Measuring Toxicity, Risk Assessment, and Public Policy

APES 2014

MEASURING TOXICITY Toxicity notes

LD 50 (lethal dose, 50%) 50% of the test subjects are sensitive

Do all species respond the same way? Is this really an accurate way to

document toxins?

MEASURING TOXICITY Oral LD50 of grain alcohol: 10.6 g/kg in young rats,

7.06 g/kg in aged rats. [4] Oral LD50 of nicotine: 50 mg/kg in rats. [5] Oral LD50 of Sodium chloride: 3000 mg/kg in rats

[6] LD50 of Tetrahydrocannabinol (active ingredient

found in Cannabis): 1270 mg/kg in rats. LD50 of batrachotoxin: estimated at 1 to 2 µg/kg in

humans. LD50 of Polonium 210: estimated at 10 (inhaled) to

50 (ingested) nanograms in humans makes this one of the most toxic substances known. One gram in theory could poison 100 million people of which 50 million would die.

MEASURING TOXICITY Moderate toxins

1g/kg body weight is lethal

Very toxic 1cg/kg body weight is lethal

Supertoxic 1mg/kg body weight is lethal

Acute Effects vs. Chronic Effects Acute: effects are caused by exposure to a

single dose Chronic: effects develop slowly due to long-term

exposure to contaminants in water, food, or the environment

For example if a person drinks too much alcohol on a regular basis then their health may suffer as a result. The alcohol does not have a long biological half-life but it is supplied on a regular basis to the body of the person.

Coffee the killer Overall, caffeine is found in the beans,

leaves, and fruit of over 60 plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding upon them.

RISK ASSESSMENT

RISK

The probability that something harmful will happen

Which is riskier?vs.

Which is riskier?

How about here?

How about here?

Who is to decide what risk means to you?

Watch out for these traps:

Risk Assessment Traps

People with an agenda tend to downplay certain risks and bring others to the forefront to further their cause/agenda

Personal experience can be your own worst enemy. Just because something hasn’t kicked your butt yet doesn’t mean it WON’T or CANNOT.

Make sure you understand what the probabilities REALLY mean.

We judge ourselves to be better than we are at most things and that can get you into trouble.

I am lucky, I am wise, that won’t happen to me! We tend to fear new technology and grab onto familiar

stuff that is actually possibly worse for us.

WHAT MAKES RISK ACCEPTABLE?

A host of risky behaviors is less common in today’s high school students than in those 15 years earlier, according to a CDC report.

The CDC has a Youth Risk Behavior Surveillance Study Survey that is given every two years since 1991. In 2005 it included nearly 14,000 students nationwide in grades 9-12

The survey shows several major changes since 1991, including wearing seatbelts, riding with drivers who had been drinking alcohol, having sexual intercourse, carrying weapons, and using condoms.

RISKY BUSINESSPeople will take risks if the danger is low.

If the danger is high, folks are less likely to take risks.

Defining RISK is a personal thing

Enjoyment Profitability Known vs. unknown Amount of Control

we perceive How dangerous the

results are Emotions are more

important than stats

How do you establish public policy?

We assess the risk to the best of our ability

And then we manage the risk as best we can.

Standards for Environmental Toxins Combined effects Different tolerances/sensitivities Effects of chronic/acute dosages Reasonability of the regulations Cumulative effects of the soup of toxins

we are exposed to on a daily basis

READ CHAPTER 17