es6b03043_si_001.pdf (1.56 MB)
Download fileEscherichia coli Reduction by Bivalves in an Impaired River Impacted by Agricultural Land Use
journal contribution
posted on 2016-09-11, 00:00 authored by Niveen
S. Ismail, Jake P. Tommerdahl, Alexandria B. Boehm, Richard G. LuthyFecal indicator bacteria
(FIB) are leading causes of impaired surface
waters. Innovative and environmentally appropriate best management
practices are needed to reduce FIB concentrations and associated risk.
This study examines the ability of the native freshwater mussel Anodonta californiensis and an invasive freshwater clam Corbicula fluminea to reduce concentrations of the FIB Escherichia coli in natural waters. Laboratory batch experiments
were used to show bivalve species-specific E. coli removal capabilities and to develop a relationship between bivalve
size and clearance rates. A field survey within an impaired coastal
river containing both species of bivalves in an agricultural- and
grazing-dominated area of the central coast of California showed a
significant inverse correlation between E. coli concentration
and bivalve density. An in situ field spiking and sampling study showed
filtration by freshwater bivalves resulting in 1–1.5 log10 reduction of E. coli over 24 h, and calculated
clearance rates ranged from 1.2 to 7.4 L hr–1 bivalve–1. Results of this study show the importance of freshwater
bivalves for improving water quality through the removal of E. coli. While both native and invasive bivalves can reduce E. coli levels, the use of native bivalves through integration
into best management practices is recommended as a way to improve
water quality and protect and encourage re-establishment of native
bivalve species that are in decline.