US Food and Drug Administration survey of cadmium, lead and other elements in clams and oysters.

Abstract

In Fiscal Years 1985/1986, the US Food and Drug Administration conducted a survey of cadmium, lead and other elements in fresh clams and oysters collected from US coastal areas in use for shellfish production. Shellfish were analysed for cadmium and lead by using a dry ash-anodic stripping voltammetric method. Other elements (aluminium, arsenic, beryllium, calcium, chromium, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, phosphorus, potassium, selenium, sodium, strontium, vanadium and zinc) were determined by using inductively coupled plasma-atomic emission spectrometry, direct current plasma-atomic emission spectrometry or hydride generation atomic absorption spectrometry. A total of 75 hardshell clam, 59 softshell clam, 104 Eastern oyster and 40 Pacific oyster samples were analysed for cadmium and lead. Average levels found were 0.09, 0.05, 0.51 and 1.1 mg/kg wet weight for cadmium and 0.24, 0.30, 0.11 and 0.06 mg/kg wet weight for lead in hardshell clams, softshell clams, Eastern oysters and Pacific oysters, respectively. The other 19 elements were determined in 10-104 samples of the four types of shellfish. These data provide baseline values for elements in clams and oysters harvested from US coastal waters.