Q 3: Chemical exposure Flashcards Preview

Y2 T1 Toxicology 200 > Q 3: Chemical exposure > Flashcards

Flashcards in Q 3: Chemical exposure Deck (16)
Loading flashcards...
1
Q

Generalizations-Metals

A

.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

2
Q

Generalizations: Non-polar-Organics

A

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

3
Q

Generalizations: Polar Organics

A

.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

4
Q

Dermal Absorption

A

.plays an important role in affecting toxicity

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

5
Q

Exposure Routes- all animals

A

Inhalation

Ingestion- food and water

Dermal

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

Total Exposure = sum of all pathways

6
Q

Do Metals generally Biomagnify?

A

NOOOO

7
Q

2 Key phases of a risk assessment

A
  1. Characterization of exposure

2. Characterization of ecological affects

8
Q

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

A

fat(lipophilic)

soils and sediments

9
Q

Non-Polar Organics have a ____ degree of biomagnification

Peristent?

A

high

YES

10
Q

Polar Organics:

persistent?

Biomagnify?

A

NOO

NOO

11
Q

How much air does a hawk breath ?

How much water does a mink drink ?

What is the surface area of a vole ?

A
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
12
Q

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 ?

A

.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

13
Q

Human Exposure Factors Handbook=

Human Average daily intakes:

Air –
Water – men; women

Food -

A

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

14
Q

Quantity of Energy used per day:

A

8,700 kilojoules

15
Q

An Exposure Scenario and Ex

A

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.

16
Q

Child-Specific Exposure Scenarios Examples

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