concentrations of nitric acid extractable cd , pb and zn in surface soils , predominated by partially decomposed litter , from 15 sites within 9.7 km of the lead-zinc smelter complex at trail , british columbia , canada , attained 36.1 , 12123 , and 1394 ppm but averaged 17.8 , 2607 , and 571 ppm , respectively .
C0006193
british columbia
C0006823
canada