Question

what is the difference between human exposure to hazardous chemicals in small amounts and their exposure to microbes?

Answer 1

People respond to chemical exposures
in different ways. Some people may
come into contact with a chemical and
never be harmed. Others may be more
sensitive and get sick. Sometimes
illness happens only if you are exposed
to a harmful substance for a long time.

Harmful effects on human for hazardous chemicals exposure:

On RESPIRATORY SYSTEM’s : It function is to supply oxygen to the body and remove carbon dioxide. It includes
the nasal passages, pharynx, trachea, bronchi, and lungs. Possible health effects of the respiratory system include
asbestosis, lung cancer, chronic bronchitis, fibrosis, emphysema, and decreased oxygen supply in blood.

On  RENAL SYSTEM’s : It function is to rid the body of waste, to regulate the amount of body fluids, and to
regulate the amount of salts in the body. It includes the kidneys, the urethra, the bladder, and the ureter.
Possible health effects of the renal system include decreased formation of urine, decreased blood flow to
kidney, decreased ability to filter the blood, prevented urine flow, kidney tissue damage, and kidney cancer.

On CARDIOVASCULAR SYSTEM’s : It function is to move nutrients, gases, and wastes to and from the body,
to help stabilize body temperature, and to fight diseases and infections by transporting white blood cells to
important areas. It includes the heart, blood, arteries, veins, and capillaries. Possible health effects include
heart failure and the inability of blood to carry the necessary oxygen to the body.

On REPRODUCTIVE SYSTEM’s: It function is to produce egg and sperm cells, to nurture a developing fetus, and
to produce hormones. For males it includes the testicles, seminal vesicles, prostate gland, and the penis. For
females it includes the uterus, bladder, vagina, Fallopian tubes, ovaries, and the cervix. Possible health effects
of the reproductive system include decreased ability to have a baby, increased baby deaths, increased birth
defects, and infertility (the inability to have children).

On NERVOUS SYSTEM’s : It function is to transmit messages from one part of the body to another. It includes the
central nervous system (the brain and spinal cord) and the peripheral nervous system. Possible health effects of
the nervous system include inability to move, loss of feeling, confusion, and decreased speech, sight, memory,
muscle strength, or coordination.

The IMMUNE SYSTEM’s function is to protect the body from tumor cells, environmental substances, and
invading viruses or bacteria. It includes the lymph system, bone marrow, white blood cells, and the spleen.
Possible health effects of the immune system include overreaction to environmental substances (allergy),
immune system slow down or failure, and autoimmunity (autoimmunity causes the body to attack itself – which
makes it more likely to have an over-reaction or infection).

The SKIN serves as a barrier to germs and other substances, prevents dehydration, and regulates body
temperature. Possible health effects of the skin include irritation, rash, redness or discoloration, dermatitis, and
health effect related to other systems and organs due to contamination through the skin.

The HEPATIC SYSTEM’s function is to break down food and store nutrients, to make proteins which are
essential for blood to clot, and to purify the body of drugs, contaminants, or chemicals. It includes the liver
and its veins. Possible health effects of the hepatic system include liver damage, tumors, accumulation of fat
(steatosis), and death of liver cells.

But these adverse health effects are dependent on the factors of the exposure. Factors that play a part in whether or not adverse health effects may result from an exposure are:

• the type of chemical;
• the amount or dose (the amount or level of a chemical a person was exposed to);
• the duration (how long did exposure occur); and
• the frequency (how many times the person was exposed).

Also, the occurrence of adverse health effects can depend on the way the chemical enters your body. Some chemicals rapidly absorb through skin, others not at all. Health effects also depend on the toxicity of the chemical that entered your body. Some chemicals are very toxic in small amounts; others are only toxic in large volumes.

Also, people respond to chemical exposure in different ways. Some people may be exposed to a chemical and not get sick. Other people may be more sensitive to chemicals and get sick more rapidly or have more severe reactions than others. Certain variables play a role in a person's susceptibility to exposure and adverse health effects such as age, gender, genetics, pregnancy or other health conditions.

For the fetus, child, and adolescent, the adverse health effects from exposure to chemicals can be much greater than for adults. The factors that affect their susceptibility include their stage of development and level of activity in the environment. The fetus is the most susceptible because their developing organs may be permanently damaged. Similarly, children, especially from one to six years of age, are also in a stage of rapid development. During this period, children may take more chemical into their bodies due to body chemistry, level of activity, and relative small body size. As children develop, chemicals introduced into the body can alter many processes essential for proper cell development. As a result, changes can, for example, cause organs within the body to be altered, impairing proper development to a mature organ. Adolescents may share in the risk due to their increased physical activity and curiosity of the world around them. For more information, see Children's Health Protection.

The human body has the ability to tolerate certain amounts of chemicals and the ability to excrete chemicals from the body. Once a person is exposed to a chemical, it may enter the blood stream, and eventually reach the liver. The liver attempts to detoxify harmful chemicals in the body by converting them to less toxic ones or ones that could be used by the body. The body naturally attempts to eliminate substances that are harmful or are not used. The kidneys filter substances out of the blood and excrete them in urine. Also, chemicals are removed from the body in feces, sweat and exhalation. However, the body may not be able to remove all the chemicals. The amount, type, and length of time you are exposed to harmful substances will determine if you are at risk for adverse health effects.

Therefore, the state and federal governments have determined health-based comparison values for contaminants that when exceeded, exposure may result in an excessive health risk.