When we think of pollutants, we tend to think of chemicals with long and sometimes unpronounceable names: hexavalent chromium, polybrominated diphenyl ethers, hexachlorobenzene. However, not all substances that are dangerous to human and environmental health are manmade – some are naturally occurring, but have been introduced, often in toxic quantities, into society at large due to ignorance or greed. The following are some naturally-occurring substances that human use (or, more often, misuse) has turned into pollutants.
When we think of pollutants, we tend to think of chemicals with long and sometimes unpronounceable names: hexavalent chromium, polybrominated diphenyl ethers, hexachlorobenzene. However, not all substances that are dangerous to human and environmental health are manmade – some are naturally occurring, but have been introduced, often in toxic quantities, into society at large due to ignorance or greed. The following are some naturally-occurring substances that human use (or, more often, misuse) has turned into pollutants.
!ADVERTISEMENT!Asbestos
A fibrous mineral mined from ore deposits all around the world, asbestos is
known for its heat-resistant properties and use throughout the twentieth century
in fireproofing materials. When the materials that contain asbestos become worn
or damaged, they can release tiny, needle-like fibers into the air that will
lodge in the lungs and other body tissues. Once inhaled or ingested, the
fibers can cause health problems such as lung scarring, asbestosis, or
mesothelioma, a cancer of the lining of the chest cavity. Mesothelioma symptoms are
similar to those of other, less serious lung problems, so the cancer often goes
undetected until the disease is in its later stages.
Lead
This soft metal is easy to work with and resists corrosion, once making it a
popular ingredient in plumbing and other construction materials. Lead pigments
were also used in paint that could be found in houses and even children’s toys.
When ingested, this heavy metal can affect nearly every system in the
body, especially the nervous system. This makes it particularly dangerous
to infants and
children, whose nervous systems are still developing. Homes and
schools built before 1978 may still contain lead-based paint, which can over
time form chips that can be ingested and dust that can be inhaled.
Mercury
Mercury is notable for being one of the few metals that exists in a liquid
state at room temperature and pressure. For this reason, it has been used
in thermometers and other measuring equipment, but the real health threat of
mercury comes from coal-burning power plants, mining operations, or the burning
of hazardous wastes. It is dangerous if breathed in, of course, but
mercury is also beginning to enter our food sources, particularly
fish and shellfish. This poses the greatest threat to developing fetuses,
infants, and children, for whom even small amounts of mercury can, like lead,
hinder the development of the nervous system.
Though the EPA does regulate these substances by putting caps on how much is
allowed to be in the air or water, scientists agree that there is no safe
minimum exposure level for any of them. For example, mesothelioma
symptoms have been known to occur in people who were exposed to asbestos
for only a short period of time. Though there is no way of eradicating
these threats completely, we can and should put a stop to the activities that
bring us into contact with them.
For further information: http://www.epa.gov/mercury/exposure.htm or http://www.mesotheliomasymptoms.com/mesothelioma-symptoms
