THE EFFECT OF RESIDENTIAL DEVELOPMENT ON GROUND‐WATER QUALITY NEAR DETROIT, MICHIGAN¹

Abstract

Two water‐quality studies were done on the outskirts of the Detroit metropolitan area to determine how recent residential development has affected ground‐water quality. Pairs of monitor and domestic wells were sampled in areas where residential land use overlies glacial outwash deposits. Young, shallow waters had significantly higher median concentrations of nitrate, chloride, and dissolved solids than older, deeper waters. Analysis of chloride/bromide ratios indicates that elevated salinities are due to human activities rather than natural factors, such as upward migration of brine. Trace concentrations of volatile organic compounds were detected in samples from 97 percent of the monitor wells. Pesticides were detected infrequently even though they are routinely applied to lawns and roadways in the study area. The greatest influence on ground‐water quality appears to be from septic‐system effluent (domestic sewage, household solvents, water‐softener backwash) and infiltration of storm‐water runoff from paved surfaces (road salt, fuel residue). No health‐related drinking‐water standards were exceeded in samples from domestic wells. However, the effects of human activities are apparent in 76 percent of young waters, and at depths far below 25 feet, which is the current minimum well‐depth requirement.

Evaluating Land Use Effects on Groundwater Quality in Lagos-Nigeria Using Water Quality Index

“…High level of NO 3 in groundwater can be attributed to seepage from dilapidated septic tanks in residential area or from runoff from agricultural land [30]. They also contribute to high level of chloride, Dissolved solids, sodium, calcium, and potassium to shallow wells [31]. Excess of NO 3 is responsible for methemoglobinemia in infants and also causes physiological distress and bitter taste, among others [23].…”

Aquifer chemistry and transport processes in the zone of contribution to a public-supply well in Woodbury, Connecticut, 2002-06

“…The dilute groundwater end point is represented by a monitoring well (well SO110), which is completed in glacial stratified deposits overlying Mesozoic rocks in a forested, undeveloped area in north-central Connecticut. Groundwater samples from other wells in undeveloped parts of Connecticut (P117) and of the study area (for example, WY86 and WY106) generally had Cl − concentrations less than 10 mg/L and Cl:Br ratios less than 400, which is the ratio that Thomas (2000) considered to be the threshold for anthropogenic sources in the midwestern United States. Cl − and Br − concentrations in shallow groundwater should be similar to those in local atmospheric deposition but slightly more concentrated as a result of evapotranspiration and some interaction with shallow glacial or alluvial deposits.…”

“…Groundwater samples that appeared to be affected by road-salt applications and by septic-tank drainfields had the largest deviation from dilute groundwater in the Cl:Br plots. Similarly, in a glacial aquifer in the Detroit, Michigan, metropolitan area, Thomas (2000) found that anthropogenic contaminants were closely related to elevated Cl:Br ratios and surmised that the greatest effect on groundwater quality was from septic-system leachate and from road-salt runoff. Cl − concentrations and Cl:Br ratios for most samples in the study area fall along the mixing curve between typical values for dilute groundwater and road salt ( fig.…”

“…(Davis and others, 1998), and because natural halite deposits are nonexistent in the Pomperaug aquifer system. Plots of Cl − concentrations and Cl:Br ratios have been used to determine the effects of road salt, sewage, and seawater or brines on groundwater quality (Davis and others, 1998;Vengosh and Pankratov, 1998;Thomas, 2000;Panno and others, 2006). Although both Cl − and Br − have similar sources and behave similarly geochemically (Fuge, 1969), Cl − is generally 40 to 8,000 times as abundant as Br − , and Cl − has a slightly lower solubility than does Br − (Davis and others, 1998).…”

Chloride concentrations, loads, and yields in four watersheds along Interstate 95, southeastern Connecticut, 2008-11: factors that affect peak chloride concentrations during winter storms

“…Piezometer samples that appeared to be affected by road-salt applications and by septic-tank drainfields had the largest deviation from dilute groundwater in the Cl/Br plots. A median Cl -concentration of 69 mg/L and a Cl/Br ratio of 460, as determined for septic effluent from private septic systems in the midwestern United States (Thomas, 2000;Jagucki and Darner, 2001), were used to represent the end point for septic-system leachate ( fig. 16).…”