• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.52-60
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• 2010

The stone-dust is an unavoidable by-product of aggregate production, which is produced about 0.8~1.0 million $m^3$ annually. The stone-dust is currently regarded as a hazard material on environment because it is classified as an industrial waste in the Waste Management Law of Korea. At present, the stone-dust is considered as a environmentally hazardous material, and is classified as an industrial waste according to the Waste Management Law of Korea. In this study, we assessed the heavy-metal contamination of the stone-dust on surrounding environments by various leaching tests. Leaching experiments (such as Korea Standard Leaching Procedure (KSLP), Soil Environment Preservation Act of Korea (SEPAK), Toxicity Characteristic Leaching Procedure (TCLP), and Synthetic Precipitation Leaching Procedure (SPLP)) show that very low heavy metals (As, Cd, Cu, Pb, Zn, Hg) and CN are leached out, or much less than each regulatory thresholds. The resuts of the leaching test with time in acidic solution (initial pH 5 and 3) indicate that pH-buffering minerals are present in the stone-dust. These results suggest that the stone-dust can not potentially affect adverse impact on surrounding environments such as surface water, groundwater and soil etc..

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.362-367
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• 2006

Waste activated sludge(WAS) collected from domestic wastewater treatment plant is biomass that contains large quantities of organic matter. However, relevant literature show that the bio-hydrogen yield using WAS was too low. In this study, the effect of pretreatment of WAS on hydrogen yield was investigated. Pretreatment includes acid and alkali treatments, grinding, heating, ozone and ultrasound methods. After pretreatment organic matters of WAS were solubilized and soluble chemical oxygen demand(SCOD) was increased by 14.6 times. Batch experiments were conducted to investigate the effects of pre-treatment methods and buffer solution, hydrogen partial pressure, and sodium ion on hydrogen production from WAS by using heated anaerobic mixed cultures. Experimental results showed that addition of buffer solution, efficient pre-treatment method with alkali solution, and gas sparging condition markedly increased the hydrogen yield to 0.52 mmol $H_2/g$-DS.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.107-114
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• 2007

This study aimed to investigate the hexachlorobenzene (HCB) dechlorinating ability of sediment microbes collected from a natural canal receiving secondary effluents from an industrial estate and nearby factories. Nine sites along the stream and one in the estuary in the Gulf of Thailand into which the canal spills were specified and sampling for sediment and water. Preliminary analysis of the sediments showed that the first four sites nearest to the discharging location were contaminated by HCB within the range of 0.18 to 1.25 ppm. Apart from that, 1,3,5-trichlorobenzene which has never been commercially produced or used in any manufacturing processes except for the transformation from higher chlorinated benzene was also identified in the range of 0.16 to 0.24 ppm. This suggested a possibility of sporadically HCB contamination in this stream. Of more important, people in the community along this canal earn their living by coastal fishery; hence, posing a risk of spreading HCB and its less chlorinated congeners via food chain from caught marine creatures to human. As a result, there is an urgent need to understand the behavior of HCB dechlorination in this stream sediment which can lead to a clean-up action in the future. Serum bottles with sediment slurries (sediment to water ratio of 1:1 (v/v) and filtered to remove particles larger than 0.7 mm) from each site were inoculated with 2 mg/l of HCB, kept anaerobically in the dark at room temperature without any nourishment, and analyzed for HCB and its less-chlorinated congeners every 6 days. Total chemical oxygen demand, suspended solids, and volatile suspended solids were in the range of 21,492-73,584, 158,100-518,100 and 6,000-32,700 mg/l, respectively. It was found that all sediment slurries began to dechlorinate HCB in 12 to 30 days and the HCB was completely removed within 42 to 60 days or so. On the other hand, there was no HCB dechlorination occurred in the controlled set which was sterilized by autoclaving prior to the addition of HCB. This implies that the HCB transformation was solely due to microorganisms' activities. HCB was dechlorinated principally via pentachlolobenzene to 1,2,3,5-tetrachlorobenzene and terminated at 1,3,5-trichlorobenzene which is the major pathway as reported by many researchers. Dichlorobenzene has not been detected in any samples within the dechlorination period of 60 days. The results indicate that the microbial matrix in the sediment of this stream has an outstanding capability to dechlorinate HCB. Existing substrates and nutrients which mainly sorbed onto the solid phase and the typical temperature in Thailand were sufficient and suitable to promote the activities of these HCB-dechlorinating microbes.

• Journal of Soil and Groundwater Environment
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• v.15 no.1
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• pp.57-65
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• 2010

Currently, the pursuit of industrialization for rapid economic growth has led to serious environmental damage and related problems because of comtamination with chemicals. Over time, this contaminaion is getting worse and worse. Most developing countries have tried to pursue their economic development and growth, however without preparation for the control and disposal of hazardous wastes. Permitting hazardous waste to be abandoned and disposed in appropriately causes soil pollution, groundwater contamination, and surface water contamination, which are all extremely serious. In particular, when hazardous wastes which include toxic chemicals are distributed around the living environment even in small amounts, concentration can occur in the food chain through ecological systems, which can therefore affect human. Chromium(VI) has contaminated soil in China. We experimented to test the immobilization, chemical reduction, and soil washing methods in order to make our experiment efficient in the purification of soil contaminated with Chromium(VI), and to prove the theoretical models by experiments testing the field applications. The field experiment showed that result of experiment satisfied with the standards of China. The result of multi-stage continuous remediation reduce the Chromium(VI) concentration to 11.95 mg/kg and 14.83 mg/kg that were equivalent to 98% and 97% removal rates. This result implied we could apply multi-stage process of Chromium(VI) contaminated soil to meet the regulatory limit of Chromium(VI).

• Journal of Preventive Medicine and Public Health
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• v.36 no.4
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• pp.314-322
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• 2003

Objectives : In this study, the exposure status of the hazardous substances from incinerators, such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), were studied , and the relationship between the exposure of these hazardous substances and their heath effects on the workers and residents near municipal solid waste (MSW) incinerators and an industrial incinerator investigated. Methods : Between July 2001 and Jure 2002, 13 workers at two MSW incinerators, 16 residents from the area around the two MSW incinerators, 6 residents from the control area, and further 10 residents near an industrial incinerator, estimated to emit higher levels of hazardous substances, were interviewed. Information, including sociodemographic information, personal habits, and work history, detailed gynecologic and other medical history were collected through interviews. Blood samples were also collected from 45 subjects, and analyzed for PCDD/DFs, by high resolution gas chromatography -high resolution mass spectrometry, using the US EPA 1613 method. In addition to the questionnaire survey, urinary concentrations of 8-hydroxydeoxyguanosine (8-OH-dG) and malondialdehyde (MDA) were measured as oxidative injury biomarkers. The urinary concentrations of 8-OH-dG were determined by in vitro ELISA, and the MDA by HPLC, using u adduct with thiobarbituric acid. Results : The PCDD/DFs concentrations in the residents near the industrial incinerator were higher than those in the controls, workers and residents near the MSW incinerators. The average TEQ (Toxic Equivalencies) concentrations of the PCDD/DFs in residents near the industrial incinerator were 53.4pg I-TEQs/g lipid. The estimated daily intakes were within the tolerable daily intake range (1-4 pg I-TEQ/Kg bw/day) suggested by WHO (1997) in only 30% to the people near the industrial incinerator. Animal studies have already shown that even a low body border of PCDD/DFs, such as 10 ng TEQ/kg bw, can cause oxidative damage in laboratory animals. Our study also showed that the same body burden of PCDD/DFs can cause oxidative damage to humans. Conclusions : The exposures to PCDD/DFs and the oxidative stress of residents near the industrial incinerator, were higher than those in the controls, workers and residents near the MSW incinerators. Proper protection strategies against these hazardous chemicals are needed. Because a lower body burden of PCDD/Fs, such as 10ng TEQ/kg bw, can cause oxidative damage, the tolerable daily intake range should be restrictedly limited to 1pg I-TEQ/kg bw/day.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.233-243
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• 2021

Photovoltaic panels are hazardous electronic waste that has heavy metal as one of the hazardous components. Each year, hazardous electronic waste is increasing worldwide and every heavy rainfall exposes the photovoltaic panel to become the source of heavy metal soil contamination. the development needs a monitoring technology for this hazardous exposure. this research use relationships between SAR temporal baseline and coherence of Sentinel-1 satellite to detected photovoltaic panel. Also, the photovoltaic plant detection tested using the difference between that photovoltaic panel and the other difference surface of coherence. The author tested the photovoltaic panel and its environment to calculate differences in coherence relationships. As a result of the experiment, the coherence of the photovoltaic panel, which is assumed to be a permanent scatterer, shows a bias that is biased toward a median value of 0.53 with a distribution of 0.50 to 0.65. Therefore, further research is needed to improve errors that may occur during processing. Additionally, the author found that the change detection using a temporal baseline is possible as the rate of reduction of coherence of photovoltaic panels differs from those of artificial objects such as buildings. This result could be an efficient way to continuously monitor regardless of weather conditions, which was a limitation of the existing optical satellite image-based photovoltaic panel detection research and to understand the spatial distribution in situations such as photovoltaic panel loss.

• Safety and Health at Work
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• v.15 no.1
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• pp.9-16
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• 2024

Background: E-waste workers in Hong Kong are handling an unprecedented amount of e-waste, which contains various neurotoxic chemicals. However, no study has been conducted to evaluate the neurological health status of e-waste workers in Hong Kong. This study aimed to evaluate the prevalence of neurobehavioral alterations and to identify the vulnerable groups among Hong Kong e-waste workers. Methods: We recruited 109 Hong Kong e-waste workers from June 2021 to September 2022. Participants completed standard questionnaires and wore a GENEActiv accelerometer for seven days. Pittsburgh Sleep Quality Index and Questionnaire 16/18 (Q16/18) were used to assess subjective neurobehavioral alterations. The GENEActiv data generated objective sleep and circadian rhythm variables. Workers were grouped based on job designation and entity type according to the presumed hazardous level. Unconditional logistic regression models measured the associations of occupational characteristics with neurobehavioral alterations after adjusting for confounders. Results: While dismantlers/repairers and the workers in entities not funded by the government were more likely to suffer from neurotoxic symptoms in Q18 (adjusted odds ratio: 3.18 [1.18-9.39] and 2.77 [1.10-7.46], respectively), the workers from self-sustained recycling facilities also have poor performances in circadian rhythm. Results also showed that the dismantlers/repairers working in entities not funded by the government had the highest risk of neurotoxic symptoms compared to the lowest-risk group (i.e., workers in government-funded companies with other job designations). Conclusion: This timely and valuable study emphasizes the importance of improving the working conditions for high-risk e-waste workers, especially the dismantlers or repairers working in facilities not funded by the government.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.33-43
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• 2013

That occur in the ocean and the efficient management of marine litter on marine pollution oil spill response one step further strategies are needed. Marine pollution accidents occurred in 2011, a total of 287 and was found in runoff 369 kL, respectively compared to the previous year decreased by 13% and 39%. Average amount of marine materials during 5-years represent the oil flow of 310.5 kL (heavy fuel oil of 106.0 kL, diesel of 178.9 kL, oily bilge water of 22.3 kL, other oil of 7.7 kL) and the waste of 62.3 tons, the hazardous and noxious substances (HNS) was 510.6 kL. Marine emissions in 2011 by type of waste that a total amount of dumping 3,972 $m^3$, and livestock manure 795 $m^3$(20%), waste water 1,431 $m^3$(36%), sewage sludge 887 $m^3$(22%), wastewater sludge, 813 $m^3$(21%), manure 5 $m^3$(0.1%), other 41 $m^3$(0.9%), respectively. The concept of marine waste and needs to be more clearly defined. Integrated management of hazardous chemicals according to the incident management system should be established. To remove of coastal pollution, response officer needs korean coast response system. Like the marine pollution response, coastal pollution response systems also require step response.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.224-227
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• 2001

In general, municipal solid waste incinerator fly ash (MSWIF) has a potential hazardous leaching of heavy metal with subsurface environment variation. Therefore, to remove the heavy metal from MSWIF electrokinetic technology were used. With constant current density condition heavy metals in MSWIF removed by ion migration. During 7 days operation 40~80% of Cr, Cd and As were removed and longer operation, 14 days treatment, showed 35~100% removal efficiency.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.153-153
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• 2003

In Korea, the number of municipal and hazardous waste incinerators have been increasing since the 1980s. In addition, municipal waste incinerators (MWI) are almost always located in residential areas. Therefore, the human health risk caused by dioxin has become a growing public concern in Korea. In this report, we describe the results of study in which serum levels of PCDDs/PCDFs in a group of workers at the MWI were compared to those in a comparison group of community residents who had never worked at the MWI.