Love Canal Follow-up Health Study - April 2001

Study Plan and Progress

April 2001

Mortality Study - Your Thoughts about Preliminary Results

In October 2000 we mailed a summary of the preliminary results of the mortality study to each of you, and asked for suggestions about future releases of study results. Many of you offered suggestions and encouragement. With few exceptions, our information sheet was understandable, and the way we released the findings was acceptable.

Many were pleased to receive a summary of the results in their mailbox, and people were understanding that the findings discussed at the Committee meeting were later summarized for participants.

We received several comments about how the results were presented. A few asked about the distinction between the overall death rate of Love Canal residents and the death rate from individual causes. Based on the results so far, Love Canal residents do not have a shorter life expectancy than others in the county or the state. However, they died more often from certain causes and less often from others. We are looking into why some of these causes of death were seen more often in the Love Canal community.

Some people wanted to see more information, so we mailed them the data tables and a narrative description about how the findings were generated. Others said that the reasons for deaths which fell within each group were not clear. Although a few expressed dissatisfaction with the way they were informed about results, most were pleased. Based on these responses, we will continue to let you know results in this way - mailing an information sheet after the Committee meeting. Those who want a more detailed description of the data (tables, protocol, etc.) or need information clarified can contact Charlene Thiemann, 518-402-7530.

Some people asked about cancer and birth defects outcomes identified from the study. We are still gathering that information and it will be reported to you in a similar way as the mortality study. Others suggested that we focus our efforts on former residents who are still living. Most of our future tasks will be consistent with those comments, as we report on cancer rates, birth weights, and congenital malformations.

Remember, we will also look at the mortality experience of individuals and link it with their likelihood of exposure to Canal chemicals and other known risk factors. We will look to see if people who were likely to have higher exposures were also more likely to have died younger, or from certain causes.

As always, we thank you for your continued feedback, and interest in the health study.

Exposure Assessment Model

You may remember from an earlier newsletter that one of the more challenging parts of the study is estimating the exposure of residents and former students of the 99th Street School to Love Canal chemicals. Eventually, we will be linking exposures to health outcomes. We began the evaluation by placing each person into a category of high, medium, or low. The categories are assigned separately within each time period for each person:

  1. 1942 to 1953 when the landfill was being used (open period);
  2. 1954 to 1976 when the dumping was finished and the Canal was at least partly covered; and
  3. 1977 to 1978 when environmental samples were collected for analyses.

The 'high' in the open period means likely to be more exposed than those in the 'medium' category for the same period. Similarly, 'medium' means likely to be more exposed than those in the 'low' category. The categories are relative to each other within each time period. This means that a 'high' likelihood of exposure in the open period may not be the same type or frequency of exposure as a 'high' in later time periods.

Initially, preliminary exposure categories were assigned based on a former resident's proximity to the canal and their expected behavior based on age for each time period. For instance, people who lived in Tier 1 during the open period likely had a potential for high exposure and were assigned an exposure category of 'high'. Also, children who lived in the study area are expected to have used the Canal area for play, so children were generally assigned a higher exposure category than adults. We then considered refining the exposure categories after our review of environmental sampling data, results of your exposure survey, court records, engineering reports, and injury reports associated with the Love Canal.

For example, mapping of chemical concentrations was part of our environmental data review. Mapping showed that a few homes north of Colvin Boulevard were very different from the rest of the homes in that neighborhood, due to small areas with higher contamination. Residents in these homes could be given a higher rating than their neighbors since they had a likelihood of higher exposure. Also, some residents believed that historically wet areas might have become more contaminated, especially along historic drainage ways called swales. Review of the data showed that the average level of Love Canal chemicals in soil along the former major swale in the area directly east of the Canal is slightly higher than the average level from other locations in the area. But the overall levels are not high. Also, during the habitability study, soil contaminant levels in Love Canal Areas 2 and 3 (east of the Canal) were slightly higher than in other areas (except for Area 1, which has a higher ranking than Areas 2 and 3). While Area 2 and 3 levels may not be high enough to indicate that residents in these homes were likely to be more exposed than their neighbors, we do not want to ignore this difference.

< Open Dumping Period 1942 - 1953formatting

After the review, we considered whether we should combine all the information so that each person would have one exposure category for each time period. Since the exposures will be linked to health outcomes, and there are uncertainties in the exposure assignments, we believe it is more useful to look at exposure scenarios in several ways rather than just one way to see if it makes any difference in the findings. We would consider:

  1. time period and tier of residence (assign exposure categories based on tier of residence and according to activities which occurred in each time period);
  2. above, plus include expected behavior (categories adjusted to include expected behavior of residents, especially children) --these are the same as the preliminary exposure categories;
  3. above, plus localized areas of higher contamination (adjust categories for those who lived near these areas of contaminated soil and sediment);
  4. Love Canal Areas 2 and 3 vs. other areas;
  5. swale vs. non-swale residences; and
  6. wet vs. non-wet residences.

< Closed Time Periods 1954 - 1978formatting

The maps display the exposure categories based on tier of residence and time period alone. They do not reflect the adjustments we will make for age/behavior, contaminated soil and sediment, swales, or other factors.

...More on the September Advisory Committee Meeting

Blood Sera Reports

In April, 2000 we sent letters to many participants for whom we have stored sera requesting permission to analyze them for Love Canal Indicator Chemicals (LCICs). By September, slightly more than half (52%) had returned the form. Upon retrieving the samples from long-term storage for analysis, we found that some samples could not be analyzed because there was not enough serum. Participants were notified by telephone if their serum sample could not be analyzed.

We also investigated a new and improved extraction technique, and discussed it with the Committee. They agreed that we should use the new technique since it is as accurate as the earlier method but much faster.

We discussed the steps taken in response to community requests for an independent review of our chemical analytic method. We met with CDC's National Center for Environmental Health to go over our proposed methods. We also participated in ATSDR's laboratory proficiency testing program and received satisfactory ratings (the other possible rating is unsatisfactory).

The sera samples may have partially thawed during a power failure some years ago. We are using calf serum to evaluate the impact, if any, on LCIC concentrations in sera. The community requested an independent review of this concern as well, so we decided to seek at least one such consultant doing similar kinds of research. Committee members will have an opportunity to review the questions we would like to have answered before they are posed to the reviewer.

93rd Street School

The Committee was interested in learning more about the 93rd Street School site, especially as it related to exposure modeling for children who played at and/or attended the school. Residents first expressed concern about the school in 1978, after reports that a swale crossing the schoolyard may have been filled with Love Canal soil. Soil sampling conducted in 1978 by DOH showed low level surface contamination on the ball diamond, while other investigations conducted in the following years indicated that soil contamination was primarily subsurface, and groundwater was not contaminated. However, a complete review of county files showed that the school district removed surface soil from the ball field sometime in 1979. It is unknown whether children were exposed to surface soil contaminants before the soil was removed, but the removal certainly prevented any further exposure. The 1978 and later investigations did not establish any completed exposure pathways - in other words, although there was contaminated soil, it was below the surface and children were not coming in contact with it. Because the school wanted unlimited use of the property, the contaminated subsurface soil was removed and replaced with clean fill. The school building itself was recently torn down. Committee members agreed with our determination that no change was needed to the exposure model for children using the 93rd Street School.

Meet the rest of the Advisory Committee...

Study Updates

All involved in the study are concerned about how to review and release the results. Results of previous studies were not always released in ways that participants felt were respectful, and sometimes the studies were challenged after being released. In part, this is because there are other interests that compete with those of the participants. These include the need for scientists to have peer review of their work before it is considered scientifically sound, the interest of the press to print newsworthy findings, and the need of Committee members to see the results in order to review the interpretations. ATSDR, the federal health agency that funds the study, requires that all results be peer reviewed before being publicly released. We sent the results of the mortality study to them first. ATSDR provided a speedy review so that the Committee could review the preliminary data in September, and the participants could receive the results shortly after that. Committee discussion was followed by mailing results to all participants.

The method developed to compare health outcome data with likelihood of exposure data was discussed with the Committee. An index has been developed which assigns an exposure value to every resident or 99th Street School student. The index will account for the category of exposure, as well as length of exposure - how long they lived in the area. Other known exposures, including occupation, smoking and alcohol consumption will be inluded in the analysis. Members helped to refine the modeling techniques that were proposed.

Efforts to locate former 99th Street school children are continuing. To date, 62% of the student roster have been contacted; 10% have replied to our request for information.

From The Chemist's Desk...

Interview with Dr. Kenneth Aldous; Chief, Laboratory of Organic Analytic Chemistry - NYSDOH Wadsworth Center for Laboratories and Research

Serum, plural sera, is the liquid portion of a blood sample.) Over the past 23 years scientists have greatly improved on ways to analyze chemicals in both environmental and biological samples. It is now possible to measure even trace amounts of some of the more lasting Love Canal chemicals in sera.

The Wadsworth Laboratories proposed to analyze the stored sera as part of the follow-up health study. This work will let participants know their individual body burden of the measured chemicals, which can be compared to the body burden of other Love Canal residents. The entire set of results will also be compared to the model of residents' exposure developed by exposure assessment experts. Measuring levels of Canal chemicals in residents' blood - taken before the Canal was remediated - may well be our best indication of individual exposure.

  • 1,2-dichlorobenzene,
  • 1,2,4-trichlorobenzene,
  • 1,2,3,4-tetrachlorobenzene,
  • 2-chloronaphthalene,
  • alpha-hexachlorocyclohexane,
  • beta-hexachlorocyclohexane,
  • delta-hexachlorocyclohexane; and
  • gamma-hexachlorocyclohexane (lindane).

The levels of each of these compounds in a participant's blood serum will be sent to that participant, unless he or she elects to not be informed of the results.

The eight chemicals to be measured were selected as indicators of exposure to chemicals from Love Canal because of their:

  • persistence (they don't break down easily),
  • known presence at high concentrations at the Canal; and
  • "marker" capabilities (these compounds were made or used by Hooker Chemical but are not generally present in the environment from typical household uses).

We call this group of chemicals Love Canal Indicator Chemicals, or LCICs for short.

For example, each sample extract will also provide data about PCB levels in human blood sera in the late 1970's. PCBs were not buried at the Love Canal, so their presence in Love Canal residents tells us only about PCB levels in general, and nothing about Love Canal exposures.

The set of sera results will take longer than individual results to release. The data as a whole must be peer reviewed (commented on by other scientists) to ensure they are scientifically reliable data. Data tables will be placed in a format that protects patient confidentiality, and all of the sera will have been analyzed and met with quality control guidelines.

The samples were stored in our freezers for the past 23 years. The Wadsworth Center has emergency power to maintain refrigeration during power outages. However, in 1993, both regular and emergency power were interrupted due to a transformer explosion. We periodically filled refrigerators and freezers with dry ice to maintain below normal temperatures, and emergency power was returned as soon as possible to meet refrigeration needs.

If thawing occurred, it happened to all the samples and the effect on LCIC levels (if any) will not interfere with our comparing LCIC serum levels with others stored in the same way. Remember, too, that the LCICs were chosen because they are persistent and don't change chemical or physical states easily (changing chemical states includes reacting with another chemical to form different chemicals or decomposing into some other compound; changing physical state includes changing from a liquid to a gas or changing into a solid state such as ice).

To find out more about possible impacts from thawing, we designed a study that uses serum specimens spiked with known levels of LCICs. We froze them at the beginning of our project. Every three months several specimens are thawed and analyzed. The data from this part of the project will provide information on the effect of a thaw-freeze cycle on the measurement of LCICs.

If we find from the study that thawing makes little difference in the measured LCIC levels of the spiked sera, we will have confidence that any thawing of the stored sera did not greatly change our measurements of LCICs. The reported concentrations measured now would be close to the value present in 1978. If we find that thawing did have an effect on the LCIC concentrations in the spiked sera, we will know that we don't have an exact measurement of the level that was present in 1978. But, since all the stored blood sera were stored under the same conditions, the effect would apply to all the sera measurements. We will still be able to compare results from each individual resident to those of others. The serum analysis will provide an accurate measurement of the concentration of LCICs present in the specimen now. Since the serum measurements are primarily being made to compare with the exposure model (which is also relative to other Canal residents), we can still use the serum data to learn more about the validity of the exposure model.

Of course, routine quality control and quality assurance techniques are a part of the method we will use to analyze the serum specimens. These data will tell us more about the accuracy and precision of our results.

How To Reach Us
Study Contact: Pat Steen
Phone: 518-402-7950
Fax: (518) 402-7959
Mail: Flanigan Square
547 River Street
Room 200
Troy, New York

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