The Impacts of Concrete on pH and Calcium Concentration in Houston’s Bayous

Abstract

As the human population grows, so does the percentage of people living in urban areas. This means that an increasing amount of landmass must be used for urban infrastructure and housing to accommodate a greater number of people. The environmental impacts of urbanization are not completely understood. However, one important aspect that may be impacted is water quality. For instance, the concrete used to construct water transport and drainage systems can leach Ca2+ions into urban rivers and increase water pH. These changes are of concern because pH range is a major factor in determining the toxicity and bioavailability of chemical compounds. Additionally, many aquatic microorganisms can only thrive within certain ranges of pH and Ca concentrations. To investigate how the concrete used in urban infrastructure impacts water quality, I studied two major rivers in Houston, TX, USA. The first, White Oak Bayou, is lined with concrete; the second, Buffalo Bayou, has a natural river bottom. These two rivers were compared with the non-urban but still geographically similar Trinity River, since river chemistry may be affected by the presence of concrete anywhere within a river’s watershed. I collected water samples from Buffalo and White Oak bayous and analyzed their major anions and cations using ion chromatography (IC) and inductively-coupled plasma mass spectrometry (ICP-MS) methods, respectively. In addition, I analyzed roughly 50 years’ worth of public water quality data for each bayou and the Trinity River. The data suggest that the concrete-lined White Oak Bayou has a higher Ca concentration and pH value than Buffalo Bayou. The results of this research expand our knowledge of the environmental impacts of water transport and drainage systems.