Chapter 19Hazardous and Toxic Materials in Our Environment

A. We are a chemical based society - by-products are often toxic and hazardous wastes.

•  1. Benefits versus Costs (impacts on ecological and human health).

•  2. Examples of hazardous materials impacts -– Dioxin in Times Beach Mo.

– PCB’s and other Toxic Materials at Love Canal

– Bhopal India - Union Carbide plant leak of isocyanate

– Pesticide spill in Rhine River

– Cyanide spill in the Romania

– Spill of MTBE in Lake Tawakani

– Mercury in Minamata Bay, Japan

Chapter 192. Definitions of Hazardous and Toxic Wastes• A. Hazardous substances are those that can cause harm to

humans or the environment• They are by-products of industry and business or household

activities-• Toxic substances are those that are poisonous to humans and the

environment.• 1. Characteristic of hazardous material

– A. Ignitability - pose fire hazard - gasoline, alcohol, paint thinner– B. Corrosiveness - corrode containers - strong acids and bases– C. Reactivity or Explosiveness - reacts spontaneously, unstable to shock,

reacts with water or air– To generate toxic gases or explode - gunpowder, nitroglycerin, some

plastics– D. Toxicity - releases toxicant - metals, some organic compounds – most

things in high enough concentrations

Chapter 192. U.S. Resource Conservation and Recovery Act (1976)

definition of hazardous waste—widely used• Wastes are toxic if they cause or significantly contribute to

an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of or otherwise managed.

• A. EPA has a list of hazardous wastes. Industry must test wastes for their hazardous nature using the four criteria. Shipping labels must specify the reason they are hazardous- Hazardous wastes must be disposed of in special ways. - hazardous waste land fill, incineration etc.

Chapter 19• Identifying Hazardous Materials

– Typically use lists of “known offenders”• Especially with regard to human health

– Many remain untested, effects unknown• International production of Hazardous Waste

– Estimated between 350-550 million tons per year– Developed nations produce 80-90%

Setting Exposure Limits - Risk Assessment• A. Threshold levels - No Observable Effect Levels in Animals

Test Results (NOEL) - Highest Test level where no effect was observed.

• B. Safety Factors - Fraction of NOEL to extrapolate to humans.– Variation by species and by country’s regulations

Chapter 19

5 - HEALTH HAZARD DATA  TOXICITY: LD50 (ORAL-RAT)(MG/KG) - 3000 CARCINOGENICITY: NTP: NO IARC: NO Z LIST: NO OSHA REG: NO  EFFECTS OF OVEREXPOSURE DUST MAY IRRITATE OR BURN MUCOUS MEMBRANES. DUST MAY IRRITATE EYES.  TARGET ORGANS NONE IDENTIFIED  MEDICAL CONDITIONS GENERALLY AGGRAVATED BY EXPOSURE NONE IDENTIFIED  ROUTES OF ENTRY> NONE INDICATED  EMERGENCY AND FIRST AID PROCEDURES INGESTION: IF SWALLOWED AND THE PERSON IS CONSCIOUS, IMMEDIATELY GIVE LARGE AMOUNTS OF WATER. GET MEDICAL ATTENTION. INHALATION: IF A PERSON BREATHES IN LARGE AMOUNTS, MOVE THE EXPOSED PERSON TO FRESH AIR. GET MEDICAL ATTENTION. EYE CONTACT: IMMEDIATELY FLUSH WITH PLENTY OF WATER FOR AT LEAST 15 MINUTES. GET MEDICAL ATTENTION. SKIN CONTACT: IMMEDIATELY WASH WITH PLENTY OF SOAP AND WATER FOR AT LEAST 15 MINUTES.

HEALTH - 1 SLIGHT FLAMMABILITY - 0 NONE REACTIVITY - 0 NONE CONTACT - 1 SLIGHT

Example of partial MSDS Sheet

Chapter 19 Endpoints for Assessing Toxicity• A. Acute Toxicity - short term high dose exposure - lethality is the

endpoint• B. Chronic Toxicity - long term low dose exposure - growth and

reproduction effects are common endpoints

• 5. Synergism, Antagonism, and Additivity of the toxicity of Chemicals

• A. Synergism - when two chemicals react to cause toxicity greater than their individual toxicities - example: smoking (and really everything) and mining

• B. Antagonism - when two chemicals react to be less toxic when together than when ether one is present alone. - water hardness and toxicity of Zinc and Copper

• C. Additivity - when exposure to two or more compounds results in toxicity equal to the sum of their individual toxicities. Most compounds have additivity

Chapter 19Persistent and Nonpersistent Pollutants

• A. Persistent chemicals are those that remain in the environment for many years unchanged. Most are Xenobiotics (man made chemicals) Examples DDT, PCB’s,dioxins,

• metals - lead, mercury, arsenic, cadmium - Their use must be carefully regulated.– Treated lumber-why doesn’t it rot?

• B. Nonpersistent pollutants are those that do not persist very long in the environment. Most are biodegradable by bacterial and fungi, break down in sunlight (process of photolysis), or disperse quickly.

Chapter 19Environmental Problems Caused by Hazardous Materials 

• A. Contamination of land• B. Contamination of Surface Water• C. Contamination of Ground Water - Serious Problem to

Solve—some cannot be solved– Many unintentional releases/incineration with very small

instantaneous concentrations can have combined effects--

Health Risks of Hazardous Wastes• 70,000 chemicals in daily use in U.S. - 1,000 new

chemicals each year.• Major concern is when used, stored or disposed of

improperly– T/F center of issue is proper use, storage and disposal

• Many unknowns, but what is known is cause for concern

Chapter 19The Toxic Release Inventory

• TRI is a listing by states of the amount of 332 toxic chemicals released each year– Only for industries etc with release greater than 50,000 lbs

• 4.4 billion lbs were released to the environment in 1998.

• Another 1.6 billion lbs went to municipal WWTPs, or private storage and treatment

• Industry released over 128 million kilograms of carcinogens in 1999

• Texas is number 1 in Toxic releases

Chapter 19Legacy of Abuse - Hazardous Waste Dumps

 

• A. Prior to 1976 disposal of hazardous wastes was basically unregulated. Country full of old hazardous waste dumps (25,000+). .

 

• B. Dumps were open pits many times in floodplains or wetlands. - Out of sight out of mind. Unlined, and spilled out into surface waters and contaminated ground water.

 

• C. Passage of Resource Conservation and Recovery Act of 1976 stopped most dumping of hazardous wastes.

Chapter 19D. Clean-up of the old hazardous waste sites was fostered by the

passage of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA -superfund).  

• 1. Set priorities for clean-up - National Priorities List - 2,500 sites at estimated clean up cost of $40 - 100 billion—opinions vary by agency– US Office of Tech Assessment—10,000 sites $100 billion– US General Accounting Office---4,000 sites $ 40 billion– US EPA------------------------------2,500 sites $ 30 billion

• 2. Made responsible parties pay• 3. $1.6 billion in funds to assist clean up• 4. Fostered research on clean up technologies• 5. Funded many lawyers and engineering companies

– Cheaper to litigate than clean up

Chapter 19Managing Hazardous Wastes Pollution Prevention Hierarchy (Best

solution is not to create Hazardous Waste)• A. Pollution Prevention• B. Waste Minimization• C. Recycling of Waste• D. Treatment of Waste• C. Disposal - incineration, deep well injection, treatment, store,

burial,

Hazardous Waste Management Choices• A. Land disposal - favored in U.S.• B. Incineration - favored in Japan and Europe - why?

Costs to industry should favor pollution prevention and waste minimization versus disposal—BUT can at same time encourage illicit disposal practices.