Table 2.
Concentrations of microplastics (MPs, >~25 µm–5 mm) along the Mississippi Gulf Coast during freshwater inflows in the summer and fall of 2019 and winter of 2020 a.
| Site # | Location/Name | Open Spillway | Closed Spillway | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n | Mean (Range) (MPs/L) |
SD | Salinity (ppth) b | n | Mean (Range) (MPs/L) |
SD | Salinity (ppth) b | ||
| 1 | St. Joe’s Pass | 2 | 196 (12–381) | NA | 0.39 | 1 | 309 | NA | NA |
| 2 | Waveland Reef | 5 | 73 (55–153) | 50 | 0.32 | 2 | 174 (39–309) | NA | 16.4 |
| 3 | Bay St. Louis | 4 | 49 (18–80) | 25 | 0.67 | 3 | 50 (0–116) | 60 | NA |
| 4 | St. Stanislaus Reef | 4 | 36 (18–65) | 20 | 0.40 | 5 | 121 (34–99) | 76 | 16.8 |
| 5 | TNC Bay St. Louis | 2 | 69 (38–100) | NA | 0.54 | 3 | 39 (15–73) | 30 | 15.3 |
| 6 | Henderson Pt. Reef | 3 | 30 (20–50) | 17 | 3.14 | 5 | 139 (20–198) | 76 | 17.2 |
| 7 | Pass Christian | 12 | 178 (55–328) | 223 | 8.1 | 3 | 176 (124–202) | 44 | 4.7 |
| 8 | Kittiwake Reef | 4 | 121 (22–196) | 82 | 4.21 | - | NA | NA | 18.9 |
| 9 | Biloxi Bay | 8 | 179 (64–278) | 82 | 13.5 | 3 | 94 (55–116) | 34 | 9.3 |
| 10 | Middle Bay | 6 | 192 (39–326) | 107 | 19 | 3 | 141 (41–263) | 112 | 17 |
a Data are blank-subtracted; NA = not available. b ppth = part per thousand; oysters require at least 8 ppth salinity to grow (Virginia Dept. of Environmental Quality).