SREL Reprint #2092

Measuring metals and metalloids in water, sediment, and biological tissues

Michael C. Newman

Introduction: Outbreaks of cadmium (Itai-Itai disease) and mercury (Minamata disease) poisoning during the 1950s made us acutely aware of the adverse consequences of high concentrations of metals in our environment. Quickly, measurement of metals and metalloids became an integral component of our efforts to monitor and correct effects of anthropogenic emissions. The widespread introduction of commercial atomic absorption spectrophotometers (AAS) in the early 1960s contributed enormously to the rapid increase in essential data.
The first quantitative AAS was developed in the 1940s. The number of commercial AAS units was increasing exponentially by 1963. The introduction of flameless atomization methods lowered limits of detection several orders of magnitude by allowing the ground state metal to stay in the analytical light path longer than with flame atomization. Today flame and flameless capabilities are incorporated together in AAS units, allowing convenient measurement of elements present in mg/g to µg/kg concentrations. Well-established, preconcentration procedures are used to remove analytes from interfering matrices as well as to concentrate them in small volumes. Flame and furnace chemistries are now sufficiently well understood to allow effective matrix modification for most elements.
Although measurement of metal concentrations has become routine and convenient, considerable work remains to be done relative to assessing metal bioactivity and speciation. Numerous sample pretreatments exist that imperfectly reflect bioavailable metal. Discussed in detail, such methods and associated assumptions would easily fill an entire book. Further, the rapid changes in this area of metal ecotoxicology would make such a volume obsolete within a few years. Consequently, only the most fundamental techniques for measuring metals dissolved in waters, or present in solid samples are described here. Hopefully, these methods will have the most general utility. Space limitations also exclude adequate description of the cold vapor methods for mercury and hydride-generation methods for arsenic or selenium.

SREL Reprint #2092

Newman, M.C. 1996. Measuring metals and metalloids in water, sediment and biological tissues. pp. 493-516 In: G.K. Ostrander (Ed.). Techniques in Aquatic Toxicology. CRC Press, Inc. Boca Raton, FL.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).