Cancer in the South End

There has been some buzz in the press and local blogs this week about the recently-released Agency for Toxic Substances and Disease Registry study, which finds, according to the P-I article published in this morning's print edition, that:

Residents of a broad swath of South Seattle from Seward Park to West Seattle face elevated cancer risks because of air pollution, according to a soon-to-be released government study.

The risks are significantly elevated in pockets of industrial pollution – and skyrocket within about 200 yards of highways, says the long-awaited study by state and federal scientists.

The affected areas are shown in the map I've grabbed from the P-I article, and risks appear highest, theoretically, in the industrial areas around Georgetown, which get pollution from factories, roads, and airplanes.

I decided to bring the study to the Colman Triangle blog because of the red, high-risk areas on the map at the north end of the Triangle (at I-90). I read the P-I article, and was curious, so I dove into the ATSDR report for more information, which I think is worth sharing.

Non-Cancer Risks

The press has focused on cancer, which I'll get to below, but the freeway at the north end of our neighborhood offers more hazards to our health. The bulk of non-cancer risks come from a chemical called acrolein, with exposure coming from car exhaust and cigarette smoke (note, are you still shopping for reasons to quit smoking?). From the report (bold type by me):

Similar to cancer risk, non-cancer hazards are highest near major roadways. Hazard indices decrease with distance from the center of highways, but exceed one (meaning risk is greater than baseline) up to a few hundred meters on either side of major highways. Acrolein is the primary contaminant associated with non-cancer hazards from road sources. The following four pollutants are the main contributors to non-cancer hazards from mobile sources in descending order.

• Acrolein
• Formaldehyde
• Diesel Engine Exhaust, Particulate Matter
• Nitrogen Dioxide

I've linked three of the agents above to the ATSDR info sheets about them. There aren't any well-defined cancer risks to these pollutants, but they do make breathing unpleasant and can affect folks with lung disease (asthma, COPD...) and children more than the rest of us.

Cancer Risks

There are a few things floating around the Colman Triangle that bring an increased cancer risk. From the report:

Diesel particulate matter, benzene, and 1,3-butadiene are the chemicals that contribute to the bulk of risk.

What kinds of cancer, you ask? Benzene is associated with leukemia (and anemia; benzene suppresses bone marrow production of red blood cells), while 1,3 butadiene appears to be associated with a "variety of tumor types."

Keep in mind that cancer results from long-term exposure, and that there are many other, non-cancer but unpleasant effects from shorter-term exposures (follow the links to read about these).

What to make of this?

I'm not a toxicologist or epidemiologist, so my ability to interpret the ATSDR study is limited to my training as a regular old physician (family doctor) and concerned citizen with two kids whose well-being I cherish more than my own. From what I've read, here's what I take away:

1. Our little neighborhood sits just south of a major interstate with tons of diesel traffic passing through, leaving us with a variety of pollutants in our air, water, and soil. The risk of toxic exposure drops with distance from the freeway (it's about 200 meters from the center of I-90 to Massachusetts), but risks still exist beyond the "red zone." We're also bounded to our west and east by Rainier and MLK, which carry plenty of pollutant-spewing trucks and cars.
2. Most of I-90 is covered in our neighborhood, which is nice. But...what happens to the pollution in the tunnel? Where does it go? The risk map is red even in the lidded areas.
   
3. Kids and the chronically ill, as usual, have it worse than the rest of us.
4. Cancer is bad, for sure, but anemia, birth defects, and lung disease are also significant effects of the pollutants found in the ATSDR study, and are likely to ruin your good time before cancer creeps in.
   
5. Smoking is still stupid. This study reminds me that smoking tobacco is similar to wrapping your mouth around the exhaust pipe of a running diesel engine.
6. The "fixes" to the problem are mostly to be found in rational public policy. Pollution standards for automobiles and factories should be designed to prevent disease and should be vigorously enforced. In our neighborhood, we can advocate for safe practices from our industrial neighbors (most of the Triangle is zoned for commercial and residential, creating a potential mini-Georgetown effect).

Those are my reflections. I look forward to comments and face-to-face discussions around the neighborhood.

Crossposted