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Date Permissions Signed
Date of Award
Master of Science (MS)
Sofield, Ruth M.
Matthews, Robin A.
Glacial retreat as a result of global climate change is causing ongoing alterations in the hydrogeochemistry of streams in the glacial foreland of the Cordillera Blanca mountain range in Ancash, Peru. Changes in water chemistry include increased concentrations of toxic metals and decreased pH, which have the potential to affect the structure of benthic macroinvertebrate communities in impacted streams. This study measured physical-chemical water quality parameters, metal concentrations, and macroinvertebrate abundances at 29 sample reaches throughout seven valleys located in Huascaran National Park. The relationships of invertebrate abundances and metrics of community structure to water quality parameters, including metal concentrations, were analyzed by non-parametric correlation. Several sensitive local taxa were identified, including the Baetidae, Heptageniidae, Helodidae, and Tabanidae families, as well as the Oligochaeta. In addition, a regional source analysis was conducted for toxic metals, which found six of seven consistently detected metals share a common source. Finally, an analysis of the cumulative criterion unit (CCU) was performed; CCU, an approach to metal mixture toxicity, can be calculated either on the basis of total or dissolved metals. Previous studies in the region used total metal concentrations. Invertebrate abundances and metrics correlated about as well or slightly better, in general, with CCU computed on the basis of dissolved metals as they did with CCU computed with total metals.
Western Washington University
Blanca, Cordillera (Peru)
Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Burgess, George L (George Livingston), "Effects of Heavy Metals on Benthic Macroinvertebrates in the Cordillera Blanca, Peru" (2015). WWU Masters Thesis Collection. 414.