Objectives:This study was conducted to evaluate the detection characteristics of Nakdong River basin (wastewater treatment plant (WWTP) effluents, tributaries and main streams) by selecting 18 kinds of pharmaceuticals which were detected frequently. It was intended to be used as basic data for advanced treatment of WWTP and securing safe water source.Methods:The selected 18 pharmaceuticals investigated in this study were acetaminophen, atenolol, carbamazepine, caffeine, diclofenac, iopromide, lincomycin, metoprolol, primidone, propranolol, sulfachloropyridazine, sulfamethazine, sulfamethoxazole, tetracycline, trimethoprim, chlorotetracycline, oxytetracycline and sulfathiazole. The residual pharmaceuticals was analyzed LC-MS/MS equipped with on-line solid phase extraction (SPE) system and the limit of quantifications (LOQ) of 18 residual pharmaceuticals were 1~5 ng/L. Sampling points were 27 from the upstream to the downstream, including mainstream, tributary, and WWTP effluents. Sampling was conducted four times in Feb., Jun., Aug. and Nov. 2018.Results and Discussion:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as the highest mean concentration of 44.9~985.4 ng/L followed by caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L). In particular, the proportion ratio of caffeine gradually decreased as going to the downstream, whereas iopromide gradually increased. However, the concentrations of caffeine in the sampling sites of the downstream were higher than those of the upstream sites. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest detected concentration at the Goryeong area in the middle stream of the Nakdong River, and then gradually decreased due to the dilution effect. Residual pharmaceuticals in the Nakdong River basin, which could not be completely removed from the WWTPs, entered into the water system and contaminated source water of the downstream. This process is a typical contaminant pattern of the source water by the emerging micropollutants.Conclusions:The most frequently detected residual pharmaceutical in all WWTP effluents, tributaries and mainstream sites was caffeine, followed by carbamazepine, lincomycin, sulfamethoxazole and iopromide. In addition, iopromide was detected as 44.9~985.4 ng/L, showing the highest mean concentration at the sampling points, and caffeine (63.2~337.1 ng/L) and carbamazepine (13.8~145.0 ng/L), sulfamethoxazole (12.3~114.8 ng/L) and diclofenac (3.1~144.1 ng/L) in order. The total concentrations of detected residual pharmaceuticals gradually increased from the upstream to the middle stream, showed the highest concentration at the Goryeong area in the middle stream of the Nakdong River basin, and then gradually decreased due to the dilution effect.

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Effects of bromide (Br -) and iodide (I -) concentrations, chlorine (Cl2) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at 20℃ than 4℃, 10℃ and 30℃. In chloramination study, addition of ammonium chloride (NH4Cl) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs (12.31 µg/mg DOC), followed by HA water (4.96 µg/mg DOC), while AOM water produced the lowest yields of I-THMs (0.99 µg/mg DOC). SUVA254 values of EfOM water , HA water and AOM water were 1.38 L/mg･m, 4.96 L/mg·m and 0.97 L/mg·m, respectively. The I-THMs yields had a low correlation with SUVA254 values (r 2 = 0.002). 소 투입농도 및 수온 상승에 비례하여 I-THMs 생성농도도 증가하다가 염소 투입농도 3 mg/L 및 수온 30℃ 이상의 조 건에서는 오히려 I-THMs 생성농도가 감소하였다. 3) 시료수의 pH가 상승할수록 I-THMs의 생성농도가 증가 하였다. 4) 수중의 NH4 + -N 농도가 증가할수록 염소와 반응하여 생 성된 클로라민에 의해 I-THMs 생성농도가 증가하였다. 5) 하수처리장 방류수, 휴믹산 조제수, 조류유래 유기물질 함유수 및 4개의 낙동강 시료수(고령, 매리, 하구 및 진천천) 들을 대상으로 한 I-THMs 생성능을 조사한 결과, 하수처리 장 최종방류수가 I-THMs 생성능(12.31 µg/mg)이 가장 높았 고, 다음으로 휴믹산 시료수(4.96 µg/mg)로 나타났고, 조류유 래 유기물질이 가장 낮은 결과(0.99 µg/mg)를 나타내었다. 6) SUVA254값과 I-THMs 반응성과의 상관성을 평가한 결 과에서 상관계수(r 2 )가 0.002로 매우 낮게 나타나 SUVA254값 과 I-THMs 생성능과는 연관성을 찾기가 어려웠다.