Effects of Chemical Pollutants on Humans and Other Mammals
Humans and other animals are exposed to chemicals via water, air, soils, dusts and their diets. These chemicals enter the body by ingestion (mainly in the diet and in water, but also on hands, in soil on vegetables and from dust swallowed in mucus), inhalation (air and dust) and by dermal contact (air, soil and water)
The types of response to toxicants which occur in humans and other mammals include :
alterations in the vital signs of temperature , pulse rate, respiratory rate and blood pressure abnormal skin colour unnatural odours effects on the eye, which include :
- miosis (excessive contraction of pupil)
- mydriasis (excessive pupil dilation)
- conjuctivitis (inflamation of the membrane covering the front of the eyeball)
- nystagmus (involuntary movement of the eyeballs)
gastrointestinal effects : pain, vomiting, paralytic ileus (stoppage of normal peristalsis)central nervous system effects : convulsions, paralysis, hallucinations, ataxia and coma
Sub-clinical (recondite) effects of toxicants in humans and other mammals include :
damage to the immune system chromosomal abnormalities modification of the functions of liver enzymes slowing of the conduction of nervous impulses
The major types of biochemical effects of pollutants are :
impairment of enzyme function by the binding of the toxicant to enzymes, coenzymes, metal activators, or enzyme substrates alteration of cell membrane or carriers in cell membranes interference with lipid metabolism, resulting in excess lipid accumulation interference with carbohydrate metabolism stopping or interfering with protein biosynthesis through toxic effects on DNA interference with regulatory processes mediated by hormones or enzymes
Teratogenesis, Mutagenesis and Carcinogenesis
Teratogenesis is the creation of birth defects arising from damage to embryonic or foetal cells mutations in egg or sperm cells.
Mutagenesis is the creation of mutations by chemicals or ionizing radiation which bring about alterations to DNA to produce inheritable traits.
Carcinogenesis ( or cancer ) occurs when xenobiotic substances cause uncontrolled cell replication ( i.e. cancer ).
