Chemical Hazards Chemist Edson Haddad 2016 Sao Paulo
ENVIRONMENTAL COMPANY OF SAO PAULO STATE – CETESB
REGIONAL CENTRE OF STOCKHOLM CONVENTION ON POPs FOR LATIN AMERICA AND THE CARIBBEAN REGION
V INTERNATIONAL TRAINING PROGRAM ON ENVIRONMENTAL SOUND MANAGEMENT ON CHEMICALS AND WASTES, ESPECIALLY ON PERSISTENT ORGANIC POLLUTANTS (POPs) AND MERCURY (Hg)
Chemical Hazards Chemist Edson Haddad
2016 Sao Paulo – SP – Brazil Safety with Chemicals • Chemicals can only be safely handled if their properties, reactions and behavior in different situations are fully known. • This knowledge allows for the selection of the appropriate PPE –Personal Protective Equipment, as well as the techniques to be employed for containment, control and environmental monitoring. Control Actions
9Neutralization, absorption, washing/dilution, soil recovery, monitoring, waste destination. I worked 20 years and had only one accident. CHEMICAL HAZARDS
COFFEE WATER OXYGEN
NO SUBSTANCE IS COMPLETELY FREE OF TOXIC EFFECTS TO THE BODY
12 POPs z PESTICIDES - Aldrin, dieldrin, chlordane, DDT, endrin, heptachlor, mirex, hexachlorobenzene and toxaphene; z INDUSTRIAL SUBSTANCES - PCBs (polychlorinated biphenyls) and HCB (hexachlorobenzene); z NON-INTENTIONAL SUB PRODUCTS – hexachlorobenzene; polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), and PCBs.
aldrin DDT
mirex
PCB Dioxins and furans 9 POPs
• PESTICIDES - chlordecone, alpha hexachlorocyclohexane, beta hexachlorocyclohexane, lindane, pentachlorobenzene; •INDUSTRIAL SUBSTANCES - hexabromobiphenyl, hexabromodiphenyl ether and heptabromodiphenyl ether, pentachlorobenzene, perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride, tetrabromodiphenyl ether and pentabromodiphenyl ether;
Chlordecone Lindane Pentachlorobenzene Rapid response to critical questions in a chemical emergency
• What is the chemical? • What specific dangers does it present?
• How can I control the risks? • How can I help the victims? • How to put out a fire? • Which personal protective equipment should I use? CHEMICAL HAZARDS Important Characteristics
• PHYSICAL STATE;
• COLOR (ALERT);
• ODOR (ALERT). CHEMICAL HAZARDS Important Properties • Physical properties – boiling temperature, fusion temperature, solid, liquid or vapor density, vapor pressure, solubility;
• Chemical properties – heat of combustion, flash point, chemical reactivity;
• Toxicological properties –LD50, LC50, IDLH, route of exposure, exposure limits. Important Characteristics • Physical State – POPs are solid but may be in the form of solution dissolved in solvents such as xylene or kerosene. Chemical Physical State Color Odor Aldrin Solid or solution Light brown to Mild (L) dark Odorless (S) chlordane Solid or solution Colorless to Aromatic acre, similar brown to chlorine DDT Solid or oily liquid Colorless Odorless crystals or off- white powder Polychlorinated Oily liquid Colorless to Mild aromatic biphenyls light yellow
Mercury Liquid Silver Odorless
Odor Limit: Kerosene = 1 ppm, Xylene = 0.05 ppm PHYSICAL PHENOMENA ‐ Changes in states of matter
fusion boiling
SOLID LIQUID GAS
solidification condensation
sublimation resublimation Boiling Temperature (ºC) • This is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure. At that temperature, the entire liquid changes to the gas state. • Substances with low boiling temperature have a high vapor pressure. These are known as volatile substances. • Boiling temperature of water = 100ºC.
• Liquids with high teb tend to contaminate by absorption. Low teb tend to contaminate by inhalation.
All POPs have a boiling temperature above 300 °C or decompose before boiling. o Mercury Teb is 357 C. Melting Temperature (ºC)
• It is the temperature for which a solid changes to the liquid state. • The higher the melting temperature, the lower must be the risk of a substance, since the mobility of the material is lower. • Water melting temperature = 0ºC. • Liquids and solids can present completely different risks (inert and reactive). The vast majority of POPs have a melting temperature exceeding 100 °C . Vapor Pressure • It is the pressure exerted by the vapors above the liquid level; • It represents the tendency of a liquid or solid to produce vapors; • Depends on temperature; • The higher the temperature, the higher the vapor pressure. Expressed in mmHg; • 760 mmHg is the maximum pressure at sea level. Vapor Pressure Temperature Water Ethyl alcohol Benzene (oC) (mmHg) (mmHg) (mmHg) -10 2.1 5.6 15
0 4.6 12.2 27
10 9.2 23.6 45
20 17.5 43.9 74
50 92.5 222.2 271
75 289.1 666.1 643
100 760.0 1693.3 1360
Vapor Pressure (mmHg) Water Benzene PCB DDT Toxaphene
17.5 at 20 ºC 74.0 at 20 ºC < 1.0.10-4 at 20 ºC 1.9.10-7 at 20 ºC 0.05 at 113 ºC
Kerosene Xylene Mercury
2.1 at 21 ºC 10 at 28 ºC 0.002 at 25 ºC 1.0 at 126.2 ºC
The vast majority of POPs have a vapor pressure below 1.10-4 mmHg at room temperature. They have low volatility. Density/Relative Density of Liquids
• Density is the ratio between the weight of a substance and the volume it occupies. D = m / v For water the density is 1 g/mL or 1,000 kg/m3
• Relative Density is the ratio between the weight of a liquid and the weight of an equivalent volume of water. It indicates how many times the substance is lighter or heavier than water. It is dimensionless. Relative Density of Liquids
d = mass / volume
Xylene = 0.84 Water = 1.0
Water = 1.0 PCB = 1.3 to 1.8
All POPs have a liquid density higher than water Liquid Density Chemical Density (g/mL) Aldrin 1.6 (20 ºC) PCB 1.3 to 1.8 (20 ºC) Chlordane 1.6 (25 ºC) Endrin 1.6 (20 ºC) Kerosene 0.8 (15 ºC) Toxaphene 1.6 (20 ºC) Xylene 0.86 (20 ºC) Mercury 13.55 (20 ºC) Density/Relative Density of Gases and Vapors
Density It is the ratio between the weight of a gas and the volume it occupies at atmospheric pressure and 0 ºC. It is expressed in g / L. Air density is 1.29 g/L.
Relative Density The relative density is in relation to the air, so it has no units. For a substance, it indicates how many times it is lighter or heavier than the same weight of air. Relative Density of Gases
Gas Relative Density (air = 1) Hydrogen Chloride 1.30 Phosgene 3.40 Chlorine 2.46 Sulfur dioxide 2.22 Hydrogen 0.07 Propane 1.52
Vapor Density The few POPs vapors are, in theory, heavier than air and therefore remain in low areas with risk of intoxication or combustion.
Only hydrogen, methane, acetylene and ethylene have vapor density lower than air.
All gases and vapors, after an appropriate time, mix with the air, regardless of the density or relative density. Water Solubility • It is the ability of a substance to dissolve in or mix with water. The solubility increases with temperature. Units: g of product/L of water or per 100 mL of water. • Important data to predict the behavior of a substance. Solubility is useful to evaluate: • Toxicity – Water-soluble chemicals can be more easily removed from the skin.
• Dispersion in water –Determining the impact and helps define removal techniques.
• Gas/vapor knock down– The efficiency of knock down procedure on a cloud.
• Extinguishing agent – Water cools the chemical and reduces its flash point. Water solubility Description Solubility (g/100 mL of water Soluble for all >>at 100 25o C) Veryproportions soluble > 50 Soluble 10 to 50 Moderately soluble 1 to 50 Slightly soluble 0.1 to 1 Insoluble < 0.1
Chemical Water Solubility Octanol/Water mg/L Partition Coefficient
Log kow
Aldrin 0.08 5.8 Chlordane 0.2 5.1 DDT 0.0028 6.0 Mirex 0.05 6.4
Mercury insoluble 5.0
POPs have low water solubility. They tend to accumulate in the sediment. Octanol/Water Partition Coefficient - Log kow
The coefficient informs the potential of a chemical agent to accumulate in animal fat by measuring your equilibrium distribution between octanol and water. 232 It is thus a way of evaluating the miscibility of a substance across the hydrophilic solvent (water) and lipophilic (oil or fat). Octanol/Water Partition Coefficient - Kow KOW = Coctanol / Cwater This coefficient numerically represents how much a liquid substance is distributed in a mix half oil and half water to a certain temperature and pressure.
The higher the Kow the greater will be the solubility in oils, and less in water. As the change in solubility of the substances is very large, a logarithmic scale is used to facilitate their interpretation.
Chemical Log KOW Interpretation Hexane 3.9 about 8,000 times more soluble in octanol than in water Butanol 0.88 about 7,500 times more soluble in octanol than in water Acetone - 0.24 about 2 times more soluble in octanol than in water
Flammable Liquids These are liquids, blends of liquids, or liquids containing suspended or dissolved solids that produce flammable vapors at a temperature of up to 60.5ºC in closed vessel tests, or up to 65.6ºC in open vessel tests, in compliance with the Brazilian standards or other internationally recognized standards. Example: Kerosene, Xylene, Styrene, Solvents
• FLASH POINT; • FLAMMABLE LIMITS. ¾ FLASH POINT: The lowest temperature at which a flammable or combustible substance releases enough vapor so that the mixture of vapor and air immediately above its surface can propagate a flame started by an ignition source.
Flammable liquids - flash point below 60.5ºC (closed vessel). Flammable Liquids 25 ºC 25 ºC
Flash point 15 ºC Flash point 30 ºC
SOURCE: FUNDACENTRO Chemical F.P.(ºC) Gasoline...... - 38 to - 45 Acetone...... - 20 Ethyl Alcohol...... 13 Xylene……...... 28 Kerosene...... > 37.8 PCB...... > 141.2 Hexachlorobenzene ...... 242 Flammable Limits
P + O2 CO2 + H2O No CombustionCombustion No Combustion
Lean Mixture Combustion Occurs Rich Misture 0% LFL UFL 100% Xylene 1,1 7 % in volume Kerosene 0,7 5 % in volume
LFL – The lowest concentration of a gas or a vapor in air capable of producing a flash of fire in presence of an ignition source (arc, flame, heat). UFL – The highest concentration of a gas or a vapor in air capable of producing a flash of fire in presence of an ignition source (arc, flame, heat). Practical considerations: • Permanent monitoring. • Elimination of ignition sources. • Grounding for transference. Flammable Limits Permanent Monitoring Flammable and Toxic Gases or Vapors Fire involving POPs • Can generate toxic gases/vapors according to the chemical nature. • Can generate hydrogen chloride (HCl) and phosgene (COCl2).
Pentachlorobenzene Characteristics of Gases
• The most dangerous state. • High mobility. • Additional hazard. • Color and odor. • Density. • Confined areas. Monitoring of Toxic Substances
• For acute exposures, the reference TOXICis the IDLH (30 minutes of exposure for irreversible effects). Chemical IDLH (ppm) Hydrogen Chloride 50 Ammonia 300 Benzene 2000 Phosgene 2 Carbon Monoxide 1500 Toxaphene 200 mg/m3 m – Xylene 900 Mercury 10 mg/m3 Effects of hydrogen chloride inhalation
Concentration in air Symptoms (ppm) 1 – 5 Odor perception 5 – 10 Mucous membranes irritation 35 Throat irritation for short exposure 50 – 100 Little tolerable 100 IDLH 1000 Risk of pulmonary edema and respiratory failure after short exposure
Center of Assistance and Toxicological Information Chemical is not synonymous with death!!!
We must be prepared for the worst • EDSON HADDAD • Emergency Response Sector • Phone: 55 11 3133 3795 • 24 h-Phone: 11 3133 4000 or 0800 113560 • e-mail: [email protected]
Thanks for your attention!!!