Eunkyung Yoon

Estimation of Excess Cancer Risk on Time-Weighted Lifetime Average Daily Intake of PAHs from Food Ingestion

ABSTRACT The purposes of this study were to quantify the time-weighted, lifetime average, daily intake (LADI) of polycyclic aromatic hydrocarbons (PAHs) through food ingestion and to estimate the excess cancer risk based on lifetime dietary PAH intake. Twenty-seven different food commodities were selected from the 2001 Korean National Health and Nutrition survey based on their frequent consumption and high PAH level. The foods were analyzed for the profile of 14 PAH congeners using high performance liquid chromatography (HPLC) and fluorescence detector. Considering the toxic equivalent (TEQ) level converted with the toxic equivalent factors (TEFs), the highest total TEQ level of PAHs in foods was detected from roasted laver at 1.2 ug TEQ/kg. For the PAH exposure assessment according to ingested foods, the average body weight was separated according to the following age groups, 1–6, 7–19, 20–64 and over 64 years, and the daily food ingestion rates from the National Health and Nutrition survey were used. The estimated Lifetime Average Daily Intake (LADI) of PAHs was 3.22 × 10–3 ug/kg/day for carcinogenic effects and was higher in the younger age groups under 20 years old than in the older groups. The dietary excess cancer risk estimated using the cancer potency of benzo(a)pyrene (7.3(mg/kg/day)−1) was 2.3 × 10−5, which is equivalent to a probability of tumor eruption in the upper gastrointestinal tract of two per hundred thousand persons.

Toxicity value for 3-monochloropropane-1,2-diol using a benchmark dose methodology.

3-Monochloropropane-1,2-diol (alpha-chlorohydrin, 3-MCPD) is a well-known contaminant that has been detected in a wide range of foods, and that is principally generated in foods prepared by hydrochloric acid hydrolysis, such as acid-hydrolyzed vegetable protein (acid-HVP). 3-MCPD is nephrotoxic to animals at high doses and induced tumors in some organs in both sexes of rodents. NITR have recently reported on the carcinogenicity of 3-MCPD in SD rats that were exposed for 2 years to drinking water. We considered that the kidney was the main target organ for 3-MCPD in SD rats and that renal tubular hyperplasia was the most sensitive endpoint. Benchmark dose analysis of the dose-response data for renal tubular hyperplasia in male and female rats exposed to 3-MCPD in drinking water for 2 years was conducted. We applied this to the benchmark dose (BMD) methodology to yield a point of departure for developing tolerable daily intakes (TDIs). The calculated BMDs and lower-bound confidence limits (BMDLs) for the critical endpoint were estimated using the seven different models. Predicted doses associated with 10% extra risk were calculated. The smallest Akaikes Information Criterion (AIC) was used in selecting the appropriate model. The model chosen by AIC for males was the logistic and for females it was the multistage. In summary, the predicted BMD(10) and BMDL(10) were 1.21 mg/kg bw/day and 0.87 mg/kg bw/day for the male rat incidence data, and values for female rats were 26.31 mg/kg bw/day and 19.47 mg/kg bw/day. In this study, the BMDL(10) of 0.87 mg/kg bw/day for male rats was suggested as the point of departure for deriving the human tolerable daily intake level of 3-MCPD.

Health Risk Assessment of Lead in the Republic of Korea

The purpose of this study was to estimate the daily exposure to lead due to food ingestion, air inhalation, and soil ingestion in the Republic of Koreas general population, and to evaluate the level of risk associated with the current lead exposure level using the proportional daily dose (3–4 μg/kg body weight/day) corresponding to the Provisional Tolerable Weekly Intake (PTWI) suggested by the Joint FAO/WHO Expert Committee on Food Additives as the toxicological tolerance level. The estimation of the daily exposure to lead via three pathways including food, soil ingestion and air inhalation was conducted as a chronic exposure assessment. For the lead exposure assessment through dietary intake, 1,389 lead residue data for 45 commodities investigated by the Korea Food and Drug Administration during the period 1995–2000 were utilized (KFDA 1996, 1997, 1998). Six hundred seventy-two air monitoring data from 7 major cities during the period 1993–2000 and 4,500 soil residue data at 1,500 sites during the period 1999–2001 were considered for the lead exposure assessment involving air inhalation and soil ingestion, respectively. The total daily exposure to lead was estimated by combining dietary intake, inhaled amount and soil intake corresponding to the typical activity of the general population, which was treated as a group of adults with a body weight of 60 kg. For risk characterization, the daily exposure to lead was compared with the toxicological tolerance level. The level of risk due to lead exposure was calculated using the hazard ratio (HR). The dietary intake of lead was 9.71 × 10−4 mg/kg/day and the total daily exposure level, including air inhalation and soil ingestion, was 9.97 × 10−4 mg/kg/day. The exposure contributions of foods, air and soil induced from the percentage of each media to the total daily exposure were 97.4%, 2.1% and 0.5%, respectively. Of the different commodity groups, the highest contribution to the total exposure came from grain, which represented 47.7% of the total. Additional exposure to lead occurs in certain population groups due to the use of tobacco, alcoholic beverages, and the intake of other foods, all factors not considered in this study. Through the comparison of the daily exposure to lead with the tolerance level based on the PTWI, the hazard ratio was estimated as being 0.25–0.33. This value implies that no increase in blood lead level is to be expected in the general population at the current lead exposure levels.