The Environment and Health - Other hazards

Toxic Wastes

Various estimates place the number of toxic-waste disposal sites in the United States at 14,000 to 20,000. Poisonous substances left over from industrial processes are buried or simply dumped at these sites, many of which present serious health hazards. Primarily, according to scientists, the open dumps, landfills, bulk storage containers, and surface impoundments at the thousands of sites spill toxic chemicals into the surrounding soil and through it into groundwater systems. Noxious fumes and even flames burst from some sites at unpredictable moments. The wastes include a huge variety of substances, among them chlorinated solvents, aromatic hydrocarbons, pesticides, trace metals, and PCBs.

The locations of many waste disposal sites remain unknown, often, until a health or environmental problem is detected. Thus the health threats posed by waste dumps may lie dormant for years and may surface only after a container has rusted through or seepage has brought poisonous slush into contact with drinking-water sources.

Waste chemicals can enter the body through skin contact and inhalation as well as ingestion. But the latter is the most common method. Where dosage is substantial, ingestion usually leads to toxic effects on the liver and kidneys. Other parts of the body may be affected as well. Skin contact may produce lesions while inhalation can have direct respiratory effects.

Improved methods of disposing of toxic wastes have combined with public awareness and governmental action to build hopes of reduced waste problems in the future. In the meantime, as environmentalists contend, the thousands of existing toxic-waste sites pose continuing health hazards.

Nuclear Radiation

Among the most dangerous of all pollutants is nuclear or “ionizing” radiation. Made up of particles of energy, this radiation can attack the atoms that form the body's cells, causing both short- and long-term damage. Human tissues like skin, bone-marrow, and intestinal cells, all of which reproduce rapidly, feel the impact of radiation most intensely. But different isotopes in ionizing radiation concentrate in different body tissues, sometimes causing cancer or genetic mutations many years after exposure. Of the most common radioactive elements in radiation from a nuclear power plant, barium resembles calcium and therefore concentrates in the bones while iodine 131 concentrates in the thyroid.

Completely invisible, radiation reaches the earth from various natural and manmade sources. Some comes from the sun and outer space; larger amounts are given off by radioactive materials, including waste from nuclear power plants, the fallout from nuclear weapons explosions, and various electronic devices. The numbers of such devices are increasing steadily; among them are lasers, X-ray machines, TV sets, and microwave ovens.

The damage done to the human body as a result of exposure to radiation varies with the intensity of the “dose” and the isotopes involved. A dose of radiation above 1,000 rem, a unit of measurement, is always fatal. Smaller doses, with exposure over an extended period of time, may also be fatal. Victims can protect themselves to a limited degree if given time. For example, they can guard against thyroid cancer by taking potassium iodide. Ingested in pill form, the medication loads the thyroid gland with iodine, thus “blocking” the iodine 131 isotope and preventing its concentration in the thyroid.

In a simple operation physicians can transplant marrow into persons exposed to the barium isotope, and thus reduce the possibility of bone-marrow syndrome. This illness cripples the body's immune system. But donor marrow must match that of the victim, and the relatives of a victim are those most likely to supply marrow that is a genetic match. If the relatives have also been exposed to radiation, no donors may qualify.