Post-Application (Re-entry) Exposure
Determining post-application (re-entry) exposure to individuals who enter a pesticide-treated turf area involves two components: the generic relationship between exposure and transferable turf residues (TTR) and product-specific TTRs. The relationship between exposure and TTR is generic because the amount of residue that dislodges from the turf and deposits on clothing, skin or cloth used in measuring TTR is proportional and dependent upon the degree of contact with the turf rather than the active ingredient in the pesticide product.
The ORETF quantified this relationship between exposure and TTR. ORETF member companies have conducted the required TTR study for their products when applied to turf as per the product label. By knowing the product-specific TTR and the generic relationship between exposure and TTR, the product-specific exposure can be calculated. This is then combined with product-specific toxicological data for the risk assessment.
Prior to the formation of the ORETF, the relationship between exposure and transferable turf residues was determined by monitoring the amount of residue that contacted the clothing and skin of individuals who performed a standardized 20-minute Jazzercise® routine on pesticide-treated turf. The Jazzercise® routine was designed to provide an upper-bound estimate of dermal exposure from contact with turf. Concurrently, transferable residues were determined by using one of a variety of techniques for determining TTR. The relationship between exposure from the Jazzercise® routine and TTR was then calculated.
This approach was often criticized. The Jazzercise® routine did not in any way simulate the actual activities that individuals perform on turf. There was no single, standard technique for measuring TTR. The ORETF addressed these criticisms by developing a standardized method for measuring TTR, which is described in the section labeled “Transferable Turf Residue (TTR) Methodology”. The ORETF complemented the Jazzercise® routine with a new Children’s Activity Patterns (CHAPS) routine that more closely resembles children’s activities on turf.