Environmental Health - Toxic Substances Hydrology Program
Four vertical cross sections through the wastewater (treated sewage) plume on Cape Cod, Massachusetts, showing the distribution of dissolved boron (B), ammonium (NH4+), nitrate (N03-), and oxygen (02) in micromoles per liter (µmol/L) during 1994. Small dots indicate data points. Ground-water flow is from left to right. Boron is used to define the wastewater plume boundary (thick dashed lines in top figure and the ones underneath it). The NH4+ cross-section shows the cloud of NH4+ in the core of the wastewater plume. The distribution of N03- is from ground water that is recharged through the infiltration beds, through the soil above the plume, and from sources upgradient of the plume. Organic matter in the wastewater has absorbed onto aquifer sediments, and the biodegradation of the organic matter and other compounds has removed dissolved 02 from ground water within the boundaries of the plume. Elevations are in meters above or (-) below mean sea level. The above graphs are a modified version of figure 3 from Böhlke and others, 2006, and are based on data from Savoie and LeBlanc, 1998.