Physical changes in the land, soil, water, and air,
associated with industrialization directly and indirectly
affect the biological environment. Direct impacts include
deaths of plants, animals, or people, caused by mining
activity or contact with toxic soil or water from mines.
Indirect impacts include changes in nutrient cycling, total
biomass, species diversity, and eco-system stability due to
alterations in groundwater or surface water availability or
Water resources are particularly vulnerable to
degradation even if drainage is controlled and sediment
pollution reduced. Surface drainage is often altered at
mine sites, and run off from precipitation may infiltrate
waste material, leaching out trace elements and minerals.
Trace elements leached from mining wastes and concentrated
in water, soil, or plants may be toxic, causing diseases in
people and other animals who drink the water, eat the
plants, or use the soil.
These potentially harmful trace
elements include cadmium, cobalt, copper, lead, iron,
Groundwater may also be polluted by mining operations
when waste comes into contact with slow-moving subsurface
waters. Surface-water infiltration or groundwater movement
through mining waste piles causes leaching of sulfide
materials that may pollute groundwater. The polluted
groundwater may eventually seep into streams to pollute
surface water. Groundwater problems are particularly
troublesome because reclamation of polluted groundwater is
An example of an area where trace elements have
affected a large part of the population is in Japan. An
increased amount of cadmium was released into the Zintsu
River Basin near the end of World War I. At this time the
Japanese industrial complex was damaged and good
industrial-waste disposal practices were largely ignored.
Mining operations for cadmium dumped mining wastes into
rivers. The cadmium influx occurred in estuarine waters and
in sediments after the intake of industrial wastes.
Farmers then used this contaminated water downstream
for domestic and agricultural purposes. This intake of
cadmium by human beings caused a chronic disease within the
Japanese population known as Itai-Itai. The name Itai-Itai
suits the disease because it is Japanese for ouch-ouch.
Itai-Itai is painful and crippling.
It attacks the bones
causing them to become so thin and brittle that they break
Many solutions and experiments have been tried to find
reason and absolution of cadmium influx, but none has given
us a perfect resolution of the cause. Such experiments as
studying the bones and tissue of victims were quite
revealing. The bones and tissue were found to contain large
concentrations of zinc, lead, and cadmium. The study of
rats showed scientists interesting results. When rats were
fed 100ppm of cadmium they lost about 3 percent of their
total bone tissue. Rats fed amounts of cadmium plus other
trace elements such as lead copper and zinc lost about 33
percent of their total bone tissue.
Cadmium in seafood is another problem in Japan so
scientists were not surprised when they found out that
cadmium has deleterious effects on most, if not all, marine
species tested. Histopathological effects of cadmium have
been studied in two species of marine finfish. However, no
scientist has reported histopathological effects in any
invertebrates. Invertebrates are more sensitive to the
metal than are finfish. There are few reports on the rates
of accumulation of cadmium in marine species, and the only
investigations we are aware of are studies on the flux of
cadmium through mussels, shrimp, and euphausids. This lack
of information caused us to undertake the present study to :
(1) determine rates of accumulation and localization of
cadmium in tissues of shrimp; (2) describe the histological
effects of cadmium in shrimp; and (3) compare the
accumulation of cadmium in shrimp from meta incorporated in
food with that of cadmium administered directly in water.
Measurement of heavy-metal concentrations in Japans
Zintsu River Basin showed that although the water samples
generally contained less than 1 ppm cadmium and 50 ppm zinc,
these metals are selectively concentrated in the sediment
and even more highly concentrated in plants. One set of
data for five samples shows an average of 6 ppm cadmium in
polluted soils. In plant roots, this average increased to
1250, and in the harvested rice it was 125 ppm.
As of late scientists have been putting their energy
and time into research more than activating ways to quickly
and efficiently solve the problem. Some structures like
specially constructed ponds have been made to collect
polluted run off from mines have been made and do help, but
they cannot be expected to eliminate all problems.
Groundwater problems are particularly troublesome because
reclamation of polluted groundwater is very difficult and
So, until scientists have fully researched the
effect of trace elements in our geologic planet our society
will just have to look towards the future.