09.03 Toxicology

Human Health Dose Response Lab

As you complete each slide of this lab activity, please fill in theAP Environmental Science Human Health Dose Response Lab Write-upwith the appropriate information and data.

The purpose of this lab is to:

Before observing your trials of the Dose Response lab, review the following descriptions for each lab variable:

  • Dose:the amount of a substance that enters a body, usually reported in comparison to body mass
  • Response:the amount and type of damage caused by the exposure to a chemical substance

One of the methods that scientist can use to determine the toxicity of a chemical compound is anLD50test. This test involves introducing different dose levels of the chemical to be tested to a group of experimental subjects. By analyzing the LD 50 for a chemical compound and comparing it to other known samples, scientists get an accurate measurement of how dangerous the dose would be to a population. Look at the sample dose response curve below.

Consider the LD50 graph of Drug X above. If you were to draw a vertical line starting at 10mg/kg on the x-axis and ending on the graphed line and draw a horizontal line starting at 50% on the y-axis and ending on the graphed line, this would represent the LD50 of Drug X.

Before you begin, form a hypothesis for this experiment. Complete the predictions below and place it into your AP Environmental Science Lab Report:

Top of Form

Prediction 1:If we increase the dose of the chemical compound, the lethal response will______.

Prediction 2:If a different drug is tested and found to have an LD50 level of 5mg/kg, this drug will be______dangerous than Drug X?

Prediction 3:Rank the following compounds from 1 – 4 regarding which substance you predict would be the most lethal based on your current body mass, with 1 representing the highest LD50 and 4 representing the lowest LD50.

Nicotine
/
Alcohol
/ Sodium Chloride
(Table Salt)
/ Sucrose
(Table Sugar)

Bottom of Form

It’s time to analyze data for the toxic chemical compound,Sodium Cyanide. You will use the data to calculate theDeath Rate (%)and graph the results to determine the LD50 level. Place these values into the first data chart of your AP Environmental Science Lab Report and create agraphto display the dose and death rate (%) results.

Sodium Cyanide (Sample size = 190)

Dose / Number of Deaths / Death Rate (%)
1 / 8
2 / 16
3 / 30
4 / 48
5 / 68
6 / 89
7 / 119
8 / 140
9 / 173
10 / 190

What is the LD50 of sodium cyanide?

It’s time to analyze data for the toxic chemical compound,Arsenic. You will use the data to calculate the Death Rate (%) and graph the results to determine the LD50 level. Place these values into the second data chart of your AP Environmental Science Lab Report and created agraphto display the results.

Arsenic (Sample size = 210)

Dose / Number of Deaths / Death Rate (%)
2 / 2
4 / 6
6 / 11
8 / 22
10 / 41
12 / 72
14 / 131
16 / 198
18 / 210

What is the LD50 of arsenic?

It’s time to complete further research. The LD50 of several chemical substances, both toxic and non-toxic, are displayed in the table below. You will calculate the amount statistically required to have a 50% chance of death for each of the substances listed in the table. You will need to complete the following steps:

  • Record your mass in pounds
  • Convert your mass to kilograms by multiplying your mass in pounds X 0.45
  • Calculate your human lethal dose

Place these values into the third data chart of your AP Environmental Science Lab Report.

Substance / LD50 (mg/kg) / Lethal Human Dose (grams) = mass (kg) X LD50 (mg/kg) / 1000
Sucrose(Table sugar) / 29,700
Ethanol / 7,060
Sodium Chloride (Table salt) / 3,000
THC(found in cannabis) / 1,270 (males)730 (females)
Aspirin / 200
Caffeine / 192
Nicotine / 50
Arsenic / 14
Sodium Cyanide / 6.4
Venom of the Australian Inland Taipan snake / 0.025
VX Nerve Gas / 0.0023
Batrachotoxin(from Poison Dart frogs) / 0.002
Polonium-210(nuclear fission waste product) / 0.00001

Reflect on the following questions, and record your answers in the conclusion of your lab report:

  1. Why is LD50 data so useful in dealing with human health and environmental toxins?
  2. Why is there controversy and concern regarding the use of synthetic organic compounds?
  3. What is the dose-response concept, and how does it relate to LD-50 tolerance?
  4. What is the importance of the threshold effect of environmental toxins?
  5. What is the process of risk assessment in toxicology, and how can it be used to evaluate the risk to human health and life?
  6. What controversial issues can develop with the use of risk assessment?