Lead is a blue-gray, heavy, soft metallic element that occurs naturally in the earth’s crust. It is a malleable metal, so it can be easily worked - you can hammer it into protective sheets or make pipes and bend them easily. It is dense, and has good shielding protection against radiation, so it is used as ballast or to shield against penetrating forms of ionizing radiation. Metallic lead is tasteless and odorless, although some of the oxides and salts of lead taste sweet. (This sweet taste of lead salts is a source of problems for children!). Lead is insoluble in water, but some of the salts do dissolve, hence lead salts can be carried long distances in water supplies. Lead fumes will be easily formed when lead is heated. Although there is not a lot of lead in the earth’s crust – lead is ubiquitous, especially in modern industry.

1. Dr. Dalia El-Shafei
Ass.Prof of Occupational Medicine

3. Lead is a blush gray metallic element which occurs naturally
(in small amounts) in the earth’s crust.
It is dense, hence its use as a ballast, ammunition, or
radiation shield.
Lead is insoluble in water, but some salts are soluble.

4. Lead is a soft, malleable
poor metal. It is also counted
as one of the heavy metals.
It is sometimes found free in
nature, Although lead makes
up only about 0.0013% of the
earth's crust, it is not considered
to be a rare element since it is easily mined and
refined.

5. Plumbing is derived from
plumbun, Latin for lead

6. Lead has a low melting point and can easily be
aerosolized by heating.
Lead can be formed into organic compounds by
some organisms, and some organic compounds
(such as “leaded gasoline”) have industrial uses.

8.  Lead poisoning is a medical condition caused
by increased levels of the heavy metal lead in
the body, and this can interfere with a variety
of body processes and causes toxicity to many
organs and tissues.
 It’s also called plumbism, colica Pictonum or
saturnism

10. "Lead makes the mind
give way."
Greek
Dioscerides - 2nd BC

11. Inlet to the body:
Through inhalation of dust & fumes. Also, ingestion
& absorption through the skin (by organic
compounds) may occur.

12. How can the human be exposed to lead??
1- Occupational exposure:- is the
main cause of lead poisoning in
adults, as in lead miners and smelters,
plumbers glass manufacturers,
construction workers …etc.
2- Paints:- is the main cause of lead
Poisoning in children. Many of the
children display pica, so even a small
amount of a lead-containing product
can contain hundreds of milligrams
of lead.

13. 3- Soil:- is the main cause of lead
poisoning in the agricultural areas.
By eating food grown in an
contaminated soil.
4- Water:- Lead from the soil or
atmosphere can end up in surface
water and groundwater. It is also
potentially in drinking water.

14. 5- Lead containing products:-
Like plastic toys, bottles, cans……etc.
6- Hunting:- Animals which are hunted
are at high risk of exposure because of
the bullets which may contain lead.
• Breast feeding is also considered as an important route
of lead exposure because of the presence of the lead in
the affected female milk.

15.  All children under the age of 6 years old.
 People living in old houses are at great risk.
 People work in industries.
 Pregnant woman & developing baby.

19. A- Distribution in the body:
- Bound to RBCs, membranes.
- Precipitate in bone, teeth.
- Exist in the plasma.
B- Excretion:
- Almost via the kidney.
- Small amount excreted through bile.
- Sweat and milk.

20. What are the Normal levels of lead??
 Adults:
Less than 20 micrograms/dL of lead in the blood
 Children:
Less than 5 micrograms/dL of lead in the blood

23. 60
40
30
25
20
15
10
2
0
10
20
30
40
50
60
BloodLead(ug/dl)
CDC
1960
CDC
1973
CDC
1975
CDC
1985
WHO
1986
EPA
1986
CDC
1990
CDC
2006?
Agency and Year
Acceptable Childhood Blood Lead Levels

34. Prevention: By the triad of:
a) Engineering control measures.
b) Good industrial hygiene.
c) Regular clinical examination and investigation.
Treatment of lead poisoning:
a) Identification of source of lead poisoning.
b) Removal from exposure.
c) Chelation therapy for symptomatic patient with
blood lead level more than 100 microgram/ dl.
d) Chelation is performed under strict medical
supervision by giving the patient injections of calcium
ethylene dianine tetra acetic acid (Ca EDTA) and/ or
oral penicillamine.

35. OSHA PEL 0.05 mg/m3, 8-h TWA
NIOSH REL 0.10 mg/m3, 10-h TWA;
ACGIH TLV 0.05 mg/m3, 8-h TWA

39. When: Exposure above “action level” >30 days/yr
What: Triggers periodic exams & biologic monitoring
(including blood level)
Removal threshold: 50 µg/dl (repeated) or 60 µg/dl once.
Repeat testing: Monthly, depending on lead level

41.  Lead poisoned workers can return to the
workplace when blood lead is <40 µg/dl.
 Symptomatic workers can remain out of the
workplace at lower levels.
 Workers whose blood lead is near 40 µg/dl
are most likely to be able to remain in the
workplace if they can perform modified
duty without lead exposure.

43. Remove from exposure, or otherwise prevent
exposure.
Workplace Home
Substitution Move
Engineering Identify and Abate
Personal Protection
Work Practices
Job Placement

46.  Not a decision to be taken lightly
 Requires close monitoring
 Inefficient process, typically reducing body
burden only 1 - 2 %
 Chelating agents may not significantly
reduce tissue levels, esp. in CNS

48.  Indicated for symptomatic Pb toxicity
 Generally less effective
 Never a substitute for control of exposure
 Unethical to give chelation for prophylaxis
 Indications for chelation depend on
symptoms and BPb (g/dl), not BPb alone

49. C/P Blood Lead Level
(µg/dl)
Chelation
Encephalopathy Any level BAL + EDTA
“High dose”
Symptomatic > 100 BAL + EDTA
“low dose”
Mild symptoms 70 -100 Succimer
Asymptomatic < 70 Medical removal