Scientific Investigations Report 2008–5168
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2008–5168
Table 6. Changes in method reporting limits for selected constituents sampled in Coeur d’Alene Lake, Idaho, calendar years 1991–92 and water years 2004–06.
[Abbreviations: μg/L, microgram per liter; MRL, method reporting limit]
Constituent | Study | ||||||||
---|---|---|---|---|---|---|---|---|---|
1991–92 | 2004–06 | ||||||||
MRL (μg/L) | Number of analyses | Number of non-detected values | Percent non-detected values | MRL (μg/L) | Number of analyses | Number of non-detected values | Percent non-detected values | ||
Total phosphorus | 1.0 | 325 | 34 | 10 | 4.0 | 402 | 2 | 0.50 | |
Dissolved orthophosphate | 1.0 | 323 | 182 | 56 | 6.0 | 404 | 314 | 78 | |
Total ammonia plus organic nitrogen | 200 | 312 | 244 | 78 | 60 | 403 | 1 | .25 | |
Dissolved inorganic nitrogen | 7.0 | 327 | 9 | 2.8 | 26 | 404 | 63 | 16 | |
Dissolved nitrite plus nitrate | 5.0 | 327 | 61 | 19 | 16 | 404 | 90 | 22 | |
Dissolved ammonia | 2.0 | 327 | 32 | 10 | 10 | 404 | 189 | 47 | |
Total cadmium | 1.0 | 126 | 117 | 93 | .040 | 404 | 44 | 11 | |
Total lead | 1.0 | 126 | 30 | 24 | .060 | 404 | 1 | .25 | |
Total zinc | 10 | 126 | 17 | 13 | 2.0 | 402 | 11 | 2.7 |