Dissolved and total recoverable metals data is collected and analyzed using the quality control and sampling techniques of USEPA Method 1638, “Determination of Trace Elements in Ambient Waters by Inductively Coupled Plasma – Mass Spectrometry.”

Ohio River Metals Translators (.pdf format)
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Current Clean Metal Data January thru June 2007 (.xls format)
Historic Clean Metal Data can be found here

ORSANCO Clean Metals Program

Historical ORSANCO metals data, collected by standard grab sample techniques for total recoverable metals analysis, indicated violations of Aquatic Life Use Criteria¹. In October 2000 the Commission adopted dissolved metals criteria believing that its total recoverable metals data indicating aquatic life impairment was not consistent with the findings of its fish population studies and that the dissolved portion of most metal contaminants was the more toxic and bioavailable component. Clean metals sampling data, collected since 1998 at three stations and at all Ohio River stations by 2003 has indicated no violations of aquatic life use criteria (<10% violations per year at all stations).

To support dissolved metals criteria and the development of numeric translators for dissolved metals a sampling plan was implemented to characterize dissolved metals concentrations in the Ohio River. Using a modification² to the clean technique devised by the Virginia Department of Environmental Quality for laboratory analysis by EPA method 1638, ORSANCO now samples all 17 of its Ohio River main stem Bimonthly Sampling Program locations for dissolved and total recoverable metals.

Sampling Technique

The clean technique for dissolved and total recoverable metals is based around collection of stream water through a peristaltic pump and Teflon tubing approved by USEPA for the collection of metals samples. Use of this equipment eliminates a sampler’s direct contact with the containers and stream sample itself and minimizes exposure of the sample and container to ambient air. All equipment used for collection is cleaned, rinsed and double-bagged by the laboratory to prevent contamination during transport and storage. Containers and equipment are manipulated with gloved hands only, for the one-person method used by ORSANCO one gloved hand is “dirty hand” and the other “clean hand” in place of a two-person team segregating tasks to one or the other person.

The dissolved portion of the sample is collected using a disposable 0.45 micron filter. One blank sample is collected for each stream sample and filter used. Prior to filtering the sample each filter is pre-wet and rinsed in the field with one-liter of blank water. The same filter is used to collect a one-liter blank. All rinse and blank water is provided by the laboratory. Using stream water the filter is purged of blank water then one liter of stream water is filtered to represent the dissolved portion. One liter of sample water is also transferred to a sample container using the tubing without the filter; this sample represents the total recoverable portion. The filter is discarded after collection of each stream water sample. Samples are held on ice for delivery to the laboratory.

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¹Cd, Cu, Pb, Zn were the cause of “partially supporting” (>10% criteria violations) designations, 305b assessments 1990-1991, 1992-1993, 1994-1995, 1996-1997.

²Procedure modification allows a two-person technique to be performed by an individual sampler.