Sterols as bio-markers for waste impact and source characterization in stream sediment.

Sterols are involved in life processes in organisms and are therefore potential biomarkers for assessment of environmental ecosystems. Current data indicate that sterols are persistent in stream sediments, since sterols are not sufficiently soluble in water to be readily detected in water samples. Stream sediment therefore can act as an integrating exposure index of pollution for animal or human waste in streams. The study reported here was conducted in two phases. Phase 1 involved development and validation of a simplified method for the determination of sterols, and Phase 2 involved application of that method to evaluate actual environmental samples. Stream sediment samples from agricultural settings, wastewater-treatment-facility outfalls, and recreational state parks in Iowa and Pennsylvania were analyzed for sterol compounds. Sterol profiles differ considerably among animals, and the study distinguished sterol profiles within stream sediments. Feces from different animal species were also analyzed to provide reference sterol profiles. Individual-sterol and total-sterol concentrations were determined. Sterols were observed in 73.4 percent of environmental sediment samples tested (n = 124) and at 100 percent of the sites (n = 18). Coprostanol, a key indicator of fecal pollution, was observed in 38.7 percent of the environmental sediment samples tested and at 72.2 percent of the sites. Samples were collected from multiple points at selected sites, and duplicate samples were analyzed at a frequency of 16.1 percent. One to five months later, additional samples were collected from the duplicate locations and were analyzed. Data generated by the study provide a basis for stream sediment monitoring that enables the chronological recording of waste impact; this method may be coupled with other measurements to determine the extent and possible source of stream contaminants.

Quality of Packaged Ice Purchased at Retail Establishments in Iowa.

The quality of packaged ice sold in retail establishments is not uniformly regulated, and its cleanliness and safety have not been recently evaluated. This investigation examined the physical, chemical, and microbiological characteristics of 18 brands of packaged ice purchased at Iowa stores. Twenty-two ice samples were melted under controlled conditions and portions were analyzed for selected analytes established as primary and secondary drinking water standards by the U.S. Environmental Protection Agency. Only one sample exceeded a primary health standard under the Safe Drinking Water Act, and that sample contained Klebsiella pneumoniae , a member of the total coliform group of bacteria. Several samples of ice manufactured in convenience stores had heterotrophic plate counts which exceeded the recommendation (<500 CFU/ml) established by the Packaged Ice Association, and none of the manufacturers met the minimum package labeling recommendations of that organization. Ice produced in convenience stores was of consistently poorer microbiological quality than ice produced by major commercial manufacturers. While ice consumption does not represent an immediate threat to personal or public health, the potential for disease transmission exists in an industry which is voluntarily self-regulated.