[A-HW18] Hydrology & Water Environment

[AHW18-P04] Evaluating the possibility of manganese accumulation in rice crops using laboratory-scale accumulation experiments

*Junyong Heo¹, Taejung Ha¹, Minjune Yang^2,3 (1.Division of Earth Environmental System Sciences-Major of Earth & Environmental Sciences, Pukyong National University, Busan 48513, Korea, 2.Division of Earth and Environmental System Sciences-Major of Environmental Geosciences, Pukyong National University, Busan 48513, Korea, 3.Wible Co., Ltd.)

Keywords:Manganese, Accumulation experiments, Rice crop

The expansion of the recreational sports sector has led to increased demand for extensive resort amenities, such as golf courses. However, constructing these facilities on foundations filled with excavated rubble can adversely affect neighboring agricultural and livestock activities because of potential heavy metal leaching into the environment. In the study area of Ilgwang, Busan, South Korea, where a golf course was recently constructed, contaminated surface water was observed, with red sediment originating from the golf course effluent. This study investigated manganese (Mn) contamination in the study area by analyzing Mn concentrations in surface water samples and conducted laboratory-scale experiments on Mn accumulation in rice crops to assess the potential impact on rice cultivation. Surface water samples were collected at 20 m intervals during March, May, July, and September. The accumulation experiment was conducted over 5 days under controlled conditions, including a temperature of 23°C, humidity at 80%, and a photoperiod of 16 hours. Rice crops were grown in 300 mL of artificially contaminated solution with different initial Mn concentrations (0, 1, 10, and 100 mg/L), and Mn concentration in the solution was measured every 24 hours. The results of this study showed a substantial reduction in Mn concentration downstream by up to 88% compared to upstream levels. The highest Mn concentration observed was 6.7 mg/L, significantly exceeding the U.S. EPA's drinking water quality standard (maximum contaminant level, MCL) of 0.05 mg/L. In the results of the accumulation experiments, the Mn concentrations in artificially contaminated solutions showed a declining trend over time, with a reduction of over 90% in Mn levels across all samples by the fifth day of the experiment. The rice sample cultivated in a 100 mg/L solution accumulated over 600 mg/kg of Mn, whereas no accumulation was observed in the 0 mg/L condition. This research is expected to underline the importance of monitoring and mitigating heavy metal contamination from artificial structures such as golf courses, potentially informing future research and policy measures.

Acknowledgements: This research was supported by the Learning & Academic Research Institution for Master's·PhD students, and Postdocs (LAMP) Program of the National Research Foundation of Korea (NRF), grant funded by the Ministry of Education (Grant No.RS-2023-00301702).