Download Elements of a Dietary Exposure assessment

APVMA Review of Fenthion
Dr Raj Bhula – Pesticides Program Manager
Dr Jason Lutze – Pesticides Residues Manager
18 Oct 2012
Agvet Chemical Management in Australia
APVMA
regulates veterinary
medicines and pesticides
up to the point of retail sale
State/Territory
Government Agencies
regulate actual use of all
chemicals
(control of use)
Work cooperatively to deliver the
National Registration Scheme
Legislative Criteria

Can only register or continue to allow registration
or use of a product if





is not an undue hazard to people (handling or exposed to
residues)
Would not be likely to have an effect that is harmful to
human beings
does not have an unintended harmful effect on plants,
animals or the environment
does not unduly prejudice trade
is shown to be effective
Criteria are defined in legislation (Agvet Code Act)
What is Fenthion?




An Organophosphorus insecticide used to control
insect pests
Mostly used for Medfly and QFF control and included
in Interstate Certification Assurances
Labels allow use on a wide range of fruits and
vegetables
Can be used in a home garden setting as well as for
commercial purposes
Chemical Review Process - Fenthion
Announced in 1994
Commenced in 1998
ARfD established
Commitment received from HAL for
data generation
Data submitted
Residues Dietary Risk report published
Consultation throughout review



APVMA consulted widely on likely outcomes of the
review since establishment of ARfD
Industry consultations commenced in 2006
Observer on Dimethoate and Fenthion Response
Coordination Committee (DFRCC)
Residues And Dietary Risk Assessment




A residues and dietary risk assessment is required
to set Maximum Residue Limits in food crops
Residues data provided to the review from chemical
manufacturer and HAL
Agree with FSANZ on dietary risk assessment
approach
Methods used are consistent with international
guidance
Dietary Exposure Assessment
Elements of a Dietary Exposure
assessment
- Health Standards

Established by Aus Govt Department of Health
–

Published the Human Health Assessment
–

Consistent with international guidance
Initial toxicology Report in December 2005 (revised with
OHS information 2012)
New health standards recommended for short-term
and long-term exposures (ARfD & ADI )
Elements of a Dietary Exposure
assessment
- Health Standards
Country
ADI (mg/kg bw/day)
ARfD (mg/kg bw)
EU
-
-
Canada (2003)
0.0001
0.002
US EPA 2001
0.00007
0.0007
WHO 2000
0.007
0.01
Australia
0.002 (2000)
0.007 (2004)
•
•
AUS standards higher than Canada and US
Based on human data, 10 fold safety factor
Elements of a Dietary Exposure
assessment
- Health Standards
Acute exposure – short term exposure (24 hour period)
to the chemical from residues in food, corresponding
to acute reference dose (ARfD)


food consumption data for various age groups and general
population
Each food type (eg apple, peach) considered separately
Chronic exposure – lifetime exposure to that chemical
from residues in food, corresponding to ADI (acceptable
daily intake)


food consumption data for general population
Consider all foods together
Elements of a Dietary Exposure
assessment
- Food Consumption Data
•
•
Provided by Food Standards Australia New Zealand
(FSANZ)
Adults (general population) - 1995 National Nutrition
Survey
•
•
Data from 13,858 Australians
Children - 2007 Australian National Children’s
Nutrition and Physical Activity Survey
•
Data from 4,487 Australian 2-16 year olds
How Large are High Consumer
Portions?

Children, 5 years (24 hours)
–
–
–
–



Apple –
Peach –
Grapes –
Tomato –
332 g (about 2)
305 g (about 2)
640 g (160 av sized)
about 1.3 or 10 small cherry toms
NOT based on average consumption
NOT based on consumption on more than 1
day
NOT based eating more than one fruit type in
a day
Elements of a Dietary Exposure
assessment
- Residue Data
•
Provided by registrant and industry (HAL)
•
Must address maximum use rate allowed on label
•
•
If it is allowed on the label, it can be done
Data was not available for all uses
•
e.g. pome, citrus
Dietary Exposure Assessment
Dietary Exposure Assessment

Once dietary exposure threshold is exceeded, uses
must be modified or removed
–

MRLs must be safe for consumers
Product labels varied and new instructions issued
Outcomes of September 2012 Report
Limit of safety
margin in ARfD
ARfD
Outcomes of September 2012 Report

Estimated exceedances above ARfD for children
(2 to 6 years) for various crops


grapes 5×; apples 9×; cherries 4×; peaches 10×;
nectarines 6×; cucumbers 12×; tomatoes 4×;
Below the ARfD and acceptable for



tropical fruit with inedible peel such as mango,
avocado, custard apple
Olive nursery stock
Melons, pre harvest peppers, post harvest chilli
peppers

Data requirement
Outcomes of September 2012 Report

How much would a 5 year old child need to eat
to exceed the health standard (ARfD)?
–
–
–
–
Apple –
Peach –
Grapes –
Tomato –
0.4 of an average size apple
0.4 of an average size peach
27 average size grapes
about 1.1 or <10 small cherry
toms
Results of chronic dietary exposure
assessment

At commencement of review
–
–
Chronic exposure > 17x the acceptable standard
Individual MRLs unacceptable
•

Citrus, stone fruit, pome fruit, grapes
Acceptable after implementation of report
recommendations
–
–
After removal of uses not supported on basis of acute
exposure
Will need to re-assess on basis of alternate uses
What Does This Mean?




This means that the new health standard, the
acute reference dose, provides a trigger for action
based on estimated dietary exposures for children
The margins of safety that are put in place to
protect consumers are inadequate
Some regulatory action is required to either
modify, restrict or remove uses
Other regulators internationally take action based
on dietary risk
What Does This Mean?



The data indicate that margins of safety are
inadequate for most uses
The MRLs for these uses represent an unacceptable
acute health risk
Take action via a proposed suspension and then
consider data gaps towards the end of the review
What Does Residue Monitoring Data Tell
Us?

National Residue Survey residue data





Exposure estimate is 9× over the acute reference dose
3 out of 1948 apples had fenthion residues
One of those samples had unacceptable residues
No treatment history
Limited monitoring data available



Data published by NSW ag covering all states (1998)
Very summarised and aggregated
A number of the samples had unacceptable residues
What Does Residue Monitoring Data Tell
Us?


Random monitoring data not very useful in acute /
short term dietary exposure analysis
Maximum residue scenario must be addressed



Random data:






Worst case is international convention
To adequately protect consumer health from acutely toxic pesticides
Not targeted – do not know if fruit was treated
May not have been treated at maximum legal rate
May not have been treated as often and legally allowed
May not have been harvested at minimum WHP
May be an extended period between harvest and sampling
More useful for chronic or long term dietary
exposure assessment
International Activity


Fenthion not registered for food producing uses
in EU, USA, Canada or NZ
No fenthion MRLs established in USA for plant
products
–



NIL tolerance for residues
All fenthion MRLs in EU at limit of quantitation
No fenthion MRLs in Canada
No fenthion MRLs in NZ
Next Steps


Propose to commence suspension in October
Will be further opportunity during the suspension
period to generate more data to support/modify
some uses
Are There Any Alternatives?



Some registered products for fruit fly control
Had only a few requests for permits for
alternative chemical options
Can provide priority assessments for permit
applications

Consolidated requests for permits encouraged

Website contains relevant permit information
Permits

Will be cancelled at time of suspension

Application needs to be made for reissue

APVMA NOT involved in ICA approvals
Thank you …
Questions please