Assessment of Lead (Pb) and Zinc (Zn) Contamination in Beach Sands by Hot Spot Analysis

Abstract

Kim, S.-M. and Choi, Y., 2019. Assessment of Lead (Pb) and Zinc (Zn) contamination in beach sands by hot spot analysis. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 321-325. Coconut Creek (Florida), ISSN 0749-0208.It is necessary to investigate contamination in beach sands for water safety because replenishing sand on eroding beaches may contain potentially toxic trace elements (PTEs). In order to understand the spatial variation and risk of PTEs in beach sands, this study uses hot spot analysis, which calculates a z-score based on the Getis–Ord Gi* statistic to identify a statistically significant hot spot sample. A high-value data sample surrounded by other high-value samples indicates a statistically significant hot spot. Using relatively cost- and time-effective portable X-ray fluorescence (PXRF) analysis, sand data are acquired from the OO beach on the eastern coast of Korea and used for hot spot analysis. The sand data of the OO beach are classified into four groups: high content with a high z-score (HH), high content with a low z-score (HL), low content with a high z-score (LH), and low content with a low z-score (LL). The HH case can be a critical hazard to human health, whereas the other cases may be insignificant. As a result, it was confirmed that Pb is mainly distributed in the northwestern and southeastern parts, and Zn is distributed in the southern part. However, all the PTE concentrations in the sample data do not exceed the soil contamination warning standards. Although Pb and Zn was detected from some samples, it was not critical from the PXRF and hot spot analysis results. The method implemented in this study may be utilized for the assessment of statistically significant contamination in beach sands.