Lead poisoning

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

2. What is Lead? 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.

3.   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.

4. What Is Plumbun ? Plumbing is derived from plumbun , Latin for lead

5. Significant Health Characteristics of Lead 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.

6. 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 What is lead poisoning???

7. "Lead makes the mind give way." Ancient Awareness Greek Dioscerides - 2nd BC

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

9. 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.

10. 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.

11. 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.

12. 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. Who is at high risk?

13. Lead in Jewelry

14. Lead in Environment

15. Metabolism: 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.

16. 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

17. Agency Blood Lead Levels

18. 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 .

19. Occupational Exposure Levels OSHA PEL 0.05 mg/m 3 , 8-h TWA NIOSH REL 0.10 mg/m 3 , 10-h TWA; ACGIH TLV 0.05 mg/m 3 , 8-h TWA

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

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

22. The Key to “Treatment” of Lead Poisoning Remove from exposure, or otherwise prevent exposure. Workplace Home Substitution Move Engineering Identify and Abate Personal Protection Work Practices Job Placement

23. Chelation 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

24. Adult Chelation Therapy 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

25. 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