Title

The Cancer Correlation

Concern about radioactive contamination from the Hanford site has existed since enriched plutonium was first produced there during World War II. In a 1965 Journal of Environmental Health article, Robert Fadeley reported a significant difference between cancer death rates in the nine Oregon counties down river from the Hanford plant and all other Oregon Counties.1 His study went on to correlate the cancer mortality rate per 100,000 population and an index to exposure to radiation in these counties.

Fadeley's index of exposure was itself a function of three separate variables. It was based directly on the extent of each county's river frontage and inversely on the product of the county's river distance to Hanford and the square of its average north-south distance to the river:

Index = F/SD2, where

Index = index of exposure,
F = river frontage.
S = stream distance to Hanford, and
D = average depth of county

The approach that Fadeley took emphasized water born contamination, noting that radiation was discovered to be magnified up the food chain from river plankton to fish and fowl and eventually to humans and other mammals. His approach did not take into account wind-borne exposure.

The Big Picture

The data provided in the following activities are those that Fadeley used in his study as well as more recent cancer data from the period 2006 - 2011. It is presented here in three different formats: data maps, scatter plots, and data tables. As you will discover each has its advantages. Click the links below to view each in its own window.

Hanford Map

Scatter Plot

Data Table
Data Table

• To sort values in the table click on the column heading - once to sort from lowest to highest, twice for descending order:

 

The big picture provided in the map gives you a chance to explore for patterns in the cancer death rates related to place - in this case, Oregon counties:

 

Cancer1964

The Columbia River flows south through Hanford in Washington and then creates the border with Oregon on its way to the Pacific Ocean. Fadeley noticed the higher incidence of cancer mortality in the Columbia River counties - particularly along the lower Columbia - compared to the rest of the state. At that point he focused on these counties, created his Index of Exposure, and looked at its relationship with cancer mortality. Looking at this data in each format is instructive. Make a map like the one below showing the Index of Exposure for the nine Columbia River counties.

 

Explorer Online

• Click the layers button ( Layers Button ) on the map legend.

• Click the Oregon Counties checkbox off.

• Click the Columbia Rivers Counties checkbox on and click the Details arrow on the right:

• Click the to Configure the layer and complete the form as follows:

• Click Done and close the legend ( Close )


Prepare a presentation slide of the map and then a second slide of a similar map showing the Cancer Mortality Rate in the Columbia River Counties for 1964.

Explorer Online

• Once your map is prepared, click on the Presentation tab and Click to add the first slide.

• Add your own title for the slide.

• You can stay in the Presentation mode to create your next and any additional slides. Just click the New Slide button (New Slide) as each new piece of the presentation is prepared.

• To share your work first save the file using Save as..., add your name to the file's name, and save in the designated folder.

Content for NSaveew Div Tag Goes Here

• Finally, click on the Share button, copy the presentation link, and paste it into an email.


To Start You Thinking -

  • 1) Is the correlation between Index of Exposure and the Cancer Mortality Rate positive or negative? That is, are higher levels of one generally associated with higher rates of the other (positive) or lower rates (negative)? Describe how this aspect of the relationship between the two variables is apparent in the maps, in the data table, and in the scatterplot.

    2) How strong is the correlation? Is there a distinct pattern (strong) or does the relationship appear random (weak) or somewhere in between?

    3) Use the scatterplot of the relationship and determine the equation of the line of best fit. Describe what the slope of the line tells you about the relationship between the Exposure Index and the Cancer Mortality Rate.

    4) Write a summary of the relationship you see in the data between river-borne exposure to radiation from Hanford and cancer mortality in the Oregon counties down river from the plant..

    5) Read Fadeley's own summary of his research. Discuss similarities and differences with your own observations.

    6) Recent cancer mortality data is available in the map, graph and table. Analyze and describe the relationship between the Exposure Index and Cancer Mortality Rate today.

    7) Critics of Fadeley's conclusions focused on the time it takes for cancer and death to result from radiation exposure. Do some research on this topic and comment.


1Robert Fadeley, "Oregon Malignancy Pattern Physiographicall Related to Hanford Washington Radioisotope Storage," Journal of Environmental Health 27:6:883-897, 1965.
Last modified in January, 2012 by Rick Thomas