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How Reliable are Chemical Property Data in the Literature?

Graph showing the variability of original log Kow data
Graph showing the variability of original log octanol-water partition coefficient (KOW) data for DDT plotted as a function of publication date. Modified from Figure 7, Pontolillo and Eganhouse, 2001.

A recent U.S. Geological Survey (USGS) report raises the question of whether scientists and managers can rely on the scientific literature for data on physical and chemical properties that describe how contaminants behave in the environment. Environmental regulations, ecosystem restoration activities, and hazardous waste clean-up actions depend on predicting the environmental fate and transport of contaminants. Scientists who make these predictions rely on the accuracy of physical and chemical property data in the literature, such as water solubility (SW) and octanol-water partition coefficient (KOW). Reduced confidence in the values of these physical and chemical properties casts doubt on the environmental predictions scientists make and the decisions based on them.

Data Questions

Two USGS scientists assessing sediments contaminated with DDT found to their surprise that the data on the physical and chemical properties of DDT were not as reliable as they first thought. After an extensive 2-year search of the literature involving over 700 references, they found errors in reporting data and references, and inadequate documentation of procedures used to measure coefficients. Their report, which has been downloaded over 8,000 times, has sparked a worldwide debate on the reliability of the physical and chemical property data (coefficients and other measurements) for many common environmental contaminants. One camp is of the opinion that it is an old problem and there are several workarounds, while the other camp feels that the poor quality of the data casts doubt on the validity of the science the workarounds are based on. Both camps agree that there is a need for higher quality data on the physical and chemical properties (coefficients, constants, and other measurements) that govern the fate of contaminants.


"The USGS claims are especially significant because of new U.S federal data quality guidelines issued by the White House Office of Management and Budget in January that establish new benchmarks for the scientific data used by federal agencies to craft regulations and policy. …some observers suggest that the uncertainties uncovered by the USGS report may not withstand this unprecedented scrutiny."
Renner, Rebecca, 2002, The KOW Controversy: Environmental Science and Technology, v. 36, no. 21, pp. 411A-413A.

The concern over this issue is heightened by the Data Quality Act (Public Law 106-554, H.R. 5658, Section 515), which requires federal agencies to set guidelines that guarantee "the quality, objectivity, utility, and integrity of information" they produce. The White House Office of Management and Budget has issued guidelines for federal agencies to develop to meet the standards of the act. Whatever the outcome of the debate, the USGS report and the new act have sparked a growing movement to create higher quality measurements of the properties, such as water solubility (SW) and octanol-water partition coefficient (KOW), that many environmental studies and policy decisions are based on.

The Report

Pontolillo, J., and Eganhouse, R.P., 2001, The search for reliable aqueous solubility (SW) and octanol-water partition coefficient (KOW) data for hydrophobic organic compounds--DDT and DDE as a case study : U.S. Geological Survey Water-Resources Investigations Report 01-4201, 51 p.

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