E Water Quality
SITE : Lake Center
SOURCE: Akita Prefectural Government
2008 2009 2010 2011 2012 2013 2014 2015
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E5 COD [mg l-1] 5.9 6.3 6.3 6.3 7.9 5.7 6.0 6.2
E7 T-N [mg l-1] 0.70 0.71 0.83 0.94 1.4 0.83 0.64 0.78
E8 T-P [mg l-1] 0.090 0.070 0.073 0.084 0.11 0.069 0.070 0.065
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* yearly average value
SITE : Deepest point
YEAR : 1985-1986
SOURCE: Data Book of World Lake Environments
E2 pH
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 8.3 7.9 8.3 7.6 8.9 8.5 7.9 7.6 7.5
2.0 - - - 8.2 7.9 8.3 7.6 8.8 8.3 7.8 7.6 7.5
5.0 - - - 8.2 7.9 7.5 7.5 7.5 7.6 7.7 7.6 7.5
E3 SS [mg l-1]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 7 5 5 5 5 6 4 4 13
2.0 - - - 7 6 5 6 6 7 5 4 14
5.0 - - - 8 6 6 5 4 5 1 4 14
E4 DO [mg l-1]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 12 9.8 9.1 8.4 9.5 8.3 9.1 10 13
2.0 - - - 11 9.8 9.1 8.2 9.1 8.2 9.1 11 13
5.0 - - - 11 9.8 8.0 7.8 6.5 6.8 8.4 10 13
E5 COD [mg l-1]
Determined by KMnO4 method.
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 3.7 3.2 4.3 4.5 5.5 6.7 5.8 3.7 4.3
2.0 - - - 3.8 3.7 4.7 4.4 6.1 6.9 5.8 5.0 4.3
5.0 - - - 3.8 3.4 4.6 4.5 5.3 6.2 6.0 5.0 4.4
E6 CHLOROPHYLL CONCENTRATION [micro l-1]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 22 13 10 9.1 14 37 19 7.1 7.3
2.0 - - - 22 13 10 8.1 13 35 14 9.4 7.7
5.0 - - - 21 15 12 8.7 10 18 12 7.5 7.8
E7 NITROGEN CONCENTRATION
Total-N [mg l-1]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 0.51 0.40 0.27 0.57 0.54 0.84 0.83 0.66 0.67
2.0 - - - 0.51 0.51 0.62 0.53 0.54 0.81 0.72 0.71 0.82
5.0 - - - 0.56 0.45 0.41 0.62 0.54 0.74 0.70 0.70 0.70
E8 PHOSPHORUS CONCENTRATION
Total-P [mg l-1]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Depth [m]
0.5 - - - 0.052 0.031 0.027 0.057 0.053 0.13 0.090 0.046 0.073
2.0 - - - 0.051 0.034 0.033 0.059 0.067 0.13 0.078 0.052 0.071
5.0 - - - 0.052 0.033 0.032 0.056 0.059 0.13 0.079 0.047 0.071
