The Fate of Wastewater-Derived Contaminants in Effluent-Dominated Waters
A significant fraction of the flow of many rivers consists of municipal
wastewater effluent. The discharge of large volume of wastewater
can result in the exposure of humans and aquatic organisms to a variety
of different wastewater-derived contaminants including a several
carcinogens and endocrine-disrupting compounds. For example, the
drinking water supply of some communities is taken from rivers that are
subjected to significant upstream wastewater effluent discharges (e.g.,
Cincinnati’s drinking water intake is located on the Ohio River
approximately 200 miles downstream of Pittsburgh’s wastewater
effluent discharge point) and wastewater effluent frequently contains
elevated concentrations of carcinogenic disinfection byproducts, such
as nitrosodimethylamine (NDMA). Many of the wastewater-derived
contaminants are removed as they pass through surface waters through a
combination of chemical, biological and physical processes. At
present, little information is available on the factors determining the
rates at which these compounds are removed from surface waters.
Research conducted by members our group has focused on the different
mechanisms through which wastewater-derived contaminants are removed
from the aquatic environment. One approach that we have been
developing relies upon the development of surrogates and indicators of
wastewater-derived contaminants as a way of quantifying different
removal processes. For this type of research the fluctuations in
contaminant concentrations can make it very difficult to detect small
decreases in concentrations that could occur through removal
processes. Therefore, we have been especially interested in
identifying surrogates and indicators that depend on ratios of
contaminants rather than absolute concentrations. In the initial
phase of her doctoral research, Lorien Fono examined enantiomers of the
pharmaceutical propranolol. Her research showed that the ratios
of the two enantiomers of propranolol could be used to quantify
biotransformation that occurred in wastewater treatment plants(see news stories on this research from Environmental Science & Technology and Nature Medicine). Application of this tool indicated that the propranolol
detected in certain watersheds was attributable to leaking sewers and
other sources of raw sewage. This observation is particularly
relevant because the leaking sewers are likely sources of
disease-causing pathogens.
More recently, we have been
applying a suite of
other tracers to stud the attenuation of wastewater-derived
contaminants
in surface waters. As part of this research, we have studied the
Trinity River in Texas, where most of the flow consists of wastewater
effluent for a period of about two weeks. During this period, most of
the compounds slowly degrade through biotranformation and photolysis.
By using these tracers in conjunction with hydrologic models that
track the fraction of the overall flow that consists of wastewater
effluent we hope to learn more about the risks to aquatic ecosystems
and human health posed by wastewater-derived contaminants.
Figure 1: Average concentrations of human
pharmaceuticals in the Trinity River. Travel time refers to
estimated travel time from the Dallas Metropolitan area.
For more information see:
Fono L.J. and Sedlak D.L. (2005) Use of the chiral pharmaceutical propranolol to identify sewage discharges into surface waters. Environ. Sci. Technol., 39, 9244-9252. DOI: 10.1021/es047965t
Fono L.J. Kolodziej E.P. and Sedlak D.L. (2006) Attenuation of
Wastewater-Derived Contaminants in an Effluent-Dominated River. Environ Sci. Technol. In press.
Sedlak D.L., Huang C.H. and Pinkston K.E. (2004) Strategies for
selecting pharmaceuticals to assess attenuation during indirect potable
water reuse. In: Pharmaceuticals in the environment. K.
Kümmerer, ed. Springer Publishers, Berlin.
Pinkston K.E. and Sedlak D.L. (2004) Transformation of aromatic ether-
and amine-containing pharmaceuticals during chlorine disinfection.
Environ. Sci. Technol., 38, 4019-4025.
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The Fate of
Hormones in the Aquatic Environment
The Fate of Wastewater-Derived Contaminants in Effluent-Dominated Waters
Formation
and Removal of NDMA in Water Recycling Systems
Oxidation of Contaminants by Iron Nanoparticles in the Presence of Oxygen
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