Figure 3: Carbon-normalized excess simultaneously extracted (SEMX) metals for the white sturgeon sediment toxicity tests. A sediment with low carbon-normalized SEMX < 130 µmol/gOC (denoted by horizontal dashed line) should pose low risk of adverse biological effects due to SEMs (i.e., cadmium, copper, lead, or zinc). For sediments with high carbon-normalized SEMX >3000 µmol/gOC (denoted by a horizontal solid line), adverse biological effects due to SEMs may be expected. For sediments with intermediate carbon-normalized SEMX >130 µmol/gOC and <3000 µmol/gOC there is considerable uncertainty about whether effects are expected [32]. Treatments included artificial sediment (CTRL), reference sediments from Lower Arrow Lake (LALL) and Genelle (GE), and site sediments from Deadman’s Eddy (DE), Northport (NP), Little Dallas (LD), Upper Marcus Flats (UMF) and Lower Marcus Flats (LMF).