Table 4-18
                 Lake Water Quality Criteria and Monthly Average Effluent
Limits
                                     for Mitigation Pumping

                                          Deep Hole Lake               Little
Sand Lake
              Avg.                     Back-          Monthly        Back-
         Momi
              Ground-    Water         ground         Average       ground
         AveS
              water      Quality        Lake           Effluent      Lake
          Effl
Parameter    Quality'    Criterion2    Concen.         Limits4       Concen)
       Lim l7

Arsenic       <.001       0.295        <.001           .46        
  <.001          .32,
Cadmium       <.001        .0022        .0016          .0026         <.0015
        .002
Chromium+ 6 <.001          .0082       <.01            .013       
  <.01           .OQ
Chromium+ 3 <.001          .085        <.001           .134       
  <.001          .09k
Copper         .003        .0143        .0025          .0143         .005
          .014
Lead          <.01         .0016       <.01           Det. Lim.   
  <.01           Det
Mercury       <.0001       .00015      <.0001          Det. Lim.6 
  <.0001         Deti
Nickel        <.01         .002        <.01            Det. Lim.7 
  <.01           Det
Zinc           .01         .0712        .011           .11           .018
          .07Z
Cyanide       <.001        .0104       <.001           .016       
  <.001          .01k
Silver        <.001        .00085       --             .00085        --
            .0OQ
Selenium      <.001        .077        --              .122          --
            .081
D.O.                      5.0o

1   Based on average concentration values from test wells DMB-18, G40-R23,
G40-L23, TW
    These test wells in the stratified drift are representative of the groundwater
water chef
    The average concentrations were calculated based on the assumption that
75% of the
    groundwater augmentation would be from WS-1 and 25% would be from WS-2
(C. Schroh
    Exxon, March 1986). Actual augmentation water quality may vary due to
localized difff
    groundwater chemistry.
2   Based on data in the literature on chronic toxicity effects to resident
Wisconsin aquatic
    (the exceptions are copper and silver in which the acute toxicity values
are listed becau
    are more stringent).
3   Average background lake data obtained from Volume VII of the EIR (1982).
4   The monthly average limits were calculated using mass balance equations.
Limits are t11
    for both expected and worst case projections and are based on water augmentation
rate
    gpm and 102 gpm for Deep Hole Lake, and 568 and 709 gpm for Little Sand
Lake.
5   The monthly average criterion is below the level of detection. The detection
limit (det.
    the Lab of Hygiene for lead is 0.003 mg/l using the atomic absorption
furnace technique
6   The monthly average water quality criterion necessary to prevent exceedance
of FDA a
    limits in fish and thus protect human health is 0.00015 mg/l. This criterion
value is near
    detection limit of most current analytical techniques.
7 The monthly average criterion is below the level of detection. The detection
limit for U
    Hygiene for nickel is .020 mg/l using the furnace technique.
8 Represents a minimum value to be maintained at the end of the pipe.

Effluent limits for the Skunk Lake mitigation discharge (Table 4-19) were
set to meet public l
groundwater quality standards (NR 140, Wis. Adm. Code). Since this lake has
a high leakage
would require continuous pumping, the in-lake water quality would have to
protect public ho
provide protection for animals drinking Skunk Lake water. Fish and aquatic
life criteria wer
deemed appropriate because no fishery is present and aquatic life is limited
by frequent wint
Since the projected effluent quality from the wastewater treatment plant
would not meet thU
for total chromium, selenium, sulfate, and total dissolved solids (TDS),
Exxon proposes to ble
wastewater with intercepted groundwater or potable water.

The monthly average limits shown in Table 4-19 were calculated using the
following mass ba
equation:



CE = CM QM - CL QL
           QE



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