## 3 Results and Discussion
### Residual Pesticides in 40 Korean Agricultural Soils
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ulsan Soils** & **Determined** & **Determined** & **Pohang Soils** & **Determined** & **Determined** \\
**Pesticides** & **Amounts (\(\mu\) kg kg\({}^{-1}\))** & **Pohang Soils** & **Pesticides** & **Amounts (\(\mu\) kg kg\({}^{-1}\))** \\ \hline  & & & & Benzobicyclon & 0.052 \\  & & & & Isoprotholane & 0.005 * \\ Ulsan 11 & Tricyclazole & 0.012 & & Oxadiazon & 0.008 \\  & & & & Tricyclazole & 0.016 \\  & & & & Thifluzamide & 0.020 \\  & & & & Fenoxanil & 0.024 \\ \hline  & & & & Flubendiamide & 0.010 \\  & & & & Isoprothiolane & 0.002 * \\ Ulsan 12 & Tricyclazole & 0.018 * & & Oxadiazon & 0.004 * \\  & & & & Tricyclazole & 0.011 \\  & & & & Thifluzamide & 0.011 \\  & & & & Fenoxanil & 0.032 \\ \hline  & & & & Carpropamide & 0.001 * \\  & & & & Flubendiamide & 0.003 * \\  & & & & Iprobenfos & 0.002 * \\ Ulsan 13 & - ** & - ** & & Isoprothiolane & 0.001 * \\  & & & & Oxadiazon & 0.004 * \\  & & & & Tricyclazole & 0.007 * \\  & & & & Fenoxanil & 0.009 \\ \hline  & & & & Carbendarzim & 0.002 * \\  & & & & Flubendiamide & 0.013 \\  & & & & Iprobenfos & 0.001 * \\  & & & & Isoprothiolane & 0.002 * \\  & & & & Oxadiazon & 0.070 \\  & & & Tricyclazole & 0.020 \\  & & & & Thifluzamide & 0.029 \\  & & & & Fenoxanil & 0.057 \\ \hline  & & & & Flubendiamide & 0.002 * \\  & & & & Isoprothiolane & 0.004 * \\  & & & & Oxadiazon & 0.011 \\  & & & & Tricyclazole & 0.004 * \\  & & & & Thifluzamide & 0.003 * \\  & & & & Fenoxanil & 0.022 \\ \hline  & & & & Carbendarzim & 0.003 * \\  & & & & Flubendiamide & 0.002 * \\  & & & & Isoprothiolane & 0.002 * \\ Ulsan 16 & Tricyclazole & 0.003 * & & Oxadiazon & 0.022 \\  & & & Tricyclazole & 0.008 \\  & & & Thifluzamide & 0.006 * \\  & & & & Fenoxanil & 0.008 \\ \hline  & & & & Carbendarzim & 0.002 * \\  & & & & Carpropamide & 0.001 * \\  & & & & Flubendiamide & 0.005 * \\  & & & & Iprobenfos & 0.005 * \\  & & & & Isoprothiolane & 0.002 * \\  & & & & Oxadiazon & 0.034 \\  & & & Tricyclazole & 0.022 \\  & & & Thifluzamide & 0.020 \\  & & & & Fenoxanil & 0.015 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: _Cont._In addition, tricyclazole was detected in unregistered crops, which could result in the unintentional generation of unsuitable agricultural products. According to the PLA system, an MRL value of 0.01 mg kg\({}^{-1}\) is applied to nonregistered crops. A factor for detecting unused tricyclazole is the possibility that pesticides remaining in the soil will be absorbed into the crops [18; 32]. Recently, [PERSON] et al. [18] reported that up to 38.50% of tricyclazole used in the soil during lettuce cultivation remained in the lettuce, proving that tricyclazole is transferred to crops. Therefore, the residue of tricyclazole in paddy soil can be transferred to crops. Further research on this translocation using rice cultivation is needed. Oxadiazon is used as an herbicide to control annual weeds in rice farming [27]. In this study, it was detected at a level of 0.002-0.070 mg kg\({}^{-1}\). The detection frequency was at 15 points in 40 soil samples, reaching 38% (Table 7). This pesticide was detected in the range of 0.028-0.359 mg kg\({}^{-1}\) in 8 samples out of 80 paddy soils, and the detection rate was 10% [14]. However, [PERSON] et al. [14] did not report residual oxadiazon in soil samples from Gyengsang Province, located in Pohang and Ulsan. Our results were different from the results of [PERSON] et al. [14]. [PERSON] et al. [33] found that oxadiazon was detected in the range of 0.001-0.836 mg kg\({}^{-1}\) after residual pesticide analysis using 150 points in Korean paddy soil. The detection frequency reached 19.3%. The authors demonstrated that this higher detection frequency was related to the use of a larger amount of oxadiazon in 2006 than other pesticides, and the half-life of the pesticide in the soil was relatively long (31-91 days). [PERSON] et al.