BIOLOGY IN HUMAN WELFARE
HUMAN HEALTH AND DISEASE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
potent carcinogen that can cause nervous system damage and birth defects
|
|
|
radioactive element with a long half-life
|
|
|
carbon-based organic compound naturally occurring in many organisms
|
|
|
stable chemical element
|
|
|
common molecule whose atoms are loosely held together by chemical bonds and therefore easily broken down
|
Detailed explanation-1: -What you should know: Mercury is a persistent, bioaccumulative, toxic pollutant. When released into the environment, it accumulates in water laid sediments where it converts into toxic methylmercury and enters the food chain.
Detailed explanation-2: -Because mercury is a persistent substance, it can build up, or bioaccumulate, in living organisms, inflicting increasing levels of harm on higher order species such as predatory fish and fish eating birds and mammals through a process know as “biomagnification".
Detailed explanation-3: -Once in the environment, mercury can be transformed by bacteria into methylmercury. Methylmercury then bioaccumulates (bioaccumulation occurs when an organism contains higher concentrations of the substance than do the surroundings) in fish and shellfish. Methylmercury also biomagnifies.
Detailed explanation-4: -Mercury occurs naturally in the earth’s crust, but human activities, such as mining and fossil fuel combustion, have led to widespread global mercury pollution. Mercury emitted into the air eventually settles into water or onto land where it can be washed into water.