Occupational Health and Ergonomics Workbook PDF

Occupational Health and Ergonomics Workbook Toxicology What is a toxic substance? Ans- These can have adverse effects on normal human physiological function. Eg: Lead, Mercury, Alcohol, Hexavalent Chromium, Acute Toxicity: Relatively short span of time. Chronic...

Occupational Health and Ergonomics Workbook Toxicology What is a toxic substance? Ans- These can have adverse effects on normal human physiological function. Eg: Lead, Mercury, Alcohol, Hexavalent Chromium, Acute Toxicity: Relatively short span of time. Chronic Toxicity: Is the result of repeated exposures over a relatively long period of time. Routes of Entry 1.Ingestion- Consuming through mouth 2. Inhalation- Respiration 3. Skin Absorption- Through Skin, 4. Injection- skin puncture, cuts Dosage: Is the amount of chemical administered per unit of body weight Lethal Dose (LD 50) = Is the dosage of a toxic chemical that can produce death of 50 % of the test animals. (Unit= mg/kg) Routes of entry: Ingestion, skin absorption, injection Lethal Concentration (LC 50)= Is the concentration of a toxic chemical in air that kills 50 % of the test animals (Unit = PPM) (mg/m3) Route of entry= Inhalation Target Organ Chemicals Hepatotoxins= Chemicals that affect liver Eg: Carbon Tetrachloride Neurotoxins= Chemicals that affect the Nervous System Eg: Lead, Reproductive Toxins Mutagens= Chemicals that cause permanent changes to DNA. Eg: Radioactive materials , Benzene, etc Teratogens= Chemicals that cause damages to a developing foetus and they cannot pass to future generations. Eg: Nicotine, Alcohol, Drugs Ototoxins = Chemicals that can affect the hearing /balance of ear. Eg: styrene, drugs- Antibiotics. Biological Hazards- Refer Yates- Learn about  Infection Type: Viral, bacterial etc..  Symptoms:  Transmission Methods; Cattle, rats Urine etc.  Target Organs: CNS, Lungs etc. Common Terms: 1. Brucellosis- Bacterial Infection Symptoms – Fever, joint pain Transmission- Through cattles. Unpasteurized milk- 2. Leptospirosis- It’s a zoonotic disease caused by bacteria Leptospira Transmission – Through cattle or rats urine Symptoms – Fever, joint pain 3. Tuberculosis- Bacterial infection that mostly affects the lungs. 4. Hepatitis A and B- Viral Infection- Basic ideas 5. Q fever- Bacterial Infection, zoonotic disease Primary reservoir of Q fever- Cattles, sheep and goats. Siderosis- Inhalation of metal fumes Eg; Magnesium, and Zinc during welding activities Byssinosis: Inhalation of Cotton dust: Lung issues Presbycusis: Age related hearing loss NIHL Biosafety Levels- 4 levels Level 1- involving minimal Potential hazard Level 2- Moderate potential hazards Level 3- serious and lethal diseases Level 4- Highest biosafety levels Biosafety cabinets- 3 classes Class 1= Minimal Protection Class 2 = Moderate Protection Class 3= Maximum Protection Is case of COVID 19- Level 4, class 3 Ventilation 2 types- Dilution ventilation and Local Exhaust ventilation Dilution vent- The fresh air is mixed with contaminated air in a quantity in which the resultant mixtures is less than the OEL. Local exhaust Ventilation- Remal of contaminated air from the source of generation. Q)What is the most important part of an LEV? Ans) Hood Design Q) In which situations are LEV’s recommended? Ans) Where the contaminants are generated in huge quantities Air changes per hour- 60 Q/V Q= Flow rate V= Volume NOISE Any unwanted sound is a noise. Noise levels- Decibels- dBA- Decibel A scale- Logarithmic scale As per OSHA- 90dB for 8 hours Noise Addition 68dbA + 55 dbA + 71 dbA +78 dbA + 79 dbA + 85 dbA + 66 dbA Noise Thump rule 1. If the difference is 0 to 1 , add 3dbA to the higher Value. 80dbA + 81dbA = 84dBA 2. If the diff is 2 to 3 , add 2 dbA to the higher value 90 dbA + 93dBA =95dBA 3. If the diff is 4 to 9 , add 1 dbA to the higher value 75dbA + 80 dBA= 81 dBA 4. If the difference is more than 10 , add 0 to the higher value 80 dbA + 91 dBA= 91dBA Example 68dbA + 55 dbA + 71 dbA +78 dbA + 79 dbA + 85 dbA + 66 dbA First thing to do is to arrange in Ascending order 55+ 66 + 68 + 71 + 78+ 79+ 85 66 + 68 + 71 + 78 + 79 + 85 70 + 71 + 78 + 79 + 85 74 + 78 + 79 + 85 79 + 79 + 85 82+ 85 87 dBA This will be an approximate answer. If you want to get the exact answer then use equation. Noise Addition Equation Q). Determine the total sound level for the following readings 80dbA, 85 dBA, 90 dBA? 10 log( 1080/10 + 1085/10 + 1090/10) = 91.5 dBA Noise Dosage Calculation Q) What is the noise dosage for a worker exposed for 85dba for 3.5hrs , 90 dbA for 1.5 hrs, 95 dBA for 2 hrs, 100 dbA for 1 hour? PEL= 85dba for 16 hrs 90dba for 8 hrs 95 dba for 4 hrs 100dbA for 2 hrs D= 100( 3.5/16 + 1.5/8 + 2/4 + ½) = 140.6% If the dosage is more than 100% then it is over exposure. OSHA std- 85 dBA for 16 hrs 90dBA for 8 hrs 95 dBA for 4 hrs 100 dBA for 2 hrs 105 dbA for 1 hrs 110 dba for 30 mins Permissible Noise Exposure Time Q) What is the allowable exposure time for a worker exposed to 93db in an 8 hr shift? Ans) 5.2 hrs Sound Attenuation – Inverse Square Law dB1 = dB0 + 20 Log10 (d0/d1) Where: dB0 = Known sound pressure level at the first location (typically measured data or equipment vendor data) dB1 = Unknown sound pressure level at the second location. d0 = Distance from the noise source to location of known sound pressure level d1 = Distance from noise source to the second location Q) If 100 dbA were measured at 10 feet from a noise source then how many decibels were measures at 50 feet? D0= 10feet D1= 50 feet dB1 = dB0 + 20 Log10 (d0/d1) Ans) 86.020 dB The Human Ear Outer ear= Middel ear= Inner ear= Oshas Hearing conservation program Required in 1. 8hr TWA sound level of 85 dbA 2. Dose of more than 50 % STS- Standard Threshold Shift= is a change in hearing threshold relative to the baseline audiogram if an average of 10 dbA or more for 2000 hz, 3000 hz and 4000 hz in either ear. STS is a recordable injury -OSHA 300log Radiation The energy or particle from a source which travels through space or other mediums Types of radiation 1. Ionizing- radiation that produces ionization in matter 2. Nonionizing – radiation that does not produce ionization in matter Ionizing radiation 1. Alpha rays Less penetrative Can be stopped by a paper Cannot penetrate through skin Eg: Radium Note: if alpha particles are inhaled or swallowed then it can damage sensitive living tissue. 2. Beta Particles More Penetrative than alpha Can be stopped by thin layer of substance such as aluminium Capable of penetrating skin Eg: Tritium. Strontuim 90 3. Gamma Rays More penetrative than alpha and beta Can damage DNA Requires denser materials such a lead Eg: selenium 75, cobalt 60 4. X rays Less penetrative than gamma rays Used in medical imaging. Alpha is having the least penetration and gamma is having the highest Nonionizing radiation- UV rays, InfraRed rays, radio frequency Q) which is the most dangerous radiation when inhaled? a. Alpha b. Beta c, Gamma d. All of the above Ans) Alpha. Which equipment is used to measure radiation? Dosimeter- worn by people Geiger Counter- detects and measure radiation  Units of Measurement Radioactivity- curie, becquerel Exposure- roentgen (R)- amount of radiation in air Dose- Seiverts(Sv) Radiation Distance Equation Q) An employee is working approx. 1 ft from a source measuring 148mrem/hr. What will be the dose rate at 3 ft? I1= 148mrem I2= ? D1= 1ft D2= 3ft I2= I1(D12/D22) I2= 16.44 mrem/h Which organization publishes cancer related substance information annually> IARC- International Agency for Research on Cancer ( Part of WHO) 1 feet = 12 inches Control Measure 1. Duration 2. Distance 3. Shielding NRC= Nuclear Regulatory Commission- regulates exposure to radioactive materials