Effects of Land Development and Season on Heavy Metal Concentrations in Urban Streams

Although it is generally understood that urban development can impact the quality of urban streams, there are many factors that affect the concentrations of pollutants being transferred from the built environment to a given output. This study examines the impact of land use surrounding urban streams, specifically, the degree of development and presence or absence of green infrastructure (GI) in these areas on heavy metal (HM) concentrations in Portland, Oregon. After collecting 1021 water quality samples from 2010-2018, we examined the difference in concentrations of HM pollutants across different combinations of land use and season. Increased levels of calcium, magnesium, and hardness were found in highly developed areas compared to lowly developed areas as well as dry season compared to wet season. More controlled studies are necessary in determining the effects of GI on HM pollutants in urban areas