Note: This story was updated on 5/10/2023 with the latest fish advisory information from the IDPH.

ILLINOIS — While the Illinois Department of Public Health has had a statewide fish consumption warning in place for decades, there are 10 locations with specific fish they caution should not be eaten by anyone.

The primary cause of the “do not eat” advisories are Polychlorinated Biphenyls (PCBs). PCBs are a group of more than 200 man-made chemicals. Though PCBs were banned in the 1970s because of their ill effects on health, they were so widely used they continue to persist in the environment, according to the IDPH website.

In a May 2023 update to their fish consumption advisories, the IDPH noted a statewide trend of declining PCB levels. In fact, there were no new PCB-related advisories added in the update with some previous advisories being relaxed or removed entirely.

Methylmercury is also to blame for a few of the “do not eat” advisories. It’s a “very poisonous form of mercury” which causes damage to the central nervous system. It forms when bacteria react with mercury, according to UCSF Health.

Unlike PCB levels, the May 2023 update noted an increase in methylmercury, leading to several new or more restrictive advisories.

Here are the 10 locations and the specific fish for each which should not be eaten, regardless of age or gender:

  • Calumet River System in Cook County
    • Common Carp 12″ or longer due to PCBs
  • Chicago River in Cook County
    • Common Carp 12″ or longer due to PCBs
  • Des Plaines River in Cook, Lake, and Will Counties
    • Common Carp 18″ or longer due to PCBs
  • Galena River in Jo Daviess County
    • Common Carp 24″ or longer due to PCBs
  • Herrin Lake #1 in Williamson County
    • Common Carp all sizes due to PCBs
  • Lake Depue in Bureau County
    • Channel Catfish 24″ or longer due to PCBs
  • Lake Michigan in Cook and Lake Counties
    • Channel Catfish all sizes due to PCBs
    • Lake Trout 30″ or longer due to PCBs
  • Lincoln Trail Lake in Clark County
    • Largemouth Bass 14″ or longer due to Methylmercury
  • Midlothian Reservoir in Cook County
    • Common Carp 20″ or longer due to PCBs
  • Mill Creek Lake in Clark County
    • Largemouth Bass 19″ or longer due to Methylmercury

As for the statewide advisory, it applies to women who are, or could become, pregnant, women who are nursing, and children under 15 years old. It states they should limit their consumption of predatory fish from any body of water in the state to one meal per week due to methylmercury levels.

The list of fish includes:

  • Bass (all species)
  • Sauger
  • Walleye
  • Flathead Catfish
  • Gar (all species)
  • Muskellunge
  • Northern Pike
  • Trout (all species)
  • Salmon (all species)

There are additional advisories in place for more than 100 bodies of water across the state, all related to methylmercury and PCBs. Many of these advisories apply to all Illinoisans regardless of age or gender. Each advisory states the contaminant of concern, the type of fish, and the recommended consumption limit based upon the species and size of the fish.

Find the full by county list here.

Below are the waters with additional warnings by county in the Chicago area with links to each specific advisory:

Cook County

DuPage County

Lake County

Will County

Kane County

McHenry County

Kankakee County

Dekalb County

Kendall County

LaSalle County

Grundy County

Boone County

Ogle County

Lee County