The area contributing recharge to this aquifer is undergoing rapid growth, generating more wastewater. We found that nitrate, a major component of wastewater and a nutrient that can degrade water quality, has increased in the creeks in this area.
In all, 56 compounds were detected in samples collected approximately monthly during 2003-05 at the intake for the Clackamas River Water plant. On the basis of this screening-level assessment, adverse effects to human health are assumed to be negligible.
Reports concentration of organic compounds here, to serve as a baseline against which future measurements can be compared and to provide a general assessment of the quality of local water treatment efforts.
We identified six compounds at concentrations less than human-health benchmarks, but within a factor of 10 of those limits. Those compounds might warrant further study to understand their transport and fate within the watershed.
The 258 organic compounds in this assessment are man-made: pesticides, solvents, gasoline hydrocarbons, personal-care and domestic-use products, pavement and combustion-derived compounds. None were found in concentrations deemed dangerous at this time.
Measured concentrations of many compounds in water people use. Some compounds are regulated as health hazards; a few of these were over the benchmark limits. Others may become issues of concern, so studies such as this give us helpful background levels.