NITROGEN- 15

ISOTOPES

(9-)

OAK PARK SUB. 5/90

SW 1/4, SEC 28, T17N,

0 180 FEET
R7W       I    I

Figure 4. Nitrogen isotope values in parts per 103 differences,
615 N for private water-supply wells in Oak Park
-z.hdi-q1,iin. Mqreh  1990,