Investigation of Subclinical and Delayed Effects:
Early in 1980, further efforts to define potential biologic effects of Love Canal exposure led to a study of chromosome breakage in peripheral blood lymphocytes from 36 volunteers living in the Love Canal area. Breakage frequencies were compared to frequencies observed in previous studies. Although no increase in frequency was seen, the presence of unusual acentric fragments (one manifestation of chromosome breakage) was reported in several subjects. (Low levels of breakage are a normal finding in human populations. Although increased frequencies of breakage are associated with increased exposure to chemicals and ionizing radiation, the significance of such findings for human health is unknown.) These findings were presented to the public before they received scientific peer review. The unusual acentric fragments were reported as being associated with increased risks of cancer and genetic abnormalities, even though there is no scientific basis for such interpretation.
The Love Canal chromosome findings were strongly debated by cytogeneticists and epidemiologists. Despite the inconclusive nature, the suggestion of chromosome damage, together with existing public concern about health effects in the Canal area, led in the summer of 1980 to the designation of the entire Love Canal area as a federal emergency zone. This was followed by renewed evacuation of residents and to an EPA program of testing of air, soil, and water systematically obtained throughout the area. Plans for further health studies were developed jointly by the University of Buffalo and the U.S. Public Health Service (PHS), but they were not carried out because of lack of funds.
These studies were to encompass voluntary medical examinations as well as observations regarding chromosome damage, nerve conduction slowing, and psychologic effects in Love Canal residents. In 1981, the PHS carried out the chromosomal part of the larger study (Health, et al, 1984). No unusual breakage frequencies were found, acentric fragments were equally distributed among Love Canal and non-Love Canal (control) residents
With this background in mind, how would you design and carry out a study to assess possible chromosome damage in the Love Canal area? Consider: