Overview
Wild freshwater clams from a clean upstream site were caged for three days at three downstream river sites and analyzed for ten metals in total soft tissue, with intake and hazard estimates for average and high mollusc consumers. Lead rose after transplantation, most at Kajang, where the wet-weight value exceeded every food guideline cited.
Key numbers
- Lead: 10.15 ± 1.81 µg/g dry weight at the original site, 27.39 ± 14.52 µg/g dw after three days at Kajang (Table 5, p. 9).
- Wet weight (author conversion): lead 1.12 µg/g at Pangsun and 4.11 ± 2.18 µg/g at Kajang; cadmium 0.02 to 0.05 µg/g (Table 8, p. 13).
- Arsenic 2.33 µg/g dw at Pangsun and 10.50 ± 8.16 µg/g dw at Semenyih (Table 5).
Methods (brief)
Pooled soft tissue oven-dried at 60 °C, microwave nitric acid and hydrogen peroxide digestion, FAAS for zinc, copper, nickel, lead and iron, and ICP-MS for manganese, cobalt, chromium, arsenic and cadmium. DOLT-3 and Soil-5 recoveries 73 to 178%. Wet-weight values use site conversion factors of 0.11 to 0.15.
Evidence Fitness
Experimental field exposure (three-day transplant), not market or harvest product. Wide CRM recoveries, and some Table 8 values do not equal Table 5 times the printed conversion factor. The printed year is 2021 (the manifest lists 2020). Raw clam tissue is a proxy for clam-chowder; that thin page is not linked.
Related evidence
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