• Korean Journal of Microbiology
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• v.52 no.1
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• pp.40-48
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• 2016

This study mainly focused on isolation of marine algicidal bacteria associated with phytoplankton blooms and characterization of algicidal activity against harmful algae. Harmful algal blooms (HABs) found naturally in surface waters have caused many environmental problems worldwide. In this study, forty bacterial strains that have capability of inhibiting harmful algal growth were isolated from Masan Bay, Jinhae Bay, Dol Island, Jangmok Bay, and the Tongyeong Sea, Republic of Korea. The bacteria were screened furthermore for the characteristics on algicidal activities against Cochlodinium polykrikoides, Chattonella marina, Skeletonema costatum, Heterosigma akashiwo, Heterocapsa triquetra, Prorocentrum minimum, and Scrippsiella trochoidea. As a result, the algicidal bacteria that were screened from double over layer agar and microscopic counts tests belonged to genera Pseudomonas, Vibrio, Bacillus, Pseudoalteromonas, Ruegeria, Joostella, Marinomonas, Stakelama, Porphyrobacter, and Albirhodobacter. One of the most important HAB species is Co. polykrikoides and the strongest algicidal activity against the dinoflagellate was 94.00% after 6 h treatment with 10% bacterial culture filtrate. In this study, Marinomonas sp. M Jin 1-8, Stakelama sp. ZB Yeonmyeong 1-11 & 1-13, Porphyrobacter sp. M Yeonmyeong 2-22, and Albirhodobacter sp. 6-R Jin 6-1 were found to be as new genera of bacteria having anti-algal activity. These results suggest that these bacteria might play an important role in controlling phytoplankton blooms.

• Journal of Environmental Health Sciences
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• v.3 no.1
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• pp.27-44
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• 1976

This study was carried out to evaluate the harmful factors in working environments and to investigate the labor productivity after improvement of environments, surveying 93 industrial establishments of 10 industries located in Youngdeungpo industrial area in Seoul. The results obtained were as follows: 1) The highest noise level of 125dB(A) was indicated at the rolling process of transport equipment manufacturing industry. 2) The best illumination level was shown in precise machinery industry and the worst was indicated in rubber products, metallic products and transport equipment manufacturing industries. 3) Thermal conditions were above threshold limit value (TLV) at more than two processes of all industries except printing industry. 4) The highest dust concentration was determined in textile and wearing manufacturing industry. 5) Organic solvents were detected at 52 processes in 93 industrial establishments and 33 processes of them showed higher than TLV. The results about harmful chemicals were as follows: a) sulfur dioxide ($SO_2$)was determined higher than TLV on welding process of metallic product manufacturing industry and heat treatment process of transport equipment manufacturing industry. b) Carbon monoxide (CO) concentration was 700ppm at heat treatment process of transport equipment manufacturing industry, indicating 14 times of TLV. c) vinylchloride concentration in the air of PVC raw material mixing process and PVC preparation process of chemical product manufacturing industry was determined higher than TLV. d) Hydrochloride (HCl) concentration in the air of wire expanding process of transport equipment manufacturing industry was determined higher than TLV. 7) Higher values of lead concentration than TLV were determined at lead welding metallic product manufacturing industry and type planting process of process of printing industry, $1.8mg/m^3$ and $0.3mg/m^3$ respectively. 9) 22, 968 of 52, 855 workers (i.e. 43.5%) in 93 industries were exposed to various harmful agents. 10) It was found that the improvement of illumination in electric apparatus manufacturing industry (from 20~40 lux to 420 lux) resulted in an increase in productivity of 6.5% per capita and a decrease in faulty products of 19%. 11) Improvement of environments using local exhaust ventilation system resulted in a decrease of harmful substances lower than TLV and an increase in productivity of 11.4%. 12) Improvement of shovelling tools based on ergonomics resulted in a reduction in energy expenditure of 25.3% and an increase in productivity of 32.2% per capita.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.57-81
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• 2010

Since the Republic of Korea is highly dependent on fossil fuels despite high oil prices, it urgently needs to renew its economic and social system to cut carbon emissions and achieve green growth. Therefore, reforming or eliminating subsidies related to the use of fossil fuels is a timely and oppropriate policy recommendation for Korea. It would be a win-win deal for Korean society as it would not only reduce the use of environmentally harmful fossil fuels but also enhance economic efficiency. In particular, cross-subsidies for industrial, agricultural and night thermal-storage power services make up more than 80 percent of all subsidies provided to the entire electric power industry sector of Korea. Of these cross-subsidies, this paper analyzes the electricity subsidy for industries, which takes up the largest share (about KRW 1.6583 trillion yearly), among the environmentally harmful subsidies in the electric power sector. Thus, the paper focuses on the analysis of ripple effect anticipated when this is reformed. To examine the effects of this subsidy reform, price elasticities were estimated using the ARDL (autoregressive distributed lag) model and quarterly data from 1990 to 2007. The main results of this study show that 1) annual energy demand for electric power in the industrial sector would drop by 12,475,930MWh and 2) $CO_2$ emissions would plummet by 2,644,897 tons per year if the subsidy were reformed. We can deduct from this that the abolition of environmentally harmful subsidies in the electric power sector in the Republic of Korea would considerably contribute to $CO_2$ emissions abatement in the country.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.51-57
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• 2022

This paper investigated catalytic and adsorption equations among the technologies for removing hazardous substances generated in the semiconductor process. As the semiconductor industry develops, harmful substances used and discharged in the semiconductor process are also increasing. Hazardous substances adversely affect the global environment in terms of atmospheric and water quality. As regulations on the emission of harmful substances are strengthened in the 21st century, it is expected that there will be limitations in industrial development in the future. Therefore, technology for removing harmful substances generated in semiconductor processes is essential. In this paper, the goal is to remove PFCs, which are harmful substances, through adsorption technology and catalyst technology. Descriptions from the semiconductor process to the technology in which harmful substances generated are removed were summarized.

• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1167-1181
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• 2021

In relation to the algae bloom, four types of blue-green algae that emit toxic substances are designated and managed as harmful Cyanobacteria, and prediction information using a physical model is being also published. However, as algae are living organisms, it is difficult to predict according to physical dynamics, and not easy to consider the effects of numerous factors such as weather, hydraulic, hydrology, and water quality. Therefore, a lot of researches on algal bloom prediction using machine learning have been recently conducted. In this study, the characteristic importance of water quality factors affecting the occurrence of Cyanobacteria harmful algal blooms (CyanoHABs) were analyzed using the random forest (RF) model for Bohyeonsan Dam and Yeongcheon Dam located in Yeongcheon-si, Gyeongsangbuk-do and also predicted the occurrence of harmful blue-green algae using the machine learning and deep learning models and evaluated their accuracy. The water temperature and total nitrogen (T-N) were found to be high in common, and the occurrence prediction of CyanoHABs using artificial neural network (ANN) also predicted the actual values closely, confirming that it can be used for the reservoirs that require the prediction of harmful cyanobacteria for algal management in the future.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.370-385
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• 2023

Cyanobacterial harmful algal blooms (Cyano-HABs) are an international environmental problem that negatively affects the ecosystem as well as the safety of water resources by discharging cyanotoxins. In particular, the discharge of microcystins (MCs), a highly toxic substance, has been studied most actively, and various water treatment methods have been proposed for this purpose. In this paper, we reviewed adsorption technology, which is recognized as the most feasible, economical, and efficient method among suggested treatment methods for removing MCs. Activated carbons (AC) are widely used adsorbents for MCs removal, and excellent MCs adsorption performance has been reported. Research on alternative adsorption materials for AC such as biochar and biosorbents has been conducted, however, their performance was lower compared to activated carbon. The impacts of adsorbent properties(characteristics of pore surface chemistry) and environmental factors (solution pH, temperature, natural organic matter, and ionic strength) on the MCs adsorption performance were also discussed. In addition, toward effective control of MCs, the possibility of the direct removal of harmful cyanobacteria as well as the removal of dissolved MCs using adsorption strategy was examined. However, to fully utilize the adsorption for the removal of MCs, the application and optimization under actual environmental conditions are still required, thereby meeting the environmental and economic standards. From this study, crucial insights could be provided for the development and selection of effective adsorbent and subsequent adsorption processes for the removal of MCs from water resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.536-544
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• 2001

Three harmful algal bloom species with similar morphology, Cochlodinium polykrikoides, Gyodinium impudicum and Gymodinium catenatum have damaged to aquatic animals or human health by either making massive blooms or intoxication of shellfishes in a food chain. Eco-physiological and hydrodynamic studies on the harmful algae offer useful informations in the understanding their bloom mechanism by giving promising data for the prediction and modelling of harmful algal blooms event. Thus, we studied the abundance of these species in the coastal area of South Sea of Korea and their effects of temperature, salinity, irradiance and nutrient on the growth for the isolates. The timing for initial appearance of the three species around the coastal area of Namhaedo, Narodo and Wando was between Bate July and late August in 1999 when water temperature ranged from $22.8^{\circ}C\;to\;26.5^{\circ}C$ Vegetative cells of C. polykrikoides and G. impudicum were abundant until late September when water temperature had been dropped to less than $23^{\circ}C$. By contrast, vegetative cell of G. catenatum disappeared before early September, showing shorter period of abundance than the other two species in the South Sea. Both G. impudicum and G. catenatum revealed comparatively low density with a maximal cell density of 3,460 cells/L and 440 cells/L, respectively without making any bloom, while C. polykrikoides made massive blooms with a maximal cell density more than $40\times10^6$cells/L, The three species showed a better growth at the relatively higher water temperature ranging from 22 to $28^{\circ}C$ with their maximal growth rate at $25^{\circ}C$ in culture, which almost corresponded with the water temperature during the outbreak of C. polykrikoides in the coastal area of South Sea. Also, they all showed a relatively higher growth at the salinity from 30 to $35\%$. Specially, G. impudicum showed the euryhalic characteristics among the species, On the other hand, growth rate of G. catenatum decreased sharply with the increase of water temperature at the experimental ranges more than $35\%$. The higher of light intensities showed the better growth rates for the three species, Moreover, C. polykrikoides and G. impudirum continued their exponential growth even at 7,500 lux, the highest level of light intensity in the experiment, Therefore, It is assumed that C. polykrikoides has a physiological capability to adapt and utilize higher irradiance resulting in the higher growth rate without any photo inhibition response at the sea surface where there is usually strong irradiance during its blooming season. Although C. poiykikoides and G. impudicum continued their linear growth with the increase of nitrate ($NO_3^-$) and ammonium ($NH_4^-$) concentrations at less than the $40{\mu}M$, they didn't show any significant differences in growth rates with the increase of nitrate and ammonium concentrations at more than $40{\mu}M$, signifying that the nitrogen critical point for the growth of the two species stands between 13.5 and $40{\mu}M$. Also, even though both of the two species continued their linear growth with the increase of phosphate ($PO_4^{2-}$) concentrations at less than the $4.05{\mu}M$, there were no any significant differences in growth rates with the increase of phosphate concentrations at more than $4.05{\mu}M$, signifying that the phosphate critical point for the growth of the two species stands between 1.35 and $4.05{\mu}M$. On the other hand, C. polykrikoides has made blooms at the oligotrophic environment near Narodo and Namhaedo where the concentration of DIN and DIP are less than 1.2 and $0.3{\mu}M$, respectively. We attributed this phenomenon to its own ecological characteristics of diel vertical migration through which C. polykrikoides could uptake enough nutrients from the deep sea water near bottom during the night time irrespective of the lower nutrient pools in the surface water.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.1-14
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• 1996

To evaluate the health risk of the workplace environment of a general hospital toward the hospital workers, a questionnaire survey on the perception of risk at the workplace environment and environmental measurements at 27 locations with 240 workers in the hospital were made from October 25th, 1993 to October 30th, 1994. The results were as follows ; 1. By the environmental measurements, 86 workers(36%) were found to be exposed to poor or harmful degree of general illumination, 193 workers(80%) were exposed to poor or harmful local illumination, 34 workers(14%) were exposed to poor or harmful degree of thermal condition and 180 workers(75%) were exposed to poor or harmful noise level, but nobody was exposed to poor or harmful dust and toluene concentration. Also nobody was exposed to poor or harmful level of radiation or anticancer/antibiotic agents. 2. The subjective perceptions on the environmental conditions felt by the workers were different from the objective findings by the environmental measurements. The workers underscored the poor illumination state and overscored the dust concentrations. Also workers oversensitized about the thermal condition, the noise level, the radiation level, the toluene concentration and anticancer/antibiotic agents 3. The sources of noise were the dialogue(179 workers) and the office instruments(131 workers). The sources of dust came from the clothes(108 workers) and the building materials(79 workers). 4. The questionnaire survey showed that the 28 workers were exposed to poor or harmful level of the antibiotics, 10 workers to alkali or acid and 6 workers to drug dust in the pharmacy but the above findings could not be proved by the environmental measurements.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.640-651
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• 2019

The study analyzed the relationship between harmful cyanobacteria and physicochemical factors in Lake Juam from 2005 to 2018. The research locations were designated St. 1 (Juam-Dam) and St. 2 (Sinpyong). Harmful cyanobacteria was found in four genera (Microcystis sp., Anabaena sp., Aphanizomenon sp., Oscillatoria sp.). The average standing crops of harmful cyanobacteria in both locations were 2,575 cells mL^-1 and 2,557 cells mL^-1 from 2005 to 2011. Since 2012, there has been a significant decrease that the measurements were 42 cells mL^-1 and 82 cells mL^-1 from 2012 to 2018. To analyze the reason for the decrease in harmful cyanobacteria, Pearson's correlation and t-tests were performed on data collected during the summer period (June-September). Pearson's correlation showed a significantly positive correlation with total nitrogen(TN), outflow, and storage and a negative correlation with electrical conductivity. T-tests were conducted in two different periods and showed decreases in total nitrogen, electrical conductivity, and residence time. The average rainfall was decreased from 263.3 mm (2005-2011) to 219.9 mm (2012-2018) and total nitrogen was decreased from 0.912 mg L^-1 (2005-2011) to 0.811 mg L^-1 (2012-2018) and the same variability was seen in TP (total phosphorus). Therefore, it seems that the low-rainfall decreased the nutrients (TN) and variability in the TP, resulting in a decrease in harmful cyanobacteria in Lake Juam.

• Environmental Engineering Research
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• v.8 no.1
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• pp.8-14
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• 2003