fertilizer by farmers, landscapers, and homeowners when it
satisfies U.S. Environmental Protection Agency and local regulations for
nutrient, metal, and pathogen content. About half of the 8 million dry
tons of biosolids produced in the U. S. each year are applied to the land.
Biosolids have been found to be rich in AWIs compared to levels in wastewater
treatment plant effluent. In addition, the 1.3 million farms raising livestock
in the U. S. generate an estimated 500 million tons of manure annually,
much of which is also applied to fields as fertilizer for crops.
This study is part of a long-term
effort by the USGS Toxic Substances Hydrology Program to determine the
fate and effects of chemicals of emerging environmental concern in aquatic
and terrestrial environments, and to provide water-resource managers with
objective information that assists in the development of effective water
management practices. It was funded in part by a Research Corporation Cottrell
College Award and a Faculty Research Grant from Eastern Washington University.
More information can be found by visiting: http://toxics.usgs.gov/highlights/earthworms.html
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