USGS Scientific Investigations Report 2012-5069  - Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007

Table 2. Median, range, and percentage of values below the method quantitation limit of microcystin concentrations in different size fractions collected between July 7 and September 14, Upper Klamath Lake, Oregon, 2007–09. 

[Microcystin values less than 0.1 µg/L (not censored) were detected, but appear to be less than the method quantitation limit after calculating aqueous concentrations from the total extracted biomass and sample volumes. The summary percent of total toxins each size fraction represents does not include 2007 data. Dissolved microcystin concentrations were not measured in 2007. Abbreviations: MQL, method quantitation limit; >, greater than, <, less than; µm, micrometer; µg/L, micrograms per liter; µg/mg, micrograms per milligram; –, samples not analyzed (no data); NA, not applicable] 

Analyte	2007				2008					2009
Analyte	Number of samples	Median (µg/L)	Range (µg/L)	<MQL (percent)	Number of samples	Median (µg/L)	Range (µg/L)	< MQL (percent)	Median percentage of total	Number of samples	Median (µg/L)	Range (µg/L)	<MQL (percent)	Median percentage of total
Dissolved (µg/L)	0	–	–	–	20	0.27	0.18–1.10	0	85.8	67	1.49	< MQL–4.87	15	43
Microcystins
Small (1.5–63 µm) (µg/L)	18	< MQL	< MQL–0.04	56	20	0.03	< MQL–0.10	35	1.5	67	< MQL	< MQL–0.10	57	0
Large (>63 µm) (µg/L)	18	1.87	0.44–17.4	0	20	0.20	0.01–1.55	0	11.7	67	1.37	0.001–24.4	0	56
Large (>63 µm) (µg/mg)	18	0.09	0.03–1.42	0	20	0.02	0.002–0.36	0	NA	67	0.15	0.001–0.96	0	NA

Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007–09

Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007–09 