Metals are the most frequently identified pollutant in rivers and lakes.
Mining and agriculture are leading sources of pollution in both rivers and lakes. Colorado did not report on the condition of wetlands. Ground Water Quality Ground Water Quality in Colorado ranges from excellent in mountain areas where snow fall is heavy, to poor in certain alluvial aquifers of major rivers. Naturally occurring soluble minerals along with human activities are responsible for significant degradation of some aquifers. Nitrates and salts from agricultural activities have contaminated many of Colorado's shallow, unconfined aquifers.