• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.673-680
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• 2013

Phosphorus accumulating microorganisms (PAOs) are influenced by various environmental factors and heavy metals. This study was performed to evaluate the effects of the selected heavy metals on the growth and phosphorus removal capacity of Bacillus sp. 3434 BRRJ, Pseudomonas aerunogisa, and Bacillus Subtilis, well known as PAOs. The heavy metals used in this study included Cu, Cd, As, and Zn. The $IC_{50}$ (median inhibition concentration) values of Bacillus sp. 3434 BRRJ for the Cu, Cd, As, and Zn were 8.07 mg $L^{-1}$, 0.18 mg $L^{-1}$, 73.62 mg $L^{-1}$ and 0.25 mg $L^{-1}$, respectively. The $IC_{50}$ values of Pseudomonas aerunogisa for the Cu, Cd, As, and Zn were 4.45 mg $L^{-1}$, 0.16 mg $L^{-1}$, 18.51 mg $L^{-1}$ and 2.34 mg $L^{-1}$, respectively. The $IC_{50}$ values of Bacillus Subtilis for the Cu, Cd, As, and Zn were 3.81 mg $L^{-1}$, 0.18 mg $L^{-1}$, 11.31 mg $L^{-1}$ and 0.47 mg $L^{-1}$, respectively. The phosphorus removal efficiencies of the three bacteria, Bacillus sp. 3434 BRRJ, Pseudomonas aerunogisa, and Bacillus subtilis were 93.12%, 71.81%, and 65.31%, respectively. Based on the results of the three PAOs obtained from the study, it appears that Bacillus sp. 3434BRRJ may have the best results in terms of their growth rate and P removal efficiencies.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.491-495
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• 2014

Phytoremediation is a technology using plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is regarded as a cost-effective, efficient, eco-friendly, and solar-driven technology with good public acceptance. This study was conducted to find the plants accumulating heavy metals in soils contaminated with Cd and Pb. Experimental plots (plot size: $0.81m^2$) was artificially contaminated using a contaminated soil collected from a field in vicinity of Wondong mine (WD). Sunflower, corn and castor were tested for their potential to remove heavy metals from the contaminated soils. The results indicated that sunflower was most effective in accumulating heavy metals and thus remedying the soils among the three crops. Dry weight and heavy metal uptake of sunflower shoot differed with growth period. For example, the Cd content of shoots including leaf and stem were 0.31mg, 2.23 mg, and 0.96 mg per plot at 4, 8 and 12 weeks after planting in Cd4-WD treatment; in addition, the dry weight of the shoots in Cd8-WD treatment was reduced due to heavy metal toxicity. This experiment showed that sunflower absorbed Cd, Pb and Zn in their shoots up to 8 weeks of planting; thereafter heavy metals uptake was diminished. This implies that the efficiency of these plants in cleaning the contaminated soils may be high at the early stage of plant growth.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.5
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• pp.555-566
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• 1996

In order to assess the long-term airborne concentrations of 6 metals such as Cr, Cd, Pb, Zn, K, and Na and the associated health resk, a great number of PM-10 samples were collected and analyzed in Kyung Hee University-Suwon Campus for three years from 1991 to 1993. The 3-year average concentration of Pb in respirable particulate matters was 142.6 ng/m$^{3}$ while that of Zn was 1,210.5ng/m$^{3}$. The corresponding hazard index from Pb Zn for the ingalation route was estimated to be 9.5.times.10$^{-2}$ and 3.5.times.10$^{-2}$ , respectively. Therefore, it can be said that there was no adverse chronic health effects by airborne Pb and Zn. However, the 2-year average concentration of Cr(6) was estimated to be 1.3ng/m$^{3}$ shile the 3-year average concentration of Cd was 3.1ng/m$^{3}$. The total cancer risk by these two metals for the inhalation route was estimated to be about 7.2.times.10$^{-6}$ . This order-of-magnitude risk estimate suggests that the ingalation risk in the study area from all carcinogenic metals including As and Ni (subsulfide) might exceed the acceptable risk criteria of 10$^{-5}$ -10$^{-6}$ by U.S.EPA.For a better risk assessment in the future, alveolar deposition of PM-10 in the study area were also discussed and an assessment was done.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.2
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• pp.70-79
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• 2013

Since crude oil contains various pollutants including heavy metals, the environmental impact should be assessed for heavy metals as well as oil itself. In order to estimate the extent of heavy metal contamination, surface sediments were collected at the intertidal and coastal zone around the Herbei sprit oil spill area during December 2007 and January 2008. Organic carbon, sulfur and heavy metals were determined to assess heavy metal contamination in sediments. The crude oils contained C, S, V and Ni, but little toxic metals such as As, Cd, etc. From organic carbon content, the highest contaminated site was estimated that oils contributed to sediments up to 10%, and this site showed high V concentration. Potentially contaminated sediments by crude oil could be differentiated from unaffected sediments through V/Al and Ni/Al ratios, which can be used as indicators of oil contamination even after the oils were fully degraded.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1509-1517
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• 2004

A study was conducted to determine the safety of feeding processed broiler litter (BL) to beef cattle. The litter was processed by deepstacking, ensiling and composting. The health issues addressed relevant to the safety of feeding litter included pathogenic bacteria, mycotoxins, heavy metals, medicinal drugs and pesticide residues. Exp. 1 evaluated the feed hygiene of processed rice hulls-bedded BL. The presence of pathogenic bacteria in BL was determined before and after deepstacking. A total of 21 BL samples were collected over a 3-year period of commercial and experimental production of BL for beef cattle. Exp. 2 evaluated the safety of meat of cattle fed deepstacked BL. In Exp. 1, there were no pathogenic bacteria, such as coliform, E. coli, E. coli O157:H7, Salmonella, Listeria and Proteus, in deepstacked BL. Levels of heavy metals (Cu, Fe, Mn and Zn) and toxic heavy metals (As, Pb, Cd and Hg) were lower than the commercial feed tolerances. Aflatoxin, medicinal drug and pesticide residues were detected at extremely low levels. In Exp. 2, the meat of the BL-fed animals exhibited few differences in all analyzed items from that of the control group, showing safety from pathogenic microorganisms and heavy metals. When BL was withdrawn for 14 days prior to slaughtering the BLfed cattle, no medicinal drug residues were detected in the meat. Pesticides in the tissues of either group of animals were much lower than the tolerances. In conclusion, processed rice hulls-bedded BL and the meat of cattle fed BL were safe from the potential hazards of pathogenic bacteria, heavy metals, aflatoxin, medicinal drugs and pesticide residues.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.358-363
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• 2005

A large amount of oyster-shell waste has been illegally disposed at oyster farm sites along the southern coast of Korea, which already created serious environmental problems. Therefore, the study was undertaken to increase the consumption of oyster shell meal as a soil amendment. The effects of oyster shell meal on dynamics of heavy metals and uptake of heavy metals by spring Chinese cabbage were evaluated in silt loam soil (in Gyeongsang National University, Jinju, Gyeongnam-do, Korea), where 0, 4, 8, 12 and 16 Mg $ha^{-1}$ oyster-shell meal fertilizer were added. Lime treatment (2 Mg $ha^{-1}$) was selected as a control. In the results of this study, cabbage yields were increased by increasing levels of oyster-shell meal fertilizer. With increasing levels of oyster-shell meal fertilizer, total heavy metals concentrations were not significant among treatments. However, 0.1N HCl extractable heavy metals concentration was significantly reduced due to increasing of soil pH. A lot of portion (ca. $80{\sim}90%$) heavy metals fraction of all fractions was residual phase in soil after harvesting. The contents of Cu, Mo, Zn in cabbage were slightly increased by increasing levels of oyster shell meal fertilizer. However, there were no toxic symptoms of heavy metals during cultivation. Conclusively, it was estimated that oyster shell fertilizer could be a good amendment to increase productivity of crop and reduce uptake of heavy metals by crop and mobility of heavy metals in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.35-49
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• 2018

This study was initiated to quantitatively evaluate the effects of five heavy metals (Cd, Cu, Zn, Pb, and Ni) on growth and P removal efficiencies of Pseudomonastaeanensis, known as the phosphorus accumulating microorganism. The heavy metals were added individually and with the binary mixture to the batch culturing system of Pseudomonastaeanensis. $IC_{50}$ and $EC_{50}$ were used to quantitatively evaluate their effects on the growth and phosphorus removal efficiency of Pseudomonas taeanensis in those treatments. Additionally, additive index value method was used to evaluate the interactive effects of heavy metals for Pseudomonas taeanensis in this study. As those heavy metals were singly added to Pseudomonastaeanensis, the greatest inhibitory effect on its growth and P removal efficiency was observed in Cd, whereas, the smallest effect was found in Ni. As the concentrations of all heavy metals added were gradually increased, its growth and P removal efficiency was correspondingly decreased. Specifically, $IC_{50}$ of Pseudomonas taeanensis for Cd, Cu, Zn, Pb, and Ni were $0.44mg\;L^{-1}$, $5.12mg\;L^{-1}$, $7.46mg\;L^{-1}$, $8.37mg\;L^{-1}$ and $14.56mg\;L^{-1}$, respectively. The P removal efficiency of Pseudomonas taeanensis was 81.1%. $EC_{50}$ values of Pseudomonas taeanensis for Cd, Cu, Zn, Pb, and Ni were $0.44mg\;L^{-1}$, $4.08mg\;L^{-1}$, $7.17mg\;L^{-1}$, $8.90mg\;L^{-1}$ and $11.26mg\;L^{-1}$, respectively. In the binary treatments of heavy metals, the lowest $IC_{50}$ and $EC_{50}$ were found in the Cd + Cu treatment, whereas, the highest $IC_{50}$ and $EC_{50}$ were found in the Zn + Pb and Pb + Ni treatments, respectively. Most of the interactive effects for the binary mixture treatments of heavy metals were antagonistic. Based on the results obtained from this study, it appears that they could provide the basic information about the toxic effects of the respective individual and binary treatments of heavy metals on the growth and P removal efficiency of other phosphorus accumulating organisms.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.97-102
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• 2007

An environmental survey from three abandoned metal mine areas was undertaken on to assess the risk of adverse health effects on human exposure to heavy metals influenced by past mining activities. Tailings contained high concentrations of heavy metals may have a impact on soils and waters around the tailing piles. In order to perform the human risk assessment, chemical analysis data of soils, rice grains and waters for As, Cd, Cu and Pb have been used. The HQ values for heavy metals via the rice consumption were significantly higher compared with other exposure pathways in all metal mine areas. The resulting HI values in three mine areas were higher than 9.0, and their toxic risk due to rice ingestion was strong in these mine areas. The cancer risk of being exposed to As by the rice consumption from the A, B and C mine areas was $5.1\;{\times}\;10^{-3}$, $6.8\;{\times}\;10^{-3}$ and $3.1\;{\times}\;10^{-3}$, respectively. The As cancer risk via the exposure pathway of rice ingestion from these mine areas exceeds the acceptable risk of 1 in 10,000 set for regulatory purposes. Thus, the daily intakes of rice by the local residents from these mine areas can pose a potential health threat if exposed by long-term As exposure.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.193-200
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• 2016

Toxicity assessment of heavy metals (As, Cr and Pb) has been investigated by using the rate of survival and population growth(r) of marine rotifer, Brachionus plicatilis. The survival rate was determined after 24 hours of exposure to As, Cr and Pb. As and Cr reduced survival rate in dose-dependent manner and a significant reduction were occurred at concentration of greater than 30 and $150mg\;L^{-1}$, but Pb had no effect on survival rate. The r was determined after 72 hours of exposure to As, Cr and Pb. As, Cr and Pb reduced r in dose-dependent manner and a significant reduction were occurred at concentration of greater than 5, 25 and $50mg\;L^{-1}$. The toxicity of heavy metals were ranked As>Cr>Pb, with $EC_{50}$ values of 12.98, 82.34 and $110.14mg\;L^{-1}$, respectively. The no-observed-effect-concentration (NOEC) of r in As, Cr and Pb exposure were 1, 12.5 and $50mg\;L^{-1}$, respectively. The lowest-observed-effect-concentration (LOEC) of r in As, Cr and Pb exposure were 5, 25, and $50mg\;L^{-1}$, respectively. From the results, the concentration of As, Cr and Pb (greater than 5, 25 and $50mg\;L^{-1}$, respectively) have toxic effect on the r of B. plicatilis in natural ecosystems. These results (including NOEC and $EC_{50}$) might be useful for the mixing toxicity assessment and toxic guide line of heavy metals in marine ecosystems.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1591-1600
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• 2015

The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity($F_v/F_m$) decreased significantly when exposed to $Cu^{2+}$ and $Hg^{2+}$ for 12 h, and decreased in the order of $Hg^{2+}>Cu^{2+}>Cd^{2+}>Ni^{2+}$ when exposed for 24h. The effective photochemical quantum yield(${\phi}{\prime}_{PSII}$), chlorophyll fluorescence decrease ratio($R_{Fd}$), minimal fluorescence yield($F_o$), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to $Hg^{2+}$, $Cu^{2+}$, and $Cd^{2+}$. These results suggest that $F_v/F_m$, as well as ${\phi}{\prime}_{PSII}$, $R_{Fd}$, $F_o$, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, $F_v/F_m$ and maximal fluorescence yield($F_m$) changed in response to $Hg^{2+}$ and $Cu^{2+}$ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.