2017 NATIONAL LAKES ASSESSMENT

Nutrient Pollution

46%

Poor

Good

Elevated

46% 1

8390/01

Nitrogen



Fair



15% 1^

45%

Poor

Good

45%

1 41% II

Elevated



w

Phosphorus

WFair0l

14%

Nutrient pollution was the most

widespread stressor measured

https://www.epa.gov/national-aquatic-resource-survevs/nla

Biological Condition

Good,
47%

Fair,

27%

Poor,

24%

Biological condition based on
macro invertebrate communities

Poor 45 % Good 34% Fair 20%

Chlorophyll a, indicates the amount of
algae and cyanobacteria present and
was in excess in 45% of lakes

Chemical Indicators

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The herbicide atrazine was detected in
30% of lakes and exceeded the EPA
"concentration level of concern" in
0.5% of lakes

•I

Microcystins were detected in 21% of
lakes and levels exceeded the EPA
recreational criterion in 2% of lakes

v>EPA

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