Independent Consultants in Environmental and Forensic Chemistry
Volume 1, Issue 2, Summer 1997
How Old is This Petroleum
(Continued from previous issue)
So how did the labs and experts do? Although eight laboratories specializing in petroleum product analyses were chosen for this study, only two laboratories correctly identified all three petroleum products (mineral spirits, diesel fuel, and lubricating oil). Five laboratories correctly identified two products with each laboratory correctly identifying the lubricating oil. Three laboratories did not identify the mineral spirits, and the remaining two laboratories missed the identification of diesel fuel. One laboratory did not identify a single petroleum product correctly.
Two laboratories declined to predict the age of the release on the basis that petroleum product fingerprinting cannot be used for age prediction. The remaining laboratories furnished the following age dating:
Lab A = less than 2 years
Lab B = less than 3 years
Lab C = less than 5 years
Lab D = between 5 and 10 years
Lab E = 1978 - 1980 (17 - 19 years)
Lab F = 1965 " 3 years (29 - 35 years)
Laboratory A predicted the age based on their identification of gasoline without manganese. Since all of this reasoning is false, Lab A's age dating is not defensible. Laboratory F based its results on the absence of tetraethyl lead, a gasoline additive. However, there were approximately 200 ppm lead present in this sample as a wear metal. Assuming that wear metals were generated from truck engine bearings manufactured approximately 10 years before the wear occurred in truck engines, then the result maybe reasonable. One laboratory submitted two signature pages for their results; one with and one without the age dating.
Three of the six laboratories that provided age estimates received the sample a second time with an attorney's request for age dating. Each laboratory called the attorney with questions about the site's history. Two laboratories declined to age date the sample. One laboratory determined that the age of the sample was 15 years old based on the site's history and sample's analysis.
It's a fair question. Data validation can add weeks to a project schedule and thousands of dollars to the project budget. The analytical laboratory is certified and highly recommended. Besides, the Quality Assurance Project Plan (QAPP) spells out the quality control requirements and corrective actions and was approved by the EPA. So everyone knows what to do and how to do it and there should be no problems. Right? Well, maybe, once in a while.
More commonly, you cannot (and should not) count on it. Communications are not always what they should be between and among project and laboratory personnel. The QAPP - approved or not - does not always get to the analyst actually doing the work. Given the enormous cost and political ramifications of decisions based on analytical data, it makes good sense to find out, up front, if what you have is what you need, if you are missing something, or if your results are reliable.
Consider the expenditure of millions of dollars in remediation costs to remove methylene chloride from deep aquifer wells when, after review of the method blank data, the wells were found to be not contaminated. Consider the increasing use of automated data reduction coupled with limited analyst training leading to responses like "I don't know, the computer just does it" when a laboratory is asked to explain how the reported results were obtained. All too often, the computer "just does it" wrong. Consider the case of a ground water treatment system that has been monitored monthly for well over a year (without validation) with very consistent results. Then one month, after being extremely high, the reported concentration of sodium was below detectable levels. The laboratory had simply missed the above linear range response for sodium in the sample; no dilutions were performed, and "ND" was reported. Mistakes do happen.
Third party data validation - by consultants experienced in the collection and analysis of environmental samples - is a valuable tool for detecting and correcting, to the extent possible, these kinds of problems.
"Are We Scaring Ourselves
ABC News Special - Aired 4/21/94, Reported by John Stossel
"Fear. It's one of our most powerful and complex emotions." "We're afraid of the air we breathe, the water we drink, and the food we eat." "And our biggest fear: crime." "But is life really so dangerous? Should we be so afraid?" So begins this 46-minute ABC News Special that compares our perceptions of today's world with reality. Violent crimes are on the rise. Chemical contamination and hazardous wastes pose a significant risk to public health and should be remediated at all costs.
Politicians and the media portray a constant epidemic of crime. We react to this epidemic by barricading ourselves in our houses, installing alarms systems, and not trusting anyone. Yet, the statistics for the past 20 years indicate that crime is on the decrease. Overall crime is down 25%. The "epidemic" appears to be fostered by sensational news coverage and politicians seeking funding for crime legislation.
"Consumer advocate" Ralph Nader came out of his bubble to state that we should not breathe, eat, touch, or ride anything. However, Stossel notes that the massive contamination at Love Canal has yet to produce any report of an increased case of cancer, that the dioxin contamination at Times Beach (see video review in previous issue) was perhaps not as bad as originally thought, and that asbestos removal from school buildings probably caused more harm than good. Spotlighted was the Smuggler Mountain site, a former silver mine, in Aspen, CO, that EPA declared a hazardous waste Superfund site in 1986 due to the high levels of lead in the mine tailings left behind. EPA proposed to demolish 150 homes and excavate and remove four feet of earth at a cost of eight million dollars. However, not one case of lead poisoning has been recorded in the last one hundred years. Average blood lead levels of the current residents were among the lowest in the country. Despite the evidence, EPA insisted that a health problem still existed.
Stossel ranks many of life's risks by estimating the number of days the average life is decreased as a result of a hazard: air travel - 1; hazardous waste - 4; fire - 18; pesticides - 27; air pollution - 61; crime - 113; driving - 182; smoking - 5.5 years; and poverty - 7-10 years. His point is that we seem to be overly concerned with the smaller risks.
Applauded as well as condemned, Stossel's special on our perception of crime and chemical hazards marked the transition for the reporter from being considered a consumer's advocate to a spokesperson for corporate interests. He has since been considered by many as an anti-environmentalist due to his unpopular questions regarding national policy and public opinion on the environment.
Are We Over-Regulating PAHs?
Presented by Dr. James Smith, Jr., PTI Environmental Services, Inc., at the Society of Risk Analysis Annual Meeting, New Orleans, 1996.
Polycyclic aromatic hydrocarbons (PAHs) are a group of more than 100 chemicals formed during the incomplete combustion of organic substances. PAHs are ubiquitous in the environment and are frequently encountered at hazardous waste sites. People are exposed to a mixture of PAHs in a variety of environmental media. Because some of these compounds have been shown to produce cancer in laboratory animals, the Environmental Protection Agency (EPA) regulates human exposure to PAHs to very low levels.
In the past, the EPA has assumed that all PAHs have the same carcinogenic potency as benzo[a]pyrene (BaP), one of the most potent of the carcinogenic PAHs. However, environmental PAH mixtures often contain PAHs that are less potent than BaP. Because insufficient information exists to determine the potency for these PAHs, the EPA estimates the potency relative to BaP. The cancer potency of a PAH mixture is then calculated as the sum of the BaP equivalent doses of the individual PAHs.
Recently, we compared the carcinogenic risk associated with PAHs in soil at a Superfund site with that associated with PAHs in shampoo containing coal tar. For the purpose of this comparison, we identified an EPA Record of Decision (ROD) that required remediation of carcinogenic PAHs in soils to 30 mg/kg to protect human health (i.e., risk of one excess cancer in one hundred thousand people). A subsequent analysis of site soils for individual PAH compounds revealed the highest concentration of PAHs found had a BaP equivalent potency of 88 mg/kg. We selected two shampoos containing coal tar from a grocery store and analyzed them for PAH content. Brand A was shown to have a total PAH content of nearly 230 mg/kg and a BaP equivalent carcinogenic potency of 45 mg/kg, half that of the Superfund site soils. Brand B had a PAH content of 35 mg/kg and a BaP equivalent carcinogenic potency of 6 mg/kg.
An estimate of exposure to PAHs in soil and shampoo was used to determine the absorbed dose in potentially exposed humans. The EPA=s ROD evaluated the potential exposure of children playing organized sports from infrequent, 12 days a year, incidental ingestion of and dermal contact with soils contaminated with PAHs. For PAHs in shampoo, we used a non-steady state approach described in EPA=s 1992 guidance entitled Dermal Exposure Assessment: Principles and Applications to estimate exposure from infrequent dermal contact with PAHs in water. We assumed that an individual shampooed only 12 times a year for three minutes and that only the surface area of the hands and one-half of the head were exposed. In every other way, the two exposure assessments used the same conservative exposure factors described in the ROD.
Cancer risk from PAH exposure depends on the relative BaP cancer potency estimate and the absorbed dose of PAHs. Therefore, a comparative analysis of cancer risks posed by PAHs in Superfund site soils and shampoos containing coal tar involves estimates of BaP cancer potency and of exposure from these sources. Both exposure estimates were performed using recommended EPA exposure algorithms and default parameters..
The carcinogenic risk associated with the PAH mixture in the Superfund soils was approximately 3H10-5 (three excess cancers in one hundred thousand people) and high enough to warrant remediation of site soils based on the EPA ROD. The carcinogenic risk associated with PAHs in shampoos containing coal tar ranged from 1H10-1 to 1H10-2 (one excess cancer in one hundred people). Yet, no reports of increased incidences of scalp cancers from coal tar shampoos have been reported.
Although the relative BaP potency of Superfund site soils was nearly twice that of the brand A shampoo, the absorbed dose of PAHs from the shampoo was many times greater than that from the soils. This resulted in an estimated 10,000-fold greater cancer risk from the shampoo than from exposure to "contaminated" soils. Should shampoos containing coal tar be regulated as a significant cancer risk to people? Or have we over-regulated PAHs? These findings suggest that cleanup levels for PAHs in Superfund site soils could be much higher without adding significantly to the carcinogenic risk of potentially exposed humans.
How do you get quality analytical data quickly and at a reasonable cost?
When characterizing a site, three factors should be considered in the proposals for environmental analyses: obtaining high-quality, defensible data; contracting for reasonable analytical costs; and receiving results in a timely manner. Any two of these factors are easily obtainable, but with sound planning, effective communication, and aggressive management, all three desired factors are achievable.
A steering committee representing 149 potentially responsible parties (PRPs) contracted Trillium to provide quality assurance consulting to ascertain the extent of contamination at a Superfund site in Criner, Oklahoma. The field sampling plan required installation of wells and borings at increasing distances from the source until no contamination was detected. To avoid expenses associated with mobilization and demobilization of the drilling contractor in the field, 24-hour turnaround times were required for the analytical results. A qualified environmental laboratory capable of performing U.S. EPA Contract Laboratory Program (CLP) analyses and generating the required deliverables was contracted to provide analytical services on a daily, rather than a per sample, basis.
The services contracted from the laboratory included the dedication of personnel, instruments, and resources necessary to analyze the project samples during a specified analytical shift. By scheduling the receipt of samples and dedicating the laboratory's efforts, project samples were analyzed by the same analyst on the same instrument with the associated quality control samples. The number of instrument tunes, calibrations, and analytical run sequences were reduced, enhancing the quality of the data and facilitating review. Data packages were forwarded to Trillium within 24-hours of receipt of the samples, and validated data were provided to the steering committee within 72 hours of sample collection. Laboratory charges totaled $300,000, a savings of $500,000 based on a cost estimate of $800,000 from another bidder to provide the same rapid-turnaround analyses. The project required intensive up-front planning, daily on-going communication, and micro-management by all participating parties. These efforts resulted in high-quality, defensible data provided within 72-hours of sample collection at a substantial savings to the client.