FUELS AND SOLVENTS IN THE GROUND

-A Case History-

New Mexico's law doesn't simply say "don't pollute." In particular, it doesn't explicitly protect the ground from the deliberate or accidental discharge dumping of pollutants. Rather, the law is written specifically to protect air and water, by delegating authority to state agencies to regulate discharges, to promulgate standards specifying how dirty is too dirty, and to enforce cleanup of spills and discharges that violate standards. Fuels, solvents, and other chemicals--such as gasoline, dry cleaning fluid, or fertilizer--are leaked into the ground all too frequently, contaminating the groundwater. Until recently, New Mexico had no uniform rule stating when or how such spills should be cleaned up. The law says that the groundwater could not be contaminated beyond certain limits (the standards), but it doesn't say that the gound itself must not be contaminated. If gasoline has percolated downward until it floats on the aquifer, that's an obvious source of pollution to the water. But if the contaminant hasn't yet reached the groundwater (aquifer) or surface water (streams, lakes), what then?

For each spill, the State agencies previously negotiated with each responsible party individually until the agency and the polluter agreed on when, where, and how much cleanup would be done to protect the water from anticipated pollution. This was a clumsy process, wasting time while generating business for the consultants and lawyers who argued each case. Therefore, late in 1993, the New Mexico Environment Department (NMED) proposed to amend the regulations promulgated by the Water Quality Control Commission (WQCC). (Confusing, isn't it--in essence, the WQCC MAKES the rules, and NMED or other agencies ENFORCE the rules).

The purpose of the new rules was to provide a uniform procedure by which a responsible party would investigate the nature and extent of the spilled contaminant, and arrive at a cleanup plan to protect the water. NMED discussed and adjusted the proposed rules with industry and citizens,both in open meetings and in individual conversations. We, and other parties, submitted plenty of comments both in writing and orally. When NMED felt confident that most parties agreed, the rules were formally proposed for a hearing. By law, the WQCC must make its decision to adopt or not to adopt the rules based ONLY on evidence presented at the hearing. NMED thought almost everyone had agreed on the proposed rules, but industry provided a surprise by withholding their objections until the hearing, and then objecting strongly. Part of the objection was that polluted ground is not polluted water, and the law provides protection only for water--therefore, by indutry's logic, there should be no regulatory requirements for pollution in the ground.

Remember--the WQCC must base a decision on evidence presented at the hearing--if no testimony in the hearing provides evidence in favor of the rules, the WQCC could not be adopted. NMCCA&W presented both technical testimony and cross examination of opposing technical witnesses. If you want a flavor of the action, read our testimony, which follows below. In case you're uninterested in the details, we'll tell the ending of the story here: legal manuevering continued for a year after the hearing, but in the end the WQCC adopted most of the proposed changes. As of April 1997, the new procedures are working. Those who would spend time and money arguing procedures rather than cleaning up are no longer in the picture.

There is a sequel to the story. Due to the details of New Mexico law, oil and gas production facilities, from the wellhead to the refinery, are regulated separately by the Oil Conservation Commission. These facilities do not come under the WQCC rules. So, in 1996, the process of seeking uniform rules for cleanup was reinacted at the Oil Conservation Commission. But that's another case history that we'll put in our web page some other time.

HISTORY OF NMCCA&W
New Mexico Citizens for Clean Air and Water (NMCCA&W) is a statewide organization of citizens who advocate environmental protection and improvement. NMCCA&W was founded in l969, primarily in response to stack emissions from large coal-burning power plants that degraded visibility more than 150 miles from the plants. We lobbied for the legislation that established the Environmental Improvement Division (which subsequently became the Environmental Improvement Department), and we worked through the regulatory hearings of the 1970s that brought modern environmental protection to New Mexico. Since then, our work has continued through many issues, hearings, and legal actions on problems including air emissions, water pollution, strip mine reclamation, and enforcement. We are as proud of our record of fairness to industry's concerns as we are of our contributions to environmental progress.

Example. I want to present one historical example of our actions, because this example will relate to my subsequent testimony on the proposed regulations that are the subject of this hearing. Regulation of sulfur dioxide (SO2) emissions from power plants was first proposed about 1973. Our dispersion modeling and our testimony on the cost and availability of control technology figured prominently in lengthy hearings. Eventually, the Arizona Public Service Company joined NMCCA&W and the Sierra Club in a settlement agreement, in which APS agreed to install minimal sulfur control, to monitor air quality at a specific location, and to increase the control if the measured pollution exceeded specified values. Subsequently, APS asked the State to re-open the hearings, seeking lower control. We sued for breach of contract, and won. When the suit was resolved in 1990, we negotiated a higher level of control as compensation for the delay in installing sulfur control. The point here is that New Mexico has cleaner skies because the citizens brought technical information to the regulatory process--technical information that otherwise would have been unavailable.

ADMINISTRATIVE NEED FOR THE PROPOSED REGULATIONS
New Mexico has regulations on stream water and ground water. Abatement of pollution in the vadose zone has been conducted under consent agreements. Additional regulations are needed for the vadose zone because

• 1) the existing consent process is inefficient;
• 2) the consent process does not provide uniform rules;
• 3) the consent process does not allow citizen testimony; and
• 4) definite rules will encourage the prevention of spills.

Increasingly, nitrates, fuels, solvents, and other chemicals appear in the ground and surface waters, although the offending substances were originally discharged into the ground, not into water. There is a threat to water in almost every spill of contaminants into the ground, so the consent agreement is an inefficient, repetitive process. It would be more efficient for the State, and more fair to industry, to have a single set of rules for all cases. The consent process leaves the citizens without opportunity to present information and without recourse if poor decisions are made. Furthermore, a uniform set of rules about discharges into the ground will encourage good practice in prevention of offending discharges--and prevention is cheaper than abatement. Although the federal laws governing wastes (known as CERCLA and RCRA have become a burden for both the regulators and the regulated parties, I have seen first hand the growth in proper handling of wastes that resulted from those laws. That prevention, which came about because polluters faced the burdens of cleanup, is the greatest benefit of those laws.

SUBSURFACE CONTAMINANT MIGRATION
The proposed regulations are based upon the way that contaminants and water migrate within the ground. The term "vadose zone" refers to all of the ground between the surface and the top of the water table. Most of us think of the vadose zone as "dry" ground, but it is not completely dry. The ground--composed by various fractions of granular soil, organic matter, and rock--is porous to varying degrees. Pore space may occupy 25-50% of the volume of ordinary soil that is dug with a shovel. Dense rock may have very little pore space, but the volcanic tuff beneath Los Alamos--which appears to be solid rock--actually has about 50% pore space. When the pore space is filled with water--as occurs beneath the water table--the soil is referred to as "saturated." Above the water table, the water is pulled up into the pore space by capillary action, much as a towel will wick up water when one end is dipped into a bucket of water. When rain temporarily forms a puddle near ground surface, that water will initially trickle downward through the pores in "saturated" flow, carrying any available soluble or suspended contaminants with it. As the flow progresses downward, the contaminants will often become physically or chemically bound by the particles of soil. The soil thereby purifies the moving water before it reaches the water table. That's why well water and spring water have historically been regarded as clean.

The ground is not saturated in the vadose zone, but water is still present as a thin film held between soil particles by capillary action. Even a very dry soil might have 5% of its total volume occupied by water. In that unsaturated condition, the water will still flow--but much more slowly. As can be demonstrated with a thin soda straw dipped into a cup, the capillary action can move water against gravity. In general, water in the vadose zone will move up, down, or horizontally, decreasing or increasing the amount of liquid between particles, until the capillary forces are just balanced by gravity. In addition to gravity and capillary forces, there is a third actor in this motion--the water vapor. Just as the air in a closed jar half-filled with water is at 100% humidity, the air in the pore spaces of the ground is at nearly 100% humidity--even in very dry soils. That's why the bottom of a steel barrel rusts when it is left standing on apparently dry ground.

In the saturated zone only water is moving in the pore spaces between the soil particles. However, in the vadose zone, water vapor moves through the pore spaces and liquid water moves in a film along the surfaces of the particles. The motion is influenced by gravity and by temperature. If two locations in the ground have different temperatures, the vapor moves toward the colder place, where it condenses, and the film of water moves toward the warmer place, where it evaporates, setting up a cycle that can transport contaminants along with the water.

The size and shape of the pores varies tremendously with different types of soil. All material properties vary--for example, among metal materials, steel may be ten times stronger than aluminum. But soil may have the greatest range of properties of any material. Permeability is a measure of how well the soil will permit water or vapor to move through it. The permeability of one soil might be different from that of another soil as much as a factor of ten thousand million.

Soil in the vadose zone is often a granular material with a film of liquid water on the surfaces of the grains, and a mixture of water vapor and air in the pore spaces between the grains. Some solid contaminants, like salt, may dissolve in the liquid film of water and be transported along with that liquid. That transport is relatively simple. However, many spills into the vadose zone are liquids, such as fuels and solvents, that form their own liquid phase while also partially dissolving into the water film and while also coexisting in the pore spaces as vapor. These volatile contaminants can therefore be transported by the flow of the non-aqueous petroleum liquid (NAPL) itself, by the movement of the water film, and by the movement of the contaminant vapor. The vapor will sometimes move faster than the NAPL or water film, and will dissolve into the water film as it moves, thereby contaminating the water film throughout a large volume of soil. The vapor may also do other damage along the way, such as seeping into a basement or sewer tunnel where it may be inhaled or cause an explosion. Sooner or later, the contaminant will reach the ground or surface water. After a volatile contaminant gets into the ground water, the movement of the ground water itself may become the dominant transport mechanism, and the contaminant will move with the groundwater, evaporating vapor upward into the vadose zone as it goes. Thus, a contaminated vadose zone will act as an enduring source of contamination for groundwater, and the groundwater may, in turn, spread the contamination to remote regions of the vadose zone.

EXAMPLE OF A LARGE PLUME
A region of subsurface vapor, contaminated water film, and/or contaminated ground water is called a "plume." As an example, I will describe a large plume at the Hanford installation in Washington state. I chose an example in another state because I want to focus on the physical nature of the plume without being drawn into a discussion of the regulatory action. At Hanford, liquid wastes containing carbon tetrachloride were discharged into the soil from 1955 to 1973, at a location where the depth to groundwater is about 180 feet. The area of groundwater with dissolved carbon tetrachloride is now more than 4 square miles, and is still growing. Carbon tetrachloride is now believed to be present in the groundwater and in the NAPL. It is also sorbed onto the soil and dissolved in the soil moisture, and it is present in the pores as a vapor. Every transport mechanism appears to have occurred--the NAPL moved downward by gravity; infiltrating water also carried contaminant downward; the dense vapor spread in all directions by gravity, by diffusion, and by atmospheric pumping; and the groundwater is transporting the contamination horizontally. Furthermore, it appears that boreholes of old wells, including water supply wells, may have provided vertical conduits for the downward migration of the contamination. A layer of low-permeability caliche, varying in thickness between 6 and 30 feet, exists at a depth near 130 feet. This layer apparently did little to retard the contaminant migration.

This example illustrates why, with multiple pathways and mechanisms for transport in the vadose zone, it may be difficult to predict future migration or even to account for past migration after it has occurred. If there is an offensive discharge into the vadose zone, the important thing is to clean it up before it spreads.

WHY NOT NUMERICAL STANDARDS FOR THE VADOSE ZONE?
Numerical standards for concentrations of contaminants, similar to those for surface and groundwater, should not be applied to the vadose zone because such standards would be technically inappropriate and because they would discourage new remediation technologies.

Technically inappropriate. Numerical concentration standards for the vadose zone would not make technical sense in most cases. The threat to groundwater or surface water does not depend simply on the concentration of the contaminant in the vadose zone. The threat depends upon the rate at which the contamination is transported to the useful water, and that rate depends upon multiple factors--including the properties of the soil, the amount of moisture in the soil, the degree to which a particular contaminant is sorbed onto the soil or is dissolved into the water film, and the distance to the useful water. No one simple recipe, such as prescribing the allowable concentration or the permissible distance to groundwater, will provide protection. For example, if a particular soil were to sorb the contaminant strongly, then a measurement of the concentration of the vapor in the pore gas would provide a poor indication of how much contaminant is present. A numerical standard for concentration of vapor in the pore space would not be appropriate. In another situation, the natural bacteria in the soil might abate the contamination faster than it is transported to useful water or property, in which case the best treatment might be to do nothing more than to monitor the situation. Engineered abatement to a particular numerical standard would be of no benefit. The proposed regulations are wise in allowing the responsible person to investigate the situation, and to propose the most logical course of action, rather than simply requiring that he reduce the concentration of contaminant to some arbitrarily specified level.

New technologies. The technology for measuring and predicting contaminant migration, and for removing contaminants from the vadose zone, is progressing rapidly. I estimate that the amount of information published and the technical choices available have more than doubled in the last six years. For example, the technique of air sparging was a novelty in 1988, but it is now taught in schools. The proposed regulations allow the responsible person to recommend his choice of methods and level of cleanup in the vadose zone. This freedom encourages the trial of new technologies that promise better, cheaper cleanup.

WHY "NO NAPL" WITHIN OR ATOP GROUNDWATER
The proposed regulations specify that a measurable amount of NAPL shall not be present within or atop groundwater. That regulation is not overly restrictive because NAPL in contact with the groundwater forms a direct source of contamination that can continuously feed into the groundwater or move with it. When dissolved, a small amount of material can contaminate a large amount of water. For example, the standard for benzine dissolved in groundwater is one part in 100,000. That means one gallon of benzine can contaminate 100,000 gallons of water.

Most NAPLs dissolve only slowly, limited in part by the area of contact between the NAPL and the water. A NAPL that is less dense than water will float on top of the groundwater. When the water table rises in response to recharge, earth tides, or temporary cessation of pumping, then globules of NAPL in the soil pores are left behind under the water, increasing the surface area for dissolution. Although the water may be treated until the dissolved concentration is below the standards, any remaining NAPL will later act as a delayed source of contamination, gradually re-establishing the original concentration in the ground water. Globules near a supply well may be entrained in the water flow, and brought up as NAPL in the water. Therefore, if NAPL is in contact with the groundwater, there is a latent source that will, sooner or later, contaminate the water. Techniques exist for skimming a thin layer of floating NAPL from the surface of groundwater. The removal rate is slow, but the hardware is simple and operates unattended. I do not know of a current method for directly removing NAPL globules embedded within the aquifer, but the search for a new method is underway. It is best to attack the problem before the NAPL reaches the water table, and the proposed specification of "no NAPL" in contact with the groundwater provides motivation for immediate action when NAPL is present in the vadose zone. A more lenient prescription might tempt the responsible party to adopt a wait-and-see attitude while the NAPL is in the vadose zone, thereby postponing the problem. If removal of NAPL from within the groundwater proves impossible, the proposed regulations permit the responsible person to propose technical infeasibility.

ANTICIPATED OBJECTIONS TO THE PROPOSED REGULATIONS
Other testimony may present objections to parts of the proposed regulations. I wish to anticipate some of those objections, and to respond to them in my direct testimony.

Legal authority. Some persons may believe that New Mexico water law does not provide authority for the Commission to regulate water contaminants in the vadose zone. I was present as a citizen when the legislature first established the Environmental Improvement Division (which has subsequently become NMED). I can assure you that the citizens were not then, nor are they now, concerned with legal technicalities. The citizens simply want pollution controlled, and whether it is called water pollution or vadose zone pollution is not important to the citizens. Damage can occur when the contaminants are ingested with drinking water, when carried into manufacturing by industrial water, or when applied to crops via irrigation. Damage can also occur when the contaminants directly enter basements or subsurface structures as vapors. As a citizen, I see little sense in arguing that only water, and not other things, can be protected from the contaminants. I conclude that there is adequate authority for regulating water contamination, whether the damage is to useful water or to other property.

Regulating the vadose zone. Some witnesses may argue that it is neither necessary nor proper to regulate the vadose zone in order to protect water. As a scientist working in vadose zone remediation, I assure you that the vadose zone contains water, and that the water in the vadose zone becomes contaminated when contaminants are present in the vadose zone. Furthermore, I note that water in the vadose zone is in a continual state of flux, moving up, down, and horizontally in response to precipitation, gravity, temperature, soil properties, and atmospheric changes. The question of protecting useful water, then, is the rate at which the vadose zone and its water will transport the contaminants to the surface water or ground water. Under the proposed regulations, abatement is not required if the rate of migration is too slow to contaminate the ground water in the "reasonably foreseeable future." This is inexact language, but both the measurements and theoretical predictions of contaminant migration are also inexact. The regulators and the regulated persons are left with a judgment call, as is true in many other bodies of law--for example, there is no quantitative language or measurement of careless driving. Although inexact, the "reasonably foreseeable future" provision is not useless verbiage. It will probably be applied in ways that are both beneficial to industry and acceptable to the citizens. In some cases, the natural soil may be so dry that damaging migration of nonvolatile contaminants would occur only over a period in excess of a thousand years. For certain other cases, scientists are developing techniques that will dry the soil or otherwise inhibit the migration of vapors so that the "reasonably foreseeable future" provision will eliminate the need for direct abatement. I conclude that the wording regarding the vadose zone is both important and technically practical.

Publication requirements. Other testimony may argue that it is not necessary to publish a notice of an abatement plan in a newspaper of general circulation throughout the state. I began my testimony with an example showing how citizen involvement is vital in obtaining environmental protection in the State. Our citizen's group relies on receiving news through newspapers of general circulation. Expertise beneficial to the State may reside anywhere in the state. It is therefore very important to publish notice of an abatement plan in a broadly circulated medium.

Why eight quarters of sampling? Some persons may argue that the successful abatement can be proved with one or two quarterly samples. In response, I note that pore gas, surface water, or ground water may appear to be clean while contaminants remain sorbed on the soil or in globules of NAPL. After some time, the contaminants may diffuse from the residual sources into the water or pore gas. Furthermore, due to the irregular motion of water or subsurface gas, the vagaries of migration, and/or uncertainties in sampling technique, the presence of the contamination may be detected only intermittently. As an example, I introduce an exhibit, which is a graph of the measured concentration of trichloroethane as a function of time, at several depths in a subsurface vapor plume. The data span the period from June of 1988 until June of 1992. The plume was not being intentionally abated during this time--only natural processes were acting as the plume increased in area and decreased in concentration. One can see that, at any single depth, the measured values of the concentration vary by about a factor of two from one sampling event to the next. This may be due to sampling procedures, or the data may represent the actual variation of the concentration of the pore gas due to atmospheric actions and/or earth tides. Whatever the cause of the variation, these data provide one illustration of why sampling over an extended interval of time is necessary to provide a estimate of the concentration.

SUGGESTED MODIFICATIONS TO THE PROPOSED REGULATIONS
(1)Section 3-203.F.1. In proposed Section 3-203.F.1, strike "using abatement technology pursuant to an approved abatement plan" and substitute "using commercially accepted abatement technology." Abatement technology is rapidly changing, and NMCCA&W wants to encourage the responsible person to propose the use of new or untried technology in his abatement plan. If a responsible party can be relieved of the requirement to meet the standards when an experimental technology proves inadequate, the regulating agency is unlikely to approve a new or untried technology. Therefore, we suggest the modification in order to encourage approval of the use of new technology, but requiring that the cleanup be achieved at least as well as can be accomplished with established technology. We believe that new technology will often prove superior to established technology.

(2)Section 3-205.. In the proposed Section 3-205.B, strike "as authorized and approved by: and substitute "under the authority of." According to this Section as proposed, an abatement plan is not required if the responsible person is abating under CERCLA or RCRA, with approval of the Environmental Protection Agency (EPA). Development of a work plan under RCRA may require several years, and the EPA may not approve the work plan until an additional year has passed after the responsible person submitted the plan. In such a case, according to the proposed Section 3-205.B, a responsible person would be required to develop an abatement plan for the State of New Mexico in parallel with developing a work plan for the EPA. This would be a waste of money, while delaying cleanup. We therefore suggest that the requirement for approvalbe removed from Section 3-205.B.

(3)Section 3-205.. In the proposed Section 3-205.H, strike "within ninety (90) days after abatement is initiated" and substitute "within one hundred eighty (180) days after the responsible party provides notice pursuant to Section 1-203 of these regulations or the director provides notice pursuant to Section 3-206 of these regulations." As proposed, this Section exempts the requirement for an abatement plan if abatement will achieve the required standards within 90 days. A well-meaning, but cautious, responsible person might fear exceeding the 90-day deadline, and elect instead to spend many months developing an abatement plan while postponing abatement itself. NMCCA&W believes the responsible person should be allowed 180 days for immediate cleanup, without formal paperwork. The objective is to achieve cleanup, not paperwork.

(4)Section 3-206.C. In proposed Section 3-206.C, strike "depending on the media affected" and substitute "as needed to select and guide an expeditious abatement process." As proposed, this Section specifies the contents of an abatement plan, depending on the media affected. The information needed for selection and execution of the abatement process depends on the situation, as well as on the media affected. In some cases, much of the described information would not be needed to assure cleanup. Development of extraneous information diverts resources from cleanup to compliance.

(5)Section 3-206.C.. In proposed Section 3-206.C.1, strike "surveyed site map with latitude and longitude coordinates: and substitute "site map with coordinates sufficient to locate the affected property and the location of all water contaminants to be abated." A surveyed site map serves the needs of the State, but does not always serve the needs of the abatement process. If not needed for abatement, a survey may divert attention and funding away from abatement.

(6)Section 3-206.C.2.b. In proposed Section 3-206.C.2.b, strike "impacts on surface water must be, in part, defined by conducting a biological assessment" and substitute "impacts on surface water may be, in part, defined by conducting a biological assessment." This changes the word "must" to the word "may." In some cases of surface water contamination, it might be necessary to determine the impact on the living organisms, if for no other reason than to avoid additional damage during abatement. However, in many cases a biological assessment would form a tally of damage done, but would not aid in achieving the specified standards for abatement. Unless restoration of the biota is required, a biological assessment should be required only as needed for optimal abatement.

--End of testimony.--