Read the full story in Great Lakes Echo.
A flame retardant has been discovered in sediment of the Great Lakes for the first time, and researchers say it may be here to stay.
Researchers sampled sediment from lakes Michigan, Ontario and Superior to track organophosphate esters, a group of chemicals that are used as flame retardants. All three locations showed that the concentration of one of them—TCPP—has increased rapidly since 2000. It has replaced a more toxic flame retardant that was phased out.
Full research article: Dandan Cao, Jiehong Guo, Yawei Wang, Zhuona Li, Kang Liang, Margaret B. Corcoran, Soheil Hosseini, Solidea M. C. Bonina, Karl J. Rockne, Neil C. Sturchio, John P. Giesy, Jingfu Liu, An Li, and Guibin Jiang (2017). “Organophosphate Esters in Sediment of the Great Lakes.” Environmental Science & Technology 51 (3), 1441-1449.
Abstract: This is the first study on organophosphate ester (OPEs) flame retardants and plasticizers in the sediment of the Great Lakes. Concentrations of 14 OPEs were measured in three sediment cores and 88 Ponar surface grabs collected from Lakes Ontario, Michigan, and Superior of North America. The sum of these OPEs (Σ14OPEs) in Ponar grabs averaged 2.2, 4.7, and 16.6 ng g–1 dw in Lakes Superior, Michigan, and Ontario, respectively. Multiple linear regression analyses demonstrated statistically significant associations between logarithm concentrations of Σ14OPEs as well as selected congeners in surface grab samples and sediment organic carbon content as well as a newly developed urban distance factor. Temporal trends observed in dated sediment cores from Lake Michigan demonstrated that the recent increase in depositional flux to sediment is dominated by chlorinated OPEs, particularly tris(2-chloroisopropyl) phosphate (TCPP), which has a doubling time of about 20 years. Downward diffusion within sediment may have caused vertical fractionation of OPEs over time. Two relatively hydrophilic OPEs including TCPP had much higher concentrations in sediment than estimated based on equilibria between water and sediment organic carbon. Approximately a quarter (17 tonnes) of the estimated total OPE burden (63 tonnes) in Lake Michigan resides in sediment, which may act as a secondary source releasing OPEs to the water column for years to come.