Water and sediment quality survey of threatened and endangered freshwater mussel habitat in the Chipola River Basin, Florida

Abstract

Reduced habitat quality may be contributing to the decline of freshwater mussels in southeastern rivers. As part of an ongoing evaluation of the quality of freshwater mussel habitat in Gulf of Mexico coastal rivers, the Chipola River was assessed during 2006 and 2007. Sediment samples were collected at 8 sites along the Chipola River on May 2 and 3, 2006, and analyzed for contaminants and tested in the laboratory for toxicity to Hyalella azteca using 29 d exposures to solidphase sediment and 96 h exposures to sediment porewater. In addition, benthic macroinvertebrate populations were sampled at each site. Using the sediment quality triad approach (chemistry, toxicity and in situ benthic assemblages) to assess habitat quality, 3 sites (1, 4 and 8) were shown to be impaired, with Site 4 being the most impaired site. H. azteca survival in porewater exposures was reduced, and trace elements were elevated in sediments at these sites; however, concentrations were not considered exceedingly high. Water quality samples collected did not violate the State of Florida's water quality standards. The lack of concordance among the test metrics (in situ benthic assemblages were not impaired) at these sites suggests marginal habitat impairment. © Inter-Research 2008.