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생분해에 따른 용존 유기물질 성상 및 중금속 구리와의 결합특성 변화
정가영(Ka Young Jung),허진(Jin Hur) 大韓環境工學會 2012 대한환경공학회지 Vol.34 No.1
본 연구에서는 수 환경 내에서 일어나는 주요 자연분획변환 과정 중 생분해 시 변화하는 용존 유기물질의 특성이 중금 속 결합특성에 미치는 영향을 조사하고자 하였다. 각각 호수와 하천 기원을 대표하는 Pony lake fulvic acid와 Suwannee river fulvic acid를 포함한 다양한 유기물을 대상으로 2주간 배양실험을 하여 변화하는 농도, 성상 및 중금속 구리 결합특성을 조사 한 결과 각 시료 내 DOC농도는 감소하고 SUVA 값은 증가하였다. 특히 포도당 및 단백질계 탄소구조 함유비율이 높을수록 미 생물에 의한 DOC 농도 분해율은 증가하였다. 포도당과 휴믹물질의 혼합비를 고려한 경우 배양 후 예측되는 혼합액의 DOC 감소율은 실제 측정값과 유사하였다. 그러나 SUVA값은 오히려 더 높게 나타나 생분해성 물질과 휴믹물질이 혼재할 경우 탄소 구조 변화로 인한 휴믹화의 진행이 더 크게 나타날 수 있음을 보였다. Synchronous 형광스펙트럼 결과 배양 후 Pony lake fulvic acid의 경우 휴믹산계 형광특성이, Suwannee river fulvic acid에서는 펄빅산계 형광특성이 크게 증가하였다. 포도당 시료에서는 배양 전 관찰되지 않았던 단백질계와 펄빅산계 형광특성이 관찰되었다. 중금속 구리와의 결합정도를 나타내는 log K 값은 미 생물 배양 전과 후 휴믹물질 종류에 따라 변화가 없거나 혹은 약간 감소하는 경향을 나타냈다. 본 실험 결과는 미생물에 의한 휴믹물질 관련 형광구조의 증가가 중금속 결합력 강화에 영향을 미치지 않거나 오히려 감소시키는 것으로 보인다. Microbial changes in the characteristics of dissolved organic matter (DOM) and the subsequent effects on the conditional stability constants of copper were investigated using 14 day-incubations of Pony Lake fulvic acid (PLFA), Suwannee River fulvic acid (SRFA) and the mixtures of the humic substances and glucose. After incubation, dissolved organic carbon (DOC) concentrations were diminished, and specific UV absorbance values and DOC-normalized fluorescence intensities increased. The microbial changes were minimal for the samples contaning humic substances only whereas they were much pronounced for the mixtures with glucose. The extent of the changes increased with a higher content of glucose in the mixtures. The same trend was observed even for glucose solution. Our results suggest that labile organic moieties may be transformed into more chromophoric and humidified components by biodegradation. For the mixture samples, the copper binding stability constants did not change or even decreased after incubation. Therefore, microbially induced enrichment of the fulvic- and humic-like carbon structures in DOM appears to result in little change or the decrease of the copper binding coefficients.
정가영 ( Ka-young Jung ),김지은 ( Ji-eun Kim ),최충호 ( Choong-ho Choi ) 대한예방치과·구강보건학회 2021 大韓口腔保健學會誌 Vol.45 No.4
Objectives: This study examines the pH and titratable acidity of pomegranate drinks sold in Korea to identify the risk of dental erosion, and to provide basic data for oral health when consuming such drinks. Methods: The experiment included 5 groups: As experimental drinks, Sunkist pomegranate (Group A), Beauty liked pomegranate (Group B), Pomegranate juice 100 (Group C) were selected, and Jeju Samdasoo and Coca-Cola were selected for negative and positive controls. The components of the experimental beverage were analyzed, and the degree of erosion was measured using the Vickers hardness number (VHN) and by scanning electron microscope images. Results: When comparing the surface microhardness before and 30 minutes after beverage immersion, there was a significant difference in the positive control group, Group A, Group B, and Group C (P< 0.05), while there was no significant difference in the negative control group (P >0.05). The difference in surface microhardness (ΔVHN) was found in Group C (-117.33±17.41), Group A (-112.90±15.19), the positive control group (-103.80±13.23), Group B (-90.82±24.60), and the negative control group (-13.44±14.60), in that order. The positive control group, Group A, Group B, and Group C showed a significant difference from the negative control group (P<0.05), and Group B showed a significant difference from Group A, and Group C (P< 0.05), whereas Group A, Group B, and Group C did not differ significantly from the positive control group (P >0.05). Conclusions: This study found that the low pH and high titratable acidity of commercially available pomegranate drinks can potentially cause dental erosion. Therefore, it is imperative to provide dietary guidance so that consumers can recognize the possibility of dental erosion when consuming pomegranate drinks and manage their oral health.