Table 2.
Copper LC50 or EC50 4-d acute value estimates for white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss)
| Species | Life stage (dph) | Average fish weighta (g) | Average fish lengtha (cm) | LC50 (µg/L), mortality onlyb | EC50 (µg/L), mortality + LOE + immobilizationb | EC50 normalized for EPA 's BLM-standard waterc (µg/L) | Hardness-dependent acute FAVd for hardness of the test waters (µg/L) | BLM-based acute FAVe for test water chemistry (µg/L) |
|---|---|---|---|---|---|---|---|---|
| Sturgeon | ||||||||
| 2f | 0.03 (0.0) | NM | >23.6 | 2.67 (2.33–3.05) | 1.51 | 35.8 | 7.9 | |
| 16f | 0.04 (0.01) | 20.9 (0.57) | 7.14 (5.0–10.1) | 4.32 (2.69–6.94) | 2.59 | 35.4 | 7.6 | |
| 30 | 0.15 (0.04) | 29.2 (2.62) | 16.4 (13.4–20.2) | 6.31 (5.26–7.57) | 4.2 | 35.8 | 7.0 | |
| 44 | 0.46 (0.11) | 44.9 (3.90) | >49.8 | >49.8 | >34.1 | 34.6 | 7.0 | |
| 61 | 1.3 (0.33) | 64.2 (6.01) | <90 | 30.8 (25.0–37.9) | 21.98 | 35.0 | 7.0 | |
| 72 | 2.02 (0.80) | 77.7 (11.08) | 74 (60–90) | 74 (60–90) | 58.96 | 34.1 | 6.4 | |
| 89 | 3.73 (1.06) | 97.57 (10.48) | 90 (77–108) | 21.9 (15.9–30.3) | 17.25 | 32.4 | 6.4 | |
| Trout | ||||||||
| 1 | 0.08 (0.12) | 14.3 (1.74) | 62.9 (56.6–69.9) | 62.9 (56.6–69.9) | 47.8 | 32.4 | 6.4 | |
| 18 | 0.10 (0.02) | 24.33 (1.06) | 56.6 (50.6–63.4) | 56.6 (50.6–63.4) | 43.4 | 35.2 | 5.9 | |
| 32 | 0.12 (0.03) | 26.67 (1.97) | 59.9 (53.1–67.7) | 59.9 (53.1–67.7) | 42.42 | 35.8 | 6.6 | |
| 46 | 0.21 (0.03) | 31.1 (1.91) | 59 (49.2–70.9) | 50.1 (41.8–59.9) | 37.84 | 35.2 | 6.2 | |
| 60 | 0.37 (0.12) | 37 (3.50) | 42.4 (34.7–51.8) | 40.8 (33.5–49.8) | 32.21 | 34.8 | 6.0 | |
| 74 | 0.41 (0.12) | 40.2 (3.16) | 60.6 (54.9–66.2) | 60.6 (54.9–66.2) | 44.34 | 35.6 | 6.3 | |
| 95f | 0.70 (0.18) | 45.43 (3.89) | 19.1 (15.8–23.0) | 19.1 (15.8–23.0) | 15.24 | 34.4 | 6.2 | |
Values in parentheses for average fish weight and average fish length (n = 10 for white sturgeon; n = 30 for rainbow trout) are the standard deviation.
Values in parentheses for LC50s and EC50s are the 95% confidence intervals.
For BLM-normalized EC50s, the BLM was used to extrapolate the actual EC50s to those expected for the “BLM-standard” water conditions, which is a moderately hard water, with pH of 7.5 and 0.5 mg/L dissolved organic carbon, following the approach used by the USEPA 30. The FAV for BLM-standard water is 4.67 µg/L 30.
USEPA 53 FAV, calculated for the test hardness, which is equivalent to 2X the Washington acute water hardness standard for copper.
USEPA 30 FAV, calculated for the individual measured test water chemistries.
The most sensitive life stage for the respective species.
Control survival for the 16 dph test was less than 90 percent, thus the EC50 calculation is not definitive.
LC50 = median lethal concentration; EC50 = median effective concentration; dph = days posthach; LOE = loss of equilibrium; BLM = biotic ligand model; FAV = final acute value; NM = not measured; USEPA = US Environmental Protection Agency; AWQC = acute water-quality criteria.