| Title |
Examination of the Applicability of TOC to Korean Trophic State Index (TSIKO) |
| Authors |
김범철 ( Bomchul Kim ) ; 공동수 ( Dongsoo Kong ) |
| DOI |
https://doi.org/10.15681/KSWE.2019.35.3.271 |
| Keywords |
Eutrophication; Trophic state classification; Trophic state index; TSIKO; Water quality |
| Abstract |
Korean Trophic State Index (TSIKO) was developed in 2006, and was composed of COD (CODMn based on permanganate method), Chlorophyll α (Chl.α) and total phosphorus (TP). However, CODMn usually represents only 50-60% of total organic matter in stream or lake water due to low oxidizing power of permanganate. This study investigated the relationship between TOC and CODMn based on the average data for the whole layer in 81 lakes in Korea, during the period 2013-2017. As a result, CODMn was found to be 1.54 times more than TOC in 66 of the freshwater lakes and 3 brackish lakes (TOC measured using thermo-oxidation method). TOC was about a quarter of CODMn in 8 coastal lakes (TOC measured using UV-persulfate oxidation method), and it appeared to be underestimated due to chloride interference. Using the data of 69 lakes with exception of 12 brackish lakes, TSIKO(TOC) was developed based on the correlation between TOC and CODMn, while TSIKO(COD) was replaced with TSIKO(TOC). However, for trophic state assessment of brackish lakes, the TSIKO(TOC) can only be utilized in case that TOC is measured through thermo-oxidation method. The determination coefficient of TSIKO(Chl) to TSIKO(COD) in 66 freshwater lakes and 3 brackish lakes was 0.83, while that to TSIKO(TOC) was 0.68. This difference could be attributed to the recalcitrant organic part of TOC. |