PREPARATION AND CHARACTERIZATION OF 
A MARINE REFERENCE MATERIAL FOR 
TRACE ELEMENT DETERMINATIONS 
Peter F. Rogerson and Walter B. Galloway 
Environmental Research Laboratory 
U.S. Environmental Protection Agency 
South Ferry Road 
Narragansett, R.l. 02882 
ABSTRACT 
A reference material for marine molluscan trace element determinations has 
been developed. It consists of 637 clams, Arctica islandica, that have been 
homogenized together and subsequently divided into 476 samples. A 
representative subsample of these has been analyzed for trace element 
concentrations. Of the 14 elements measured, 10 had relative standard 
deviations from the mean of 7% or less. 
INTRODUCTION 
The study of pollution in marine systems often involves the measurement of 
trace element concentrations in organisms over extended periods of time (1,2). 
Development of valid time trends from such data requires a strict quality 
control program at every stage of data collection, from field sampling through 
final statistics, to ensure that data from any single point in time is comparable 
to that collected at all other times. This paper describes some of the efforts 
undertaken to provide control over the laboratory analysis of marine organisms 
for trace element concentrations. Specifically, we describe the preparation and 
characterization of an in-house reference material which can be used as a 
benchmark sample for quality control, a known sample for methods 
development, or an intercalibration sample. 
EXPERIMENTAL 
Marine molluscan samples are prepared for flame atomic absorption 
spectroscopy as follows (3): 
1. Thaw sample. 
2. Using stainless steel instrument, shuck into a dry, labeled, tared 
beaker. Determine wet weight. 
1 
