Water Pollution due to Heavy metals, Pesticides, Oils and Detergents

Presented byJoy H JonesRoll No 08

M2 EE

Heavy Metal contamination in Water Body

Heavy Metals•The term heavy metal refers to any

metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations.

Heavy Metals• Heavy metals are naturally occurring

elements that have a high atomic weight and a density at least 5 times greater than that of water.

Heavy Metals

HEAVY METALS• are natural components of the Earth's crust• they cannot be degraded or destroyed• to a small extent they enter our bodies via food,

drinking water and air• as trace elements, some heavy metals (e.g.

copper, selenium, zinc) are essential to maintain the

metabolism of the human body• however, at higher concentrations they can lead

to poisoning• heavy metal poisoning could result, for instance,

from drinking-water contamination (e.g. lead pipes), high ambient air concentrations near emission sources, or intake via the food chain

Heavy metals• Heavy metals are dangerous because they tend

to bioaccumulate. • Bioaccumulation means an increase in the

concentration of a chemical in a biological organism over time, compared to the chemical's concentration in the environment.

• Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted.

Heavy MetalVillagers from Sahecun, in southern China, are suffering from hideous swellings caused by heavy metal pollution(lead) from a mine that closed a decade ago. Huang Guiqiang, 58, said: 'The lumps over my body are incredibly painful, and interspersed occasionally with periods where I can't feel anything at all in my body’

Heavy Metal• Heavy metal toxicity can result in

▫ damaged or reduced mental and central nervous function, ▫ lower energy levels, ▫ Damage

blood composition, lungs, kidneys, liver, and other vital organs.

▫ Long-term exposure may result in slowly progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer's disease, Parkinson's disease, muscular dystrophy, and multiple sclerosis.

Allergies are not uncommon and repeated long-term contact with some metals or their

compounds may even cause cancer

Heavy Metal•The main threats to human health from

heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO

Lead•Exposure to inorganic lead occurs in mines

and smelters as well as welding of lead painted metal, and in battery plants.

• Low or moderate exposure may take place in the glass industry.

•Lead is present in fuels, on burning it will enter the air

•Airborne lead can be deposited on soil and water, thus reaching humans via the food chain.

Lead•In adults, inorganic lead does not

penetrate the blood–brain barrier, whereas this barrier is less developed in children. The high gastrointestinal uptake and the permeable blood–brain barrier make children especially susceptible to lead exposure and subsequent brain damage.

Lead•Acute exposure to lead is known to cause

proximal renal tubular damage.• Long-term lead exposure may also give

rise to kidney damage 

Lead•IARC (International Agency Research on

Cancer) classified lead as a ‘possible human carcinogen’ based on sufficient animal data and insufficient human data in 1987.

• lung cancer, stomach cancer and gliomas can be caused due to lead

•A notably serious effect of lead toxicity is its teratogenic effect

Arsenic

•Arsenic is a widely distributed metalloid, occurring in rock, soil, water and air.

• Inorganic arsenic is present in groundwater used for drinking in several countries all over the world (e.g. Bangladesh, Chile and China),

•Organic arsenic compounds (such as arsenobetaine) are primarily found in fish, which thus may give rise to human exposure

Man affected with Heavy metal (Arsenic)

Arsenic•The latest WHO evaluation concludes that

arsenic exposure via drinking water is causally related to cancer in the lungs, kidney, bladder and skin, the last of which is preceded by directly observable precancerous lesions.

Arsenic

•Uncertainties in the estimation of past exposures are important when assessing the exposure–response relationships, but it would seem that drinking water arsenic concentrations of approximately 100 μg/l have led to cancer at these sites, and that precursors of skin cancer have been associated with levels of 50–100 μg/l.

Cadmium•Found in

▫Zinc smelting,▫ waste batteries, ▫e-waste, ▫paint sludge,▫ incinerations & fuel combustion

Cadmium entering in Water body

Cadmium•Cadmium is toxic at extremely low levels.• In humans, long term exposure results in

renal dysfunction.• Cadmium is also associated with bone

defects, viz; osteomalacia, osteoporosis and spontaneous fractures, increased blood pressure and myocardic dysfunctions.

Cadmium -effects

MercuryThe mercury compound cinnabar (HgS), was used in pre-historic cave paintings for red colours, and metallic mercury was known in ancient Greece where it (as well as white lead) was used as a cosmetic to lighten the skin.

In medicine, apart from the previously mentioned use of mercury as a cure for syphilis, mercury compounds have also been used as diuretics [calomel (Hg2Cl2)], and mercury amalgam is still used for filling teeth in many countries26

Mercury

Inorganic Mercury•Acute mercury exposure may give rise to

lung damage. Chronic poisoning is characterized by neurological and psychological symptoms, such as tremor, changes in personality, restlessness, anxiety, sleep disturbance and depression.

•Renal dysfunctions are also caused by mercury exposure

Organic Mercury•Methyl mercury poisoning has a latency

of 1 month or longer after acute exposure, and the main symptoms relate to nervous system damage31.

•High doses may lead to death, usually 2–4 weeks after onset of symptoms.

•

Organic Mercury• The Minamata catastrophe in Japan in the 1950s was

caused by methyl mercury poisoning from fish contaminated by mercury discharges to the surrounding sea.

• Minamata disease was first discovered in Minamata city in Kumamoto, Japan, in 1956. It was caused by the release ofmethylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968.

• This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay, which, when eaten by the local populace, resulted in mercury poisoning. While cat, dog, pig, and human deaths continued for 36 years,

Minamata

• In the early 1970s, more than 10,000 persons in Iraq were poisoned by eating bread baked from mercury-polluted grain, and several thousand people died as a consequence of the poisoning.

•However, the general population does not face significant health risks from methyl mercury exposure with the exception of certain groups with high fish consumption.

Organic Mercury•As of March 2001, 2,265 victims had been

officially recognised as having Minamata disease (1,784 of whom had died)[2] and over 10,000 had received financial compensation from Chisso