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Updated polychlorinated biphenyl mass budget for Lake Michigan

Environmental Science & Technology

By:
, , ORCID iD , , , , and
https://doi.org/10.1021/acs.est.7b02904

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Abstract

This study revisits and updates the Lake Michigan Mass Balance Project (LMMBP) for polychlorinated biphenyls (PCBs) that was conducted in 1994–1995. This work uses recent concentrations of PCBs in tributary and open lake water, air, and sediment to calculate an updated mass budget. Five of the 11 LMMBP tributaries were revisited in 2015. In these five tributaries, the geometric mean concentrations of ∑PCBs (sum of 85 congeners) ranged from 1.52 to 22.4 ng L–1. The highest concentrations of PCBs were generally found in the Lower Fox River and in the Indiana Harbor and Ship Canal. The input flows of ∑PCBs from wet deposition, dry deposition, tributary loading, and air to water exchange, and the output flows due to sediment burial, volatilization from water to air, and transport to Lake Huron and through the Chicago Diversion were calculated, as well as flows related to the internal processes of settling, resuspension, and sediment–water diffusion. The net transfer of ∑PCBs is 1240 ± 531 kg yr–1 out of the lake. This net transfer is 46% lower than that estimated in 1994–1995. PCB concentrations in most matrices in the lake are decreasing, which drove the decline of all the individual input and output flows. Atmospheric deposition has become negligible, while volatilization from the water surface is still a major route of loss, releasing PCBs from the lake into the air. Large masses of PCBs remain in the water column and surface sediments and are likely to contribute to the future efflux of PCBs from the lake to the air.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Updated polychlorinated biphenyl mass budget for Lake Michigan
Series title:
Environmental Science & Technology
DOI:
10.1021/acs.est.7b02904
Volume:
51
Issue:
21
Year Published:
2017
Language:
English
Publisher:
ACS Publications
Contributing office(s):
Wisconsin Water Science Center
Description:
11 p.
First page:
12455
Last page:
12465
Country:
United States
Other Geospatial:
Lake Michigan