Toxicology 

1.  Go to the EPA website and find the IRIS (Integrated Risk Information System) database. Use the “Browse A to Z List of Chemicals” or the “Search IRIS” to find information for your compounds*. Click on the compound, and then open the PDF Summary document. Fill out the following tables, showing the following information for the compounds listed below.  If no data exist, enter “n/a”.

a)  Oral RfD.  List the RfD with units (usually mg/kg-d), the type of data (eg., NOAEL, LOAEL, BMD, BMDL, etc) that the RfD is based on and its value with units, the toxic effect (health effect), how the Uncertainty Factor (UF) was computed (detail each factor of 10), and the confidence in the RfD.

b)  Inhalation RfC.  List the RfC with units (usually ug/m3), the type of data (eg., NOAEL, LOAEL, BMD, BMDL, etc) that the RfC is based on and its value with units, the toxic effect (health effect), how the Uncertainty Factor (UF) was computed, and the confidence in the RfC.

c) Carcinogenic Slope Factor - oral.  List the SF with units (usually 1/(mg/kg-d)), the weight of evidence of carcinogenicity (A, B1, B2, etc), the toxic effect (type of cancer), and the extrapolation method used.

d)  Carcinogenic Slope Factor - inhalation.  List the SF with units (usually 1/(ug/m3)), the weight of evidence of carcinogenicity (A, B1, B2, etc), the toxic effect (type of cancer), and the extrapolation method used.

e) Discuss the relative toxicities of these 7 compounds (to one another) as: (1) noncarcinogens, (2) carcinogens, and (3) identify which compound you believe to be the most toxic overall.

*Compounds: acetone, arsenic (inorganic), 1,3-butadiene, cyclohexane, methyl ethyl ketone, 2,4,6-trinitrotoluene, and Heptachlor. The first line is done as an example. Note: Some may not have data; if that is the case, write n/a.

Discuss the relative toxicities of these 7 compounds to one another as: 

• Noncarcinogens

• Carcinogens

• Which do you think overall is the most toxic?

2.  Text problems, Ch5:  1,3,7,13,16,22,23,25,27,28,29,30.