## 3 Results and Discussion  
### Synthetic Musk Fragrances in Personal Care Products  
First, an SMF analysis was performed on the PCPs. Table 2 shows the analysis results for 36 PCPs, including shampoo, detergent, and perfume. The most widely detected SMF was found to be HHCB, which was detected with a frequency of 86.1% among all PCP samples. It was most often detected in hair care products, with a maximum concentration of 4917 \(\upmu\)g/g (median, 395.8 \(\upmu\)g/g) (Table 2). HHCB was especially found in all hair care products and perfumes (100% frequency). The second most frequently detected SMF after HHCB was AHTN, with a maximum concentration of 442.9 \(\upmu\)g/g in 47.2% of all samples (Table 2). Even though 80% of hair care products contained AHTN, the AHTN concentration in hair care products was much lower than that of HHCB, with a median value of 1.19 \(\upmu\)g/g. The HHCB and AHTN concentrations in PCPs observed in this study were similar to those reported in previous studies in the United States [33], but much higher than those reported previously in China [26]. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline
**Category** & **pg/L** & **DPMI** & **ADBI** & **AHMI** & **HHCB** & **ATII** & **AHTN** & **MA** & **MX** & **MK** & **Sum** \\ \cline{2-13} \multirow{3}{*}{\begin{tabular}{} \end{tabular} } & Range & N.D. & N.D.-0.83 & N.D.-0.67 & 0.09\(\rightarrow\)4916.99 * & N.D.-58.85 & N.D.-442.87 & N.D. & N.D. & N.D.–18.76 & 0.13-5012.41 \\ \cline{2-13}  & Median & N.D. & N.D. & N.D. & 395.82 & N.D. & 1.19 & N.D. & N.D. & N.D. & 455.51 \\ \cline{2-13}  & Frequency (\%) & 0 & 20 & 20 & 100 & 40 & 80 & 0 & 0 & 20 & \\ \hline \multirow{3}{*}{\begin{tabular}{} \end{tabular} } & Range & N.D. & N.D.-0.04 & N.D.-0.02 & N.D.-19.40 & N.D.-0.01 & N.D.-7.10 & N.D. & N.D. & N.D. & N.D. & N.D.-26.50 \\ \cline{2-13}  & Median & N.D. & N.D. & N.D. & 0.01 & N.D. & N.D. & N.D. & N.D. & N.D. & 0.03 \\ \cline{2-13}  & Frequency (\%) & 0 & 11.1 & 11.1 & 77.8 & 11.1 & 44.4 & 0 & 0 & 0 & \\ \cline{2-13}  & Range & N.D. & N.D. & N.D.-11.2 & 0.34-0.49 & N.D. & N.D. & N.D. & N.D. & N.D. & 0.34-1.61 \\ \cline{2-13}  & Median & N.D. & N.D. & 0.56 & 0.41 & N.D. & N.D. & N.D. & N.D. & N.D. & 0.97 \\ \cline{2-13}  & Frequency (\%) & 0 & 0 & 50 & 100 & 0 & 0 & 0 & 0 & 0 & \\ \hline \multirow{3}{*}{\
\begin{tabular}{} \end{tabular} } & Range & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D.-213.95 \\ \cline{2-13}  & Median & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. & N.D. \\ \cline{2-13}  & Frequency (\%) & 0 & 0 & 0 & 33.3 & 0 & 0 & 0 & 0 & 0 & \\ \hline \multirow{3}{*}{
\begin{tabular}{} \end{tabular} } & Range & N.D.–21.93 & N.D. & N.D.\(\rightarrow\)0.02 & 0.29\(\rightarrow\)157.73 * & N.D.–1.69 & N.D.-3.90 & N.D. & N.D. & N.D. & N.D.-392.5 & 0.29-163.71 \\ \cline{2-13}  & Median & N.D. & N.D. & N.D. & 72.58 & N.D. & N.D. & N.D. & N.D. & 0.41 & 88.27 \\ \cline{2-13}  & Frequency (\%) & 41.7 & 0 & 8.3 & 100 & 16.7 & 41.7 & 0 & 0 & 58.3 & \\ \cline{2-13}  & Range & N.D–18.69 & N.D.-0.83 & N.D.-1.12 & N.D.-4916.9* & N.D.-58.85 & N.D.-442.87 & N.D. & N.D. & N.D.–392.5 & N.D–5012.41 \\ \cline{2-13}  & Median & N.D. & N.D. & N.D. & 2.44 & N.D. & N.D. & N.D. & N.D. & N.D. & 8.03 \\ \cline{2-13}  & Freq.\% & 13.9 & 8.3 & 13.9 & 86.1 & 19.4 & 47.2 & 0 & 0 & 25 & \\ \hline \end{tabular}  
* *: The mass (MS) detector saturated and an accurate value calculation was not available; N.D indicates less than detection limit.  
\end{table} 
Table 2: Concentration (sg/g) and detection frequency (%) of synthetic mask fragrances in personal care products. The most frequently detected SMF after HHCB and AHTN was MK, which was detected at a maximum concentration of 39.3 \(\upmu\)g/g only in perfume and hair care products. Not all PCPs were found to contain MA and MX (Table 2). These results were consistent with the trends of domestic SMF usage reported in Korea, with significantly higher HHCB usage (60.6 tons/year) than AHTN (2.0 tons/year) and MK (11.6 tons/year) in 2006 [9].