66863-Chptr4PrblmSolns

7/29/2019 66863-Chptr4PrblmSolns

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4.1 4.10 The solutions for these problems are the solutions for problems 4.1 - 4.10 inthe 2nd edition Solutions Manual.

4.11 a.

( ) 3-101.05rems8,000deathcancer1yr70

yrrem0.12riskDenver =

=

( ) 3-100.35rems8,000

deathcancer1yr70

yr

rem0.04risklevelSea =

=

b. Denver deaths due to cosmic radiation exposure:( )

yrdeaths8.6

rems000,8

death1people1057.0

yrperson

rem12.0 6 =

( )yr

deaths1,077people000,100

yrdeaths189

people100.57Expected 6 =

=

c.

( )

==

rems8,000

deathcancer1yrN

yrrem0.04-0.1210risklIncrementa 6-

months)2suggests4.3(Tableyr0.10.08

108,000N-6

==

d.

( )yr

deaths1,500rems000,8

deathcancer1

yrperson

rem0.04people10300 6 =


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4.12 Radon exposure of 1.5 piC/L equivalent to 400 mrem/yr (0.4 rem/yr):

a.

( )yr

deaths15,000people10300rems8,000

deathcancer1

yrperson

rem4.0 6 =

b.

lifetimedeathcancer103.5

lifetime

yr70

rems8,000

deathcancer1

yr

rem0.4Risk 3-=

=


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4.13-4.14 The solutions for these problems are the solutions for problems 4.13 - 4.14in the 2nd edition Solutions Manual.

4.15 Data is taken from Tables 4.9 and 4.10

a.( )( )( )

( )( )( )( )durationfreqrateintakePFyrd365lifespanbody wtrisk

conc=

( )( )34-

32-

6-

mg/m104.93

life

yr25

yr

d250

d

m20

mg

dkg102.9

yr

d365

life

yr70kg7010

=

=

b.( )( )( )

( )( )( )( )durationconcrateintakePFyr

d365lifespanbody wtriskfreq

=

( )( )d/yr52

life

yr25

m

mg104.93

d

m20

mg

dkg102.9

yr

d365

life

yr70kg7010

3

4-32-

7-

=

=


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4.16 a. Use Table 4.11 oral RfDs and Table 4.10 for other factorsHItotal =HIarsenic +HImethylene chloride

3.5mg0.060

dkg

L

mg0.560

mg0.0003

dkg

L

mg0.070

kg70d

L1HI =

+

=

b. No, this is not a safe level, since the HI >1.

c. Use Table 4.9 for PFs and Table 4.10 for other factorsrisk =riskarsenic +riskmethylene chloride

( )

+

=L

mg0.560

mg

dkg0075.0

L

mg0.0700

mg

dkg75.1

yr

d365

life

yr70kg70

life

yr10

yr

d250

d

L1

risk

-4101.8risk = Since this risk is 10-6, it would probably not be consideredacceptable


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4.17 a.

( )

5-

3

3

107

yr

d365

life

yr70kg70

life

yr25

yr

d250

d

m20

m

mg0.00002

mg

dkg50

risk =

=

b. ( ) ( ) workers15107workers220,000 -5 =

c. The 2006 U.S. cancer rate of 24% taken from text in Section 4.2 is the sameas the 1992 rate given in Table 4.1

( )( ) workers52,815workers1524.0workers000,220 =+

d. From Table 4.11 RfDs for both arsenic and mercury are 0.0003 mg/kgd

( )0.11

m

mg0.0001

m

mg0.00002

kg70dkg

mg0.0003

d

m20

HI33

3

=

+

=

Since the HI is less than 1 the non-cancer hazard is acceptable, despitethere being a cancer risk greater than 10-6.


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4.18 4.26The solutions for these problems are the solutions for problems 4.15 - 4.23 inthe 2nd edition Solutions Manual.

4.27 260 million people, 2L/day, 360d/yr, 30yr, find risk and incremental cancers for,

a.trichloroethylene at 0.005 mg/L:

Risk =CDI x Potency

Risk =2L/d x 0.005 mg/L x 360 d/yr x 30 yr

70 kg x 365 d/yr x 70 yrx

1.1x10-2

mg/kg- d= 6.6x107

cancer =260x106 people x 6.6x10-7cancer/ person life

70 yr/lifetime= 2.5 cancer/yr

b. benzene at 0.005 mg/L:



2.9x10-2

mg/kg- d= 1.75x106


70 yr/lifetime= 6.5 cancer/yr

c. arsenic at 0.01 mg/L:

cancer/yr785eyr/lifetim70

lifeperson/cancer2.11x10xpeople260x10

=cancer

10x11.2d-mg/kg

1.75x

yr70d/yr x365xkg70

yr30d/yr x360xmg/L0.01x2L/dRisk

4-6

4

=

==

d. carbon tetrachloride at 0.005 mg/L:



0.13

mg/kg-d= 7.9x106


70 yr/lifetime= 29 cancer/yr

e. vinyl chloride at 0.002 mg/L:



2.3

mg/kg-d= 5.6x105


70 yr/lifetime= 206 cancer/yr


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f. PCBs at 0.0005 mg/L:



7.7

mg/kg- d= 4.6x105

cancer = 260x106 people x 4.6x10-5cancer/ person life

70 yr/lifetime=172 cancer/yr

4.28 4.33The solutions for these problems are the solutions for problems 4.25 - 4.30 inthe 2nd edition Solutions Manual.

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66863-Chptr4PrblmSolns