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.I. 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 



