Freshwater mussel (Unionidae) shells document the decline of trace element pollution in the regional watersheds of Chicago (Illinois, USA)

W. Aaron Wilson, Andrea K. Fritts, Mark W. Fritts, Jason M. Unrine, Andrew F. Casper

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The present study analyzed trace element concentrations from the shells of native freshwater mussels collected from the headwater tributaries of the Illinois River (USA). These analyses were conducted to determine whether (A) anthropogenic enrichment could be observed and (B) whether enrichment had decreased following the enactment of Clean Water Act legislation in the 1970s. Collections archived in museums allowed comparison of the pre-Columbian period, the mid-20th century, and the early 21st century. The element Cu was consistently elevated above pre-Columbian baselines, while the elements As, Cd, Fe, and Zn were elevated in some collections. Although higher than baseline, concentrations Zn consistently declined from the mid-20th century to modern times, although differences occurred at individual sites. There was evidence for food web influence: the element Mn was significantly negatively correlated to sediment primary productivity as indexed by shell δ13C and Cu was positively correlated to trophic position as reflected by shell δ15N. Zn correlated to stream order across all time periods. We conclude that a mixture of historic factors affecting pollution control and land use patterns in the watershed led to sometimes conflicting effects on trace element bioaccumulation in mussel shells.

Original languageEnglish
Pages (from-to)179-196
Number of pages18
Issue number1
StatePublished - Jul 1 2018

Bibliographical note

Funding Information:
The authors thank N. Braus, M. Ciocan, D. Dominguez, and J. Fernandez for their diligent work in preparing samples, S. Shrestha for analyzing samples, and C. Gilliland and T. Beasley for assistance collecting specimens. K. Cummings and the Illinois Natural History Survey provided access to historical specimens and the Illinois State Archeological Survey provided access to archaeological specimens. This research received funding from the Matching Research Awards Program through the University of Illinois, Prairie Research Institute, and National Science Foundation STEP grant DUE 0757053.

Publisher Copyright:
© 2018, Springer International Publishing AG, part of Springer Nature.


  • Biomonitor
  • Bivalves
  • Historical ecotoxicology
  • Metal pollution
  • Sclerochronology
  • Stable isotopes

ASJC Scopus subject areas

  • Aquatic Science


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