Researchers Test Composite Samples To Monitor Pollution

University Park, Pa. - The cost of getting into compliance can be reduced by analyzing a mix of soil and water samples from the same contaminated site, according to Pennsylvania State University researchers.

"Analyzing composite samples will lower costs because fewer overall samples are examined," said Glen Johnson, a doctoral researcher at Penn State's Center for Statistical Ecology and Environmental Statistics.

Chemically analyzing individual samples often is the most expensive aspect of pollution monitoring programs. Although most technicians already know about mixing samples, the researchers say their studies refine the method for use in most environmental and public health applications.

"Some information about individual samples is lost upon mixing, but our studies show that critical information is recoverable by retesting select individual samples. The result is unbiased and reliable when properly implemented," said G.P. Patil, director of statistics at the Penn State Center.