Friday, March 2, 2012

PAHs Polycyclic Aromatic Hydrocarbons

Study on Behavior and Kids:

Air Pollution Tied to Behavior Issues in Kids

During the prenatal period, the women in the study carried personal air monitoring units that recorded levels of a representative polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P).

 In multivariate analyses, Perera and colleagues found:
  • High prenatal exposure, as measured by air monitoring, was associated with a significantly higher symptom score of Anxious/Depressed in the children -- 1.45 times that of the low exposure group (P<0.0001).
  • High exposure was also associated with an elevated symptom score of Attention Problems -- 1.28 times that of the low exposure group (P=0.001).
  • Similarly, detectable DNA biomarkers of exposure were associated with Anxious/Depressed symptoms -- 1.23 and 1.46 times that of the nondetectable group for maternal and cord blood, respectively. The associations were significant at P=0.019 and P<0.001.
  • The same was true for Attention Problems – the risk increases were 1.25 and 1.32 times that of the nondetectable group for maternal and cord blood respectively. The associations were significant at P=0.003 and P=0.002.

Research Updates from the USGS:

Coal-Tar Sealcoat a Major Source of PAHs to Air and to Children Living Nearby - 2/13/2012

Four new reports examine the contaminants polycyclic aromatic hydrocarbons (PAHs) found in house dust, streams, lakes, soil, and air

Children living near coal-tar-sealed pavement are exposed to twice as many PAHs from ingestion of contaminated house dust than from food, according to a separate new study by Baylor University and the USGS, published in the journal Environmental Pollution. Several PAHs are probable human carcinogens and many are toxic to fish and other aquatic life.

Scientists estimate that the amount of PAHs released to air nationwide each year from new applications of coal-tar-based sealant are similar to or greater than annual PAH emissions from vehicles. USGS scientists measured PAHs in air above parking lots, with and without sealcoat, in suburban Austin, Texas. In a second study, PAH levels in air and in dried sealant were tracked for one year following sealant application to a parking lot. Two hours after sealcoat application, PAH emissions were 30,000 times higher than those from unsealed pavement. Parking lots with three to eight-year-old sealant released 60 times more PAHs to the air than parking lots without sealant.

Some governments have taken action on use of coal-tar-based sealcoat. Fifteen municipalities and two counties in four states (Minnesota, New York, Texas, and Wisconsin), the District of Columbia, and the state of Washington all have enacted some type of ban, affecting almost 10.4 million people. Several national and regional hardware and home-improvement retailers have voluntarily ceased selling coal-tar-based driveway-sealer products.

Two kinds of sealcoat products are widely used: coal-tar-based and asphalt-based.  The coal-tar products have PAH levels about 1,000 times higher than the asphalt products. Asphalt-based sealcoat is more commonly used on the West Coast and coal-tar-based sealcoat is more commonly used in the Midwest, the South, and the East. (More...)

NEW Publications in Peer-Reviewed Scientific Journals

  1. Mahler, B.J.; Van Metre, P.C.; Crane, J.L.; Watts, A.W.; Scoggins, M.; Williams, E.S., Coal-tar-based pavement sealcoat and PAHs: Implications for the environment, human health, and stormwater management. Environ. Sci. Technol., 2012. [download PDF] NEW
  2. Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. PAH volatilization following application of coal-tar-based pavement sealant. Atmos. Environ. 2012. [download PDF] NEW
  3. Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement. Chemosphere, 2012. [download PDF] NEW
  4. Williams, E. S.; Mahler, B. J.; Van Metre, P. C. Coal-tar pavement sealants might substantially increase children's PAH exposures. Environ. Pollut. 2012. NEW

Highlights below from 1985 "Summaries & Evaluations" report of the International Agency for Research on Cancer (IARC):


5.2 Experimental data

Three high-temperature tars, one undiluted and two as benzene extracts, all produced skin tumours, including carcinomas, when applied to the skin of mice. Each of five blast-furnace tars and two extracts of blast-furnace tars produced skin tumours, including carcinomas, after topical application to mice. Each of five pharmaceutical coal-tar preparations caused skin tumours, including carcinomas, when applied to the skin of mice.

Two unspecified coal-tars both caused skin tumours, including carcinomas, after application to the skin of mice. Lung tumours but no skin tumour were produced in rats after application of a coal-tar to the skin. A fourth, unspecified coal-tar produced tumours when applied to the ears of rabbits.

Intramuscular administration of a coal-tar fume condensate to mice in one experiment gave evidence of sarcoma formation.

Five creosotes or creosote oils all produced skin tumours, including carcinomas, when applied to the skin of mice. One of the creosotes also produced lung tumours in mice after skin application. In two limited studies, a basic fraction of creosote oil was not carcinogenic for the skin of mice.

In two experiments, anthracene oils produced skin tumours (and, in one experiment, carcinomas) when applied to the skin of mice.

Six coal-tar pitches and three extracts of coal-tar pitches all produced skin tumours, including carcinomas, when applied to the skin of mice. An extract of roofing-tar pitch had both initiating and promoting activity in separate experiments.

In one experiment, mice developed skin tumours, including carcinomas, after whole-body exposure to pitch powder.

Extracts of roofing-tar emissions were mutagenic in S. typhimurium in the presence of an exogenous metabolic system and were mutagenic in two mutation assays and induced sister chromatid exchanges in cultured mammalian cells, both in the presence and absence of an exogenous metabolic system.

Creosote and a coal-tar-creosote mixture were mutagenic in S. typhimurium and were positive in the mouse lymphoma L5178Y system, in the presence of an exogenous metabolic system.

5.3 Human data

A cohort study of US roofers indicated an increased risk for cancer of the lung and suggested increased risks for cancers of the oral cavity, larynx, oesophagus, stomach, skin and bladder and for leukaemia. Some support for excess risks of lung, laryngeal and oral-cavity cancer is provided by other epidemiological studies of roofers. Roofers may be exposed not only to a mixture of pitches but also to bitumens and other materials.

5.4 Evaluation

There is sufficient evidence for the carcinogenicity in experimental animals of coal-tars, creosotes, creosote oils, anthracene oils and coal-tar pitches.

There is sufficient evidence that occupational exposure to coal-tars as it occurs during the destructive distillation of coal is causally associated with the occurrence of skin cancer in humans (IARC, 1984a). The findings of the few studies available on other occupational exposures to coal-tars are consistent with that evaluation.

There is sufficient evidence that coal-tar pitches are carcinogenic in humans.

There is limited evidence that coal-tar-derived creosotes are carcinogenic in humans.

Taken together, the data indicate that coal-tars and coal-tar pitches are causally associated with cancer in humans and that creosotes derived from coal-tars are probably carcinogenic in humans. (MORE.... )

Again all that was from 1985 !!!!!

Also some notes on PAH's in seafood from the gulf oil spill:

Email sent from EPA staff to FDA staff obtained by the NRDC. (stating PAH exposures could be too high in those that consumed more gulf seafood)

And a a table of FDA recommendations for vulnerable populations as compared to what they probably should have been (links to article):

Table From:

Seafood Contamination after the BP Gulf Oil Spill and Risks to Vulnerable Populations: A Critique of the FDA Risk Assessment -oct2011

____________Start Original Post from Thursday, April 14, 2011________________

On April 14th at noon in the US capital  the USGS will briefed Congress, the media and the public on increasing levels of polycyclic aromatic hydrocarbons (PAHs) in urban lakes studied in 40 cities across the nation.

They also released a PDF just over a month ago with some updated findings on them:

Coal-Tar-Based Pavement Sealcoat, Polycyclic Aromatic Hydrocarbons (PAHs), and Environmental Health

Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat—the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots—as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large

There are no U.S. health-based guidelines for chronic exposure to PAHs in house dust. The only existing guideline is for a single PAH—benzo[a]pyrene—issued by the German Federal Environment Agency Indoor Air Hygiene Commission (Hansen and Volland, 1998). The guideline advises minimizing exposure to concentrations of benzo[a]pyrene greater than 10 mg/kg in dust to avoid adverse health effects. That guideline was exceeded for 4 of the 11 apartments with coal-tar-sealcoated parking lots and for 1 of the 12 apartments with a parking lot with a different surface type. Also of concern is exposure to the sealcoated pavement surfaces themselves through play activities. Dust on some of the sealcoated parking lots had a concentration of benzo[a]­pyrene that was more than 50 times higher than the German guideline.

Tumors in brown bullhead catfish from the Anacostia River,
Washington, D.C., are believed to be related to elevated PAH
concentrations (Pinkney and others, 2009). Photograph by A.E.

Apartments with coal-tar-based sealcoat on the parking lot had
much higher concentrations of PAHs, both in indoor dust and
in parking lot dust, than  apartments with an unsealed asphalt or concrete parking lot or with a parking lot with asphalt-based sealcoat. Concentrations shown are for the sum of the 16 U.S. Environmental Protection Agency priority pollutant PAHs (Mahler and others, 2010), in milligrams per kilogram (mg/kg).

Concentrations of PAHs in dust swept from sealed parking lots in
central and eastern U.S. cities, where coal-tar-based-sealcoat
use dominates, were about 1,000 times higher than in western
U.S. cities, where asphalt-based-sealcoat use dominates.
Concentrations shown on the map are the sum of 12 PAHs, in
milligrams per kilogram (Van Metre and others, 2009).

Additional (new study just released):

PAH/Aromatic DNA Adducts in Cord Blood and Behavior Scores in New York City Children

Results: Higher cord adducts were associated with higher symptom scores of Anxious/Depressed at 4.8 years and Attention Problems at 4.8 and 7 years, and with Diagnostic and Statistical Manual of Mental Disorders (DSM)oriented Anxiety Problems at the 4.8 years.
Conclusions: These results suggest that PAH exposure, measured by DNA adducts, may adversely affect child behavior, potentially affecting school performance.

You may remember some discussion of them during the GoM oil spill:

Polycyclic Aromatic Hydrocarbons on the Gulf Coastline

EPA is focusing on these pollutants because they are present in weathered oil and are also released from burning oil, and, at elevated concentrations, could potentially cause health problems, including long-term health effects such as cancer.

They ARE present in oil/tar sands and in areas where these are geologic features  as in near the Athabasca river and lake in Canada, watershed pollution and tumors in fish are noted, especially by aggressive environmental groups it seems, and their concerns also seem justified: 


Proceedings of the National Academy of Sciences (PNAS) have also shown that industrial air pollution and watershed destruction directly caused by the oil/tar sands has contaminated the river with heavy metals and petroleum compounds called polycyclic aromatic hydrocarbons (PAHs).

NOAA publication on nearby ocean contamination from a Aluminum processing facility :

Polycyclic Aromatic Hydrocarbons and Fish Health Indicators in the Marine Ecosystem in Kitimat, British Columbia
As expected, given that fish metabolize PAHs and do not accumulate them in their tissues (Varanasi et al. 1989b), we found that levels of PAHs in muscle tissue of flatfish were very low—well below concentrations that would constitute a health risk to humans consuming the fish. The same may not be true, however, of mussels, clams, crabs, or other shellfish that, unlike fish, do accumulate PAHs in edible tissue (Meador 2003). 

Even though fish do not accumulate PAHs, their metabolites can be toxic and we found that the PAHs released from smelter operations were having some effects on the health of flatfish from Kitimat Arm. English sole from this area had PAH-related DNA damage and liver lesions rarely found in sole from the reference sites outside Douglas Channel. However, bile metabolite levels in salmon and flatfish, as well as prevalences of liver disease and DNA damage in flatfish, were lower than would be expected considering the concentrations of high molecular weight PAHs in sediments at sites near the smelter, where PAHs have been discharged in the past. Furthermore, neither yellowfin sole nor English sole showed significant evidence of PAH-related reproductive dysfunction as is commonly observed in other contaminated industrial areas such as Puget Sound (Johnson et al. 1998, 1999). While we found that yellowfin sole from sites within Kitimat Arm tended to be smaller and have reduced condition in comparison to fish from other sites, these effects were not clearly correlated with levels of PAH exposure. Overall, these findings support earlier studies indicating the limited and reduced bioavailability of soot associated, smelter-derived PAHs.

Older references and a link to a 2005 USGS publication:

PAHs and Coal-Tar-Based Pavement Sealcoat


Pollutants' role in birth defects heading entry-title becomes clearer

Levels of polycyclic aromatic hydrocarbons linked to neural tube defects.

these defects happen in the first few weeks of pregnancy and the more information there is available on their causes, the more chance there is of reducing their occurrence. The new study also discovered one indication of a true link, the so-called 'dose-response relationship'.


  1. The effects on humans needs to be studied more and the effects of lower doses are inconclusive, but none the less worthy of great concern. The effects on wildlife particularly amphibians is pronounced and probably worthy of greater scrutiny and better regulation.

  2. Asphalt shingles contain polycyclic aromatic hydrocarbons. So does roofing paper.

  3. Non PAH containing sealcoat is also available now it should be noted.

  4. Epoxy ( ) Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A,

  5. More reasearch should be going on to determine the impact of PAH in our environment,due to its carcinogenic and mutagenic effect.

  6. It seems like a real problem.

  7. sorry Vani - redid my mail and didnt see your comment. - ill put a email link in the upper left.

  8. There are kinds of seal-coat that do not contain PAHs. If a product is of that nature it should say so in the ad.

  9. Yikes. BTW what was that Vani comment you took out?

    Time magazine has published a new article on the rapid pace of ocean acidification. Also numerous links in the article.

  10. oh just a weird advertisement or something - nothing bad.

    Ill add the acidification story to that last acidification blog.