What risks do these pollutants pose to us? To determine this we need to understand the following

Risk = Exposure x Harm Risk – Possibility of suffering from a hazard that causes harm, disease, economic, or environmental loss Risk assessment – Identifying hazards – Determine probability – Assess severity Risk Management – Determine seriousness – How can it be reduced? – How much should we spend? Probability – Likelihood that an event or effect will occur

Types of Risks Cultural Physical Biological Chemical

Biological Hazards Non-transmissible – Not spread through living organisms – Cannot be spread between contact – Examples Asthma Heart disease cancer Transmissible – Can be spread through living organisms – Examples AIDS Malaria STD

Viral Diseases – Ability to adapt and evolve – influenza = largest threat because it is airborne and highly contagious Sexually Transmitted Diseases – 23% of Americans have an STD and don’t know it

Biological Risks Cause Disease: Chronic Disease: – slowly impair body function – Cancers, diabetes, heart disease, obesity Acute Disease: – Rapid onset – Ebola, flu Infectious Disease: – Caused by pathogens – STDs, flu, cold, viruses, protist infections, fungi

2011 Data

Various Biological Risks Will be filled in via class powerpoint slides

Toxicology: The study of chemical risk Toxicity: measure of harmfulness ChemicalsSourcesImpact NeurotoxinsLead, mercuryDisrupt nervous system, paralysis, impaired learning CarcinogensAsbestos, radon, tobacco, PCBs, formaldehyde Cause cancer and cell damage TeratogenThalidomide, alcohol, heavy metals Impair fetal development Birth defects AllergensPenicillin, codeine, danderTrigger immune response Endocrine disruptors Pharmaceuticals, atrazine herbicide, DDT, insecticides, phthalates in cosmetics and plastics Impair hormone functions Decrease sperm count Gender benders

Toxicology: the study of toxins Toxicity – measurement of how harmful a substance is Dose – Amount of a substance that is absorbed, inhaled, ingested What impacts the effect of a toxin? – Size of dose over given time – Who is exposed to dose Genetic makeup Body detox system

Factors that impact dose: Solubility – Water soluble Acids, salts – Oil / fat soluble Pesticides, PCBs, mercury, metals Persistence – Ability to withstand breakdown – Persistent Organic Pollutants Pharmaceutical medicines pesticides Bioaccumulation – Molecules are absorbed and stored in organs and tissues of single organism Biomagnification – Toxins increase as they move through food chain DDT

Various Chemicals that cause long term harm (poisoning) Will be addressed in class PowerPoints

5. Chemical Interactions Antagonistic: Decrease in harm when mixed – Chemicals to prevent anticoagulation – Dimercaprol: treats arsenic, mercury, lead poisoning – Bretylium: adrenaline blocker – Prozac: blocks 5HT receptors Synergistic: Combined effect increases harm more than either by themselves – Asbestos + smoking – Smoking and birth control

Response to Toxins Chronic Effect – Permanent and long lasting Radium Girls Smoking Lead or mercury poison Acute effect – Immediate harmful reaction Overdose to drugs Running leads to increased heart rate Response = type and amount of health damage due to exposure

QUESTION: Because there is variation within a population. When we are using risk management, who should we protect? The most sensitive or the average?

Toxicity

Lethal Dose LD 50 – Lethal dose Amount of chemical needed for 50% of the population of animals in test population to die within 14 days. LC 50 – Lethal concentration Concentration needed to cause death to 50% within 14 days. Poison – Chemical with an LD 50 of 50mg or less per kg body weight Percentage of population killed by a given dose Dose (hypothetical units) LD 50

DOSE RESPONSE CURVES Graphs that show the effects of various dosages of a toxin on a group of test organisms.

Nonthreshold dose response Any dosage causes harm with an increase in dose.

Threshold Dose Response A threshold must be met before detectable harmful effect Medicines Water