Evaluation Of Biomonitoring Data Research Articles

Biomonitoring Equivalents for benzene

Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline such as a reference dose (RfD) or tolerable daily intake (TDI). BE values can be used as a screening tool for the evaluation of population-based biomonitoring data in the context of existing risk assessments. This study reviews available health based risk assessments and exposure guidance values for benzene from the United States Environmental Protection Agency (US EPA), Texas Commission on Environmental Quality (TCEQ), California’s Office of Environmental Health Hazard Assessment (OEHHA) and the Agency for Toxic Substances and Disease Registry (ATSDR) to derive BE values for benzene in blood and urine. No BE values were derived for any of the numerous benzene metabolites or hemoglobin and albumin adducts. Using existing physiologically based pharmacokinetic (PBPK) models, government risk assessment values were translated into corresponding benzene levels in blood assuming chronic steady-state exposures. BEs for benzene in urine were derived using measured correlations between benzene in urine with benzene in blood. The BE values for benzene in blood range from 0.04 to 1.29μg/L, depending upon the underlying non-cancer risk assessment used in deriving the BE. Sources of uncertainty relating to both the basis for the BE values and their use in evaluation of biomonitoring data, including the transience of the biomarkers relative to exposure frequency, are discussed. The BE values derived here can be used as screening tools for evaluation of population biomonitoring data for benzene in the context of the existing risk assessment and can assist in prioritization of the potential need for additional risk assessment efforts for benzene relative to other chemicals.

Biomonitoring Equivalents for di-isononyl phthalate (DINP)

Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline such as a reference dose (RfD) or tolerable daily intake (TDI). BE values can be used as a screening tool for the evaluation of population-based biomonitoring data in the context of existing risk assessments. This study reviews available health based risk assessments and exposure guidance values for di-isononyl phthalate (DINP) from Health Canada, the United States Consumer Product Safety Commission (US CPSC), and the European Food Safety Authority (EFSA). Controlled dosing data reporting the urinary excretion fractions of major DINP metabolites following administration of labeled DINP are reviewed, and BE values corresponding to the available exposure guidance values are derived assuming chronic, steady-state intake and excretion at those exposure values. The BE values range from 1500 to 3600 μg/L (1900–4600 μg/g creatinine) based on the sum of three oxidative metabolites. Sources of uncertainty relating to both the basis for the BE values and their use in evaluation of biomonitoring data, including the transience of the biomarkers relative to exposure frequency, are discussed. The BE values derived here can be used as screening tools for evaluation of population biomonitoring data for DINP in the context of existing risk assessments and can assist in prioritization of the potential need for additional risk assessment efforts for DINP relative to other chemicals.

Biomonitoring Equivalents for DDT/DDE

Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline such as a reference dose (RfD) or tolerable daily intake (TDI). BE values can be used as a screening tool for the evaluation of population-based biomonitoring data in the context of existing risk assessments. This study reviews available health based risk assessments and exposure guidance values for DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, CAS #50-29-3) and related metabolites and degradation products DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane, CAS #72-55-90) and DDD (1,1-dichloro-2,2-bis(p-chloro-phenyl)ethane) based on both non-cancer and cancer risk assessments from the Food and Agriculture Organization/World Health Organization (FAO/WHO), the United States Environmental Protection Agency (US EPA), and other organizations. Laboratory data on distribution and toxicokinetics of DDT and metabolites and estimates of human elimination half-lives were used to estimate BE values (lipid-adjusted blood, serum, or plasma concentrations) corresponding to the various non-cancer exposure guidance values and cancer risk-specific doses. The BE values based on non-cancer risk assessments range from 5000 to 40,000 ng/g lipid for the sum of DDT, DDE, and DDD. The BE values corresponding to a 1E-05 cancer risk level for DDT and DDE based on the US EPA assessment are 300 and 500 ng/g lipid, respectively. Sources of uncertainty relating to both the basis for the BE values and their use in evaluation of biomonitoring data are discussed. The BE values derived here can be used as a screening tools for evaluation of population biomonitoring data for DDT and related compounds in the context of the existing risk assessment and can assist in prioritization of the potential need for additional risk assessment efforts for DDT relative to other chemicals.