COOPERATIVE EXTENSION UNIVERSITY OF CALIFORNIA
ENVIRONMENTAL TOXICOLOGY NEWSLETTER

Vol. 2 No. 5 July 15, 1982

INTRODUCTION

In the past two years in my position here I have encountered numerous people concerned about the carcinogenic potential of chemicals used in agriculture. At the Genetic Toxicology Symposium last November I heard the majority of speakers say that in relation to other environmental factors, agricultural chemicals probably play a minor role in human carcinogenesis. Because cancer is not a single illness, there are many different risk factors depending on the particular cancer type and site. One risk factor that comes up time and again with respect to many types of cancer is smoking. Many of you have already experienced my non-smoker militancy. Here are some of the reasons why. (Ed.Note. Emphasis and underlines in the following articles inserted by author.)

SMOKING AND CANCER

The Department of Health and Human Service's (DHHS) 1982 report to Congress on the health consequences of smoking presents a comprehensive evaluation of the relationship between cigarette smoking and cancer. It identifies cigarette smoking as the major single cause of cancer mortality in the United States.

Since 1937 cancer has been the second most frequent cause of death in the United States and will account for an estimated 430,000 deaths this year. This increase in mortality has occurred in the face of remarkable improvements in survival rates associated with some cancer sites through earlier or better diagnosis and treatment. Unfortunately, however, these advances have failed to counter the increases in mortality from smoking-related cancer.

Tobacco's contribution to cancer deaths is currently estimated to be 30%. This means that 129,000 Americans are likely to die of cancer this year because of the higher overall cancer death rates for smokers as compared to nonsmokers.

Lung Cancer and Smoking

Cigarette smoking is the major cause of lung cancer in the United States. Lung cancer alone accounts for fully 25% of all cancer deaths in this country; it is estimated that 85% of lung-cancer cases are due to cigarette smoking.

The American Cancer Society estimates that 111,000 persons will die of lung cancer in 1982 - 80,000 men and 31,000 women. The lung-cancer death rate for women is currently rising faster than that for men, reflecting the more recent adoption of smoking by large numbers of women. The 5-year survival rate for lung cancer is less than 10%. This rate has not changed appreciably in over 15 years.

Lung Cancer and Involuntary Exposure to Smoking

The DHHS report states that 3 epidemiologic studies examined involuntary or passive smoking and lung cancer in nonsmokers this past year. Two studies found a statistically significant correlation between involuntary smoking and lung-cancer risk in nonsmoking wives or men who smoked. The third noted a positive, but not statistically significant, association. While the nature of this association is unresolved, it does raise the concern that involuntary smoking may pose a carcinogenic risk to the nonsmoker.

Cancer of the Larynx, Oral Cavity, and Esophagus

Smokers have a mortality-risk ratio for laryngeal cancer at least 5 times greater than that of nonsmokers. All 3 forms of tobacco carry approximately the same excess relative risk of at least 5-fold. The long-term use of snuff appears to be a factor in the development of oral cancer, particularly of the cheek and gum.

Cancer of the Bladder, Pancreas, and Kidney

Cigarette smoking is a contributory factor for the development of cancer of the bladder, pancreas, and kidney. The term "contributory factor" by no means excludes the possibility of a direct role of smoking in the causation of these types of cancer. The consistent demonstration of an excess risk of cancer of these sites among smokers in comparison with nonsmokers suggests that if smoking were not to exist in these populations, a measurable proportion of these diseases would not occur.

Stomach Cancer

Cancer of the stomach has been declining as a cause of death in the United States for many years.

Numerous epidemiologic studies have noted a link between smoking and cancer of the stomach. This association is smaller than that noted between smoking and other cancer sites. The nature of this association cannot be determined at this time because of a lack of supporting clinical and animal-experimentation evidence.

Lower-Tar Cigarettes

Smokers of filtered or lower-tar cigarettes have statistically lower death rates from lung cancer than do smokers of nonfiltered or higher-tar brands. This reduced risk was also noted for laryngeal cancer. However, cancer death rates for smokers of lower-tar cigarettes were still significantly higher than those noted for nonsmokers.

Cessation of Smoking

Even after many years of cigarette smoking, stopping smoking reduces one's cancer risk substantially compared with that of the continuing smoker. The more years one refrains from smoking cigarettes after stopping, the greater the reduction in excess cancer risk. Fifteen years after stopping cigarette smoking, for example, a former smoker's lung-cancer risk is reduced to nearly the level observed for nonsmokers. There is no single action an individual can take to reduce the risk of cancer more effectively than to stop smoking - particularly smoking cigarettes.

(Morbidity and Mortality Weekly Report, February 26, 1982/ Volume 31, Number 7.)

Mushroom Poisoning Among Laotian Refugees - 1981

In the period, December 1-3, 1981, 7 Laotian refugees were seen at a Sonoma County California hospital for apparent mushroom poisoning; 6 had nausea, vomiting, diarrhea, dehydration, and elevated liver enzymes. All persons had eaten mushrooms that were gathered and eaten on November 30, although 1 week earlier 20-30 Laotians had eaten mushrooms gathered in the same area without incident. The incubation period was variable, but most patients experienced gastrointestinal distress within 8 hours. Several remaining cooked mushrooms were examined at Sonoma State University; all but 1 were identified as Russula species.

Laotians customarily gather wild mushrooms in their homeland and attempt to identify poisonous species by boiling the mushrooms with rice; if the rice turns red, the mushrooms are deemed poisonous. Because the Sonoma County mushrooms did not cause a color reaction, it was assumed they were safe to eat.

In the United States, mushrooms of the genera Amanita and Galerina produce amanitins and phallotoxins, which are common causes of mushroom poisoning. The most feared fungi are those that produce amanitin, which include the "deathcap" Amanita phalloides. A. phalloides has become increasingly common in the San Francisco bay region in recent years. The odor of fresh A. phalloides is similar to raw potatoes. Symptoms generally begin 6-24 hours after ingestion and may include the explosive onset of violent abdominal pain, vomiting, and diarrhea. After a short phase of improvement, hepatic, renal, and central nervous system damage may ensue. The mortality rate is 50%, and those who recover do so slowly.

The Russula toxin has not been identified, but it results in a shorter incubation period -- 1-2 hours -- followed by minor gastrointestinal and parasympathetic symptoms and hallucinations.

Nontoxic mushrooms may grow in the same area with toxic ones, and even trained mycologists may confuse toxic varieties with edible ones because of the extensive variations among species. There are no simple tests to identify poisonous mushrooms and no safe ways to detoxify the poisonous varieties.

In the last 5 years, 16 outbreaks involving 44 cases of mushroom poisoning were reported to CDC; 23 cases were from California. In 1981 in California, death in Santa Cruz County and 2 in Marin County were attributed to mushroom poisoning.

(Morbidity and Mortality Weekly Report, June 4, 1982/ Volume 31 /Number 21.)

Authors Note: There are no simple chemical or color tests that will aid in the identification of poisonous mushrooms. Positive identification of many edible species is relatively easy. I have hunted and eaten "wild" mushrooms for the last 10 years without adverse effect. I have one rule: If not absolutely sure; don't eat it! For those of you who deal with mycophiles, don't use the word "Toadstool" to mean poisonous mushroom, it's an obsolete term and also very poor manners.

Unintentional and Intentional Injuries -- United States

Injuries rank as the fourth leading cause of death in the United States, exceeded only by heart disease, malignant neoplasms, and cerebrovascular diseases. In terms of years of life lost prematurely, however, injuries rank first. In the United States alone in 1980, there were over 70 million injuries and 150,000 unintentional injury-related deaths. Motor-vehicle deaths account for nearly 35% of all injury-related deaths; homicides and suicides account for over 30%; and burns, falls, and drownings account for nearly 18%.

The societal cost of injuries is high -- estimated at more than $83 billion per year; yet relatively little effort has been devoted to the prevention of injuries. This imbalance is, in part, the result of a widespread misunderstanding of injury causation. Often, cause is characterized by the term "accident", which connotes chance or fate, while actually many injuries, like diseases can be prevented. Automatic or "passive" protection is gaining recognition as the major focus of prevention efforts because it requires no individual action by those protected and has considerable potential for preventing injury morbidity and mortality.

1. Since the introduction in 1972 of childproof caps on aspirin and other medication containers, there has been a substantial reduction in childhood poisonings. In the period 1971-1977, deaths attributable to ingestion of analgesics and antipyretics decreased 41% for all age groups.

Two other areas in which control measures are likely to decrease injuries include tap-water-scalds and childhood automobile injuries. Each year 4,000 persons require extended hospital care for tap-water-scalds. Tap-water-scald injuries can be virtually eliminated by limiting water-heater temperature to no more than 120 F (48.9C).

(Morbidity and Mortality Weekly Report, May 14, 1982/ Volume 31/Number 18.)

PHENOXY HERBICIDE UPDATE

While 2,4,5-T and 2,4-D pesticides have been used in agriculture, forest management, and commercial and residential landscaping for over 30 years, there is still no conclusive evidence that they and/or TCDD are mutagenic, carcinogenic or teratogenic in man, nor that they have caused reproductive difficulties in the human.

(The Health Effects of "Agent Orange" and Polychlorinated Dioxin Contaminants, American Medical Association, October 1, 1981.)

Author Note: I have a complete copy of this report as well as other papers that have been published recently about phenoxy herbicides and TCDD. Recent data out of Seveso, Italy indicate that so far, chronic effects from TCDD have been minimal in the population acutely exposed to very high doses of this extremely toxic compound. Prospective epidemiological studies of that population will continue and perhaps in the next 10 years we will know much more.

Arthur L. Craigmill, Ph.D