2016 SCIENTIFIC REPORT



Risk assessment report

Bisphenols, Parabens, Pthalates

This is a summary of the contents of the risk assessment report for 14 chemical substances released by the National Institute of Food and Drug safety Evaluation (NIFDS) in April 2020. The full report can be found on the website of the NIFDS (nifds.go.kr)

Food Safety Risk Assessment Division

1. PURPOSE OF THE ASSESSMENT REPORT

Chemicals are permitted to be used at a certain level considering safety and effectiveness of each use. However, since chemical exposure can unintentionally take place through various products and living environments, consumers may be concerned about the possible health effect of exposure to chemicals through product use.

After the humidifier disinfectants accident in 2010, there has been widespread anxiety about the use of chemicals and health concerns caused by multiple exposures to chemicals. The Ministry of Food and Drug Safety (MFDS) performed risk assessment for 14 chemicals to be exposed through the various sources and routes, such as three bisphenols, four parabens and seven pthalates. The purpose of the assessment report is to support the management of risks associated with the presence of these chemicals in various matrices in human life.

2. METHODOLOGY

Risk assessment was performed according to the four stages: hazard identification, hazard characterization, exposure assessment, and risk characterization. For exposure assessment, we conducted two different approaches. Total exposure level of chemical was calculated through direct assessment using human biomonitoring, and through indirect assessment based on scenario-based exposure for each source, such as food, cosmetics, consumer products and environmental source. And the main causes of exposure were verified by comparing their results.

The content of chemicals in products collected in domestic and foreign literature surveys and the content actually analyzed in domestically distributed products were used in scenario-based exposure assessment. Exposure factors such as food intake, product dose, and internal absorption rate, etc. are based on the guidelines from the MFDS and the Ministry of Environment.

To evaluate the risk of chemical exposure, health based guidance values (HBGV) should be available. Various risk assessment agencies or institutions have derived different values for the HBGV. In this report domestic HBGV were applied first. And in cases where domestic HBGV was not set, the assessment was conducted by applying a value which was set in other risk assessment agency such as EFSA. If the HBGV was set, the Hazard Index (HI) was applied for risk characterization. If not, Margin of Exposure (MOE) was applied.

3. OVERALL SUMMARY AND CONCLUSIONS

1. Bisphenols ; Bisphenol A, Bisphenol F and Bisphenol S

Bisphenol A (BPA) is the best known bisphenol analogue. BPA is used for the manufacturing of polycarbonates and epoxy resins. In some cases, they are used to produce developers for thermal printing paper, plastic antioxidants, and tooth sealers. According to literature, the total BPA production has increased by an average of 2.5% per year over the past five years and it is estimated to grow 3.6% per year through 2023.

Because of the concern about BPA’s potential risk in humans, BPA is replaced by structurally similar bisphenol analogues such as BPF and BPS. BPA, BPF and BPS have been detected in many environmental and human samples. They are readily biotransformed in the environment, and do not bioaccumulate in food chains. Although BPF exists naturally in some plants, there is no evidence in general that bisphenols occur naturally. They can be exposed to the human when people use diverse products for daily life. The social concern about bisphenols has increased as research results suggest that the toxicity of substitutes might be similar to BPA due to their similar structures.

In Korea, the use of BPA in baby bottles is prohibited since 2012. Going further, use of BPA has also been prohibited from infant utensils, containers and packages since 2019.

In this assessment report, the current exposure level of Koreans to the three bisphenol analogues was checked, their health effects were comprehensively evaluated.

Food was the main source of BPA exposure. In all age groups, exposure through food accounted for more than 70% of the total exposure. And as the age increased, the contribution of food was assessed to be higher. Exposure through environmental media and inhalation exposure were insignificant. Information about sources of exposure to BPF and BPS was very insufficient.

BPA was detected in >90% urine samples from the general population biomonitoring survey in 2010-2018. Urinary levels of BPA showed a trend to decrease with age in Koreans, with 13-18 years old Korean adolescents having the lowest BPA levels. The total level of BPA which was calculated based on the BPA concentration in urine was 0.013 ㎍/kg bw/day in geometric mean for all age groups. The exposure of the 95th person was 0.079 ㎍/kg bw/day. Since the detection rates of BPF and BPS in the urine were low, it was hard to estimate their level of exposure statistically. However, the urinary levels of BPF and BPS were lower than that of BPA.

The total exposure of BPA in the body was considerably low than the HBGV of BPA (20 ㎍/kg bw/day). The estimated HI for all age were lower than 1. This indicated negligible risk of adverse health effects in the general population of Korea.

As a result of reviewing the epidemiological studies about health effects of BPA on the human, the number of epidemiological evidences in Korea was found to be smaller than that of other countries. Further, it was difficult to confirm a clear causal relationship because the studies were at the level of cross-sectional studies. Since 2015, with the start of epidemiological research using a domestic cohort, studies on the relationship between exposure to BPA and its health effect have been regularized. In domestic birth cohort-based epidemiological research, a relationship between BPA exposure before birth and health effects such as obesity and ADHD was found. In case of adults, no statistically significant relationship with indices of health effect was observed except obesity. However, there are many limitations in determining whether exposure to have a direct impact on health, using the results of individual epidemiological research presented so far. Conclusions from epidemiological evidence of BPA were (1) evidence of an association between BPA exposure and health effects is limited; (2) further studies are needed on plausibility of a causal relationship between low dose BPA exposure and health effects.

3.2. Parabens ; Methylparaben, Ethylparaben, Butylparaben and Prophylparaben

Parabens are chemicals for a long time been used in various products as preservative, and people can be exposed to them by various routes and products such as food or cosmetics.

As new risk information on parabens (disturbance to the endocrine system, reproductive and developmental toxicity, etc.) was reported recently, social concerns related to the use of parabens in products have been raised. In this assessment, exposure sources to parabens were investigated, and a risk assessment on the total exposure level was conducted.

The total exposure of parabens was calculated through direct assessment using biomonitoring of the urine, and through indirect assessment based on source-to-dose exposure scenarios. Considering the exposure routes of various media such as food, cosmetics, other living chemical products, and the environment, exposure scenarios were prepared for domestic conditions. And the main causes of exposure were verified by comparing their results.

The health effects of parabens were measured comprehensively through domestic cohort-based epidemiological research (cohort-based research on patients and the control group) and meta-analysis by systematic literature examination.

The total daily exposure of the four parabens calculated by scenario-based exposure assessment was 87.836 μg/kg bw/day. The daily exposure quantities by food, cosmetics, other living chemical products, and environmental media were 5.509 μg/kg bw/day, 73.106 μg/kg bw/day, 9.221 μg/kg bw/day, and 0.001 μg/kg bw/day respectively. The main exposure source differed according to the properties of the four parabens respectively, but in all of them, exposure through environmental media was negligibly low. Methylparaben was confirmed in the order of cosmetics, living chemical products, and food. Furthermore, it was confirmed that exposure to ethylparaben occurred through food; propylparaben through cosmetics; and butylparaben through consumer products.

In a similar study of the U.S., exposure to parabens was found to be 1.092-2.43 mg/kg bw/day (methylparaben 0.79-1.61 mg/kg bw/day; propylparaben 0.3-0.8 mg/kg bw/day; and butylparaben 0.002-0.02 mg/kg bw/day). Based on this, it can be said that the level of exposure to parabens in Korea is lower than in the U.S.

In the biomonitoring-based exposure assessment, the total exposure level to the four parabens was 11.7-23.2 μg/kg bw/day by age. And this was lower than the results of the scenario-base exposure assessment (87.836 μg/kg bw/day) through various exposure sources. Generally, conservative scenario is used in the source to dose exposure assessment method. There is a risk of overestimation depending on the level of information the assessment uses.

Parabens are used in various products, but after exposure to the body, they are metabolized and quickly excreted through urine. The total exposure in the body using human biomonitoring is considered a suitable method for estimating the possible actual exposure by reflecting physiological and metabolic processes, etc.

The domestic HBGV is set to 10 mg per kg of body weight per day for the sum of methylparaben and ethylparaben. The risk confirmed as the result of exposure assessment for methyl- and ethylparaben was assessed to be safe. For propylparaben and butylparaben, no HBGV has been set in Korea. Hence, the MOE method compared to the toxicity value was applied. If the MOE is greater than 100 for propylparaben and more than 1,000 for butylparaben, it is considered safe. Accordingly, it was assessed that both propylparaben and butylparaben had the MOE of more than 1,000.

As a result of reviewing the epidemiological studies about health effects of parabenes on the human, the epidemiological evidences in Korea was limited to confirming the direct causal relationship between exposure of parabens and the various health effects.

3.3. Pthalates ; DEHP, DBP, BBP, DEP, DnOP, DIDP, DINP

Phthalates are one of the plasticizers added to soften plastic products. Phthalate plasticizers have excellent compatibility with PVC. Di-ethylhexyl phthalate (DEHP) is the most representative phthalate plasticizer, and about 2 million tons are produced annually worldwide. DEHP is also the most produced plasticizer in Korea: 440,000 tons in 2006; 340,000 tons in 2010; and 300,000 tons in 2016. But, its production volume is decreasing continuously.

Phthalates come with a high likelihood of exposure to the human through some sources such as cosmetics, food packages, toys, paints, leather products, carpets, environment and etc. Especially, it is also known that children may be exposed to phthalates by hand-to-mouth behavior or sucking a toy, etc.

Phthalates have a low level of acute toxicity, but remain in the environment. Animal experiments show that in some animals, phthalates caused chronic toxicity related to reproduction in ways such as female infertility or reduction in sperms. Furthermore, studies have reported that phthalates may enter the human and cause disturbances of the endocrine system. Such disturbance interferes with or confuses hormonal activity. These studies are raising the necessity to safely control phthalates.

As interest in environmental hormones has been growing from the late 1990s, countries have raised a need to regulate the use of phthalates. Accordingly, global regulations on phthalate plasticizers are getting stronger.

The MFDS manages the transfer of phthalates. To do so, the MFDS has set the use standards and dissolution standards for DEHP, DBP, BBP, DnOP, DINP, DIDP, and DEHA under the Standards and Specifications Concerning Apparatus, Containers and Packages of the Food Sanitation Act. Cosmetics cannot be made using DEHP, DBP, and BBP. The Ministry of Environment designated and manages DEHP, DBP, BBP, DEP, DnOP, DIDP, and DINP as existing chemicals to be registered as environmental hazard factors. Environmental hazard factors are required to undergo risk assessment on hazardous substances contained in kids’ items, etc.

The US EPA classified DEHP as probable human carcinogen (B2). The IARC (International Agency for Research on Cancer changed its classification, from Group 3 (Not classifiable as to its carcinogenicity to humans) to Group 2B (Possibly carcinogenic to human). In 1987, the US EPA recommended that DEHP be substituted with a less toxic substance for use as a plasticizer.

The European Chemical Agency (ECHA) has classified DEHP, DBP, BBP and DIBP as substances that disturb the endocrine system. It judged that their impact on human health raised concerns at the same level as defined by Regulation (EC) No 1907/2006 (ECHA, 2017). The EU (European Union) classified DEHP, DBP, and BBP as Category 2 (Reproductive toxins) according to Directive 67/548/EEC. It prohibited their use in toys for infants and toddlers, etc., and restricted the use of DINP, DIDP, and DnOP in children's items that may be put in the mouth. Besides, DEHP was classified as Category 1B (Reproductive toxins) in accordance with Regulation (EC) 1272/2008(CLP), based on recent researches focusing mainly on DEHP. Japan also adopted the EU regulation from 2001.

Although safety control measures like restriction on the use of phthalate plasticizers were strengthened, new hazard information on their use has been revealed. In addition, there is an increasing number of reports on phthalate detection from toys, stationery, household items, etc. except food. Such information worsens consumer anxiety about the hazard of phthalates.

Therefore, in this study, a human risk assessment was conducted for seven phthalates: 1) to find the total exposure level in the human considering various sources and routes of exposure; and 2) to draw up measures to reduce exposure for the major sources by analyzing the exposure contributions of each source such as food and cosmetics. In addition, the recently reported exposure to phthalates and its effects on human health were analyzed by systematic literature review and meta-analysis. In addition, an assessment of health effects was conducted through domestic cohort-based epidemiological research.

The risk assessment results for seven phthalates are as follows:

DEHP is a representative phthalate plasticizer and its use is regulated the most in various human application products such as food containers, cosmetics and toys. Daily DEHP exposure rates based on scenarios for various exposure sources like food and cosmetics were 19.915 μg/kg bw/day for infants; 8.920 μg/kg bw/day for toddlers; 5.684 μg/kg bw/day for primary school students; 15.389 μg/kg bw/day for secondary school students; and 14.660 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (40 μg/kg bw/day) was lower than 1, the level of exposure to DEHP was not risky.

By biomonitoring, it was found that the internal total DEHP exposure for Koreans reduced in all age groups from 2009 until recently. In particular, it decreased sharply in the high exposure range (95th). This is considered to be the result of the strict control of use of DEHP for food containers, cosmetics, kids’ items, etc. as mentioned earlier. The main sources of exposure to DEHP by age were kids’ items > house dust > food for infants; food > house dust > kids’ items for toddlers; food > other consumer products > house dust in the case of primary school students; and other consumer products > household items > food in the case of secondary school students and beyond.

The biomonitoring-based values obtained for internal total exposures in all age groups were lower than the scenario-based values by sources like food and cosmetics. Regarding infants, kids’ items and house dust with high exposure contribution were considered to require more examination for determining them as probable sources, since data on other sources were limited.

The Ministry of Environment investigates internal exposure every year for all ages from three and older, starting from the Korean National Environmental Health Survey (2015-2017). So, it is necessary to continuously observe the exposure of sensitive groups like infants and toddlers and children based on this assessment result.

DBP is a low molecular weight plasticizer. Its use is restricted for various products, along with DEHP. DBP is used as a solvent in making cosmetics and household chemical products, too.

According to domestic and foreign literature surveys, the level of DBP cosmetics and kids’ items was monitored. kids’ items It was found that the amounts of DBP skin transfer through kids’ items were less than the detection limit (non-detection level) based on a survey by the Ministry of Environment (2018).

Daily DBP exposures based on scenarios for various sources of exposure like food and cosmetics and kids’ items were 3.735 μg/kg bw/day for infants; 2.033 μg/kg bw/day for toddlers; 1.488 μg/kg bw/day for primary school students; 3.684 μg/kg bw/day for secondary school students; and 3.537 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (10 μg/kg bw/day) was lower than 1, the level of exposure to DBP was not risky.

Like DEHP, DBP was detected from most of the subjects’ human samples. The internal total exposure to DBP reduced in all age groups from 2009 until recently. In particular, it decreased sharply in the high exposure (95th) range. However, biomonitoring data on toddlers and school children were announced for the years of 2010-2012 and 2015-2017 respectively. Hence, additional observation is necessary to check their reduction trend compared to adults.

The main sources of exposure to DBP by age were various: kids’ items > food for infants; food > kids’ items for toddlers; food > cosmetics > other consumer products for primary school students; and other consumer products > cosmetics > food = household items for secondary school students and beyond. While exposure through various sources such as food, cosmetics, household items and other consumer products was confirmed for secondary school students and beyond, kids’ items contributed the most to exposure for infants. This could be because of oral exposure caused by their behavioral feature (sucking their hand or products like a toy). Meanwhile, in this assessment, two separate exposure assessments, viz. scenario-based and biomonitoring-based, were conducted together.

The results obtained by the scenario-based exposure assessment were higher than that of the biomonitoring-based exposure assessment done by the Ministry of Environment in 2015-2017. The values of the scenario-based exposure assessment may be over-or under-estimated. In other words, it is hard to reflect the actual exposure conditions by this mode of assessment because data on monitoring and exposure factors for all sources are not enough. Recently, there is an increasing number of reports that the method of estimating total exposure in the body based on human biomonitoring is appropriate for analyzing actual exposure. So, in the case that exposure to substances can occur through various products such as DBP, it will be effective to monitor the exposure level in the body continuously by jointly using human biomonitoring.

Since the Korean National Environmental Health Survey conducted by the Ministry of Environment between 2015 and 2017, the level of DBP exposure in the body has been surveyed for all ages over three. Therefore, it is necessary to continuously observe changes in future exposure levels based on the results of this assessment.

BBP is used as a material to increase flexibility of plastic. It is also used as an additive to produce household chemical products. Like DEHP and DBP. There are restrictions for its use in various products.

According to surveys of domestic and foreign literature, BBP monitoring information was reported not only on food but also on plastic bags, plastic containers and toys. As a result of direct analysis of cosmetics on the Korean market, no BBP was found in the entire range of cosmetics. In addition, according to studies conducted by the Ministry of Environment (2018) and Shim Gi-tae, et al. (2018), the amounts of oral/skin transfer in kids’ items were at the detection limit (non-detection level).

Daily exposures to BBP based on scenarios for various exposure sources such as food and cosmetics and kids’ items were 1.566 μg/kg bw/day for infants; 1.196 μg/kg bw/day for toddlers; 1.062 μg/kg bw/day for primary school students; 0.883 μg/kg bw/day for secondary school students; and 0.844 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (200 μg/kg bw/day) was lower than 1, the exposure level for BBP was not risky.

BBP was detected in more than 85% of the survey subjects during the 2010-2012 survey, and more than 95% in the survey held by the Ministry of Environment between 2015 and 2017. Despite the increase in biomonitoring results, the total BBP exposure in the body reduced for all age groups from 2010 until the most recent survey. In particular, it decreased sharply in the high exposure range (95th). However, biomonitoring data on toddlers and school children were announced for the years of 2010-2012 and 2015-2017 respectively. So, additional observation is necessary to check if data on children show a reduction trend like data on adults.

Among the main sources of exposure to BBP, food contributed the most to exposure in all age groups. Cosmetics and consumer products were also exposure contributors for secondary school students and beyond. According to recent surveys of the MFDS and the Ministry of Environment, BBP was not detected in cosmetics and household items. As the amount of oral/skin transfer was almost ignorable (less than the detection limit), it seems that the contribution of cosmetics and household products to exposure is very minor.

Meanwhile, this study conducted both scenario-based and biomonitoring-based assessments of total exposure for the body. BP has a lower internal exposure concentration than DEHP and DBP, and its exposure shows a trend of yearly decrease. Therefore, it would be better to steadily observe changes in internal exposure through biomonitoring than to use the existing scenario-based assessment.

DEP is used as a plasticizer for non-PVC-polymers. In other cases, it is used as a lubricant and solvent. Although there are no domestic or foreign regulations on DEP, the Ministry of Environment designated and controls it as an existing chemical to be registered and as an environmental hazard factor.

According to a study of domestic and foreign literature, data on monitoring of DEP were very limited. In foreign materials, the DEP concentration in food was pretty low and DEP was detected in some cosmetics. In the study of Shim Gi-tae, et al. (2018), DEP was not detected in kids’ items and household chemical products in direct analysis. However, it was partly detected from synthetic resin products such as raincoats and floorings and shopping bags.

Daily DEP exposures based on scenarios for various exposure sources were 11.171 μg/kg bw/day for infants; 7.383 μg/kg bw/day for toddlers; 13.365 μg/kg bw/day for primary school students; 22.644 μg/kg bw/day for secondary school students; and 22.827 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (400 μg/kg bw/day) was lower than 1, DEP’s exposure level was not risky.

For infants, toddlers, and primary school students, cosmetics >food contributed the most to exposure. For secondary school students, exposure contributions were high in the order of other consumer products > cosmetics > food.

The DEP content was relatively higher in cosmetics compared to other phthalates (perfume 955.480 μg/g). It seems that the exposure amount was high in scenario-based exposure assessment because the skin absorption rate was very conservatively set at 50% according to the cosmetics guideline. Also, the assessments on other consumer products were conservative using 75 percentile. So, additional research is required to compensate for such difference including compensation for exposure factor.

Meanwhile, there are no recent biomonitoring data at the national level after the MFDS survey (2010-2012). Therefore, reassessments will be made if recent data become available.

DnOP is used as a plasticizer for PVC-polymers and non-PVC-polymers. Its use is restricted for various products like utensils, containers, and packages, and infants’ leather products. DnOP is under control after designation as an existing chemical to be registered and as an environmental hazard factor.

In surveys of domestic and foreign literature, it is reported to be detected in very small amounts in food, and in small amounts or in quantities that cannot be detected in cosmetics, kids’ items and household chemical products. In the monitoring of kids’ items (2000 items) conducted by the Ministry of Environment (2018), DnOP was not detected in all and the skin transfer amount was also below the detection limit (non-detection level).

Daily DnOP exposures based on scenarios for various sources of exposure were 11.077 μg/kg bw/day for infants; 1.249 μg/kg bw/day for toddlers; 0.780 μg/kg bw/day for primary school students; 0.638 μg/kg bw/day for secondary school students; and 0.594 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (1,130 μg/kg bw/day) was lower than 1, DnOP’s exposure level has not been considered risky.

For all age groups except infants, food contributed the most to exposure. For infants, kids’ items like toys contributed highly to exposure. It seems that their behavioral feature of sucking a toy, etc. had an impact on the assessment result.

Biomonitoring of DnOP was first executed in the Korean National Environmental Health Survey of 2015-2017 done by the Ministry of Environment. In the biomonitoring study, DnOP was detected in more than 99.4% of the subjects. Though it was a little lower than the internal concentration for the U.S., a direct comparison of values was difficult because of differences in the number of subjects, year, etc.

This time, in biomonitoring-based exposure assessment on DnOP, internal concentration could not be estimated using values of external exposure. This was because there was no exposure factor. Hence, a reassessment will be made when in-product monitoring data and exposure factor for estimating external exposure, etc. become available for DnOP.

DIDP is commonly used as a plasticizer for PVC and its consumption is increasing in contrast to reduction in the use of DEHP. The use of DIDP is restricted for utensils, containers and packages and kids’ items (infants’ leather products and kids’ oral products). DIDP was not detected from kids’ items (2000 items) that were investigated by the Ministry of Environment (2018).

Daily DIDP exposures based on scenarios for various exposure sources were 4.766 μg/kg bw/day for infants; 2.971 μg/kg bw/day for toddlers; 1.878 μg/kg bw/day for primary school students; 1.649 μg/kg bw/day for secondary school students; and 1.576 μg/kg bw/day for adults. As the hazard index compared to the health based guidance value (150 μg/kg bw/day) was lower than 1, DIDP’s exposure level is not considered risky.

The contribution of food to exposure was high in all age groups, and infants also showed high exposure through kids’ items. It is believed that oral exposure due to their behavioral characteristics (behavior of sucking products such as toys, etc. or their hand) is the main factor. It was difficult to find the exposure contribution of other product groups.

When the Korean National Environmental Health Survey was conducted between 2015 and 2017, DIDP was detected in more than 89.5% of the subjects by human biomonitoring. Compared with the level of exposure to DIDP in the body presented in foreign countries such as the U.S., Spain, Germany, etc., the level of exposure in Korea was low.

When the biomonitoring values are calculated using the formula to estimate external exposure, the results are: 0.15 μg/kg bw/day for infants; 0.12 μg/kg bw/day for primary school students; 0.09 μg/kg bw/day for secondary school students; and 0.20 μg/kg bw/day for adults. Exposure differences compared to scenario-based exposure assessment were more than 10 times.

Since there are no biomonitoring data for infants, their external exposure could not be calculated.

Moreover, DIDP exposures show a major difference by the two exposure assessment methods. This may be because monitoring data on exposure sources except food are not enough and the estimation model of external exposure using human biomonitoring is limited.

In this assessment, the DIDP exposure level was evaluated safe and lower than data reported in foreign studies. However, additional research is necessary to identify a steady trend of internal exposure reduction and to investigate exposure factors pertaining to various products.

Consumption of DINP is increasing along with DIDP. Its use is restricted for utensils, containers and packages and kids’ items. Domestic and foreign literature studies report monitoring data and the amounts of oral/skin transfer through food, cosmetics and kids’ items.

Daily DINP exposures based on scenarios for various exposure sources were 27.344 μg/kg bw/day for infants; 8.857 μg/kg bw/day for toddlers; 3.520 μg/kg bw/day for primary school students; 3.389 μg/kg bw/day for secondary school students; and 3.207 μg/kg bw/day for adults. Since the hazard index compared to the health based guidance value (150 μg/kg bw/day) was lower than 1, DINP’s exposure level is not considered risky.

The main exposure sources of DINP by age were various: kids’ items > food > house dust for infants; food = kids’ items > house dust for toddlers; food > other consumer products > house dust for primary school students; and food > household items > other consumer products for secondary school students and beyond.

In human biomonitoring, the DINP detection rate in the body showed an increasing trend in the 2015-2017 survey (Ministry of Environment) compared to the 2010-2012 survey (MFDS): DINP was detected from samples of most subjects (99.3%). However, the domestic exposure level was far lower than the results for the U.S.

When the biomonitoring values are derived using the formula to estimate external exposure, the results are: 0.41 μg/kg bw/day for infants; 0.40 μg/kg bw/day for primary school students; 0.27 μg/kg bw/day for secondary school students; and 0.38 μg/kg bw/day for adults. Exposure differences compared to scenario-based exposure assessment were up to more than 20 times. It seems that DINP shows a major difference in exposure for the same reason as DIDP.

In this assessment, the DINP exposure level was evaluated safe and lower than data reported in foreign studies. However, considering more and more DINP is being used to replace DEHP, additional research is necessary to examine the main exposure factors of DINP in various products.

Conclusion of Individual risk assessments of seven phthalates show that “they have no risk at the current domestic exposure level. Meanwhile, the seven phthalates can be exposed in the form of complexes as well as individually through products like food and cosmetics. Hence, the Total Exposure Hazard Index (TEHI), which adds up all individual risks of the seven phthalates, was analyzed. As mentioned earlier, the scenario-based exposure assessment has a risk of overestimation according to its conservative approach. Therefore, it reveals up to more than 20 times of differences from biomonitoring-based exposure assessment that reflects actual situations. Accordingly, between the two methods, TEHI was based on biomonitoring-based exposure assessment that reflected actual levels of internal exposure. If TEHI was no more than 1, the phthalate was considered to be of no hazard concern.

The formula to calculate TEHI is as below:

|TEHI = Hazard Index (Exposure route 1) + Hazard Index (Exposure route 2) + … + Hazard Index (Exposure route i) |

Age-specific TEHIs of the seven phthalates studied were all no more than 1 except for infants. Therefore, it was concluded that the exposure levels were of no concern about hazard. For infants, there were no recent representative biomonitoring results since 2010 and 2011 due to limits in human sampling, etc. For this reason, their TEHI could not be calculated unlike other age groups. However, TEHI was no more than 1 when the biomonitoring result for infants, which was reported between 2010 and 2011, were applied. Hence, it was considered to have no hazard concern. If recent biomonitoring data are acquired, it will be necessary to change and reevaluate internal exposure levels of infants.

The purpose of the risk assessment is to supplement the limitations of existing risk assessment methods, and to evaluate the actual amount of exposure that reflects actual exposure situations of the public considering various sources and routes of exposure. In addition, it aims to determine whether there is a risk in substances that have similar toxicity and the possibility of multiple exposure, such as phthalates. For this purpose, accurate assessment of exposure is important.

As confirmed in this assessment, in case of phthalates, it is effective to apply the new biomonitoring assessment method together with the existing scenario-based exposure assessment to compensate for the conservativeness and limit of scenario-based assessment. Accordingly, this risk assessment indicates that compared to data and the technical level of assessment of major phthalates such as DEHP, DBP, and BBP, data on plasticizers used as alternatives for DEP, DnOP, DIDP, and DINP are limited. The development level of exposure assessment technologies like the PBPK model also seems to be insufficient. Four phthalate plasticizers are used more than before in place of DEHP and DBP under strong regulations. Hence, additional monitoring of those four exposure sources and research to develop their assessment technology are necessary.

This report conducted meta-analysis of the relationship of exposure to phthalates with various health effects, such as obesity, thyroid effect, metabolic syndrome, diabetes, cardiovascular disease and cancer, etc. These health effects were confirmed through literature review based on epidemiological evidence reported so far. The results of meta-analysis revealed some relevance to DEHP and BBP, etc., but no health effects showing clear causal relationship were found. Especially, because domestic epidemiological studies were cross-sectional, it was decided that evidence is not enough to confirm a causal relationship between exposure to phthalates and health effects.

However, various epidemiological study results on low-dose phthalate exposure and health effects have been reported recently. Among them, the health effects on metabolic syndrome and thyroid were confirmed in a domestic cohort-based cross-sectional study. In this context, further research will be needed to develop measures to reduce exposure and to identify the causal relationship between exposure to phthalates and health effects.

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