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chemical testing results for wells and springs collected during second quarter 1992 sampling
(end of May, beginning of June) are provided in Table 6 as a general reference for the
discussion below.

Because of the variation in lithologic and hydrologic properties of the hydrogeologic units

and presence of naturally occurring petroleum hydrocarbon containing deposits in the area,
concentrations of individual chemical constituents display a wide range of values between
sampling points. However, concentrations of individual chemical constituents at the various
sampling points have remained relatively consistent between sampling events (Janes, 1991;

Meredith/Boli & Associates, Inc., 1992a and 1992b). Some general characteristics of
groundwater quality at the project property and a few hydrochemical trends have been
identified, as summarized below. The concentration and distribution of select analytical
parameters at the project property are shown on Plate 8, which presents second quarter 1992
data. Surface springs water quality data shown on Plate 8 is from the first quarter 1992
sampling period, when more springs were available for sampling.

Groundwater quality in the eastern portion of the project property is generally good.
However, groundwater has been degraded by naturally occurring crude oil hydrocarbons,
locally within the west and northwest portions of the project property. Areas where
groundwater has been impacted by naturally occurring crude oil and oil-related brines
include the Elsmere and Tunnel areas of the Newhall Oil Field, and locally occurring tar

deposits and active oil seeps (Plate 8). As an example, several monitoring wells at the
project property became fouled with tar during the course of the investigation. Naturally
occurring petroleum hydrocarbons were found in monitoring wells MW-l, MW-2, MW-21,
C-10, C-11, and C-15 as dissolved phase, and in wells C-10 and C-11 as floating phase
(Table 6; Plate 8). The above wells are nearly all located west of the Whitney Canyon fault

and completed in either Eocene Rocks or lower Towsley Formation (Meredith/Boli &
Associates, Inc., 1992a). In addition, groundwater west of the fault and in the Elsmere and
Tunnel areas is characterized by relatively high concentrations of total organic carbon
(TOC) and total petroleum hydrocarbons (TPH), and elevated chemical oxygen demand
(COD) (Table 6; Plate 8). Finally, elevated concentrations of both magnesium and sodium

were also detected in groundwater from Eocene rocks near the Whitney Canyon fault
(Janes, 1991; Meredith/Boli & Associates, Inc., 1992a and 1992b).

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