Permanent darkness, uniform temperature and humidity, and low amounts of food available characterize the cave environment. High species diversity is found here. Scientists have identified over 500 species in this longest cave system, including threatened and endangered species. A characteristic of aquatic cave-dwelling species is their extreme longevity. A cave crayfish, for example, may live 30 or more years as opposed to its common relative whose life expectancy is one or two years.

Air pollution from coal fired power plants built prior to 1977 threatens underground biota at Mammoth Cave National Park. Unless these coal fired plants are brought up to Best Available Retrofit Technology standards, I believe much of the unique life of the cave will be compromised. Here's why: Biomagnification and bioaccumulation of toxins.

Cave life is threatened by chronic low-level pollution -- little spills, the slow buildup of rain contaminants, and airborne toxins that descend to earth by dry deposition. The chief threats for purposes of this hearing are the heavy metal components of coal fired emission haze, such as cadmium, mercury, and lead carried as particulate matter or fly ash. Toxin uptake occurs when ingestion exceeds pathways of elimination. Thereafter, concentration of the toxin increases by two processes: biomagnification and bioaccumulation.

Biomagnification occurs along food chains. Since no organism is 100% efficient each species must eat much more than its own weight to survive. Thus instantaneous biomagnification of the toxin concentration occurs at each step along the chain, and higher concentrations of toxins are at the top than at the bottom of the food chain.

Also, bioaccumulation takes place all through an individual's lifespan. Toxins increase and accumulate in species higher in the food chain since they are progressively larger and long-lived. Aquatic cave organisms are especially long lived and are doubly at risk.

Consequences of biomagnification and bioaccumulation are seen long before the toxin builds up to lethal concentrations. Resistance decreases to natural environmental stresses, reproduction suffers, and hormonal disturbances appear.

Following heavy metal deposition from coal fired plant emissions in Hidden River Cave, KY, there has been a roller coaster of partial recovery and remobilization that can continue for at least decades. This adds to the biomagnification and bioaccumulation that occurs with chronic toxicity. Uncontaminated sediment has covered toxic metal deposits in the cave. But with regular storms and 20- or 100- year floods, the buried sediments are re-exposed and again may cause problems.

The Mammoth Cave region covers an area seven times larger than the park. All rainfall penetrates the soil and is conducted underground by openings and sinkholes. There is no runoff. There are no surface streams, no large wetlands. Water and entrained emission particulates are conducted underground swiftly without natural filtration, purification, or major dilution.

Regional storm water carries heavy metals from coal fired plant emissions into the caves to cause severe damage, if not irreparable harm.

I have focused on the underground effects of coal fired emissions. I will not discuss parallel threats to terrestrial and aquatic ecosystems above ground. But I do want to describe an additional, related threat to both surface and underground resources in the Mammoth Cave Region.

Six miles from Mammoth Cave National Park, a development group seeks to build a 4,000-acre industrial park and airport on the Sinkhole Plain. Its components include roads, offices and industrial buildings, an airport, a rail yard, and a trucking and transportation center. Construction is slated to begin in 2002. Critics have pointed out the anticipated concentration of diesel switch engine and diesel truck emissions to an already substandard air quality.

If high levels of haze and smog forming pollutants from coal fired power plants continue to violate the Class One airshed standards for the park, Park values will be overwhelmed by the new Transpark development. The natural resources that U.S. Congress meant to protect at Mammoth Cave National Park may be spoiled forever if air quality rule making is not taken seriously. I urge the application of BART rules to previously grandfathered plants as soon as possible to protect Mammoth Cave National Park.

(I am indebted to Dr. Thomas Poulson, a noted karst ecologist, for his scientific contribution to this summary of the toxic effects of biomagnification and bioaccumulation.)

Roger W. Brucker
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