Response No.                                      Response

         Criteria and effluent limitations have been developed for the pollutant
         the discharge. The effluent limitations are based upon a given set
of k
         regarding stream and effluent flow and the ambient water chemistry.
         expands or effluent flow rate changes, appropriate modifications
to the
         limitations would be made.

         Short of performing an in-depth bioassay study after the discharge
is c
         way to accurately determine the extent of bioaccumulation of heavy
a
         organisms or in the bottom sediment of Swamp Creek. Consequently,
         aquatic biota, as a result of bioaccumulation of heavy metals, were
no
         in the DEIS. There are no data available in the literature relating
subl
         and aquatic life to bioconcentration or bioaccumulation levels of
heavw
         there any data in the literature, except for mercury, relating levels
of
         potential impacts to human health.

         As part of the monitoring plan, the Department intends to require
that
         acute bioassay studies of their effluent on a quarterly basis. In
additic
         required to conduct chronic bioassay studies prior to the time of
each
         reissuance.

         If additional information on bioaccumulation becomes available,
and ti
         monitoring results on Swamp Creek provide evidence that toxicity
levE
         exceeded, then more restrictive limits would be imposed to protect
aq

         Due to the lack of literature data on sublethal effects of bioaccumulat
         organisms or carcinogenic impacts to humans, it is impossible to
develi
         defensible standard, on that basis, for regulatory action. It also
shoulc
         the toxics data base is constantly expanding as new information
becom
         Standards are set based on the best available scientific data.

   316   See response #307. The Department would recommend that the MWDJ
         include provisions for Exxon' s continued collection, treatment
and disl
         after mine/mill closure.

   317   See response to comment #395.

   318   Refer to the "Monitoring and Quality Assurance Plan" submitted
by E
          1985 for some of the sampling procedures to be followed for biological
          specific submittals - QA/QC documents and protocols for individual
m
          will be required of Exxon. These documents/protocols would need
DNI
          initiating any monitoring program.

          Before water would be discharged from the lagoons to Swamp Creek,
s
          features would ensure compliance with the effluent limitations.
First,
          entering the lagoon would occur. The lagoons would have sufficient
ca
          wastewater until testing results were available. If the water met
the X
          it would be pumped to Swamp Creek or would be used in conjunction
w
          mitigation plan. If it did not meet the effluent limitations, the
water
          back through the treatment system or to the reclaim ponds.

          Other safety features currently planned include equipping the control.
          computer console for monitoring the performance of the system.
The
          extensive instrumentation and control system to monitor the performa

          Effluent from each of the systems and the lagoons also would be
analy
          pH, specific conductance, and turbidity to alert operators of any
short



effluent quality. If upset conditions would occur, alarms would alert a
adjustment is required.



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