Health Effects of Hazardous Materials

Hazardous materials can damage the natural ecosystem, including the human population. The table shown below lists as examples the sources and effects of a few common hazards. All of the effects have been statistically verified on humans.

Hazardous Material / Uses, Where Found	Known Effects
2,4D (dichlorophenoxyacetic acid) >1,500 type of pesticides including broadleaf herbicides, weed'n feed	nervous system damage
Malathion insecticide, mosquito spray	damage to nervous, neurological, and respiratory systems, death
Arsenic wood preservative, mining byproduct	gastro-intestinal damage, skin damage, death
Lead (formerly) leaded gas, lead pipes, tobacco smoke, batteries	damage to nervous, neurological and gastro-intestinal systems, death
Mercury fish, lamps, dental fillings, thermometers	damage to nervous, neurological and gastro-intestinal systems, death
Cadmium burning of fossil fuels, tobacco smoke, mining byproduct, batteries	damage to gastro-intestinal and respiratory systems, death
Toluene gasoline, paints, adhesives, cleaning agents, tobacco smoke, some plastics	damage to nervous and neurological systems, death

Scientists distinguish between two processes in how a particular chemical acts in the environment:

• Bioaccumulation — the increase in concentration of a pollutant from the environment to the first organism in a food chain
• Biomagnification — the increase in concentration of a pollutant from one link in a food chain to another

Together these phenomena mean that even small concentrations of chemicals in the environment can find their way into organisms in high enough dosages to cause problems. DDT is the classic example. Extreme concentrations of DDT in animals at the top of the food chain (and the corresponding health effects) led to its being banned in most industrialized countries.

Another area of concern is hormone disrupting chemicals. Most, though not all, of the hormone disrupting chemicals involve chlorine. These have been linked to breast cancer, lower sperm counts, early female puberty and other reproductive abnormalities. These and similar concerns have led governments to target chlorine containing compounds for minimization and elimination programs.

Even if we know that a particular chemical has specific effects at certain concentrations, it is not possible to know what happens when that chemical is combined with other materials in the environment. How does a spray program for mosquitoes affect someone on a smoggy day? What if that person also lives close to a contaminated site or is exposed to other chemicals at work?

The potential for us to be exposed to a variety of hazardous substances grows with the variety of new compounds being invented. Each of these in isolation may have little or no effect on us, but their cumulative consequences could be quite different.

"Ecosystems are not only more complex than we think, but more complex than we can think."
— Frank Egler, 1977

(Source: September 2000 WasteWatch)