Q 3: Chemical exposure

Question 1

Generalizations-Metals

Answer 1

.Metals like lead, cadmium copper

.Metals tend to be water soluble

.Metals tend NOT to biomagnify

.Uptake directly from water most significant for aquatic organisms

.Uptake from food for non-aquatic organisms

.Organo-metals behave more like organic compounds
-methylmercury

Question 2

Generalizations: Non-polar-Organics

Answer 2

Like DDT and other organochlorines

.Poorly water soluble

.Accumulate in fat – lipophilic

.Bind to soils and sediments and move with them

.Persistent and so get long range transport

.High degree of biomagnification

.Food ingestion is major route of exposure

Question 3

Generalizations: Polar Organics

Answer 3

.Like endocrine disruptors, BPA

.Charged = make molecules more water soluble

.Generally NOT persistent

.“Pseudo-persistent” due to constant inputs

.Water and product contact main exposures

.Generally do NOT biomagnify

Question 4

Dermal Absorption

Answer 4

.plays an important role in affecting toxicity

.DDT is more readily absorbed across the skeletal chitin of insects than the skin of humans

Question 5

Exposure Routes- all animals

Answer 5

Inhalation

Ingestion- food and water

Dermal

Exposure(medium) = Concentration(m) * Amount(m) * Efficiency

Total Exposure = sum of all pathways

Question 6

Do Metals generally Biomagnify?

Answer 6

NOOOO

Question 7

2 Key phases of a risk assessment

Answer 7

1. Characterization of exposure

2. Characterization of ecological affects

Question 8

Non-polar-organics accumulate in ____. They Bind to ____ and ______ and move with them.

Answer 8

fat(lipophilic)

soils and sediments

Question 9

Non-Polar Organics have a ____ degree of biomagnification

Peristent?

Answer 9

high

YES

Question 10

Polar Organics:

persistent?

Biomagnify?

Answer 10

NOO

NOO

Question 11

How much air does a hawk breath ?

How much water does a mink drink ?

What is the surface area of a vole ?

Answer 11

How much air does a hawk breath ?
F = 0.48 m3/day M = 0.42 m3/day
How much water does a mink drink ?
F= 0.11 g/g/day M= 0.099 g/g/day
What is the surface area of a vole ?
Prairie vole= 139cm2
Meadow vole M=161cm2, F= 143cm2

Question 12

Wildlife Exposure Factors Handbook=

EX:

How much air does a hawk breath ?

How much water does a mink drink ?

What is the surface area of a vole ?

Answer 12

.US-EPA compilation of data for ‘model’ species (34 spp)

.Provides a complete data set for each organisms

.Range of Organisms that represents most wildlife of concern

.Can extrapolate factors to your animal of choice by comparing to similar species

Question 13

Human Exposure Factors Handbook=

Human Average daily intakes:

Air –
Water – men; women

Food -

Answer 13

Air – 11,000 L (388 cubic feet)
Water – 3 L men; 2.3 L women

Food - Everyone eats different things so no way to know

Question 14

Quantity of Energy used per day:

Answer 14

8,700 kilojoules

Question 15

An Exposure Scenario and Ex

Answer 15

An exposure scenario generally includes facts, data, assumptions, inferences, and sometimes professional judgment about how the exposure takes place.

An exposure scenario considers the physical setting, potential uses of a contaminated resource, the population that may be exposed (infant, child, or adolescent), fate and transport of contaminants, and how exposure may occur including ingestion, dermal contact, and inhalation.

e.g. Ingestion of Contaminated soil and dust in and around the home: Young children aged 1 to <6 years.

Question 16

Child-Specific Exposure Scenarios Examples

Answer 16

• Children are different
• Children are smaller
• Undergoing critical development
• They eat more – growing faster
• Children eat dirt !!