13 risk assessment

Question 1

what is risk assessment?

Answer 1

is there or was there a problem?
do we need to do anything about it?
-chemical releases
-contaminated sites
-chemical regulation

Question 2

what is the graph of risk assessment framework?

Answer 2

Question 3

what is risk assessment retrospectively?

Answer 3

-existing chemicals and contaminated sites
-how much of the chemical is there
-how much chemical would cause adverse effects
-are adverse effects actually occurring
-could the chemical plausibly by causing the adverse effects
-what is the degree of damage caused by the chemical

Question 4

what is risk assessment prospectively?

Answer 4

-before we use the chemical. Pre-registration
-what are the concentrations likely to be
-what concentrations cause adverse effects
-are adverse effects likely to occur
-can we mitigate the possibility of adverse effects
-if no, do not register chemical for use

Question 5

how do you get exposed to chemicals?

Answer 5

-everyday life
-workplace exposures
-contaminated site exposures

-short-term exposures
-long-term exposures
-repeated exposures

Question 6

how do we characterize a risk?

Answer 6

Question 7

Question 8

what is problem formulation (site conceptual model)?

Answer 8

site conceptual models can be relatively simple

Question 9

what is the graph of a complicated site conceptual model?

Answer 9

Question 10

what are generalizations of metals?

Answer 10

-metals like lead, cadmium copper
-metals tend to be water soluble
-metals tend NOT to biomagnify (except mercury)
-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 11

what are generalizations of non-polar organics?

Answer 11

-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 12

what are generalizations about polar organics?

Answer 12

-like endocrine disruptors, biphenol A (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 13

what are common exposure pathways graph?

Answer 13

Question 14

what are exposure routes (all animals and people)?

Answer 14

-inhalation
-ingestion (food and water)
-dermal

Question 15

what is dermal absorption?

Answer 15

-can play an important role in affecting toxicity
-DDT is more readily absorbed across the skeletal chitin of insects than the skin of humans
-can be species dependent

Question 16

what is the wildlife exposure factors handbook?

Answer 16

-US-EPA compilation of data for ‘model’ species (34 spp.)
-provides a complete data set for each organism
-range of organisms that represents most wildlife of concern
-can extrapolate factors to your animal of choice by comparing to similar species
-‘allometric scaling’ can adjust for size

Question 17

what are the characteristics of selective models?

Answer 17

Question 18

what are wildlife questions?

Answer 18

Question 19

what is environmental exposure?

Answer 19

-using this information we can calculate intakes for organisms
-we can assess which are the major routes of exposure
-we can ‘model’ concentrations
-need to be very careful of ‘uncertainty’

Question 20

what is the human average daily intakes?

Answer 20

-air: 11,000L (388 cubic feet)
-water: 3L men, 2.3L women
-food:???

Question 21

what is the average nutritional intake of humans?

Answer 21

Question 22

what is human ingestion exposure?

Answer 22

-different people eat different things
-conduct “market Basket” surveys
-different populations can be exposed differentially depending on their diet
-for example consumers of diets high in ‘fatty’ foods such as meat and dairt products may be more highly exposed to non-polar organics such as dioxins and PCBs that biomagnify thru the food chain and accumulate in fat

Question 23

what is an exposure scenario?

Answer 23

-an exposure scenario generally includes facts, data, assumptions, influences 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
-ex: ingestion of contaminated soil and dust in and around the home: young children aged 1 to <6 years

Question 24

what are exposure scenarios in children?

Answer 24

-children are different
-children are smaller
-undergoing critical development
-they eat more: growing faster
-children eat dirt