7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 1/10

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 2/10

Lead occurs naturally in the earth's crust, usually aslead sulphide PbS (galena). However, as a result of human activity, in the atmosphere nowadays lead isfound mainly as PbSO4 and PbCO3.

Lead is malleable, and relatively low melting point,and therefore it has been used since ancient times totransport water through lead tin water pipes.

Lead is generally resistant to corrosion - but it willdissolve weakly in acid (low pH) water, or even in water of a very high pH.

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 3/10

Lead has been used, as an organic alkyl compound -tetraethyl lead (CH3CH2)4Pb- to prevent 'knocking'in petrol (gasoline) engines by increasing the 'octane value' of the fuel.

It was mixed with gasoline to increase the octanenumber so as to increase the performance andefficiency of engine.

LEADED fuels destroyed catalytic convertor results inescaping out harmful gases. alternative is ferrocene.

(CH3CH2)4Pb + 13 O2 → 8 CO2 + 10 H2O + Pb

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 4/10

Paint and lead dust

Medicines and cosmetics

Children’s toys and jewelry   Lead acid batteries

 Water pipes

Exhaust emission from leaded petrol

Car batteries

Fertilizers and pesticides

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 5/10

Effects on soil :

once deposited on upper layer of soil it retained for many 

 years, reduce fertility of it.

atmospheric lead moves into micro-organisms and grazing foodchains.

Effects on plants :

plants absorb lead from soil and it retain inn their roots. Thislead reaches to leaves and reduce photosynthesis process and

leaves turn yellow and lie down

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 6/10

It can enter the human body through uptake of food

(65%), water (20%) and air (15%). Lead can enter (drinking) water

through corrosion of pipes. This is more likely to happen when the

 water is slightly acidic.

Lead can cause several unwanted effects, such as:

 A rise in blood pressure

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 7/10

Disruption of nervous systems

Brain damage

Kidney damage

Diminished learning abilities of children

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 8/10

reduced intelligence

poor growth

poor bone development

poor muscle coordination irritability 

anxiety 

high blood pressure

ringing in the ears (a very common lead poisoningsymptom)

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 9/10

  Lead acid battersLead

–acid batteries,

invented in 1859 are theoldest type of rechargeablebattery. Despite having a very low energy-to-weight ratioand a low energy-to-volume

ratio, their ability to supply high surge currents meansthat the cells maintain arelatively large power-to-

 weight ratio. These features,along with their low cost,make them attractive for usein motor vehicles to providethe high current requiredby automobile starter motors.

7/27/2019 Lead and Environment

http://slidepdf.com/reader/full/lead-and-environment 10/10

Raising the pH of the domestic water supply (i.e. making itmore alkaline) by adding lime (calcium hydroxide), oradding calcium phosphate.

substituting, voluntarily or by legal prohibition, the use of 

lead in domestic paints, plumbing, toys, petrol etc. Renovation of Older Homes and Child-Occupied

Facilities

Providing guidance and support to individuals exposed to

lead