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Metals in nereid polychaetes: the contribution of metals in the jaws to the total body burden

Analyses of the jaws of Nereis virens have shown that various metals are present in detectable quantities; in order of decreasing concentration these are (with ranges (μg/g dry weight) in brackets) – zinc (10130–18360), sodium (1150–2690), magnesium (616–1080), calcium (531–1130), iron (444–1180), manganese (510–952), potassium (270–960) and copper (4–80), with also lead (8·7), cadmium (0·1) and silver (< 0·1). The most concentrated metal, zinc, is not uniformly distributed throughout the jaw, the highest level occurring in the distal tip (45740 μg/g), falling to a much lower level in the basal part (1790 μg/g). The contribution of some jaw metals to the total body burden varies according to body size: in small worms the jaw zinc accounts for over 40% of the total but in large worms it accounts for 30% or less; jaw manganese contributes over 50% of the total in small worms, dropping to about 20% with increasing size. For silver, cadmium, copper, iron and lead the jaws generally contribute less than 1% to the total body burden.