“A consistent chemical signature for coal tar sealant PAHs has not been determined, but monitoring results combined with the correlation of PAH hot spots to sealed parking areas strongly implicates sealants as a primary/concentrated source of PAHs in Austin stream sediments”. (PAHs in Austin TX-May 2005, page iv).
Barton Springs is the main discharge point for the Barton Springs segment of the Edwards Aquifer of Texas. Barton Spring Pool is a spring-fed swimming hole, fed from the Barton Spring, which is a major attraction in Austin, TX. From the mid 1970’s, (City population was over 251,000) when major development around the pool started to take place along with the extension of the MoPac highway into South Austin, it became apparent that any form of development commercial or residential was going to be met with resistance. As portions of South Austin were being developed from the mid-1970’s and the 1980’s (city population was approximately over 345,000), an environmental movement was beginning to emerge that stated purpose was to oppose any and all development in Austin, TX. The environmental groups’ main objection with the land development was going to have a negative impact upon the local aquifer and the Barton Springs Pool. Since the aquifer provided spring water to the pool it also served the purpose of providing drinking water to the Austin area. Fears of the aquifer being taxed, additional pollution from the added population from individuals moving into the newly developed area and developing areas which were mostly open space were the primary objections of the environmentalist.
In May 1997, US Fish & Wildlife Service put Barton Springs Salamander on the endangered species list. This was after a five plus year fight between local environmental groups/activists and the US Fish & Wildlife Service/Department of the Interior and state government.
Federal Register-April 30, 1997. Listing the Barton Springs Salamander as an endangered species
US Fish & Wildlife Service Barton Springs Salamander Recovery Plan-2005
-“PAHs are trace contaminants that occur naturally in crude oil, coal, and other hydrocarbons. They also are produced by combustion of hydrocarbons, resulting in many urban sources including: industrial and power plant emissions; car and truck exhaust; tires; and asphalt roads and roofs. Eliminating PAHs from urban runoff is difficult because of their varied sources”. (page 3)
-“Total PAH concentrations in recently deposited sediment in Town Lake are about 16 times the concentrations in 1960, increasing from about 700 ppb in 1960 to 11,400 ppb in 1998. The increase corresponds with increases in traffic in greater Austin”. (page 3)
-“The relation of PAH concentrations to Austin traffic is evidence of the importance of nonindustrial sources of PAHs to streams and lakes and indicates that vehicle emissions, road and tire wear, and engine oil leaks could be major sources of PAHs.” (page 3)
Historically the City of Austin has been routinely testing their water, soil and sediment for quality. PAHs were detected in areas of Town Lake (a segment of the Colorado River that flow through downtown Austin receiving water from other urbanized creeks) since 1991. Sediments in four urbanized creeks were sampled and identified at PAH “hot spots”. One of these “hot spots” was in the Barton Springs Pool.
E-mails between City of Austin and federal scientist on contamination-May 2, 2002
TDH letter to COA City Manager-August 28, 2002 regarding BAP levels in Barton Springs Pool
Starting on January 19, 2003, the Austin Statesman started to run a series of articles titled “Toxic Water-An Austin Treasure at Risk”.
Austin Statesman “Toxic Water-An Austin Treasure at Risk” article series
One of the first articles was about how levels of pesticides, PAHs, dioxins, and other environmental contaminates were threatening the Barton Creek and Barton Creek Pool. One of these articles is titled “Detection Methods-City Test Standards are far too lenient, scientist say.” The article goes to state that the testing standards used by the Watershed Protection Department are lax and often non-existent.
Coincidently on the same day, COA’s Watershed Protection Department announced they discovered that the primary source of PAHs in the watershed was from refined tar based pavement sealer.
COA press conference dated January 19, 2003
Austin Statesman City's monitoring keeps springs safe for public. January 19 2003.
USGS letter to COA Watershed Protection Department regarding sampling-February 14, 2003.
Note-USGS only performed screening levels analyticals and could not determine the source of the PAHs based on the information given in this letter.
As a result of these articles, pressure from environmental groups and public fear, the city decided to close Barton Spring Pool until they were able to ascertain if it was safe for humans and water life. COA asked TDH, ATSDR and TCEQ to make a determination regarding human and aquatic health risks:
ATSDR-Health Consultation Barton Springs Pool, April 18, 2003.
Summary of ATSDR Health Consultation
The TDH and ATSDR were asked by TCEQ, COA, Lower Colorado River Authority (LCRA) and USGS to determine the public health significance of PAHs found in the Barton Springs Pool.
TDH and ATSDR reviewed over 14, 500 data points collected over the past 12 years.
TDH and ATSDR determined that swimming and playing in Barton Springs Pool poses no apparent public health hazard.
TCEQ: Barton Springs Pool and Barton Creek Area Investigation-May 29, 2003
Summary of Barton Springs Pool and Barton Creek Area Investigation
Barton Springs Pool-Chemical contaminants associated with sediments in Barton Springs Pool do not present a human health risk to swimmers who frequent the pool.
Barton Creek-sediments form Barton Creek are not at levels that would be a concern for human health.
Spyglass Tributary-sediments from the Spyglass Tributary are not at levels that would be a concern for human health.
Sediment and soils-Lost Creek Boulevard and adjacent to Barton Creek-Exposures to these soils and sediments would not pose an unacceptable risk to human health.
Apartment Tributary- In conclusion, the surficial sediments in the apartment tributary do not pose an imminent human health risk. In reviewing the soil and sediment data collectively, it appears the extent of PAH contamination is relatively limited.
TCEQ: Barton Springs Pool Sediment Toxicity Evaluation to Aquatic Life-May 28, 2003.
To summarize TCEQ’s Barton Springs Pool Sediment Toxicity Evaluation to Aquatic Life study:
-Toxicity testing was performed using standard EPA and ASTM protocols (page 1).
-Numerical standards have not been adopted for contaminants in sediments. Since this is the case, sediment screening levels used included those developed by NOAA, TCEQ’s Surface Water Quality Monitoring and those from TCEQ’s Ecological Risk Assessment Program (page 2).
-“With few exceptions, the results of the physico-chemical analyses of Barton Springs Pool sediement (combined with the water column data from previous samplings) indicate that the quality of the pool is better than expected from typical water bodies in urbanized areas” (page 4).
-“However, recent studies indicate that because PAHs are nearly always found in the environmental as mixtures, they should be evaluated as such” (page 4).
-“In the interim, a total PAH number of 12.2 mg/kg (ppm) has been recommended for the protection of benthic invertebrates in freshwater sediments (page 4).
-“Since none of the samples exceeded the recommended value of 12.2 mg/kg (ppm), and because some of the samples contained lower concentrations of total PAHs that the two samples that were not different from the control, it is unlikely that PAHs caused the sublethal effects to Hyalella (page 4).
-“There were no lethal effects observed to either species of test organisms compared to their respective controls”.
-Recommendations: “Although growth effects to once (i.e., Hyalella) of two test species were observed, based on discussions with EPA about the lack of mortality in either organism, the lack of growth effects to the other test organism (i.e.,Chironomus), and the lack of correlation between the physico-chemical data and the Hyalella growth effects, the evidence suggest that the aquatic life use in Barton Springs is not impaired by sediment toxicity. The pool should not be placed on the State’s 303(d) list for ambient sediment toxicity but the growth effects observed in the tests with Hyalella do warrant continued contamination monitoring and toxicity testing”(page 5).
TCEQ: Barton Creek Sediment Toxicity Evaluation to Aquatic Life-July 29, 2004
To summarize TCEQ’s Barton Creek Sediment Toxicity Evaluation to Aquatic Life study:
-Because of low flow conditions in the creek, TCEQ was unable to collect additional sediment samples until May 2004.
-Toxicity testing was performed using standard EPA and ASTM protocols (page 1).
-Numerical standards have not been adopted for contaminants in sediments. Since this is the case, sediment screening levels used included those developed by NOAA, TCEQ’s Surface Water Quality Monitoring and those from TCEQ’s Ecological Risk Assessment Program (pages 1-2).
-“With few exceptions, the results of the physico-chemical analyses of Barton Creek sediement indicate that the quality of the creek is better than expected from typical water bodies in urbanized areas” (page 4).
-“There were no lethal effects observed to either species of test organisms compared to their respective controls.” (page 4)
-“…data suggests the aquatic life uses in Barton Creek are not impaired by sediment toxicity.” (page 5)
-“Barton Creek should not be placed on the State’s 303 (d) list for ambient sediment toxicity at this time….”. (page 5)
USGS Fact Sheet 089-03 entitled “Quality of Sediment Discharging from the Barton Springs System, Austin, Texas, 2000-2002”. One of the finding of this study is that PAHs concentrations from sediments that were from more-urbanized areas were 10 to 100 greater than sediment from lightly-developed areas. The final conclusion of this study was “The results of the study described in this report indicate that urbanization of the watershed has not yet resulted in extensive degradation of the quality of sediment discharging from the Barton Springs System”.
PCTC response to COA Watershed Protection Department pertaining to refined tar based pavement sealer-January 8, 2004
-“The highest concentrations were consistently detected at Williamson, with concentrations in some samples exceeding 10,000 ppb…” (page 21)
-“PAH concentrations at Barton Above, Shoal, and Boggy were about 5 to 8 times lower than those at Williamson; however, ΣPAH9 concentrations at Shoal exceeded the PEC in two of the nine samples. Concentrations of PAHs at Barton 71 and Barton Springs were 13 and 19 times lower than at Boggy, the site with the next-highest concentrations.” (page 21)
-“Samples from Williamson show the lowest ratios, typical of combustion sources; these samples also have the highest PAH concentrations. Barton Above, Shoal, and Boggy have ratios that are slightly higher. The highest ratios, reflecting a more petrogenic (natural) source, are detected in sediment from Barton 71. Ratios intermediate between those at Barton 71 and the urban sites are detected in Barton Springs sediment, even though concentrations are similar to those at Barton 71. The ratios thus reflect the contribution of anthropogenic PAHs of a combustion origin to the suspended sediment at the more urbanized sites and indicate that, although concentrations of PAHs are relatively low at Barton Springs, some sources might be anthropogenic.” (page 21)
-“ In the national sediment core data, concentrations of PAHs correlate well with urban land use, increasing by a factor of about 50 as urbanization increases from 0 to 100 percent. In a national context, PAHs concentrations in suspended sediment from Barton 71 and Boggy are lower than would be predicted on the basis of land use in their watersheds, and concentrations at Shoal are similar to those in similar land use settings. Concentrations at Barton Above and Williamson, however, are about 10 times higher than would be predicted on the basis of land use in their watersheds. This indicates either that there is an anomalous number of sources of PAHs in these watersheds, that characteristics of the watersheds are such that sediment contaminated with PAHs is efficiently delivered to the creeks, that dilution by “clean” soil is less, or some combination of these factors”. (page 40)
-“Different creeks are affected by different contaminants, but in general suspended sediment at the more urban sites have elevated concentrations of hydrophobic
Contaminants”. (page 59)
-“Loads of almost all contaminants were correlated with sediment load.” (page 59)
-“Yields of contaminants are correlated with urbanization.” (page 59)
-“Occurrence of hydrophobic contaminants in the urban creeks sampled are consistent with those found in Town Lake bed sediment.” (page 59)
-“Sediments discharging from Barton Springs is relatively uncontaminated.” (page 60)
How the City determined Coal Tar Pavement
Sealer is to blame for PAH contamination
The city traced the levels of PAHs in Barton
Creek above the pool to elevated levels along
a dry creek bed which PAHs increased upstream
to the proximity of an apartment complex parking
lot (Barton Hills Park Place Apartments).
Graphic:
Contaminants’ path to the creek
Graphic:
Photo showing dry creek bed
The following quote is from the Texas Commission
on Environmental Quality report titled “Barton
Springs Pool and Barton Creek Area Investigation-May
29, 2003” which explains how the city
tied coal tar based pavement sealer into the
waterways PAH contamination:
TCEQ:
Barton Springs Pool and Barton Creek Area Investigation-May
29, 2003
-“A visual inspection of the apartment tributary and surrounding area did not reveal any other potential sources of surficial contamination (e.g. seeping
tar). However, the surficial soil samples collected both in the head of the apartment tributary and in the landscaping bed contained large amounts of a fine black powdery substance; visibly different from the soil and sediment samples which contained lower PAH levels”. (TCEQ-2003,page 7)
also,
“The City of Austin also collected scraping samples of the parking lot’s sealant for chemical analysis. BaP levels in the two sealant samples were 1030 and 1830 mg/kg (ppm)(Note-samples have been cross-contaminated with other sources of PAHs and not chemically fingerprinted to determine PAH source). This data corresponds well with other data that the City of Austin has amassed on PAH levels in coal-tar based parking lot sealants. Specifically, the City of Austin has also collected soil and debris samples from areas representing worst-case runoff samples from parking lots around the city, both non-asphalted and asphalted using coal-tar based sealants. The correlation between high PAH levels and asphalted parking lots using coal-tar based sealants was remarkable. This is not surprising given that coal tar is known to contain high levels of PAHs”(TCEQ-2003, page 8).
“Based on the above data, the TCEQ has concluded that the contamination in the apartment tributary is most likely due to the coal-tar based sealant used on the parking lot. These sealants are known to wear relatively quickly, often requiring replacement every two to three years. It is apparent that the worn sealant runs off of the parking lot over time, impacting surficial soils and sediments in nearby drainage areas”(TCEQ -2003-page 8).
Conclusion of COA’s theory of the part that refined tar based sealer play in the role of environmental PAHs:
In conclusion, the surficial sediments in the apartment tributary do not pose an imminent human health risk.. In reviewing the soil and sediment data collectively, it appears the extent of PAH contamination is relatively limited, i.e. the PAHs are not carried far downstream or are quickly diluted. In the head of the apartment tributary, PAH levels in sediments and soils are elevated, but decline sharply the farther downstream the sediment samples were collected. PAH levels in sediment samples from Barton Creek declined even more” (TCEQ-2003, page 8).
To summarize how The City of Austin (COA) connects Refined Tar-Based Pavement Sealer to the PAH contamination:
-COA assumed that PAH contamination originated from the surface and not from something buried underground.
-COA assumed that no other types of sources of surficial contamination could be found (e.g. seeping tar).
-A fine, black, powdery substance was found at the head of the apartment tributary and in the landscaping bed.
-COA collected scrapings of refined tar based sealer from the pavement which was high in PAHs, which would prove their theory about coal tar sealer being the cause (even though there were other sources of PAHs on those scraping and COA never chemical fingerprinted those scrapings). The assumption was based upon one chemical parameter.
-Apparently there are no other sources of PAHs that exist except for coal tar and refined tar based sealer in the City of Austin. The hundreds of other studies documenting the thousands of other sources of PAHs must have been incorrect.
-COA is basing their conclusions on very little analytical data. Initially COA was basing their refined tar based sealer theory on one PAH compound-Benzo(a)pyrene.
-According to IARC 1985, Coal tar is known to contain high levels of PAHs. Note that Refined Tar Based Sealer is made from Refined Tar, not Crude Coal Tar (as TCEQ and COA states).
However, there are flaws with COA’s and TCEQ’s assumptions:
-According to IARC 1985, Coal Tar is known to contain high levels of PAHs. This part is true that Crude Coal Tar tends to have higher PAH levels than that of asphalt. PAH levels in Crude Coal Tar are variable in composition that is due the PAH contents that are in various coal streams. The problem is that Coal Tar Based Pavement Sealer is made from Refined Tar.
It would appear that COA, TCEQ and USGS are confused when they make statements regard PAH content in Coal Tar where they should be stating PAH levels in refined tar. Not to mention that refined tar is only 20-25% of the total formula for a typical finished refined-tar based pavement sealer. Crude Coal Tar (Coal Tar) and RT-12 are very different in chemical and physical composition. RT-12 is derived from the distillation of coal tar. This is another example of one of the many weak links made by COA and USGS.
-COA determined that PAH contamination originated from the surface and not from something buried underground. One theory that has been offered by various scientist is that the PAH contamination may be due to waste generated from various Manufactured Gas Plants (MGP) three of which operated in the City of Austin (one near West Fifth and West Ave. The second was near Colorado and West Second Sts. and the third being at East Third and Medina Sts). One of these plants (according to old maps) was in the Barton Creek area. These plants which produced gas from a coal gasification process, helped light the city from 1873 to 1928. There are three articles from the Austin American Statesman that help support this fact.
Toxic
chemical taint Barton Waters, January 19, 2003
by Kevin Carmody and Mike Ward, Austin American-Statesman.
Austin’s
19th century coal gas plants provided light,
left pollution, January 19, 2003 by Mike Ware,
Austin American-Statesman.
Clues
about a Hot Spot: Apartment Site near Barton
Creek was a gravel pit, January 19, 2003 by
Kevin Carmody and Mike Ward, Austin American-Statesman.
Photo # 1 which was taken in 1940 which
show the gravel pits.
Photo # 2 which was taken in 2004. The
apartments were built in the early 1970s.
1887 map that shows one of the MGP on West Street
between 3rd and 5th Sts.
Geomatrix Consultants, Inc.-Report of Barton Springs Area Site Investigation, March 27, 2003
A common practice among MGP was to dump their wastes (BTX, coal tar, etc.) into a quarry, cave or other similar depression. It is possible that the former quarry may be such a site. In response to these allegations, The City of Austin contracted with Geomatrix Consultants, Inc. (reference: Geomatrix Consultants, Inc.-Report of Barton Springs Area Site Investigation, March 27, 2003) to perform a site investigation. During this site investigation it should be noted that there are no standardized protocols for roadway/parking lot scrapings. Also, Geomatrix ran analyticals for ΣPAH16 which is insufficient in determining the chemical fingerprint source of the PAHs since an expanded set of analyses were needed in order to determine the PAH profile. The analyticals that were run could only be used as a screening method at best and could not determine the source of PAHs to be asphalt, motor oil, or tire particulate. It should be noted that a Geomatrix performed a visual inspection of the samples to distinguish between tire particles and abraded sealer which is highly uncertain on normal visual inspections. See Environmental Forensics section under PAHs.
Issues to note about the Site investigation:
-The pavement scrapings had no established EPA/ASTM protocols to follow regarding sampling
-PAH testing performed was only a screening for PAHs and could not possibly determine source of PAHs since there was certainly cross contamination of various PAH sources.
-Only five borings were completed and may be insufficient to do a true site characterization.
At Boring B1 (in the Area of Primary Concern-the sampling location with the highest concentration of PAHs), the highest overall PAH level was ΣPAH16=138.54 ppm. The total PAH and individual compound concentrations in this sample were generally consistent with levels reported for urban soils (ATSDR 1995) and for urban sediments (Talley et. al. 2002). This would suggest that the deposited roadway debris at this location is not substantially different in PAH content than typical urban environmental sources.
-COA attributes all PAH contamination from Refined Tar Based Sealers and no other sources. Refer to “About PAHs” section for information about other sources of PAHs. The analysis that COA ran was Σ PAH13-16 was insufficient to determine the source of PAHs (see PAH section on Environmental Forensics).
-A fine, black, powdery substance was found at the head of the apartment tributary and in the landscape bed. COA concluded that this black substance that they found had to be refined tar-based sealer based on the fact that it was near the apartment tributary (the result of refined tar-based sealer breaking down and washing off). This black substance could have been a number of different substances other than coal tar sealer (asphalt binder from the pavement, car tire shavings, etc). It is difficult to also prove that the PAHs from this black substance as all from the substance itself and not PAH from the substance and PAHs from other sources which would have contaminated the black substance.
-The COA 2005 Study was never put out for a conventional peer review process. The reason for the peer reviews is to allow the scientific community to examine the evidence and prove or disprove the hypothesis put forth in the study. COA would argue that they have an internal review process, as many government agencies do, but cannot be considered to be the same.
-Another falsehood in this study is in the following quote from this study: “The significance of parking lot sealants as a source of PAHs in urban streams sediments is indicated by an estimated application rate of over 600,000 gallons of undiluted sealant in the Austin area, which may contain 50% coal tar or more” (PAHs in Austin TX, page iv). First, using Table 5.1 Watershed Characteristics on page 5-3, making some base assumptions (industry accepted coverage rates, recoat every sealed parking lot annually and all sealer is refined tar-based) the range of annual refined tar-based sealer sold into Austin, TX (on an undiluted basis) is 20,813 to 41,668 gallons annually. As you can see, Austin’s estimate is grossly overstated.
The part of the sentence has two inaccuracies in it. First, refined tar sealer does not contain crude coal tar but refined tar (see About Coal Tar). Second, refined tar-based pavement sealer (finished) contains typically 20-25% of refined tar.
-Another potential large PAH producing source near the Barton Springs Pool is that the South Mo-Pac Highway (a six lane highway) lies just approximately 2000 ft. northwest of the Barton Pool. Another source would be the one track rail line that runs down the middle of the highway (The Missouri-Pacific Railway). No mention of this as potential point sources was mentioned in any of the reports. In 1999, the traffic volume on this roadway was 134,000 cars per day (CAMPO 1999). This volume is expected to increase to 225,000 cars per day (TxDOT 2006). Link to population and traffic increases:
ftp://ftp.dot.state.tx.us/pub/txdot-info/aus/mopac1/population_traffic.pdf
Click here for a satellite map of the area.
-Another large potential source of PAHs would be from the three power plants operated by Austin Electric. One plant is primarily powered by natural gas (with fuel oil alternative). The second plant is powered by natural gas. The third plant is powered by coal.
In the study, “Urban Sprawl leaves it PAH Signature” (Van Meter et al. 2000) states the following: “One intriguing possibility suggested by the results of this study is that urban growth or sprawl outside the watershed may adversely affect water quality within the watershed. This is most evident when a watershed has undergone only a relatively minor change in degree of urbanization. For example, Austin, TX, is one of the most rapidly growing cities in the country, but the majority of the growth there has occurred around the fringes of the city and outside of the watershed of Town Lake. This growth has contributed to large increases in vehicle traffic in the Town Lake watershed; traffic on MoPac Expressway, most of which lies within the watershed and which crosses Town Lake, almost doubled between 1990 and 1997. The large increases in traffic offer an explanation for why PAHs more than doubled in Town Lake from 1975 to 1990 while percent urban land use only increased by 5%. This suggests that urban sprawl in outlying areas may affect traffic patterns and water quality in the inner city”.
Also in the same study, “The presence and distribution of PAHs in the environment are largely a product of the incomplete combustion of petroleum, oil, coal and wood. Anthropogenic (man-made) sources such as vehicles, heating and power plants, industrial processes, and refuse and open burning are considered to be the principal sources to the environment”.
In addition, “The increase in PAHs in new urban settings cannot be attributed solely to urbanization of the watersheds. This is most clearly illustrated by those watersheds in which urban levels are stable. The increase in PAH concentrations in these watersheds is, however, coincident with increases in automobile use. Among the sources of PAHs related to automobiles are tire wear, crankcase oil, roadway wear, and car soot and exhaust. Trends in PAH from the 1970s to the present compare well to trends in VMT on freeways and major arterial streets for the associated urban areas for all sites and ages of urban development”.
-Below is a chart which shows the change in population from 1940-2010 in the city of Austin, TX:
Year |
Total
Area Population |
1940 1950 1960 1970 1980 1990 2000 2005 2010 |
87,930 132,459 186,545 251,808 345,890 465,622 656,562 700,407 800,000 (estimated)* |
Source: Ryan Robinson, City Demographer, Department of Planning, City of Austin. December 2005.
2010 estimate: www.ci.austin.tx.us/smartgrowth/
Other COA Studies
A Photographic Method for Estimating Wear of Coal Tar Sealcoat from Parking Lots, Mateo Scoggins, Tom Ennis, Nathan Parker and Chris Herrington; City of Austin, Watershed Protection and Development Review Department, 2009.
The purpose of this study was to digitally quantify black (sealed areas) vs. lighter (unsealed area) using a color standard (18% grey card). The raw data was entered into an imaging program (NIH Image) to determine the % sealed. There are a few problems that should be pointed out:
-The standard (grey card) was an arbitrary color choice (as there is no standard for color of sealer or asphalt pavement) and there is no standard method for determining for estimating sealcoat wear.
-The images were shot in 1.5 megapixels or low resolution
-The Nikon D50 Digital SLR is a low resolution camera (maximum resolution of 6 megapixels). This would not be considered to be a “photographic quality” camera where the resolution is around 12-13 megapixels.
-NIH Image is almost exclusively used in microbiology applications.
-This study claims that in a New York Academy of Sciences (NYAS) “estimated the contribution of PAHs to the New York/New Jersey Harbor, and although they concluded that coal tar sealcoat was a major contributor, they were not able to appropriately constrain loading from this source, indicating a very wide range, from 11% to 46% of the total PAH load into the harbor”. The NYAS study actually states that it was estimated that only 1% of the PAHs applied to a parking lot are released over the life of the sealer (3 to 5 years) (NYAS-2007, pg. 65).
-In a recent presentation given by an official from the City of Austin Watershed Protection Department (January 15, 2010) they claim that the mean annual loss of “coal tar sealants” was found to be 3.1% per year. This is different from the published study.
-Two incorrect statements made by COA is “Coal tar sealcoats are using in an emulsion form containing up to 35% refined coal tar, which is on the order of 50% PAHs by mass” (COA 2009). There are two things that are incorrect in this sentence. First, refined tar makes up 20-25% of the finished sealer, not up to 35% as COA claims. Second, COA makes a statement that refined coal tar (which should be referred to as refined tar) contain 50% PAHs. If you refer to the footnote, this refers to an NIST Standard for complex mixture of PAHs from Crude Coal tar (Coal tar is not the raw material that sealer is made from. Refined tar is the raw material that sealer is made from).
Amphibian Studies
Barton Springs Salamander. Source:
http://water.usgs.gov/ogw/karst/img/features/edwards/bartonSalamander.jpg
The Effects of Coal Tar Based Pavement Sealer on Amphibian Development and Metamorphosis; Pamela Bryer, Jan Elliott and Emily Willingham. Ecotoxicology, 15, 241-247, 2006.
There are several problems with this study:
-Small sample size
-Selected doses were well above known lethal levels. The outcomes were pre-determined by design.
-Testing did not meet EPA or ASTM protocols.
-These studies did not meet scientific standards requiring description of materials used such as source of test material was not disclosed and lack of full chemical characterization precludes repeat of experiment by others.
-The focus of the study is designed around the notion that elevated concentrations of refined tar-based sealant pose a risk to amphibians and no other source of PAHs would have the same effect.
-The authors further obscure the facts by comparing refined tar-based sealer to coal smoke and from chimney soot.
Occurrence of polycyclic aromatic hydrocarbons below coal-tar-sealed parking lots and effects on stream benthic macroinvertebrate communities: Mateo Scoggins, Nancy McClintock, L. Gosselink and Pamela Bryer. Journal of North American Benthological Society, 2007, 26(4): 694-707.
-“We attempted to identify the sources of PAH in the sediment of our study streams using ratio methods, but we were unsuccessful and found no significant clustering of field data with known source data” (page 702).
-“Our inability to associate PAH contamination in our study streams with coal-tar sealant might have been because we analyzed on the 16 EPA priority PAHs in field sediments or because of extensive weathering and mixing with other materials as the coal-tar sealant abrades and moves from parking lot to stream systems”(page 702).
-Testing did not meet EPA or ASTM protocols.
-The authors assumed that any “high” source of PAHs could only be refined tar-based sealer based and nothing else. Any other source of PAHs would be considered “background” and of no consequence to the study.
-Small sample size
Coal-Tar based pavement sealant toxicity to freshwater macroinvertebrates: Pamela Bryer, Mateo Scoggins and Nancy McClintock. Environnemental Pollution, 2009.
-Small sample size
- Selected doses were well above known lethal levels. The outcomes were pre-determined by design. It is interesting to note that the low and medium dosing of PAHs, the number or organisms and species richness (abundance) either increased or remained the same when compared with the control group (page 3).
-These studies did not meet scientific standards requiring description of materials used such as source of test material was not disclosed and lack of full chemical characterization precludes repeat of experiment by others.
- Testing did not meet EPA or ASTM protocols.
-The study mentions a link between refined tar-based pavement sealer and PAHs in sediments of urban water bodies. The references given were Van Metre and Mahler-USGS and Scoggins-COA. The authors want to give you the impression that the science is settled, where that could not be further from the truth (page 1).
-This study claims that refined tar-based pavement sealers may be contributing a large portion of the PAH loading seen in urban stream sediments (page 1).
-The statement “Coal tar is a hazardous waste byproduct of the coking of coal and is a frequent waste product in steel and electric industries (ATSDR 1996). Currently, coal-tar byproducts is recycled into products that are presumably relatively inert, such as pavement sealants, therefore avoiding hazardous waste disposal issues described by the Resource Conservation and Recovery Act , RCRA, (40 CFR 261.31 and 40 CFR 261.32)(ATSDR 1996)”(page 1) is filled with numerous inaccuracies. First, Refined tar-based pavement sealer is made from refined tar (see Coal Tar and PAHs section of this site). Second, crude coal tar is not a hazardous waste byproduct. It is a crude product that is further refined into other products. Much in the same way that crude oil is refined into other petroleum based products. Third, the authors used the ATSDR Toxicological Profile for Creosote (a wood preservative which is a refined tar-based product) and is no way similar to refined tar. In addition, when consulting the Toxicological Profile that was referenced by the study, the above mention statements were not contained within the profile in any way in that document. Refined tar is not a recycled product to avoid EPA’s hazardous waste laws. This is an example how COA is attempting to support a preconceived notions about refined tar and refined tar-based sealer (page 1).
-In the high dose PAH experiment; somehow there was a decrease in total PAH by almost 15% from start of the experiment to the end of the experiment.
Two studies which are not referenced in any of the above mentioned studies are:
TCEQ: Barton Springs Pool Sediment Toxicity Evaluation to Aquatic Life-May 28, 2003
TCEQ: Barton Creek Sediment Toxicity Evaluation to Aquatic Life-July 29, 2004
See the beginning portion of this section to read more about these two studies.
