Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Chemical Contamination and Bivalve Health in the Milwaukee Estuary: An Integrated Assessment Case Study (2017 - 2018)



Pawel Jaruga, Neil Fuller, Kimani Kimbrough, Michael Edwards, Eric Davenport, Amy Ringwood, Ed Johnson


The Milwaukee Estuary is a highly urbanized and industrialized watershed that was designated as an Area of Concern (AOC) under the 1987 Great Lakes Water Quality agreement. Significant remediation efforts have been conducted in recent years to improve habitat quality for resident biota and reduce levels of contamination. In 2017 and 2018, an integrated assessment of environmental contamination and bivalve health was conducted within the estuary, combining multiple approaches such as 'omics techniques, passive samplers, and analysis of contaminants in dreissenid mussel tissue. Sites included locations within the Milwaukee harbor, river tributaries, and offshore sites in Lake Michigan. Both caged and in situ collected dreissenid mussels were used for assessment. For tissue contaminants, the highest levels of pharmaceuticals and personal care products were consistently found in harbor sites compared to tributaries and offshore locations, with concentrations found to be in the highest cluster for 2018 studies compared to basinwide data. Conversely, concentrations of pesticides and PAHs were generally higher in river tributary sites, excluding 2018 wherein a large herbicide spike was recorded in mussels collected from two offshore sites. Total PAH concentrations in dreissenid mussels caged in river tributaries in both years were within the highest basinwide cluster compared to historic data for the Great Lakes, supporting previous studies within the estuary. For passive samplers, aqueous contaminant data was compared to benchmarks including Tier 1 ECOTOX apical effect benchmarks and water quality benchmarks. In both years of study, toxicity quotients for several compounds were found to exceed benchmarks, including the PAH fluoranthene, the insect repellent DEET, the neonicotonoid pesticide, imidacloprid, and the herbicide atrazine, suggesting the potential for deleterious effects on biota. For metabolomic analyses, 2017 in situ studies identified different metabolic profiles between mussels collected from an offshore site compared to three harbor locations, supporting a previous study using nontargeted analyses. However, the temporal caging metabolomic study and 2018 analyses suggested that environmental conditions and other factors may have contributed more to observed differences in metabolic profiles than contaminants. Different findings were observed for DNA damage analyses between years, with few overall trends observed in 2017 studies, but a notable increase in levels of DNA damage at the highly contaminated Kinnickinnic River site in 2018. Conversely, few overall differences between sites of varying contamination were noted in levels of cellular biomarkers (analyzed in 2018 only) including acetylchlolinesterase, total glutathione, and lipid peroxidation. Overall, the findings of the present study provide fundamental information regarding contamination and ecological health of aquatic invertebrates within the Milwaukee Estuary AOC and can be used to contextualize future studies following remediation efforts.
NOAA Institutional Repository


Great Lakes Restoration Initiative, Milwaukee Estuary, tissue contaminants, DNA damage, Cellular Biomarkers, targeted Metabolomics


Jaruga, P. , Fuller, N. , Kimbrough, K. , Edwards, M. , Davenport, E. , Ringwood, A. and Johnson, E. (2024), Chemical Contamination and Bivalve Health in the Milwaukee Estuary: An Integrated Assessment Case Study (2017 - 2018), NOAA Institutional Repository, [online],, (Accessed June 17, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created June 3, 2024