Hazardous Pollutants and Waste Management

Chapter 17 and 21

“All substances are poisons: there is none which is not a poison.  The right dose differentiates a poison and a remedy." Paracelsus (1493-1541)

Risk: probability of suffering harm from a hazard that can cause injury, disease, death or economic loss or damageRisk assessmentRisk management

Biological, chemical, natural, cultural and lifestyle hazards

Biological HazardsInfectious disease (flu, malaria, TB)Transmissible disease (measles, HIV)Nontransmissible disease (cancer, asthma,

diabetes, malnutrition)

Major concerns include flu, AIDS (HIV), Hepatitis B, malaria and emergent diseases (west nile, Ebola)

Eliminate through infectious disease prevention, education, vaccines, improving quality of life and decreasing malnutrition

Chemical HazardsToxic chemical: can cause temporary or permanent

harm or death to humans or animalsTop 5 include: arsenic, lead, mercury, vinyl chloride

(plastics) and PCBs

Carcinogen: promotes cancerArsenic, benzene, formaldehyde, gamma and UV radiation,

PCBs, radon, tobacco smoke, vinyl chloride

Mutagen: increases frequency of mutations

Teratogen: cause harm or birth defects to fetus/embryoAlcohol, benzene, formaldehyde, lead, mercury, PCBs,

phalates, thalidomide, vinyl chloride

Chemical Hazards

Neurotoxins (disrupt nervous system—brain, spinal cord)PCBs, arsenic, lead, pesticides, methylmercury

Endocrine disruptors (alter hormones and development)BPA, Aluminum, atrazine, DDT, PCBs, mercury,

pthalates

Immune system disruptors (limit immune response)Arsenic, methylmecury, dioxins

Evaluating Chemical HazardsToxicity: measure of the harmfulness of the

productDose: amount ingested, inhaled, or absorbedResponse: damage to health, may be acute or

chronic Depends on age, genetic makeup, solubility of

compound (water vs. oil) and persistence

Dose-response StudiesTests on animals with measure doses of chemicalPlot results of chemical tests to determine curve

and lethal doses

LD50

Lethal dose 50: Amount of chemical that kills 50% of a test population within 18 days. Varies depending on substanceDetermines if a new substance is more or less lethal

than other chemicals usedUsually tested on rats…then extrapolated to humans

Gives values for acute toxicity

Lower LD50 = More toxic

The Dirty DozenBPADioxinsPthalatesPCBsArsenicBenzeneFormaldehydeMercuryAsbestosLeadVinyl Chloride (PVC)Ethylene Glycol

*Go to http://toxtown.nlm.nih.gov/text_version/chemicals.php and click on “Chemicals” at the top of the page.

*Find your chemical on the list and answer the following questions…

1. Describe what the chemical is. What products/processes is it found in?

2. Where is the chemical located in the environment? How does it get there? How are humans exposed to it?

3. What are the health concerns?

Waste ManagementSolid waste: any unwanted or discarded

material we produce that is not a liquid or a gasIndustrial solid waste- produced by mines,

farms and industry (40%)Municipal solid waste (MSW)- produced by

homes and workplaces; ends up in landfills/incinerators (60%) Average 4.5 pounds per person per day!

Hazardous toxic waste- threatens human health because it is poisonous, chemically reactive, corrosive or flammable

WasteManaging waste refers

to controlling the environmental harm of waste, not decreasing its production

Reducing waste is concerned with producing less waste and pollution (prevention)

Recycling is reusing or repurposing materials instead of throwing them away

What do we throw away?Paper (31%)Food (13%)Yard waste (13%)Wood (7%)Rubber, Leather

and Clothing (8%)

Plastic (12%)Metal (8%)Glass (5%)Other (3%)

RecyclingImportance…

Decreases use of energy making products

Decreases waste and pollution (amount into landfills)

Increases jobsSaves $$$

Primary (closed-loop) recycling: materials recycled into new products of the same type (aluminum to aluminum)

Secondary (open-loop) recycling: waste materials converted into different products (plastic to clothing)

Burning and Burying Waste

Waste-to-Energy Incinerators (13%)Garbage and waste is burned, water is boiled and energy is

createdProduces high number of pollutants

Sanitary Landfills (54%)Waste buried underground in layers, alternating with clay,

plastic or foam; sides of landfill are lined to prevent leaching of chemicals; pipes to collect leaching liquid (prevent soil and water contamination)

Methane (byproduct of decomposition) is collected and burned for fuel

Concerns about chemicals leaking to groundwater (leachate)

Hazardous WastePriority in reducing waste

Most comes from industrial processes (textiles, computer manufacturing, dry cleaners, service stations)

Difficult to dispose of…responsibility is on company or homeowner

Can convert to non-hazardous substancesPhysical, chemical or biological methodsMust be treated before disposal

Stored foreverDeep well disposalSurface impoundmentsSteel Drums

LegislationResource Conservation and Recovery Act

Manages hazardous waste, “cradle-to-grave” tracking

CERCLA (Superfund Act)Identifies contaminated sitesEPA manages National Priorities List

Currently about 1200 sites Funding for clean-up is lacking

Brownfield: abandoned industrial and commercial sites, contaminated with hazardous waste