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Ground-water quality in northeastern St. Joseph County, Indiana

Water-Resources Investigations Report 95-4092

Prepared in cooperation with the Indiana Department of Natural Resources, Division of Water
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Abstract

This report describes the ground-water quality of a 220-square-mile area in northeastern St. Joseph County, Indiana. Ground-water samples were collected from 30 monitoring wells at 20 sites during May 1992; the wells were screened in either a shallow or a deep sand and gravel aquifer. Samples were analyzed for general water-quality properties, nutrients, major ions, trace elements, industrial organic compounds, and pesticides.

In general, the ground water is a slightly basic, very hard calcium bicarbonate water with a median dissolved-solids concentration of 310 milligrams per liter. The only constituent to exceed a U.S. Environmental Protection Agency Maximum Contaminant Level in the water samples was nitrate (which was exceeded in water samples from two wells).

Concentrations of methylene-blue-active substances (detergent additives), chloride, and nitrate plus nitrite in the shallow aquifer were significantly higher (at the 0.05 probability level) than in the deep aquifer. The higher concentrations of these constituents in the shallow aquifer may be attributable to human activities. Concentrations of silica, ammonia, arsenic, antimony, barium, iron, and manganese in the deep aquifer were significantly higher than in the shallow aquifer; with the exception of ammonia, most or all of these constituents are probably from natural sources.

No industrial organic compounds were detected in the water samples. Four pesticides - alachlor, carbofuran, metolachlor, and triazines - were detected in water samples; the highest pesticide concentration in a water sample was 1.0 microgram per liter of alachlor.

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Ground-water quality in northeastern St. Joseph County, Indiana
Series title:
Water-Resources Investigations Report
Series number:
95-4092
Year Published:
1995
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Indianapolis, IN
Contributing office(s):
Indiana Water Science Center
Description:
vi, 50 p. :ill., maps ;28 cm.
First page:
1
Last page:
50
Country:
United States
State:
Indiana
County:
Saint Joseph
Online Only (Y/N):
N
Additional Online Files (Y/N):
N