Environmental Engineering Reference
In-Depth Information
contaminants in the environment and their rate of intake was studied. The third step
was dose-response assessment to find the relation between the amount of exposure
and the risk involved. It was followed by risk characterization, which estimated the
potential impact of the hazard based on the severity of its effects and amount of
exposure. The last part of the study curtailed risk management and communication,
wherein suggestions to divide the region into successive risk-zones were made.
Hazard Identification
Lead:
Lead is a highly toxic substance, exposure to which can produce a wide
range of adverse health effects. Lead poisoning has been known to affect the health
of children more than that of the adults. Over the years, tens of millions of children
have suffered its health effects. Children under the age of six are especially vulner-
able to its harmful effects, because their brains and central nervous system are still
being formed. Even very low levels of exposure can result in reduced IQ, learning
disabilities, attention deficit disorders, behavioural problems, stunted growth,
impaired hearing, and kidney damage. At high exposures, it can even result in death
(GuidottiandRagain
2007
).
Among the adults, lead can increase blood pressure and cause fertility problems,
nerve disorders, muscle and joint pain, irritability, and memory or concentration
problems (Schwartz et al.
1990
;StaudingerandRoth
1998
). However, the adverse
health effects require very high concentrations of lead as compared to children.
Apart from these health effects, lead poisoning has also been known to cause gas-
trointestinal tract disorders, nausea, diarrhoea, weight loss, muscular weakness,
bone degradation, among other things. In pregnant women, high levels of lead can
easily be transferred to the foetus. This is a very serious problem, which can have
adverse effects on the unborn child for the rest of its life.
Several studies have tried to find a link between exposure to lead and an increase
in cancer rates among the general population. Some of these studies have found a
small increase in lung cancer risk. Some studies have also found an increased risk
of stomach cancer with higher lead exposure. However, the link between lead expo-
sure and cancer is not clear, and more studies are needed to better define the possible
link between lead exposure and cancer risk.
Zinc:
Zinc in general is an essential requirement for a healthy body; it is critical in
supporting the immune system, which protects us from pathogens, infections, and
disease. However, it can be very harmful if it is present in excess amounts. Zinc
poisoning is a potentially life-threatening emergency. Excessive absorption of zinc
in the body can cause copper retention in the cells along the intestine, which pre-
vents the body from properly absorbing copper. This copper deficiency can cause
anaemia symptoms, such as fatigue, weakness and pale skin. Apart from copper
deficiency, excessive zinc consumption may also irritate the intestinal tract, causing
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