TEMPEST - A Task Exposure Matrix for Pesticides

Construction of TEMPEST - Stage 7

Independent exposure estimation for each decade * task * pesticide combination by two occupational hygienists

Two occupational hygienists then independently assessed the task-pesticide combinations and assigned a score for the intensity of exposure to each. This was done for both inhalation and dermal exposure routes, for all tasks across the seven decades, using a five point scale (no exposure, very low, low, medium and high).

The hygienists based their exposure estimates on information about active ingredients, amount used per hectare, likely application technique and the probable use of personal protective equipment. This was informed by their knowledge of application practices used at that time. Exposure was allocated by each assessor according to the scales shown in tables 7a and 7b below. The tables include related workplace exposure limits (WEL) for inhalation and the equivalent for dermal exposure respectively.

Table 7a: Inhalation exposure estimation score categories and WEL Guidance for Airborne concentrations while performing a given task.

Assessment	Description	Label
0	No exposure	No exposure
1	0-5% WEL*	Very low
2	6-25% WEL*	Low
3	26-100% WEL*	Medium
4	>100% WEL*	High

* WEL – Workplace exposure limits published by HSE in EH40/2005 (ISBN 0717629775).

Table 7b: Dermal exposure estimation score categories and WEL guidance. Active ingredient skin loading (whole body) rate while performing a given task

Assessment	Description	Label
0	No exposure – also used when material does not have an Sk notation**	No exposure
1	>0-<1 mg/hr	Very low
2	1-10 mg/hr	Low
3	11-100 mg/hr	Medium
4	>100 mg/hr	High

**Sk notation – ‘…some substances have the ability to penetrate intact skin and become absorbed into the body, thus contributing to systemic toxicity; these substances are marked … with an ‘Sk’ notation’. Workplace exposure limits EH40/2005, page 43, HSE 2005.

The list of 17 pesticide usages (as in table three) were linked with one or more of the 81 tasks to yield 248 task/pesticide combinations in each of the seven decades, resulting in 1736 exposure assessment records in the TEMPEST database.

Once the data from the pesticide usage database was incorporated with these pesticide/task items there were a total of 846 task * pesticide * decade combinations where there was a probability of pesticide use, ie that was greater than 0%. Each of these then needed to be quantified (scored) for both dermal and inhalation exposure, resulting in a total number of 1692 exposure assessments being made by each assessor.

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