fo7A

HYDROGEOLOGIC ISSUES OF RELEVANCE

AT CIBA-GEIGY CORPORATION'S

TOMS RIVER PLANT

TOMS RIVER, NEW JERSEY

PREPARED FOR

CIBA-GEIGY CORPORATION

ARDSLEY, NEW YORK

BY

TOMS RIVER PLANT

SCIENTIFIC ADVISORY COMMITTEE

GEORGE F. PINDER, Ph.D., Chairman

JOHN A. CHERRY, Ph.D.

R. ALLAN FREEZE. Ph.D.. P.Eng.

STAVROS S. PAPADOPULOS. Ph.D.. P.E.

236281

FEBRUARY . 1988

T) C I B 004 1279

TABLE OF CONTENTS

Page

LIST OF FIGURES

LIST OF TABLES i v

REPORT

1.0 INTRODUCTION 2

2.0 HYDROGEOLOGIC CHARACTER OF THE KIRKWOOD FORMATION l

2.1 Vertical Hydraulic Conductivity 3

2.1.1 Upper Kirkwood 3 2.1.2 Primary Kirkwood 8

2.2 Continuity of the Upper Kirkwood q

2.2.1 Depositional Environment 10 2.2.2 Lithologic Logs 10 2.2.3 Geophysical Logs H 2.2.4 Sieve Analyses H 2.2.5 Standard Penetration Tests 11 2.2.6 Vertical Gradients 12 2.2.7 Modeling Results 12 2.2.8 Conclusions 12

2.3 Primary Kirkwood 13

3.0 EFFECT OF TOMS RIVER ON REGIONAL FLOW SYSTEM 14

3.1 The "Barrier" Term 14 3.2 Factors Controlling a Ground-Water Divide 14 3.3 Cohansey Sands 16 3.4 Kirkwood No. 1 Sand 16 3.5 Kirkwood No. 2 Sand 17 3.6 The RI-9 Area 18 3.7 Possible DNAPL Migration Across the Toms River 18

4.0 MIGRATION OF NON-AQUEOUS PHASE LIQUIDS 19

4.1 Principles of NAPL Flow 19 4.2 Relation of DNAPL Migration to Lithology 20 4.3 Occurrence and Migration of DNAPL at Toms River 21

4.3.1 Field Evidence of DNAPL Occurrence 21 4.3.2 Sources of DNAPL 22

4.4 DNAPL Discharge to the Toms River 23

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TABLES OF CONTENTS

(continued)

Page

5.0 CONTAMINATION OF THE KIRKWOOD NO. 1 SAND 24

5.1 Inorganic Contaminants 24 5.2 Organic Contaminants 25

5.3 Distribution of Contaminants 26

6.0 REFERENCES 29

FIGURES

TABLES

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LIST OF FIGURES

One-Dimensional Analysis of Piezometer Data from Aquitard Test at the Toms River Plant

Schematic Representation of Ground-Water Flow near River Valley Systems

Schematic Representation of NAPL Movement Through the Unsaturated and Saturated Zones

Location of Kirkwood No. 1 Sand Wells at the Toms River Plant

i i i

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LIST OF TABLES

I - Kirkwood No. 1 Sand Wells Technical Specifications

I I - Selected General Chemistry Compounds, Including Tritium for the Kirkwood No. 1 Sand Wells

I I I - Identified Volatile and Semi-Volatile Organic Compounds for the Kirkwood No. 1 Sand Wells

IV - Fractional Organic Content and Related Information from the Upper Kirkwood Unit

V - Contaminant Retardation Factors for Selected Soil Samples and Contaminants Calculated Using the Chiou Formula

i v

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1.0 INTRODUCTION

The Scientific Advisory Committee was appointed by CIBA-GEIGY Corporation

to provide technical advice and review of the hydrogeological studies carried

out by ENVIRON and AWARE at CIBA-GEIGY's Toms River Plant site. We have had

several meetings over a two-year period and have become quite familiar with

the site and with the measurement programs and modeling activities employed.

The purpose of this report is to state our views with respect to the

important hydrogeological issues at the site. The request by CIBA-GEIGY to

make such a statement was prompted in part by the U.S. Geological Survey's

(USGS, 1987) review for the U.S. Environmental Protection Agency of AWARE's

"Hydrogeologic and Related Environmental Investigation," (AWARE, 1986).

We have identified the primary issues at the site as those involving:

(1) the hydrogeologic character of the Kirkwood Formation, (2) the effects of

the Toms River on the regional flow system, (3) the potential migration of

dense non-aqueous phase liquids (DNAPLs), and (4) the potential contamination

of the Kirkwood No. 1 Sand. In the following sections we address these

issues.

2-° HYDROGEOLOGTC CHARACTFR DF THE KIRKWOOD FORMATION

In developing the conceptual geologic model of the Toms River Plant and

vicinity, AWARE characterized the Kirkwood Formation by five major

hydrostratigraphic units (AWARE, 1986, Table 4-10):

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1) Upper Kirkwood

2) Kirkwood No. 1 Sand

3) Primary Kirkwood

4) Kirkwood No. 2 Sand

5) Lower Kirkwood

Two of these five units, the Kirkwood No. 1 and No. 2 sands, were

classified as aquifers. The remaining three, the Upper, Primary and Lower

Kirkwood, were classified as aquitards.

The review of the AWARE (1986) report by the USGS (1987) takes issue with

the references to the Kirkwood Formation as "the Kirkwood aquitard" or the

"Kirkwood Formation aquitard" in parts of the AWARE report. The USGS also

questions . (1) the characterization of the Upper, Primary and Lower Kirkwood as

"aquitards", and (2) the continuity of these units throughout the Toms River

area.

During our interactions with AWARE's and ENVIRON's hydrogeologists, we

had been accustomed to interpreting terminology such as "the Kirkwood

aquitard" as a reference to the lower-permeability units of the Formation and

not to the No. 1 and No. 2 Sands. We agree, however, that this is not obvious

to outside reviewers and that the use of this terminology in the AWARE (1986)

report was imprecise.

Of the three units classified by AWARE as aquitards, the Upper Kirkwood

and the Primary Kirkwood have the greatest significance with respect to the

potential for vertical contaminant migration at the site. The Upper Kirkwood

lies between the extensively contaminated Cohansey Sand and the Kirkwood No. 1

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Sand and the Primary Kirkwood separates the Kirkwood No. 1 Sand from the

Kirkwood No. 2 Sand, which is a source of water supplies in the vicinity of

the site. Regardless of whether the Upper and Primary Kirkwood should be

referred to as "aquitards" or by some other term, the results of

investigations at the site clearly indicate that these two units have lower

vertical hydraulic conductivities than overlying and underlying, more

permeable units and that they are laterally continuous at the plant site. The

sections that follow address the questions raised by the USGS (1987) on the

characterization and continuity of these two units.

2.1 VERTICAL HYDRAULIC CONDUCTIVITY

2.1.1 Upper Kirkwood

An aquifer test was conducted by AWARE to determine the vertical

hydraulic conductivity of the Upper Kirkwood at the Toms River Plant. The

test was conducted by pumping well 193, which is open to the Cohansey Sand,

and observing the drawdown in a piezometer P-279, also open to the Cohansey

Sand, and in three other piezometers (P-278, P-277 and P-276) open to

different depths within the 65-foot thickness of the Upper Kirkwood at the

site. All four piezometers were located at approximately equal radial

distances from the pumped well. Under radial flow conditions within the

Cohansey Sand, this setup provides a vertical profile of the drawdown caused

by pumping. AWARE (1986) analyzed the test data using the Neuman and

Witherspoon (1972) ratio method and determined the hydraulic diffusivity of

the upper 9.5 ft and the upper 35 ft of the Upper Kirkwood. Using a specific

storage of 9.5 x 10"5 per foot, calculated from matrix and water

compressibility and void ratio data, AWARE (1986, Table 4-17) reported

3

CIB 004 1287

vertical hydraulic conductivities of 1.9 x 1<T4 cm/sec for the upper 9.5 feet

and of 1.2 x 10"3 cm/sec for the upper 35 feet of the Upper Kirkwood.

During this test, the uppermost piezometer within the Upper Kirkwood

(P-278) had a drawdown larger than that in the piezometer open to the Cohansey

sand (P-279). This suggests a relatively higher hydraulic conductivity in

the upper part of the Upper Kirkwood which resulted in a radial flow component

within this part of the Upper Kirkwood. Under these conditions the

applicability of the Neuman and Witherspoon (1972) method, which assumes

vertical flow throughout the confining bed, is questionable.

Although the uppermost (P-278) and intermediate (P-277) depth piezometers

within the Upper Kirkwood responded to the pumping of the Cohansey Sand soon

after the beginning of the test (AWARE, 1986, Figure 4-38), the lowermost

piezometer (P-276) did not have any measurable drawdown for about 250 minutes

into the test. This indicates that the lower part of the Upper Kirkwood has a

lower hydraulic conductivity than the upper part of the Upper Kirkwood at the

test location. To estimate the vertical hydraulic conductivity of this lower

interval of the Upper Kirkwood, a one-dimensional, numerical vertical ground­

water flow model was used by a member of the Scientific Advisory Committee.

The model simulated vertical ground-water flow in the interval between

piezometer P-277 and the Kirkwood No. 1 Sand. The drawdown in piezometer

P-277, approximated in a step-wise manner at 5-minute time intervals, was used

as the head condition (forcing function) on the upper boundary of the model.

The Kirkwood No. 1 Sand underlying the Upper Kirkwood was assigned a vertical

hydraulic conductivity of 1.5 x 10"3 cm/sec equal to one-tenth of its reported

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horizontal hydraulic conductivity (AWARE, 1986, Table 4-20), and a specific

storage of 6 x lO'* per foot. The hydraulic diffusivity of the simulated

Upper Kirkwood interval was adjusted until the model closely reproduced the

drawdowns observed in piezometer P-276. Emphasis was placed in reproducing

the early drawdowns in P-276 which are least affected by the hydraulic

parameters assigned to the Kirkwood No. 1 Sand.

The computed response of piezometer P-276 for three values of hydraulic

diffusivity and the observed drawdown data from the piezometer are compared on

Figure 1. Based on this comparison, the hydraulic diffusivity of the lower

part of the Upper Kirkwood is estimated to be about 0.07 ft2/min (1.1

cm2/sec). Using the specific storage of 9.5 x 10"5 per foot (3.1 x 10"6 per

cm) calculated by AWARE, the vertical hydraulic conductivity of the lower part

of the Upper Kirkwood is calculated to be 6.6 x 10-6 f t / m i n ) Q r 3 3 x 1 Q_ 6

cm/sec. (Note that the value of specific storage used in this calculation is

relatively high and that a lower specific storage value would indicate a lower

vertical hydraulic conductivity.)

A similar approach was not used to estimate the vertical hydraulic

conductivity of the interval between piezometers P-278 and P-277 because i t is

apparent that the water levels in piezometer P-277 were also affected by

factors other than the downward propagation of the drawdown observed in P-278.

A rough estimate of the vertical hydraulic conductivity of this interval can

be made by observing that an almost steady-state flow condition had been

reached near the end of the test (see AWARE, 1986, Figure 4-38). The steady-

state drawdown in piezometer P-278 was about 1.3 ft and that in P-276, about

0.18 f t . Although the water level in P-277 is fluctuating due to external

5

CIB 004 1269

factors, a steady-state drawdown of about 1.0 f t can be projected from the

earlier water-level trend. Thus, the change (caused by the test pumping) in

the hydraulic gradient across the 25-foot interval between P-278 and P-277 is

(1.3 - 1.0J/25 = 0.012. The change in the hydraulic gradient across the 22-

foot interval between P-277 and P-276 is (1.0 - 0.18)/22 = 0.037. Under

steady-state flow conditions the change in the rate of flow across both of

these intervals should be the same. Therefore:

0.037 K277.276 = 0.012 K278_277

where K277_276 and K278.277 are the vertical hydraulic conductivities of the

interval between P-277 and P-276, and P-278 and P-277, respectively. Using

this relationship and the value of K277_276 estimated from the modeling

approach, the vertical hydraulic conductivity of the interval between P-278

and P-277 is estimated to be about 10"5 cm/sec.

The rate of vertical ground-water flow across a layered system is

controlled by the harmonic mean of the vertical hydraulic conductivities of

each layer. Therefore, the vertical hydraulic conductivities estimated above

represent the harmonic mean for each interval and do not preclude the presence

of more permeable layers within each interval. Similarly, the rate of

vertical ground-water flow and, hence, of contaminant migration across the

Upper Kirkwood is governed by the harmonic mean of the vertical hydraulic

conductivities estimated for each interval of the Upper Kirkwood. Thus, even

i f the vertical hydraulic conductivity of the uppermost 13 feet of the Upper

Kirkwood is assumed to be as high as 10'3 cm/sec, the harmonic mean vertical

hydraulic conductivity that would control vertical flow across the entire

thickness of the Upper Kirkwood would be 6 x 10-6 cm/sec.

CIB 004 1290

The test site is reported (AWARE, 1986, p. 4-33) to have been selected at

a location where the geology is generally representative of the geology of the

Toms River Plant. As discussed further below, the Upper Kirkwood is continuous

across the plant site and the lithologic and geophysical logs of wells at

different parts of the site do not indicate significant differences in the

lithologic composition of the Upper Kirkwood. Nevertheless, it is possible

that the vertical hydraulic conductivity at other parts of the plant may be

somewhat different than that at the test site. However, it is difficult to

conceive of a site-wide average vertical hydraulic conductivity greater than

10-4 cm/sec, which is the value reported by AWARE (1986, Table 4-20) and used

by ENVIRON (1986) in the numerical aquifer simulation model of the Toms River

Plant. A value of 10"4 cm/sec is a reasonable and possibly conservative

estimate vertical hydraulic conductivity of the Upper Kirkwood. This value of

hydraulic conductivity is one to two orders of magnitude lower than that of

overlying and underlying aquifers.

A vertical hydraulic conductivity which is one to two orders of magnitude

lower than that of overlying and underlying aquifers is also supported by the

laboratory determinations of the vertical hydraulic conductivity for five

"undisturbed" samples from the Upper Kirkwood. These laboratory-determined

vertical hydraulic conductivities were 4.8 x 10"8 cm/sec for one sample with

high clay content and ranged from 1.2 x 10'5 cm/sec to 3.7 x 10-5 cm/sec for

the remaining four samples (AWARE, 1986, Tables 4-12 and 4-15).

In addition to the evidence provided by the vertical hydraulic

conductivity values determined from the aquifer test data and in the

CIB 004 1291

laboratory, evidence of a lower hydraulic conductivity in the Upper Kirkwood

is also provided by the results of sieve analyses of a large number of samples

obtained during previous and recent drilling operations. In general, samples

from the Upper Kirkwood contain 10 to 20 percent more fine grained materials

(percent passing a No. 200 sieve) than samples from the Cohansey Sand.

I f the Upper Kirkwood has an effective vertical hydraulic conductivity on

the order of 10"4 cm/sec, i t can be expected to restrict vertical ground-water

movement and, in areas where the gradient is downward, delay downward

contaminant migration. However, i t cannot be expected to preclude such

downward migration indefinitely. In terms of its conductivity, relative to

overlying and underlying layers, the Upper Kirkwood plays the role of an

"aquitard" in the aquifer-aquitard system, but i t cannot be expected to

provide long-lasting effective containment of contaminant migration.

2.1.2 Primary Kirkwood

The Primary Kirkwood separates the Kirkwood No. 1 Sand from the

underlying Kirkwood No. 2 Sand. Investigations conducted to date by AWARE on

behalf of CIBA-GEIGY and by consultants to U. S. Environmental Protection

Agency have concentrated on the shallower parts of the hydrogeologic system

underlying the Toms River Plant. Thus, l i t t l e data are available on the

hydraulic properties of the Primary Kirkwood. Based on the laboratory-

determined vertical hydraulic conductivity of one "undisturbed" sample (AWARE,

1986, Table 4-12), AWARE reported a vertical hydraulic conductivity of 10'5

cm/sec for the Primary Kirkwood (AWARE, 1986, Table 4-20).

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CIB 004 1 2 g 2

While data on direct measurements of the vertical hydraulic conductivity

of the Primary Kirkwood are limited, a low value of vertical hydraulic

conductivity is indicated by the several feet of head difference between the

Kirkwood No. 2 Sand and the Primary Cohansey (AWARE, 1986, Figure 4-43). In

calibrating the aquifer simulation model of the Toms River Plant, ENVIRON

(1986) had to use a vertical hydraulic conductivity of 2 x 10'7 cm/sec for the

Primary Kirkwood to reproduce the observed head differences. Analyses

conducted with the model indicated that the head differences between the

Primary Cohansey and the Kirkwood No. 2 Sand are very sensitive to the

vertical hydraulic conductivity of the Primary Kirkwood. This leads to the

conclusion that the vertical hydraulic conductivity used in the model is of a

correct order of magnitude.

2.2 CONTINUITY OF THE UPPER KIRKWOOD

In the previous section we have presented a summary of the evidence that

leads us to believe that portions of the layer lying between the Lower

Cohansey Sand and the Kirkwood No. 1 Sand - herein called the Upper Kirkwood -

has a lower hydraulic conductivity than either sand layer. If this layer is

continuous across the CIBA-GEIGY site, it will play a significant role in the

hydrogeological behavior of the site. First, a one-to-two order of magnitude

difference in hydraulic conductivity will be sufficient to produce vertical

flow paths across the Upper Kirkwood. Second, the lower conductivity will

delay the migration of contaminants from the Cohansey to the Kirkwood No. 1

Sand in those areas where gradients are downward. Third, the smaller grain

sizes decrease the potential for DNAPL migration across the Upper Kirkwood.

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And fourth, Its presence and properties will influence the design of remedial

pumping scenarios.

As discussed in the following paragraphs, there is considerable evidence

that the Upper Kirkwood is continuous across the site. Its thickness

apparently varies from 15 to 40 feet and it is commonly 20-30 feet thick.

2.2.1 Depositional Environment

The Kirkwood Formation is a marginal marine depositional sequence. In

such an environment, one would expect stratigraphic layering to extend over

considerable lateral distances. One would expect individual layers to show

relatively homogeneous properties. One would not expect to find channel-

cutting or cut-and-fill heterogeneity common in alluvial or glacial

depositional environments. The alleged continuity of the Upper Kirkwood is

therefore consistent with the depositional environment.

2.2.2 Litholooic Loos

The geologic logs based on split-spoon sampling of a large number of

drill holes that extend through the Upper Kirkwood indicate a distinct change

of lithology between the Cohansey and the Upper Kirkwood. It is not a change

from sand to clay, as might be expected for a highly effective aquitard but,

rather, a change from a relatively clean and coarser sand to a finer sand with

a higher proportion of silt and clay fractions. The lithologic change is

clearly evident in terms of color and texture. The Upper Kirkwood layer was

identified in all drill holes in a consistent stratigraphic position. There

seems little doubt that it is an identifiable layer and there is no borehole

evidence that it is absent at any point on the site.

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2.2.3 Geophysical Loos

The natural gamma logs that are available show discernible offsets at the

boundaries between the various Kirkwood layers. It is unlikely that there

would be any significant disagreement over the interpretations of theOogs,

given their compatibility with the geologic logs. They provide confirmatory

evidence of the occurrence of continuous layers of different properties in the

Cohansey/Kirkwood sequence.

2.2.4 Sieve Analv<;p<;

The results of the sieve analyses and, in particular, the content of

fine-grained materials as indicated by the fraction passing a No. 200 sieve

(percent fines), provide quantitative confirmation of the textural differences

between the Upper Kirkwood and its underlying and overlying sand layers. The

differences are identifiable at all drill hole locations. Hydraulic

conductivity values are strongly influenced by percent fines. The observed

differences in percent fines between the Upper Kirkwood and adjacent sands are

compatible with hydraulic conductivity differences of two orders of magnitude.

2-2.5 Standard Penetration TPSTC

The standard penetration tests provide further confirmation of the

difference in physical properties between the coarser, cleaner sands of the

Lower Cohansey and Kirkwood No. 1 and the finer, dirtier sands of the Upper

Kirkwood.

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2.2.6 Vertical Gradients

If the Upper Kirkwood acts as a continuous restricting layer across the

site one would expect significant differences in head to build up across it.

In fact, the measurable head differences are quite small, generally less than

0.5 feet. Their absolute value,however, is highly influenced by the existence

of a recharge/discharge boundary that runs right through the center of the

site. This boundary separates a zone of upward gradient from a zone of

downward gradient across the Upper Kirkwood. Along it, gradients are zero,

and near it, gradients would be expected to be small. Large head differences

across the Upper Kirkwood in such circumstances cannot be expected.

2.2.7 Modeling Results

The computer model used at the site included a continuous Upper Kirkwood

layer with a hydraulic conductivity approximately 2 orders of magnitude lower

than the overlying or underlying sands. While the heads in the sands were not

particularly sensitive to the Upper Kirkwood conductivity, this 3-layer

geometry did serve to produce output that could be calibrated against

measured head values. While the modeling cannot be said to prove the

existence of a continuous Upper Kirkwood, it is strongly supportive of this

geometry.

2.2.8 Conclusions

These multiple lines of evidence lead to the conclusion that the Upper

Kirkwood is a continuous layer of significant thickness across the Toms River

site, and that the differences in physical properties support the finding of a

one-to-two order of magnitude difference in vertical hydraulic conductivity

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between the Upper Kirkwood and the underlying and overlying sands. However,

i t must be emphasized that the average vertical hydraulic conductivity may be

as high as 1CT4 cm/sec and, while this layer serves to restrict and delay

contaminant migration, i t cannot be expected to prevent or preclude i t . In

fact, as is documented in Section 5.0 of this report, there is emerging

evidence to suggest that inorganic contaminants have already traversed this

layer. The timing of the migration is consistent with the view of the Upper

Kirkwood as a continuous layer with an effective vertical hydraulic

conductivity of 10-4 cm/sec or less.

2.3 PRIMARY KIRKWOOD

The description of the Upper Kirkwood, presented above, coupled with the

discovery of inorganic contaminants in the Kirkwood No. 1 Sand, reduces the

credibility of the Upper Kirkwood as a totally effective aquitard. Under such

circumstances, attention will turn to the Primary Kirkwood - the low-

permeability layer that lies between the Kirkwood No. 1 and No. 2 Sands.

Much less information is available for the Primary Kirkwood than for the

Upper Kirkwood. However, all information currently available is encouraging.

It appears that the Primary Kirkwood is continuous across the site and that i t

has a thickness on the order of 35-45 feet. Lithologic logs describe i t as a

sandy silt-clay. Standard penetration tests indicate a much denser formation

than the Upper Kirkwood. The computer model required a regional hydraulic

conductivity value of 2 x 10"7 cm/sec for the Primary Kirkwood. Therefore, i t

is likely that the Primary Kirkwood functions as an effective aquitard.

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3-° EFFECT OF TOMS RIVFR nu REGIONAI F)nu wrfu

In their review of the AWARE (1986) report, the USGS (1987) questioned

the use of the term "groundwater barrier" to describe the role of the Toms

River in the hydrogeological system at the site. They questioned not only the

term, but also the concept that there is no underflow to the east beneath the

Toms River. Therefore, they questioned the AWARE conclusion that there can

be no contamination east of the Toms River floodplain discharge zone emanating

from the site. We address these issues in the following sections.

3.1 THE "BARRIER" TERM

We agree that use of the term "barrier" when referring to hydrologic

boundary or ground-water divide might be misleading to those not familiar with

hydrogeological terminology. The term might conjure up a physical barrier to

flow, rather than a boundary (across which flow does not travel) created by

the convergence of two flow systems. We will use the term ground-water divide

rather than ground-water barrier in this report.

3.2 FACTORS CONTROLLING A GROUND-WATER DIVIDE

Consider a cross-section across a river valley (Figure 2a), with a

topographic rise to the right and another to the left. I f the water table i

a subdued replica of the topography, as is normally the case, a flow syst

will exist in the unconfined surficial aquifer at the site such that flow i

toward the river from both sides. If the river valley is quite wide and the

aquifer quite thick, the discharging flow lines will emerge vertically from

below at the center of the river valley which constitutes the discharge area.

Flow lines will converge from both sides of the river. No flow will travel

s

em

s

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across this discharge area and the center of the river valley will constitute

a ground-water divide.

Consider now the same case but with yet another valley (or more pertinent

to our discussions, the Atlantic seashore) further to the right (Figure 2b).

In addition, assume that a layered aquifer-aquitard system exists under the

extent of the assumed topography. Considering a generally left-to-right

ground-water flow direction, horizontal flow in the confined aquifers of this

system will either go all the way to the rightmost discharge area, or will be

deflected up into the first valley. The situation is controlled by (1) the

topography (which controls the total head available to drive the system),

(2) the thicknesses and depths of the aquifers and aquitards, and (3) the

relative hydraulic conductivity contrast between the aquifers and aquitards.

For any given permeability contrast, and any particular elevation differences

between the ridges and valleys, it is difficult to predict a priori to what

depth the flow lines will be captured by the first valley. Or worded another

way, it is difficult to know whether the valley will constitute a ground-water

divide in all the aquifers or just the uppermost ones. The question must be

answered by field measurements at nested piezometers in or near the discharge

area, and/or by computer modeling of the entire system. In the following

sections we summarize these lines of evidence as they pertain to the question

of whether the Toms River floodplain constitutes a ground-water divide for

(1) the Primary and Lower Cohansey Sand, (2) the Kirkwood No. 1 Sand, and

(3) the Kirkwood No. 2 Sand.

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3.3 COHANSEY SANDS

There seems l i t t l e doubt that the Primary and Lower Cohansey Sands are in

hydraulic connection with the Toms River and that the Toms River is a ground­

water divide for flow in these surficial aquifers. No flow line, and hence,

no contaminant migration is expected to go past the Toms River valley

discharge area from the west side to the east side (or vice versa) in the

Cohansey Sand.

3.4 KIRKWOOD NO. 1 SAND

There is considerable evidence that the Toms River floodplain also acts

as a ground-water divide for the Kirkwood No. 1 Sand. Water-level data from

the only available piezometer nest that straddles the Upper Kirkwood in the

Toms River discharge area show an upward gradient across the Upper Kirkwood.

This is not a sufficient condition, but i t is surely necessary.

More important, the computer model shows all flow lines in the Kirkwood

No. 1 Sand converging on the Toms River floodplain from both sides. This

result is very robust; the converging flow occurs even when the relative

hydraulic conductivity values of the various layers in the Cohansey/Kirkwood

system are significantly changed in the model, within the expected range of

hydraulic conductivity for these layers. Only i f the hydraulic conductivity

of the Upper Kirkwood were to be several orders of magnitude lower than the

10"4 cm/sec value used in the model, could west-to-east flow across the river

floodplain occur in the Kirkwood No. 1 Sand. But in this case, the Upper

Kirkwood would be a much more effective aquitard, and no contaminant migration

to the No. 1 Sand would be expected. Our earlier negative finding that the

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CIB 004 1 3 0 0

Upper Kirkwood is not a particularly effective aquitard 1s, therefore,

balanced in part by the fact that any dissolved contaminants that reach the

Kirkwood No. 1 Sand under such conditions would discharge at the Toms River

discharge area and would not migrate farther east of the Toms River

floodplain.

3.5 KIRKWOOD NO. 2 SAND

The available field measurements of vertical gradients between the No. 2

Sand and the overlying aquifers in and near the Toms River discharge area show

large upward gradients from the No. 2 Sand to the surface. However, because

the data are sparse, conclusions on this aquifer must be largely based on the

model studies.

Natural flow conditions in this aquifer have been greatly affected by

pumpage at the Parkway Station wellfield east of the Toms River. For pumping

rates based on available records at the Parkway Station wellfield, and for a

hydraulic conductivity of 2 x 10'7 cm/sec for the Primary Kirkwood, the model

results show horizontal flow in the Kirkwood No. 2 Sand to be from west to

east under Toms River to the Parkway Station wellfield. The area under the

Toms River Plant is almost all within the capture zone of this wellfield. The

Toms River, therefore, is not a ground-water divide for the No. 2 Sand.

However, i t must be emphasized that with a vertical hydraulic conductivity of

2 x 10'7 cm/sec, the Primary Kirkwood constitutes a very effective aquitard to

both dissolved contaminants and DNAPLs and there is no reason to expect

vertical contaminant migration through the Primary Kirkwood into the Kirkwood

No. 2 Sand. Thus, even though the flow system in the Kirkwood No. 2 Sand

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traverses under the Toms River floodplain toward the east, it is very unlikely

that contaminant migration will ever follow this route.

3.6 THE RI-9 AREA

In the RI-9 area, ground-water contamination has occurred in the Toms

River floodplain on the east side of the Toms River. The Toms River meanders

back and forth across the floodplain that constitutes the Toms River discharge

area. The RI-9 area is on the east side of the river at a westward-looping

meander within the river floodplain discharge area. In the confined aquifers

below the Cohansey the ground-water divide aligns more or less with the center

of the floodplain irrespective of the actual location of the river itself.

Thus, the occurrence of contamination at the RI-9 area is not at odds with the

conceptual model of the Toms River floodplain as a ground-water divide for the

Cohansey Sands and the Kirkwood No. 1 Sand.

3.7 POSSIBLE DNAPL MIGRATION ACROSS THE TOMS RIVER

The USGS has suggested that if DNAPLs were moving in the Kirkwood No. 1

Sand from west to east, they would not discharge up into the Toms River

discharge area because of their density, but would continue to flow down dip.

If this dip took them under the valley, it could be argued that the Toms River

is not a ground-water divide for DNAPLs in the No. 1 Sand. In principle, we

cannot disagree, although we find the scenario most unlikely. Not only is

there no evidence of DNAPL presence in the Kirkwood No. 1 Sand, but also as

discussed further in the next section, DNAPL migration across the river is not

consistent with the known physical processes that dictate DNAPL movement.

18

CIB 004 1302

4.0 MIGRATION OF NON-AOUFOUS PHASE I TnilTfK

Compounds of low solubility, such as petroleum products and many of the

chlorinated hydrocarbons, may occur as non-aqueous phase liquids (NAPLs).

When the NAPL compound is less dense than the aqueous phase, it is termed

LNAPL (see Figure 3a) and when more dense than the aqueous phase, it is termed

DNAPL (see Figure 3b). Of the two NAPL types, DNAPL is far more troublesome.

DNAPL exhibits physical characteristics that make it difficult to find

and remove from an aquifer. When introduced into the subsurface, whether

through spills, leaking tanks, or deteriorating drums, experiments indicate

that some DNAPLs move vertically downward through the unsaturated and

saturated zones. In the case of some DNAPLs, this downward migration may be

arrested if the DNAPLs encounter geological units of fine grain size. When

this situation arises, the DNAPLs tend to move laterally in a direction

coinciding with the direction of dip of the lithologic interface. This

direction is not necessarily the same as the direction of ground-water flow.

Thus, the geometry of the water-table surface is not helpful in predicting the

direction of flow of DNAPLs.

4.1 PRINCIPLES OF NAPL FLOW

NAPL behavior is described by the generally accepted mathematical-

physical relationships describing multiphase flow in porous media. These

expressions contain experimentally determined parameters that reflect the

physical-chemical properties of the NAPL. These must be determined before the

NAPL behavior can be predicted. Thus to describe the NAPL migration

19

CIB 004 1303

quantitatively, the character of the NAPL liquid and its physical-chemical

properties must be known.

In addition, there are additional parameters that describe the

interaction between the NAPL and the aquifer materials. These parameters are

determined via experiments on NAPL saturated samples of the aquifer. While

the physical and chemical parameters are easily determined, the interaction

parameters are much more difficult to obtain.

The parameters of greatest importance are the fluid density, the fluid

viscosity, the permeability, the relative permeability and the saturation-

pressure relationship. The density dictates whether the liquid is an LNAPL or

DNAPL. The velocity of the NAPL is inversely proportional to the viscosity.

Thus, the NAPL of lowest viscosity moves most rapidly. The velocity of the

NAPL is directly proportional to the product of the permeability and the

relative permeability. The permeability is a measure of the transmissive

properties of the aquifer and the relative permeability accounts for the

resistance to NAPL flow due to the occurrence of aqueous phase in the aquifer,

and vice versa. The relationship between the saturation of the NAPL and its

fluid pressure is given by the saturation-pressure relationship. This

relationship also indicates the residual saturation that will remain in the

aquifer after a DNAPL plume has passed.

4.2 RELATION OF DNAPL MIGRATION TO LITHOLOGY

The permeability, relative permeability and saturation-pressure

relationships are the parameters of interest in a discussion of the importance

of lithology on DNAPL migration. Of these, the saturation-pressure

20

CIB 004 1 3 0 4

relationship is the most important. It is well known that most DNAPLs are

principally non-wetting fluids with respect to a water-saturated porous

medium. In other words, DNAPL, in contact with a uniform water-saturated

medium, will not spontaneously displace the water and enter the medium. A

certain additional pressure is required to force the DNAPL to displace the

water. In the case of tetrachloroethylene (PCE), the required entry pressure

into a homogeneous fine-to-medium sand is approximately 20 cm of water or,

equivalently, 11.4 cm of PCE. The PCE may s t i l l not enter the finer formation

i f a strong upward pressure gradient exists.

Recall that.DNAPL migrates vertically downward until a lithologic unit is

encountered that resists DNAPL entry. The hydrogeologic property that

controls entry is the saturation-pressure relationship. Finer materials

normally require higher DNAPL pressures to force DNAPL into water-saturated

pores. The PCE that encounters soils finer than the sand described above will

require a DNAPL thickness greater than 11.4 cm to enter the finer formation,

even i f the aqueous phase is moving into the finer formation. In the next

section we will relate this information to the lithology of the Toms River

site.

4.3 OCCURRENCE AND MIGRATION OF DNAPL AT TOMS RIVER

4-3.1 Field Evidence of DNAPL Occurrence

DNAPL has not been found in situ at Toms River. On the other hand,

evidence of DNAPL presence is strong. The evidence consists of plastic well-

casing degradation (well 744-0111) and discovery of an asphalt-like material

21

inside the well casing. In addition, there are high concentrations of organic

compounds in the ground water near this and other wells.

4.3.2 Sources of DNAPl

Anecdotal evidence suggests that there are three probable sources of

DNAPL contamination: the old drum landfill, the fire prevention area, and the

plant processing area. Well 744-0111 is near the old drum landfill and DNAPL

at this location could possibly come from that source. High HNU readings at

the new well 1141 indicate that DNAPL may have leaked from the processing

area. The high concentrations of contaminants (2.5 to 5% of the solubility of

the observed compounds) at RI-9 suggest the possibility of the fire prevention

area as a DNAPL source. However, wells 1118 through 1122, drilled in this

area did not encounter DNAPL.

There remains the question of the effectiveness of the more silty units

of the Cohansey and Kirkwood as retardants to the downward migration of

DNAPLs. This question is only marginally related to discussions of

permeability presented elsewhere that address the downward movement of the

aqueous phase. Whether or not these more silty units (Cohansey/Kirkwood

Transitional and Upper Kirkwood) have impeded or will impede the movement of

DNAPLs cannot be determined until DNAPL samples have been obtained and

suitable laboratory tests performed.

Determining the presence and extent of DNAPL contamination and obtaining

samples of DNAPL are not trivial tasks. To date DNAPL was not found in the

nearly two hundred wells installed at the Toms River site by consultants to

CIBA-GEIGY and to the U.S. Environmental Protection Agency. Indirect

22

CIB 004 1306

evidence, such as high concentrations of contaminants in the aqueous phase,

similar to those found in the RI-9 area, may be the only means of detecting

the presence of DNAPL, and DNAPL composition may have to be synthesized on the

basis of the aqueous phase contaminants found at the site.

4.4 DNAPL DISCHARGE TO THE TOMS RIVER

The USGS (1987) correctly states that DNAPL will probably not discharge

to Toms River. Such upward movement would be unlikely given our current

understanding of the system. If, on the other hand, the yellow clay unit were

found to act as a DNAPL barrier and the yellow clay surface intersected the

stream channel, DNAPL could hypothetically reach the river. Because, as

mentioned earlier, DNAPL leaves a trail of residual saturation behind it as it

migrates, the volume is gradually depleted. Therefore, to reach the distance

from the drum landfill or the processing area to the Toms River without being

depleted by either residual saturations or ponding in local depressions on the

clay would require enormous volumes of DNAPL. Thus, movement from these

sources to the river seems very unlikely.

The fire prevention area is close to the river and deserves further

consideration. Anecdotal evidence indicates that the quantities of solvent

used at this location were relatively small so that the residual saturation

phenomenon would soon deplete the source if it were to migrate as a separable

phase toward the river. Moreover, there has heretofore been no clear evidence

of migration across the floodplain. Although relatively high aqueous phase

concentrations have been encountered at RI-9, the rapid decrease in the

concentrations east of RI-9 is not consistent with DNAPL presence in this

area.

23

CIB 004 1307

5.0 CONTAMINATION OF THE KIRKWOOD NO. 1 SAND

The Kirkwood No. 1 Sand is an extensive and continuous, nearly flat-lying

aquifer of moderate permeability that underlies the Toms River site. This

discussion focuses on the question of whether or not contaminants in the Lower

Cohansey aquifer or the Primary Cohansey aquifer have migrated into the

Kirkwood No. 1 Sand. New chemical data from monitoring wells in the Kirkwood

No. 1 Sand that were not available when the AWARE (1986) report was written,

nor when it was reviewed by the USGS (1987) are discussed in this section.

The question of whether or not contamination occurs at present in the

Kirkwood No. 1 Sand will be addressed by inspection of monitoring-well data

from this aquifer. Eight monitoring wells exist in this aquifer (Figure 4).

Their designation numbers, dates of installation, sand pack lengths, well-

screen lengths and depths, and aquifer thickness at the well locations are

indicated in Table I.

The samples collected from Kirkwood No. 1 monitoring wells in the two

early rounds in 1986 were analyzed for organics but not diagnostic inorganics.

The more recent round of samples (1987) were analyzed for an extensive suite

of inorganics (major ions, minor constituents and trace metals) as well as for

volatile and semi-volatile organics.

5.1 INORGANIC CONTAMINANTS

The results of the inorganics analyses from the second sampling round

(the 1987 results) are considered first. The most recent results (see Table

II, which lists in summary form the pertinent chemical data from the eight

Kirkwood No. 1 wells) provide clear evidence that four of the eight wells are

24

CIB 004 1308

contaminated by several inorganic constituents, the most diagnostic of which

are bromide, chloride, sulfate and sodium. Sulfate is the only species to

exceed the recommended maximum concentration for drinking water.

The inorganics contamination in the Kirkwood No. 1 is important because

it shows conclusively that the most mobile constituents in the Cohansey

aquifers have entered the Kirkwood No. 1 Sand. The less mobile constituents

such as the volatile and semi-volatile organics which are .common at

substantial concentrations in the Cohansey aquifers, have apparently not yet

migrated into the Kirkwood No. 1 at any of the monitoring locations.

It is not possible to estimate when inorganic contaminants first entered

the top of the Kirkwood No. 1 Sand. In the 1987 sampling, tritium was

analyzed in samples from well 126 in the Kirkwood No.l Sand. This is one of

the four wells that shows contamination from inorganics. The well was pumped

for three hours and eight samples collected during the pumping period. The

tritium analyses of these samples gave values of 0.53 ±0.09 TU (tritium

units) to 1.1 ±0.09 TU. This represents a small but significant amount of

tritium. These levels are consistent with the inorganics contamination of the

well which shows that leakage from the Lower Cohansey into the Kirkwood No. 1

Sand occurred. These tritium values probably represent vertically-averaged

values. Tritium at the top of the aquifer may be higher.

5.2 ORGANIC CONTAMINANTS

In contrast to our conclusion that inorganic contaminants have entered

the Kirkwood No. 1 Sand, we conclude that the organic contaminants, although

25

CIB 004 1 3 0 g

widespread in the Cohansey aquifer, are not present in any of the monitoring

wells in the Kirkwood No. 1 Sand.

The first sampling for organics showed an uncommon volatile (z-propanone)

and some other organics (Table I I I ) , particularly unidentified base neutral

organics. It is known and recognized that QA/QC problems plagued the first

sampling. In the second sampling in December 1987, which was done under a

much more stringent QA/QC protocol, these identified and unidentified organics

were not detected, except for one reporting of low-level methylene chloride

(below the limit of quantification). In this second sampling, one

unidentified semi-volatile and one base neutral organic were reported, neither

of which were detected in the first sampling. We do not regard the methylene

chloride, which is a common laboratory contaminant, as a plausible or

significant finding. We conclude, therefore, that, to date, there have been

no confirmed reportings of any organic contaminants in the Kirkwood No. 1

Sand. The eight Kirkwood No. 1 wells need to be sampled again for organic

constituents to provide additional testing for the presence of organics in the

Kirkwood No 1 aquifer. Inorganic constituents and and tritium should also be

determined for these samples.

5.3 DISTRIBUTION OF CONTAMINANTS

The eight monitoring wells in the Kirkwood No. 1 aquifer are all situated

in the northern part of the Toms River site (Figure 4). Two of the wells

where inorganic contamination has been detected are situated just east of the

equalization ponds where relatively high concentrations of organics and

inorganics are present in the Upper Cohansey. Few data are available from

this area in the Lower Cohansey. These and other wells with inorganic

26

CIB 004 1310

contamination are situated away from the equalization ponds: one about 1,000

feet to the east and beneath the area of contamination in the Upper Cohansey

and the other about 700 feet to the north of the equalization ponds and

beneath the contaminated areas in the Lower and Primary Cohansey.

We will now address the issue of why organic contaminants apparently do

not occur in any of the monitoring wells, particularly those that show strong

inorganics contamination. As far as we are aware, the waste waters that

probably began to enter the ground-water zone in the 1950's contained both

inorganic and organic contaminants that now characterize the contamination in

the Cohansey aquifers. We expect that the organic contaminants' travel more

slowly through the Upper Kirkwood than the mobile inorganics such as bromide,

chloride, sulfate and sodium. This expectation is based on the fact that the

volatile and semi-volatile organics that exist in appreciable concentrations

in the Cohansey aquifers undergo adsorption in the Upper Kirkwood.

Retardation factors estimated by AWARE for several samples from the Upper

Kirkwood, based on the compound solubility and on the solid-phase organic

carbon measurements (Table IV), are presented in Table V for compounds

commonly found at the Toms River site. The smallest values of retardation

factors are those determined for a sample from boring 179 (see Table V).

These retardation factors are about 2.7, 3.2 and 3.5 for benzene,

trichloroethylene and carbon tetrachloride, respectively. From this

information and the Kirkwood monitoring well results, we conclude that in

areas where hydraulic gradients are directed downward in the Upper Kirkwood,

organic contaminants from the Cohansey aquifers are migrating downward in the

Upper Kirkwood unit toward the Kirkwood No. 1 Sand. We expect that some of

27

CIB 004 131

these organic contaminants will soon begin to enter the top of the Kirkwood

No. 1 Sand.

Although we have concluded that the monitoring wells in the Kirkwood No.

1 aquifer provide no confirmed evidence of organic contamination, we cannot

draw conclusions on whether or not organic contaminants exist elsewhere in

this aquifer. Additional monitoring wells stiould be installed in the Kirkwood

No. 1 aquifer with emphasis on locations where major plume concentrations

occur in the Cohansey aquifer, particularly the Lower Cohansey, and with

emphasis on locations where DNAPL inputs to the Cohansey aquifers are most

likely to have occurred. In addition to providing evidence as to whether or

not organics have entered the Kirkwood No.l Sand, these additional monitoring

wells would establish the directions of lateral flow throughout the aquifer

and they would serve as a useful monitoring network when remedial measures

begin in the Cohansey aquifers.

These additional monitoring wells in the Kirkwood No. 1 Sand could be

used likewise to determine whether DNAPLs have moved through the Upper

Kirkwood into the No. 1 Sand. Existing monitoring wells show no evidence of

DNAPL occurrence in the Kirkwood No. 1 Sand, and movement of DNAPLs through

the Upper Kirkwood is very unlikely. However, monitoring for DNAPL would be a

worthy effort. If DNAPL occurs in the Kirkwood No. 1 Sand, it must dissolve.

The dissolved constituents must travel with the flowing ground water. Thus,

when a monitoring well shows no, or even low, concentrations of organic

contaminants, it can be concluded that DNAPL does not exist within the capture

zone of that well.

28

CIB 004 1312

6.0 REFERENCES

AWARE Incorporated, 1986, Hydrogeologic and related environments Investigation: report prepared for Ciba-Geigy Corporation, Toms River Plant, Toms River, New Jersey.

ENVIRON Corporation, 1986, Formulation and calibration of numerical qrnnnri-water flow model of the Ciba-Geiov Toms River Plant area: report prepared for Ciba-Geigy Corporation, Ardsley, New York.

NEUMAN, S P. and P. A. WITHERSP00N, 1972, Field determination of i the hydraulic properties of leakv multiple aquifer systems: Water Resources Research, vol. 8, no. 5.

PINDER, G. F., and L. M. ABRIOLA, 1986, On the simulation of nonaqueous nhase organic compounds in the subsurface- Water Resources Research, vol 22 no. 9. '

U.S. GEOLOGICAL SURVEY, 1987, Technical review of "Hydrooeolooic and related environmental investigation report. Toms River Plant. Toms River. NPW Jersey" prepared by AWARE. Inc.. Nov. iQRfi- report prepared by water Resources Division, New Jersey District, March 23.

29

CIB 004 1313

3D m

FIGURES

C I B 004 1314

10

- *

ui ui

z

o Q

< CC Q

0.1

0.01

T 1 I I I I I f

UPPER • KIRKWOOD

I I I I I I

NOTE: Distances are measured to the mid­point ol the sand-packed interval ol the piezometers.

1 1—I I I 111 — I I — I I I I I I

i

O Observed data, P277

• Observed data, P276

::^: ;Vi-i- ---'*^'-v.-v.-:\v.': '..'.•..•..•.•.KIRKWOOD #1 SAND."-*.

15

_ i — i * i i 1 1

K v / S s = 0 . 0 6 ft2/tnin

Response Functions

J—tr /1 • « • «• - i 1 • * i 1 1 1

10 100 TIME IN MINUTES

1,000 10,000

ONE-DIMENSIONAL ANALYSIS OF PIEZOMETER DATA FROM AQUITARD T E S T AT THE TOMS RIVER PLANT

FIGURE

1

a.)

b.)

SCHEMATIC REPRESENTATION

OF GROUND-WATER FLOW NEAR RIVER VALLEY S Y S T E M S

FIGURE

2

C I B 004 1316

GROUND SURFACE

CAPILLARY FRINGE

WATER TABLE

NAPL, CORE DIFFUSION ZONE (soluble component,)

a.) LNAPL

Ground Surface

Gas Zone (evaporation envelope)

b.) DNAPL

After Pinder & Abriola, 1986

SCHEMATIC REPRESENTATION OF NAPL MOVEMENT

THROUGH THE UNSATURATED AND SATURATED ZONES FIGURE

3

CIB 004 1317

CIB 004 1318

00

m

TABLES

C I B 004 1319

TABLE I

KIRKWOOD NO. 1 SAND WELLS TECHNICAL SPECIFICATIONS

Screened Sand Pack ' Total Interval Interval Aquifer

Well Date Depth Depth Depth Thickness* Number Installed (Feet) (Feet) (Feet) (Feet)

1108 3/18/86 140 127 to 137 120 to 140 21 1109 3/26/06 145 130 to 140 128 to 145 21 1 110 4/1/86 153 138 to 14« 125 to 153 19 1124 9/16/86 156 144 to 154 141 to 15ft 21 1125 9/17/86 136 124 to 134 121 to 136 22 1126 9/22/86 153 140 to 150 137 to 153 21 1127 9/30/86 106 192 to 102 189 to 106 23 1128 9/25/86 147 134 to 144 131 to 147 20

*Thickness based on patterns established by oilier s i te wells, not by w« I 1 s shown here.

CIB 004 1320

TABLE II

SELECTED GENERAL CHEMISTRY COMPOUNDS, INCLUDING TRITIUM FOR THE KIRKWOOD NO. 1 SAND WELLS

O H CO

8 8

U M

Well No. Nitrate Sulfate Chloride Bromide Bicarbonate Calcium pH Conductivity Tr<--..-Sample Date ppb ppb ppb ppb p p b uccivi.y .r

ppb umhos/cm ( T l M

1108 12, 15'87

1109 12/15/87

1110 12,15 87

1124 10.'29/86 12/15/87

1125 10/2') '80 12 15 07

1126 10 2'» 8h 12 15.87

1127 10/29,86 12V15 87

1128 10/29/86 12/1587

Method Blank 12/15/87

Field Blank 12 15 87

18,000

20,000

ND

NA ND

NA ND

NA ND

NA NA

NA ND

ND

ND

120.000

150,000

6,000

NA 44,000

NA i», 700

NA 440,000

NA 5,800

NA 5,700

ND

ND

NA = Not Analyzed ND = Not Detected BMDL = Below Method Detection Limit

68,000

46,000

3,700

NA 22,000

NA 1.800

NA 56,000

NA 3,900

NA 4,000

ND

ND

6, 100

5,200

ND

NA 1,000

NA ND

NA 2, 100

NA ND

NA ND

ND

ND

ND

ND

!,600

NA 2,600

NA 6,000

NA ND

NA 7,000

NA 6,200

ND

2, 100

22,000 5.9 2,900

9,000 5.2 4,900

BMDL 7.0

NA BMDL

NA 25,000

. NA BMDL

ND

ND

NA 6.9

NA NA BMDL 6.0

NA 6.6

NA 7.0

NA NA BMDL 7.0

NA

NA

45

NA 130

NA 31

NA 420

NA 35

NA 42

NA

NA

NA

0.19 KA

0.03 NA

0.00 NA

0.00 NA

NA

KA

TABLE I I I

IDENTIFIED VOLATILE AND SEMI-VOLATILE ORGANIC COMPOUNDS FOR THE KIRKWOOD NO. I SAND WELLS

Well No. Sample Date

1108 4/11/86 12/15/87

Toluene ppb

ND ND

bis (2-Ethylhexyl) Phthalate

ppb

ND ND

2-Propanone ppb

NA ND

Phenolics Total ppb

120 ND

Methylene Chloride ppb

42 ND

1109 4/11/86 12/15/87

ND ND

ND ND

NA ND

50 ND

ND ND

1110 A 11/86 12/15/87

ND ND

ND ND

NA ND

ND ND

ND ND

1124 12 '3/86 12/15/87

ND ND

BMDL ND

29 ND

37 ND

ND BMDL

1125 12/3/86 12 /15/87

ND ND

BMDl. ND

ND ND

230 ND

ND ND

1126 12 '3/86 12 15,87

23 ND

28 ND

ND ND

53 ND

ND ND

112; 12/3,86 12/15/87

ND ND

ND ND

51 ND

27 ND

ND ND

1128 12'3, 86 12/15/87

ND ND

ND ND

39 ND

40 ND

ND ND

O H 09

Method Blank

Field Blank

12/3/86 12/15/87

12/15/87

ND ND

ND

ND ND

ND

ND ND

ND

ND ND

ND

ND ND

ND

U W N NA = Not Analyzed

ND = Not Detected BMDL = Below Method Detection Limit

LE IV

FRACTIONAL ORGANIC CONTENT AND RELATED INFORMATION FROM THE UPPER KIRKWOOD UNIT

O M 03

O

u to

Sample Fractional Soil Boring Sample Depth Organic Descrip-Number Number (Feet) Content A(%) t i o n D

RI-24XD

17<)

180

XCO3 Tritium (TU)

I Fines (Passing -200 Sieve)

Laboratory Hydraulic Conduc­t i v i t y 1 -(cm/sec)

In Si:u Hydraulic Conduc­t i v i t y 0

(cm.< sec)

RI-24XD 15

18

48

38

121-123 0.73 Dark Cray fine SAND, some S i l t , trace fine Cravel, micaceous

155-157 0.20 Dark Cray fine SAND, l i t t l e S i l t

103-105 0.0") Cray to Drown medium to fine SAND, l i t t l e S i l t , trace f ine Grave I , micaceous

78-80 0.4 1 Dark Cray medium to fine SAND, some S i l t , trace fine Gravel, micaceous

<0.0l

<0.0l

<0.0l

0.08 + 0.08

0.08 + 0.08

0.78 + 0.10 4.1 x io~3

<0.01 -0.02 + 0.09 19.2 1.8 x 10"* 5.0 x IT

A D C

Mean Fractional Organic for a l l Kirkwood aquitards is 0.85% as based on 15 samples Soils described using system of Burmeister, 1958 Vertical Hydraulic Conductivity as measured with a t r i a x i a l cell-based constant volume variable head permeameter Lateral Hydraulic Conductivity as based on variable head recovery tests

TABLE V

CONTAMINANT RETARDATION FACTORS FOR SELECTED SOIL SAMPLES AND CONTAMINANTS

CALCULATED USING THE CHIOU FORMULA

KRIN6 SAMPLE SW1PLE UTHOlCBIC wu: „ f K . r^ICA- , ?

mm m m DEPTH UNIT DENSITY CLBS/FT-3) (X) U) ; tutlCLES/Li

Kd x s t t s t i t

R

RI-24ID IS 121-123 U. KIRKUOOD 120 "0.4 0.73

RI-24ID 16 155-157 U. KIRKWOOD 120 0.4 0.2

! BENZENE 22B00 6.36 0.046 14.92 ! CARBDNTETRACHLORISE 5200 9.09 0.066 20.-! ! CHLOROBENZENE 4420 9.45 0.069 21.71 ! CHLOROFORM 47200 4.69 0.036 11.72 ! I,2-JICHL0RQBENZ£NE 680 14.87 0.109 33.56 ! 1,3-OICHLORSSENZENE 469 16.27 0.119 36.63 ! 1,4-DlCHLOROBENZENE 333 17.67 0.129 39.70 ! 1,2-TP.ANS DICHLOROET 6180 6.72 0.064 20.09 : ETHYLBENZENE 1430 12.42 0.091 28.20 ! TETRACHL0R9ETHYLENE 904 13.88 0.101 31.40 i TOLUENE 5590 8.93 0.065 20.56 : TRICHLOROETHYLENE 8330 8.11 0.059 16.76

! BENZENE 22eoo 6.36 0.013 4.81 : CARBONTETRACHLORIOE 5200 9.09 0.016 6.45 i CHLOROBENZENE 4420 9.45 0.019 6.67 ! CHLOROFORM 67200 4.89 0.010 3.94 : 1,2-BIMLOROBENZENE 660 14.87 0.030 9.92 : I.J-5ICHL0R0BENZENE 469 16.27 0.033 10.76 : 1,4-DlCHLOROBENZENE 333 17.67 0.035 11.60 ! 1,2-TSANS DICHLOROET 6180 8.72 0.017 6.23 : ETHYLBENZENE 1430 12.42 0.025 8.45 ! TETRACHLOROETHYLENE 904 13.8B 0.026 9.33 ! TOLUENE 3590 8.93 0.018 6.36 ! TRICHLOROETHYLENE 8330 8.11 0.016 5.87

! BENZENE 22800 6.36 0.006 2.72 ! CARBONTETRACHLORIOE' 5200 9.09 0.008 3.45 i CHLOROBENZENE 4420 9.45 0.009 3.55 ! CHLOROFORM 67200 4.89 0.004 2.32 i 1,2-01CHL0R0BENZENE 660 14.87 .0.013 5.01 : 1,3-DICHLOROBENZENE 469 16.27 0.015 5.39 i 1,4-DICHLORQBENZENE 333 17.67 0.016 5.77 ! 1,2-TRANS DICHLOROET 6180 8.72 O.OOB 3.35 1 ETHYLBENZENE 1430 12.42 0.011 4.35 : TETRACHLOROETHVLENE 904 13.BB 0.012 4.75 : TOLJENE 5590 B.93 0.006 3.41 ! TRZCHiOROETHYiENE 6330 8.11 0.007 3.19

: BENZENE 22600 6.36 0.026 6.62 ! CARBONTETRACHLORIOE 5200 9.09 0.037 12.16 i CHLOROBENZENE 4420 9.45 0.039 12.63 : CHLGRGFOR* 67200 4.B9 0.020 7.02 : 1,2-DICHLDROBENZENE 680 14.87 0.061 19.29 : 1,3-D1CKL0R3BENZENE 469 16.27 0.067 21.01 : 1,4-DICHLOROBENZENE 333 17.67 0.072 22.74 ! 1,2-TRANS DICHLOROET 6180 8.72 0.036 11.72 ! ETHYLBENZENE 1430 12.42 0.051 16.26 ! TETRACHLOROETHYLENE 904 13.88 0.057 18.07 TOLUENE 5590 . 8.93 0.037 11.99 TRICHLOROETHYLENE 8330 8.11 0.033 10.96

179 46 103-105 U. K1RCND0D 120 0.4 0.09

160 36 76-80 U. KIRKHOGD 120 0.4 0.41

S S I I S B I C t t n g i x » B t K t t t C 8 t g U « t • " " • m i i i i i i n : : » : t i t i : t n t i t i i m i i i i i i i t i u t i i i i i i i t U I I I S I I I

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