Subject: South Florida wastewater disposal and regulations.
We have reviewed EPA 816-R-01-07, the associated regulation proposal,
and the material on the related CD. We must advise you that we do not find
the analysis to be conclusive. Partly this is due to methodology, and partly
to important neglected factors.
In the case of injection wells, the analysis appears to be based on
the median of leakage rates. In this connection, a definition of the median
is that there is a 50% chance that the derived rate is too small. A proper
method would be to determine the distribution of the data, and to select
a value having negligible risk. Since the distribution is limited in one
direction, the analysis should be by the extreme value methods of Gumbel,
see NBS applied math. Series 33. The Prudence Principle indicates that
the selected percentage should be small, perhaps one percent or lower.
We do not find the risk analysis to be convincing. For example, the
effect of fresh water on marine organisms is not considered. We found no
data from in-situ measurements, especially of fresh water to brakish or
saline environments, the liftime of organisms, and especially, the effect
of the selection process on the genetic diversity of organisms.
Possibly the worst offense is neglect of cumulative impact, measured
both geographically and in duration. One well may have negligible impact,
but this is no guarantee that the sum of dozens to hundreds of wells is
also negligible. The east coast of Florida is bordered by the Gulf stream,
in such places as Palm Beach very close to the shore. Conditions at, say
Canaveral, are almost certainly different from those to the south. And
there are eddies fringing the Gulf Stream, which can have the effect of
concentrating leakage materials. We may have this situation here, the result
of a known counter-current shown on charts. Today, almost all the time,
there is a light tan to brown scum left by each receeding wave, sometimes
small, other times a foot or so wide. We have ask for an investigation,
but so far have seen no action. Also, something is killing our beach life,
the coquina and "sand fleas". For the past three years, there has been
an almost complete die-off of coquina at the half-grown stage on considerable
parts of our beaches. We submit that a survey of the beaches from Miami
northward is needed before injection is permitted to continue.
We urge suspension of the proposed rulemaking pending re-evaluation
of risk, especially with inclusion of cumulative impact. We ask that this
be made a part of the record.