The ecosystem provides a diverse array of environmental conditions for organisms, and only those that are capable of successfully adapting to these conditions within their habitats can endure, thrive, and proliferate. Further, the environmental conditions within these habitats can significantly affect the bioavailability of chemicals that are introduced therein, thus resulting in varied adverse impacts on the organisms. The present study aims to evaluate the sensitivity of Yuukianura szeptyckii - a species adapted to riparian - to heavy metals following ISO guideline 11276, with the objective of assessing its potential as an indicator species for ecotoxicological evaluations in riparian habitats. The findings revealed that cadmium and copper both had significant toxic effects depending on their concentrations. For cadmium, the LC50 was 280 mg kg-1, EC50 was 66 mg kg-1, and NOEC and LOEC were 25 and 50 mg kg-1, respectively. For copper, the LC50 was 911 mg kg-1, EC50 was 151 mg kg-1, and LOEC was 50 mg kg-1. Comparative analysis with previous results for the international standard species Folsomia candida and the domestic standard species Allonychiurus kimi indicated that Y. szeptyckii exhibited even greater sensitivity to toxicity values. The adverse effects on survival and reproduction were closely associated with the influx concentration of heavy metals in their bodies. Altogether, the results suggest that Y. szeptyckii is a sensitive species for ecotoxicological assessments in riparian habitats, thus making it suitable as an indicator species, particularly in riparian ecosystems that are characterized by relatively high humidity conditions.

This study conducted an investigation into the effects of fruit type and cultivation practices (organic and conventional) on soil characteristics and soil arthropod communities within apple, blueberry, grape, peach, and pear orchards. The collection of soil arthropod communities was achieved through the utilization of pitfall traps, with concurrent measurements taken for soil moisture content, electrical conductivity, and temperature. The findings of this study unveiled substantial impacts attributed to fruit type and cultivation practices on soil characteristics. Specifically, within organic apple orchards, discernibly higher levels of soil moisture content, electrical conductivity, and temperature were observed when compared to their conventional counterparts. The investigation into soil arthropod communities yielded a total of 1,527 individuals, classified in to five phyla and 15 orders. The range of abundance, species richness, and diversity indices varied across conventional and organic orchards. Cultivation practices were found not to exert a significant influence on soil arthropod community characteristics. However, Non-metric Multidimensional Scaling (NMDS) analysis indicated a significant differentiation in soil arthropod community structure based on cultivation practices. This study underscores the importance of considering vegetation structure and environmental characteristics that may influence soil arthropod communities comprehensively when assessing the impact of cultivation practices on soil arthropods. Furthermore, it emphasizes the need to account for both the characteristics and structure of soil arthropod communities in understanding the implications of cultivation practices on these organisms.

Many changes in the scale and structure of the Korean rice cropping system have been made over the past few decades. Still, insufficient research has been conducted on the sustainability of this system. This study analyzed changes in the Korean rice cropping system’s sustainability from a system ecology perspective using an emergy approach. For this purpose, an emergy table was created for the Korean rice cropping system in 2011, 2016, and 202, and an emergy-based indicator analysis was performed. The emergy analysis showed that the total emergy input to the rice cropping system decreased from 10,744E+18 sej year-1 to 8,342E+18 sej year-1 due to decreases in paddy field areas from 2011 to 2021, and the proportion of renewable resources decreased by 1.4%. The emergy input per area (ha) was found to have decreased from 13.13E+15 sej ha-1 year-1 in 2011 to 11.89E+15 sej ha-1 year-1 in 2021, and the leading cause was a decrease in nitrogen fertilizer usage and working hours. The amount of emergy used to grow 1 g of rice stayed the same between 2016 and 2021 (specific emergy: 13.3E+09 sej g-1), but the sustainability of the rice cropping system (emergy sustainability index, ESI) continued to decrease (2011: 0.107, 2016: 0.088, and 2021: 0.086). This study provides quantitative information on the emergy input structure and characteristics of Korean rice cropping systems. The results of this study can be used as a valuable reference in establishing measures to improve the ecological sustainability of the Korean rice cropping system.

본 연구의 목적은 질산, 황산, 암모니아수, 과산화수소에 대한 생태독성평가를 통해서 사고대비물질들에 대한 기초 독성 데이터베이스를 구축하여, 향후 화학사고 발생시 환경 피해에 관한 의사결정에 과학적 근거를 제공하는 데 있다. 이를 위해 본 연구에서는 사고대비물질 중 토양의 물리·화학적 성질을 변화시킬 수 있는 질산, 황산, 암모니아수, 과산화수소를 대상으로 국내 토착 절지동물인 김어리 톡토기 (Paronychiurus kimi)를 이용한 생태독성평가를 수행하였다. 7일간의 급성독성평가와 28일간의 만성독성평가를 수행하였으며, 시험물질 농도에 따른 토양의 pH 변화를 관찰하였다. 토양의 pH는 질산, 황산, 과산화수소, 암모니아수의 농도가 10,000 mg kg-1 soil dry wt.일 때, 각각 2.86, 2.72, 7.18, 9.69이었다. 질산, 황산, 과산화수소, 암모니아수에 대한 만성독성평가 결과, LC50 값은 각각 2,703, 5,414, 3,158, 859 mg kg-1 soil dry wt.이었으며, P. kimi의 산란 수에 대한 EC50 값은 각각 587, 2,148, 1,300, 216 mg kg-1 soil dry wt.이었다. 비록 본 연구에서는 사고대비물질들의 유입에 따른 토양 pH의 변화만이 조사되었지만, 본 연구의 결과는 P. kimi가 사고대비물질에 의해 변화된 토양의 pH뿐만 아니라 사고대비물질의 유입에 의해 감소된 유기물 함량과 생성된 반응 산물에 의해서도 사망률과 산란수에 영향을 받을 수 있음을 의미한다. 대부분의 사고대비물질들이 토양의 특성을 변화시킬 수 있다는 점을 감안할 때, 토양의 특성 변화와 이에 따른 생물 영향을 고려한 화학사고 후 평가 및 복원 방법이 필요하다.

Acute and chronic toxicities of methyl ethyl ketone and methanol were investigated on Paronychiurus kimi (Collembola), for evaluating the potential effects of accidental exposures of these chemical substances on the terrestrial environments. This study was undertaken to establish a toxicity database for these chemical substances, which was required for the preparation of the response compensation and liability act for agricultural production and environmental damage. The 7-d acute toxicity and 28-d chronic toxicity were conducted using the OECD artificial soil spiked with varying, serially diluted concentrations of methyl ethyl ketone and methanol. Mortality was recorded after 7-d and 28-d of exposures, and the number of juveniles were determined after 28-d of exposure in the chronic toxicity test. In both assessments, methanol was more toxic than methyl ethyl ketone in terms of mortality (LC50) and reproduction (EC50). The 7-d LC50 of methyl ethyl ketone and methanol were 762 and 2378 mg kg-1 soil dry wt., respectively, and the 28-d LC50s were 6063 and 1857 mg kg-1 soil dry wt., respectively. The 28-d EC50 of methyl ethyl ketone and methanol were 265 and 602 mg kg-1 soil dry wt., respectively. Comparison of results obtained in this study with literature data revealed that P. kimi was more sensitive to methanol than other soil invertebrates. However, given the high volatility of the chemicals tested in this study, further studies are necessary to improve the current test guideline, or to develop new test guidelines for an accurate assessment of chemicals that require toxicity databases for chemical accidents.

In this study, the effect of hydrogen peroxide (H2O2) pre-treatment for sewage sludge prior to anaerobic digestion wasassessed using a batch test with an objective to decrease nitrogen, dissolved sulfide and siloxane in sewage sludge. Atotal of 6 sets of experiments (Blank, 20, 40, 60, 80 and 100g H2O2/kg wet sludge) were carried out, each with duplicates.To assess the effect of different dosages of H2O2 on anaerobic digestion, the treated sewage sludge was used for biochemical methane potential (BMP) test and SCODcr concentration. Due to the H2O2 pre-treatment, solubilization of SCODcr in pretreated sludge increased by 89% compared to raw sewage sludge, whereas T-N and NH3-N concentrationdecreased. Cumulative methane yields were increased for all pretreated samples due to increased sludge solubilizationthrough H2O2 pre-treatment. In addition, dissolved siloxane concnetrations were decreased for all pretreated samples. Thus,a reduction in dissolved siloxane concenrtation can decrease the siloxane generation potential of sludge during anaerobicdigestion. However, dissolved sulfide concentration remained same. Although H2O2 dosage did not show any furtherimpact on dissolved sulfide, they have significantly decreased T-N, NH3-N and dissolve siloxane concentrations beforeanaerobic digestion.

2011년말 기준으로 공공하수처리시설은 505개소로 2001년 184개소, 2010년 470개소 등 지속적으로 증가하고 있으며, 이에 따라 하수처리시설에서 발생하는 슬러지량도 증가하고 있다. 슬러지를 처리하는 방안으로 고화, 매립, 해양배출, 혐기성 소화 등의 방법이 있으나, 고화 및 매립은 2차 환경오염에 대한 우려가 있고 해양배출은 2012년부터 전면 금지되었다. 이에 환경부에서는 공공하수처리시설에 설치된 혐기성 소화조의 효율 개선사업을 통해 소화효율을 향상시켜 메탄의 생산량 증대와 슬러지 감량화를 도모하고 있다. 슬러지의 감량화 및 바이오가스 발생량의 증대를 위해 혐기성 소화 전에 슬러지를 전처리시키는 다양한 기술 개발이 이루어지고 있다. 혐기성 소화 공정은 가수분해, 산 생선, 초산생성 및 메탄생성 단계로 구분될 수 있으며, 이 중 가수분해 단계는 율속단계로서 전체 혐기성 소화공정의 효율 및 속도를 조정하기 때문에 가수분해 단계가 쉽게 이루어지기 위해 가용화라는 슬러지의 전처리를 수행하는 것이다. 전처리 공정의 방법으로는 열적처리, 화학적 산화, 기계적 처리, 생물학적 처리 등이 있다. 이 중 생물학적 처리 공정은 고온 호기성 박테리아를 배양시킨 후 소화조에 주입하여 슬러지의 혐기성 소화효율을 향상시키는 방법과 소량의 산소를 주입하지만 일정한 혐기 조건과 낮은 환원 조건을 유지하면서 미생물의 성장과 효소 합성 및 활성을 유발시켜 슬러지의 가용화 및 소화효율을 향상시키는 방법이 있다. 이에 본 연구에서는 공기의 주입을 통한 생물학적 전처리 방법이 슬러지 내에 존재하는 유기물뿐만 아니라 질소와 실록산 등의 거동에 미치는 영향을 분석하여 공기 주입을 통한 생물학적 전처리 방법이 혐기성 소화효율 향상과 반류수질, 바이오가스 정제시설 중 실록산 제거시설 등에 미치는 오염부하의 저감 가능성을 평가하고자 하였다. 실험결과, ORP는 공기 주입기간이 길어질수록 약간씩 증가하였으나 -247 ~ -268 mV의 환원조건을 나타내었으며, DO는 0.00 ~ 0.22 mg/L로 나타났다. 따라서 슬러지 전처리를 위해 공기를 주입하여도 소화조 내의 혐기성 조건에 미치는 영향은 미미할 것으로 판단된다. SCODcr의 경우에는 공기를 주입에 따라 SCODcr의 농도가 증가하여 공기주입에 의한 가용화 효과가 있는 것으로 나타났다. 총 질소와 암모니아성 질소의 경우 공기주입기간이 길어질수록 농도가 감소하는 경향을 나타내었다. 이는 DO 농도가 1 mg/L 이하의 조건을 유지하고 있어 공기주입에 의한 동시 질산화 및 탈질 현상이 발생한 것으로 판단된다. 따라서 공기주입에 의한 전처리 방법이 슬러지 내 질소의 부하를 감소시켜 암모니아성 질소로 인한 혐기성 소화의 저해 가능성과 혐기성 소화 후 반류수 및 방류수에 영향을 미치는 질소 부하를 저감시킬 수 있을 것으로 판단된다. 실록산의 경우 공기주입 기간 증가에 따라 공기를 주입하지 않은 슬러지 내의 실록산 농도가 6.06 mg/kg에서 공기주입 4일째에는 3.43 mg/kg으로 감소하여, 공기주입 전처리 방법을 통해 바이오가스 정제 시설 중 실록산 처리 공정에 미치는 실록산 부하를 저감시킬 수 있을 것으로 사료된다.