What exactly are cancer clusters and how are they related to Superfund sites?
By Kathryn E. Vinson, MS, CCRC
I love history. Its one of the topics that make my inner nerd super happy. As both of my boys studied Texas History in their social studies courses this year, I decided to take them on a tour of historic places around the state. My mom grew up close to the San Jacinto Battlefield. For those of you unfamiliar with Texas history – this is the battle where Santa Anna surrendered to General Sam Houston (I told you I’m a history nerd).
At any rate, as Mom was driving us to the battlefield, through Galena Park, the area where she grew up, she said, “We called this area ‘The Pits,’ it was just a field of waste. You knew it was liquid, but there was a really gross crust that formed on the top of it.” Now it is a field with high berms of dirt bordering it, and signs that say “STAY OFF!”, and “PROPERTY OF THE US GOVERNMENT.” Not exactly something that you want to see in your neighborhood.
Side story – since I began writing for Cancer Horizons, my husband has been after me to write about Superfund Sites and how they might contribute to cancer. I guess you could say I was waiting for inspiration. As many of you know, my mom’s youngest sister succumbed to non-Hodgkin Lymphoma (NHL) back in 1993. Mom’s family moved to Galena Park when Deede was just a baby. This is when the inspiration hit me. Could these fields of waste have contributed to her illness?
What is a Superfund Site
I think that is one of the big questions that we need to answer – what exactly is a Superfund Site? Many of us have heard the term, but aren’t really sure what it is.
Per the EPA, (directly quoted from their website):
Thousands of contaminated sites exist nationally due to hazardous waste being dumped, left out in the open, or otherwise improperly managed. These sites include manufacturing
facilities, processing plants, landfills and mining sites.
In the late 1970s, toxic waste dumps such as Love Canal and Valley of the Drums received national attention when the public learned about the risks to human health and the environment posed by contaminated sites.
In response, Congress established the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in 1980.
CERCLA is informally called Superfund. It allows EPA to clean up contaminated sites. It also forces the parties responsible for the contamination to either perform cleanups or reimburse the government for EPA-led cleanup work.
The sites that have been found, and meet the criteria set forth by the EPA, are put on what is called the National Priorities List, so that work can begin on clean up. Some of these sites/companies/owners/etc. were criminally negligent, some were just oblivious to the harm in the days prior to environmental studies. I found out that there is a Superfund Site about four miles from where I grew up – a dry cleaner that was dumping their waste chemicals on the ground and caused a ground water bloom of known carcinogens. Doesn’t that just give you a warm and fuzzy feeling?
What are disease clusters?
Something that is more difficult to define are disease clusters, or in our realm, cancer clusters. We’ve all seen it before – what seems to be a higher than average incidence of a disease in a relatively small geographic area. There just has to be a connection, a causative agent – right?!
An article by Goodman, Naiman, Goodman, and LaKind (2012) helped shed some light on the difficulties in making these associations into something more concrete. Remember how in the past I’ve said that we can’t define causation from correlation? Well, this is a prime example. Their data showed that of 567 proposed cancer clusters examined over a 20 year period of time, only 72 cancer clusters were confirmed, and only 1 cancer cluster was able to be verified with an established cause. The authors state that one of the biggest difficulties in establishing these sites as definitive causes of cancer/disease clusters is that people tend to move. We move into and area, we leave an area. In my aunt’s case, for example, she lived in Central Texas by the time she was diagnosed, so by CDC standards, her illness was correlated with that area, rather than where she lived as a child. By the same token, a person may move to an area and get sick. Was their illness caused by their previous residence, or the new one? Its pretty hard to tell.
Back to Galena Park
I read an article in Texas Monthly that detailed the sicknesses that have befallen an area just north of Galena Park. It seems that a papermill located in Galena Park, long since closed, partnered with a waste disposal firm to take care of their industrial waste. This was back in the late 60s – the waste was transported from the mill a bit north and buried on the banks of the San Jacinto River in unlined pits. Over the years, the waste leached from the soil and began flowing down stream. With Hurricane Ike in 2008, and then Hurricane Harvey in 2017, those pits have been dumping waste in terrible amounts.
When I talked to Mom about this, she recalled that yes, those were paper mill pits that she recalled. Was the paper mill dumping their waste right in their backyard prior to 1967? I don’t know and can’t say, but it sure sounds like that may have been the case.
The Texas Monthly article details the diseases that have been identified in the population north of where Mom grew up. Many types of cancer, Lupus, seizure disorders, and more have been seen in higher numbers in that area. Sadly, there are five Super Fund sites within about a 10 mile radius of what are known as the San Jacinto River Waste Pits.
More recent research
Since the article by Goodman, et al in 2012, many more investigations have been undertaken to look at specific Superfund locations and diseases that have been prevalent. In 2017, the results of a study by Kirpich and Leary suggested “…a potential association between increased HRS (hazardous ranking score) and increased proxy water exposure of hazardous wastes around Superfund sites with increased adult cancer incidence rates.” In plain English – they found that there was a correlation between contaminated ground water near Superfund sites and increased rates of adult cancers. This goes back to the correlation and causation conundrum. They tell us in their conclusion that “Within the United States, cancer registries are defined and run by each state and they do not routinely include geographical or exposure histories that indicate length of residence at the time of cancer diagnosis, an thorough residential history… However, these exposure histories are essential to thoroughly investigate the effect of environmental exposures on cancer.”
A 2014 study by Levine, et al, studied Superfund sites in relation to inflammatory breast cancer (IBC). In their supporting materials, they also note an increase in NHL in residents of a northern Nevada county close to a Superfund Site. Their data also shows an increase in IBC near the Superfund sites close to where my mom grew up. Then in 2017, Webber and Stone, found an increased incidence of NHL in residents close to Superfund sites in Kentucky. As the distance from the sites increased, the rates of NHL decreased. Also in 2017, Amin, Nelson, and McDougall “…identified a significant positive association between Superfund density and overall cancer rates across the 48 contiguous USA, in addition to a significant trend for number of superfund sites per county and the corresponding cancer rates.”
What does it all mean?
Are these Superfund sites the causes of increased cancer (and other diseases) incidence? Maybe, maybe not. There is an awful lot of evidence indicating that they are. But here’s the problem with retrospective studies – when you look back – there is a chance that you are missing something. People moving in or moving out, infectious diseases that can increase cancer risks, smoking, dietary influences – the list goes on and on. Its hard to say that there is one definitive cause for a type cancer – in many cases it arises from the perfect storm of risk factors – and yes, among these may be proximity to Superfund sites.
Knowledge is power. Know where you live or are moving to. Do the research.
As always, much love, many prayers, and abundant blessings to all of the warriors out there!