PHCZ Levels and Locations in 3 Great Lakes (image) University of Illinois at Chicago Share Print E-Mail Caption Blue bars indicate location and amount of PHCZs in 3 Great Lakes. Credit Credit: An Li. Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.