노란잔산잠자리(멸종위기야생생물 II급) 약충은 내성천 일대 서식하는 것으로 알려져 있다. 2019년 3월 서식이 확인된 37개 지점의 하상 0.2㎡ 면적에서 채취한 퇴적물 입도 분석 및 개체수와의 상관관계를 분석하였다. 입도 분석 결과 ‘조립사’(500 ~ 1,000 ㎛) 52.5%, ‘극조립 사’(1,000 ~ 2,000 ㎛) 25.6%, ‘중립사’ (250 ~ 500 ㎛) 17.2%, ‘세립사’(125 ~ 250 ㎛) 3.1%, ‘극세립사’(63 ~ 125 ㎛) 1.0%, ‘실트’(63 ㎛미 만) 0.7% 순으로 나타났다. 노란잔산잠자리 약충의 개체수는 ‘극세립사’(63 ~ 125 ㎛), ‘세립사’(125 ~ 250 ㎛)와는 양의 상관관계를, ‘조립사’ (500 ~ 1.000 ㎛)와는 음의 상관관계를 나타내었다. 본 연구 결과를 통해 노란잔산잠자리 약충이 고운 모래를 서식처로 활용하고 있는 것을 확인 하였으며, 이러한 연구결과는 이후 내성천 일대 하상 환경변화 모니터링에 활용 할 수 있을 것이다.

The purpose of this study is to find out the effect of particle size of sediment on adsorption of fluoride. Particle size is classified as sand, silt and clay. Adsorption equilibrium time, adsorption isotherms and the effect of pH were investigated through batch tests. The pHpzc of sand, silt, clay was respectively 6, 8, 4.5 and AEC (anion exchange capacity) was highest in silt, respectively 0.0095, 0.0224, 0.014 meq g-1. Adsorption of fluoride on the sediment was in equilibrium within 300 minutes from all particle size. The experimental data of isotherms at various pH were well explained by Freundlich equation. As the experimental results of the effect of pH, the adsorption efficiency of sand and silt were reduced after the pHpzc. However, the adsorption efficiency of clay was maintained after the pHpzc, and decreased rapidly higher than pH 12.

본 연구에서는 HEC-RAS의 하상변동모형을 이용하여 고농도의 유사가 중소규모의 저수지에 유입하여 삼각주를 형성하는 과정을 유사의 입도분포를 고려하여 해석하였으며, 다음과 같은 결론을 얻을 수 있었다. 먼저, 삼각주의 시공간적인 분포와 년간 저수지에 퇴적되는 입도별 퇴사량을 합리적으로 예측할 수 있었다. 또한 저수지의 특정위치에서 특정시기에 어떤 입도의 유사가 주로 퇴적되는지를 합리적으로 예측할 수 있었다. 이러한 유사의 입도분포를 고려한 모의와 분석은 수자원관련 시설물의 계획 및 유지관리에 필요한 유용한 정보를 제공해 줄 수 있을 것으로 판단된다.

Sediments of Little Scioto (LS) River in Ohio was contaminated by poor disposal of creosote from Baker Wood Creosoting Facility. Among the primary compounds of creosote, Polycyclic Aromatic Hydrocarbons (PAHs) are the most common ingredient. PAHs are known for toxic, carcinogenic and mutagenic compounds. There are many difficulties to remove the PAHs in nature environment because their characteristics are having a less water-solubility, volatile and low mobility properties as increasing the molecular weight. The generation of hydroxyl radicals (ㆍOH) and hydrogen peroxide (H2O2) forms as well as high temperature (5000 K) and pressure (1000 atm) by a physico-chemical effects of ultrasound during a cavitation collapse can promote the degradation and desorption of PAHs in sediment And it can also produces shock wave and microjets which are able to change the size and surface of particle in solid-liquid system as one of physical effects. Therefore, we explored to understand the role of particle size, the effect of elimination for PAHs concentration by ultrasound and optimize the conditions for ultrasonic treatment. The condition of various size of particles ( > 150㎛, < 150㎛) and solid-liquid ratio (12.5g/L, 25g/L) for the treatment was considered and ultrasonic power (430 W/L) with liquid – hexane extraction and microwave extraction method were applied after ultrasound treatment.