금강수계에서 과불화화합물 중 PFOA, PFOS, PFHxS의 검출 특성에 관한 연구 = A Study on the Detection Characteristics of PFOA, PFOS, and PFHxS among Perfluorinated Compounds in the Geum River Basin

국문 초록 (Abstract)

금강수계 내 과불화화합물(perfluorinated compounds, PFCs)의 기초 조사를 위해, 오염원으로 추정되는 하, 폐수처리장과 금강수계 주요 하천을 대상으로 분포 실태를 조사하였다. 조사 대상 물질은 환경 잔류성과 위해성이 확인되어 연구가 진행된 PFCs 중, 스톡홀름협약 규제 물질로 등록되고 국내에서도 수질오염 물질로 관리되고 있는 PFHxS, PFOA, PFOS의 3종이다. 본 연구는 금강수계의 PFCs 관리에 필요한 기초자료를 제공하는 데 목적을 두고 있다. 금강수계 PFCs 농도에 영향을 미칠 것으로 예상되는 주요 하, 폐수처리장(12지점)과 금강의 중, 하류에 있는 지천(2지점)과 본류(1지점)를 중심으로 총 15지점을 선정하여, PFCs 3종을 LC-MS/MS를 사용하여 분석을 진행하였다. 시료의 전처리는 수질오염공정시험기준(ES 04506.1) 및 잔류성오염물질공정시험기준(ES 10390.1, ES 10363.1a)을 참고로 하여 수행하였으며, HLB cartridge와 SPE (solid phase extraction)를 사용하여 고상추출법을 적용하였다. 조사대상 하, 폐수처리장의 경우 94% 이상의 비교적 높은 PFCs 검출률을 나타냈으며, 일부 측정지점에서는 PFOS와 PFOA는 하, 폐수의 유입수보다 유출수에서 더 높은 농도를 나타내는 경향을 보였다. 또한 하천에서의 검출량은 10ng/L 이하로 낮은 수준이지만 이미 금강수계 전반에 존재함을 확인하였다. 일부 하, 폐수처리장의 방류수가 합류된 이후의 수계지점에서 PFCs 3종의 총합농도 및 PFOA의 평균농도가 가장 높게 검출되어 하, 폐수처리장이 PFCs의 주요 오염원이 될 수 있는 것으로 조사되었다. 폐수처리장 공정 수에서 검출된 PFCs의 농도는 1차 침전지 유출수 > 2차 침전지 유출수 > 2차 침전지 유입수 > 1차 침전지 유입수의 순서로 높았으며, PFHxS를 제외한 나머지 물질은 유입량보다 유출량이 증가하거나 유사하여 PFCs가 처리장에서 효율적으로 저감되지 않고 일부 증가하는 경향을 나타냈다. 본 연구를 통해 PFCs는 이미 금강수계 전반에 존재함을 확인하였으며, 주요 유입원을 찾아 처리함과 동시에 지속적인 모니터링을 통해 환경 중 거동을 연구해야 할 것으로 판단된다. 또한 이러한 잔류성오염물질의 영향을 좀 더 명확하게 확인하기 위해 PFOS, PFOA, PFHxS 항목 이외에 다양한 PFCs 항목 및 전구체에 대한 분석 등 추가 연구가 필요할 것으로 사료된다.

다국어 초록 (Multilingual Abstract)

The present study conducted a preliminary investigation of perfluorinated compounds (PFCs) within the Geum River Basin, focusing on potential contamination sources such as downstream areas, wastewater treatment plants, and major rivers in the basin. The targeted substances for this study were PFHxS (Perfluorohexane Sulfonate), PFOA (Perfluorooctanoic Acid), and PFOS (Perfluorooctane Sulfonate)—three PFCs that have been subjects of extensive research due to their environmental persistence and potential hazards. These substances are listed under the Stockholm Convention and are managed as water pollutants in South Korea. The findings of this study are intended to serve as foundational data for the management of PFCs in the region. A total of 15 sampling points were selected, focusing on key sites expected to influence the concentration of PFCs in the Geum River Basin, including 12 points from major downstream areas and wastewater treatment plants, as well as two tributaries (located in the middle and lower reaches of the Geum River) and one point along the main river. The three PFCs were analyzed using LC-MS/MS. Sample preparation was carried out following the water quality pollution testing standards (ES 04506.1) and the residual pollutants testing standards (ES 10390.1, ES 10363.1a). Solid-phase extraction (SPE) was performed using HLB cartridges to extract the compounds. The investigated downstream areas and wastewater treatment plants exhibited relatively high PFCs detection rates of over 94%. In some measurement points, PFOS and PFOA tended to show higher concentrations in the effluent compared to the influent. Additionally, while the concentrations in the rivers were low, below 10 ng/L, the presence of PFCs was confirmed across the entire Geum River Basin. At sites where effluent from wastewater treatment plants joined the river system, the total concentration of the three PFCs and the average concentration of PFOA were found to be the highest, indicating that wastewater treatment plants could be significant sources of PFC contamination. The concentrations of PFCs detected in the treatment plant processes were highest in the effluent from the primary sedimentation tank, followed by the effluent from the secondary sedimentation tank, influent to the secondary sedimentation tank, and influent to the primary sedimentation tank. For most substances, except for PFHxS, the concentrations in the effluent were either higher or similar to those in the influent, suggesting that PFCs were not efficiently reduced in the treatment plants, with some showing an increasing trend. This study confirmed the widespread presence of PFCs throughout the Geum River Basin. It is necessary to identify and address the major sources of these contaminants while conducting continuous monitoring to study their behavior in the environment. Furthermore, to better understand the impacts of these persistent pollutants, additional research is needed, including the analysis of various other PFCs and their precursors, beyond the commonly studied PFOS, PFOA, and PFHxS.