| Abstract | Three marine biological tissue samples (dogfish muscle, scallops, swordfish muscle) were distributed to 51 Canadian and 3 American laboratories, 43 of which submitted results. Values were collated for the six metals for which all had been asked to analyze: copper, zinc, arsenic, cadmium, mercury and lead. Most laboratories perform well for copper and zinc at the concentration studied. Performance is also generally good for cadmium and lead where the metal concentrations are repectively greater than a few tenths and several mg/kg of dry tissue. Less than forty percent of the labs produced satisfactory results for cadmium at the 0.08 mg/kg level in dogfish, and less than twenty-five percent for lead in swordfish at the 0.3 mg/kg level. Less than fifteen percent could cope with the even lower level of lead in the scallops. A good part of the difficulty lies in the insufficient sensitivity of flame atomic absorption and plasma emission procedures for these metals. Those that analyze for mercury (less than half the participants) generally do well at levels greater than 1 mg/kg but only a small number did well with the scallops sample at 0.05 mg/kg of mercury. About half the laboratories submitted results for arsenic with generally good performance. With but few exceptions, sample preparation techniques appear to be adequate for the six metals in the three samples. Except for low mercury and cadmium, performance is comparable to recent International Council for the Exploration of the Sea studies. Results for sodium, calcium, chromium, manganese, iron, and nickel are also tabulated. |
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