Table 1.
Environmental factors and large zooplankton Hg data for Malletts and Missisquoi Bays on sample dates in 2005–2008. Data are from the Lake Champlain Monitoring Program. TP = total phosphorus, TN = total nitrogen, Chl a = Chlorophyll a, na = not available. Mean and standard error (in parentheses) are given for THg, MeHg, and %MeHg in large zooplankton.
| Bay and sampling date
|
TP (mg/L) | TN (mg/L) | Chl a (mg/L) | Phytoplankton density (cells/ml) | Zooplankton density (no./ml) | Mercury in large zooplankton, DW (>202 μm)
|
||||
|---|---|---|---|---|---|---|---|---|---|---|
| Year | Month | THg (ng/g) | MeHg (ng/g) | MeHg (%) | N | |||||
| Malletts Bay | ||||||||||
| 2005 | August | 8.4 | 0.23 | 3.76 | na | na | 78 (14) | 18 (0.7) | 25 (3) | 3 |
| 2006 | August | 8.6 | 0.32 | 4.54 | 239,000 | 31,000 | 71 (3) | 28 (0.4) | 39 (1) | 3 |
| 2007 | June | 9.8 | 0.40 | 2.90 | 48,800 | 63,600 | 333 (28) | 25 (4) | 78 (17) | 3 |
| 2007 | August | 7.0 | 0.30 | 2.95 | 166,000 | 27,900 | 620 | na | na | 1 (July) |
| 2008 | June | 17.1 | 0.35 | 2.35 | 42,500 | na | 308 (56) | 91 (18) | 30 (4) | 3 |
| 2008 | August | 13.7 | 0.32 | 3.70 | 62,500 | na | 195 (54) | 98 (4) | 54 (13) | 2 |
| Missisquoi Bay | ||||||||||
| 2005 | August | 74.7 | 0.52 | 29.00 | na | 321,000 | 24 (1) | 3 (0.2) | 14 (1) | 3 |
| 2006 | August | 43.0 | 0.63 | 17.00 | 1,360,000 | 118,000 | 30 (1) | 10 (0.4) | 34 (3) | 3 |
| 2007 | June | 48.0 | 0.70 | 21.30 | 6370 | 10,300 | 65 (42) | 33 (14) | 46 (7) | 3 |
| 2007 | August | 50.8 | 0.35 | 4.84 | 179,000 | 9350 | 440 | na | na | 1 (July) |
| 2008 | June | 41.9 | 1.00 | 14.60 | 150,000 | na | 74 (6) | 31 (5) | 42 (10) | 2 |
| 2008 | August | 63.8 | 0.59 | 26.80 | 22,200,000 | na | 25 (20) | 4 (2) | 27 (12) | 2 |