Bill Reid, a terrestrial ecologist at the Pacific Northwest Laboratories,
raised some pertinent issues regarding the risks of noxious materials into
the waste stream. In particular, he asked about the sample scheme used to
"prevent the introduction of noxious materials, including heavy metals and
nasty organics" into sewage. He also asked about the "racial proportions"
in the community and nearby large landowners.
Below I offer my response to the technical issues, but, more importantly,
for the implied environmental racism aspect of Mr. Reid's posting, I asked
the assistance from a resident who also is an elected representative of the
people living in Sierra Blanca.
There is no surefire way to avoid someone dumping a large amount of
anything into a sewer line. It is certainly no great consolation that this
also is true in our drinking water. Up to 75% of the water from the sewer
is returned to the pool from which our drinking water is drawn downstream,
after the solid materials are removed, so that we can assume that some of
these "nasty organics", if present, may reappear in drinking water.
By the way, the Sierra Blanca project (viz., MERCO Joint Ventures, which
has the contract with NYC) recently received a "Clean Texas 2000" award for
Since 1987 New York City has had an active investigative and enforcement
division that monitors sewage treatment plant inputs and outputs on a daily
basis for any changes in the toxics. They use an extensive GIS monitoring
and tracking procedure to identify industrial and residential sources of
pollution. Their effectiveness in improving the quality of the sludge has
been remarkable, and now 80% of their sewage is used beneficially in Ohio,
Colorado, Florida, Virginia, Arizona and Texas. In Florida it is blended
with fertilizer for citrus grove application, and in Arizona some is used
on pecan and pistachio groves as well as cotton. Colorado use is on dry
land wheat farms.
Heavy metals (and E. coli) are checked before shipping to Texas and any
containers with levels above EPA standards are rejected. Two additional
series of tests are performed in Texas before application. New York City
has further reduced the levels of copper and lead by treating pipes with
ortho-phosphate to reduce corrosion. Although well within current EPA
standards at present, there clearly will be continuing improvements in
quality of sludge for land applications.
It is also noteworthy that the regulations were written with acid soils and
high rainfall areas (the most troublesome conditions for heavy metals) in
mind. West Texas is another matter. Due to the naturally alkaline soils
in the area of land application, heavy metals are bound and generally
unavailable to plants. In fact, supplements of copper, selenium, zinc, and
other heavy metals are supplemented in livestock feeds and human diets.
The amount applied in these soils is very small relative to the amounts of
these elements naturally present in the soil. By chemical analysis, dust
is potentially more toxic to animals than the sludge by several orders of
magnitude. Tests of plant tissue by Texas Tech scientists, who are
conducting the research on this project, have shown no change in heavy
metal uptake, whether from natural sources or from sludge (after two full
growing seasons of perennial grasses).
However, the risk assessment ultimately is limited to the presence of
toxins that are detectable. EPA originally tested over 400 potential
pollutants for which a test existed, and reduced the list to those included
in the regulations after concluding for a variety of reasons that the
others were not threatening to health and safety.
There are numerous examples where we have unwittingly poisoned ourselves by
not knowing what to test for. Dioxin comes to mind. When I first used
2,4,5-T herbicide for mesquite brush on my land, the presence of dioxin as
a contaminant was unsuspected. It wasn't until 2,4,5-T was dispersed at
orders of magnitude larger applications as a component of Agent Orange that
a toxic contaminant was suspected. The possibility of "phantom toxins"
remains a possibility with sludge, drinking water, air, organically grown
vegetables, and soft drinks, to name a few examples.
We must remain eternally vigilant in our caution to avoid poisoning
ourselves and our environment, and then hope for a healthy dose of good
luck. EPA has a mandate to review all regulations, and I do not doubt that
additional tests will be added in due time. Test protocols will continue
to evolve as a matter of appropriate monitoring.
In the meantime, the best estimates of potential hazards are included in
the existing tests. We know sludge is a valuable organic fertilizer and
sorely needed in the rangeland soils. It seems entirely rational to me to
use a recognized beneficial organic resource with minimal risks in
preference to creating undisputed problems by filling limited landfills to
avoid phantom risks. That farmers, including organic farmers, in many
places purchase sludge (or composts or pellets made from it) suggests they
also agree and speak with their money.
In the case of noxious organics in the sludge, there is extensive
biological degradation in treatment before application. This is both good
and bad. It generally achieves extensive decomposition of all organic
materials, which is one way to reduce pathogens and levels of organic
pollutants. However, it is fortunate that much of the organic matter
remains and can further be utilized by soil organisms to produce humus for
soil improvement. Personally, I would like to see sewage processing move
toward "on site" biological processing where more organisms would find
nutritional value from the original waste and shift more of the
detoxification toward existing processes in the ecosystem. Biological
systems including artificial wetlands, are more desirable than less natural
processing using engineering schemes, in my opinion. Of course, this is a
complex topic and no specific statement can be made on these options
without careful study.
The last question raised by Mr. Reid is potentially more harmful to the
community than the scientific and technical questions addressed above. Mr.
Reid wrote, "Also, perhaps you could describe the racial composition of
both the town and the large landowners? I do believe there is a
difference, and I am sure there has been such a study."
In itself it seems like an innocuous request. However, in light of the
controversies fanned by NBC, a few newspapers, and certain activists, it is
not so neutral after all. There could be an innuendo of real or possible
racial discrimination, which, if true, would be a serious issue, indeed. I
shared both my original posting and Mr. Reid's response with Mr. Wayne
West, who was elected by the people of Sierra Blanca to serve on the
Hudspeth County Commissioner's Court. His grandfather was one of the three
original patriarches from near Coyame, Mexico, who founded the town almost
a century ago. The voting returns are public information. He is not one
of the "large landowners" in the area. He clearly represents a large
Hispanic majority of the community, and he also is respected by most of the
"large landowners". Commissioner West responded as follows:
"There have been many questions about the Merco Project in Sierra Blanca
and many opinions and conclusions. The most asked question is - 'will the
project be detrimental to the health of all residents?' My duty to all of
the residents of this county is to make sure there is no harm at all. I
have asked many questions to all involved, both pro and con, and at this
time I have not found any dangers to the Public health."
"The TNRCC has ok'd the project and the EPA are in my opinion the people we
have trusted to evaluate the project. My concerns go beyond theirs and
that is how to keep our people and all health safe."
"Too many times outside people try to create problems for someone else."
"My old Grandpa used to say - 'Look at your own back yard before you tell
someone else about their's. I think that my fellow County Commissioners
and myself feel this way.
I believe that we, as non-residents of a community, must be very careful
not to "find" problems where none exist. Every community has a
characteristic dynamic among the citizenry, and small communities
effectively "have no secrets." Generally there is a much stronger tendency
to settle differences directly and personally than among residents in urban
communities. This is one of the features that has attracted some of the
newer residents, Hispanic and Anglo, to move to Sierra Blanca and settle
with their spouses and families. There are about 700 people living there.
No strangers live in Sierra Blanca. Social issues are discussed at church,
on the street, at fiesta, at the football game, and so forth. Television
has not replaced informal talking among neighbors as the principal source
(I appreciate the assistance of Mr. Wayne West and Dr. Patricia Behrens in
the preparation of this reply. Also, Mr. Reid's concern echoes that of
many others, initially including myself. I'm satisfied that this is a well
monitored and well managed project, and is much more beneficial in all
aspects than the alternatives available at this time.)
R. H. (Dick) Richardson * (512) 471-4128 (w)
Zoology Department * (512) 471-9651 (FAX)
University of Texas * (512) 476-5131 (h)
Austin, TX 78712 * email@example.com