API PUBL 4733:2004 pdf download

API PUBL 4733:2004 pdf download.Risk-Based Screening Levels for the Protection of Livestock Exposed to Petroleum Hydrocarbons.
A Toxicity Reference Value TRV) is a daily dose of a chemical expressed in milligrams of chemical per kilogram of body weight of the livestock receptor per day (mgfkg-bw/day) and represents a concentration associated with an effect level or threshold. TRVs were developed for the protection of livestock at the population level (i.e., herd) of ecological organiiation and are generally doses at or below which no adverse health effects (e.g.. mortality. growth. and reproduction) to the indicator species are expected. even if exposure occurs over an extended duration. TRVs for livestock in this report were developed from the exposure assumptions in Table I and available toxicological data presented in Table 2.
Risk-Based Screening Levels (RHSLs) are threshold concentrations in site media (e.g. soil, water, and air) at or below little-to-no likelihood of significant unacceptable risks to livestock are expected. RBSLs were developed based on a food-web model integrating livestock exposures and TRVs. In this framework. livestock RBSLs were developed for complete and significant exposure pathways, which included drinking water RBSLs expressed in milligrams per liter (mgiL) and soil RBSLs expressed in milligrams per kilogram (mg/kg). The following sections describe the exposure and effects assessments used in this report to develop livestock TRVs and RBSLs for complete and potentially significant exposure pathways.
4.1 Exposure Assessment
As discu’.scd previously, the main csposurc pathways for cattle, sheep, goats. camels, horses, and other potential livestock receptors are incidental soil ingestion. water ingestion. and direct ingestion. Direct ingestion of chemicals is generally not addressed in a Ibod-web nnlel: however, this pathway should be assessed on a site-specific basis if considered potentially complete. Exposures are generally measured by estimating the intake rates for livestock in kilograms per day (kg/day) or liters per day (Liday) and cons erting them to doses.
Dose calculation models provide a method of conservatively estimating exposure through the food chain. To ensure conservatism in the overall exposure estimates. it is recommended that the lesser of either the 95% upper confidence limit (UCL) of the mean concentration or the maximum detected concentration in site media (i.e., soil and water) be selected to represent the exposure point concentration (EPC). As dose estimation through modeling generally requires conservative exposure assumptions. exposures measured through modeling tend to be overestimated when conipared with actual exposures. The equation used to calculate daily ingested petroleum hydrocarbon dose for livestock was as follows:
4.2 Exposure Assumptions
The following sections describe the input parameters used in the dose model (Equation I) above.
Eposurc assumptions used in the development of TRVs and RI4SLs in this report are presented in
Table I,
4.2.1 Body Weight
Body weights are available in various literature sources. Cattle and other livestock can range in size depending on their production value (e.g.. dairy or beef cattle) and age (e.g.. calves, growing caitlc. 1.nishing cattle, mature cows or bulls), as well as their location (e.g.. livestock from third world countries tend to be smaller). In this approach. parameters have been provided for three subsets of the cattle receptor: dairy cattle, beef cattle, and calves. The average cattle body weights were taken from the NRC reports on nutrient reqLiirements for daiiy cattle and calves (NRC’ 21X)l. 2000).
Dairy Cattle — Ng el al. (191(2) cited a 1979 value of 41(0 kg for dairy cows, noting that individual cows from dairy herds were larger than their proposed value, as maure weights of dairy cattle vary from 400 kg for small breeds to over 6S0 kg for large breeds (NRC 2001). However, an average value of 540 kg was used in this report.