• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.450-461
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• 2006

In this study, sorption kinetics of lead (Pb) and cadmium (Cd) onto coastal sediments were investigated at pH 5.5 using laboratory batch adsorbers. Four different models: one-site mass transfer model (OSMTM), pseudo-first-order kinetic model (PFOKM) ,pseudo-second-order kinetic model (PSOKM) and two compartment first-order kinetic model (TCFOKM) were used to analyze the sorption kinetics. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM, PFOKM and PSOKM in describing sorption kinetics of Pb and Cd onto sediments. Most sorption of Pb and Cd was rapidly completed within the first three hours, followed by slow sorption in the subsequent period of sorption. All models predicted that the sorbed amount at the apparent sorption ($q_{e,s}$) equilibria increased as the CEC and surface area of the sediments increased, regardless of initial spiking concentration ($C_0$) and heavy metal and the sediment type. The sorption rate constant ($k_s,\;hr^{-1}$) in OSMTM also increased as the CEC and BET surface area increased. The rate constant of pseudo-first-order sorption ($k_{p1,s},\;hr^{-1}$) in PFOKM were not correlated with sediment characteristics. The results of PSOKM analysis showed that the rate constant of pseudo-second-order sorption ($k_{p2,s},\;g\;mmol^{-1}\;hr^{-1}$) and the initial sorption rate ($v_{o,s},\;mg\;g^{-1}\;hr^{-1}$) were not correlated with sediment characteristics. The fast sorption fraction ($f_{1,s}$) in TCFOKM increased as CEC and BET surface increased regardless of initial aqueous phase concentrations. The sorption rate constant of fast fraction ($k_{1,s}=10^{0.1}-10^{1.0}\;hr^{-1}$) was much greater than that of slow sorption fraction ($k_{2,s}=10^{-2}-10^{-4}\;hr^{-1}$) respectively.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.320-329
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• 2023

Cadmium (Cd), a heavy metal found in the aquatic environment, accumulates in organisms through the food chain. In the study, we investigated the survival rates, measurement of body Cd levels, and expression analysis of the stress response genes (Heat shock protein 70: HSP70 and Heat shock protein 60: HSP60) and antioxidant enzyme Glutathione S-Transferases (GST) on benthic oligochaete worm Tubifex tubifex exposed three concentrations of Cd, to analyze the bioaccumulation and changes of stress gene expressions to exposure toxicity of the Cd-spiked sediment. Survival rates of T. tubifex exposed to the Cdspiked sediment were 93% at 0.4 mg kg^-1 Cd, 96% at 1.87 mg kg^-1 Cd, and 93% at 6.09 mg kg^-1 Cd for 10 days. Cd concentration in the body of T. tubifex was higher than that in the sediment. After Cd exposures for 10 days, the body Cd levels were 18.4 mg kg^-1, 13.06 mg kg^-1, and 79.11 mg kg^-1 at exposed three concentrations of Cd, respectively. Upregulation of HSP70 gene expression was observed at all concentrations of exposed Cd as a time-dependent manner, whereas transcriptional expression of the HSP60 gene increased as a timedependent manner in T. tubifex exposed to the relative high concentration (6.09 mg kg^-1) of Cd. However, GST gene expression increased on day 1 at all concentrations after Cd exposures, and then downregulated until 10 days. These results indicate to ecotoxicological and molecular effects in benthic oligochaete worm T. tubifex to Cd-spiked sediment and provide the basic information for the utilization of environmental toxicity assessment using the T. tubifex as a aquatic pollution indicator species.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.324-332
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• 2001

Foods constitute a large portion of heavy metal exposure toward general population and attract a deep concern with respect to assuring human health. This study summarized published data in Korea on the content, and dietary intake of heavy metals and assessed their risk potential in comparison with foreign data. An analysis for the yearly fluctuation of metal contents including arsenic, cadmium, mercury and lead by flood group (marine fishes, coastal shellfishes, freshwater fishes, cereal grains) exhibited a decreasing trend from the 1970s to the 1990s. When compared with domestic standards of heavy metals, their mean contents were below the limit and their maximum values seldom exceeded the limit. The data on the dietary intake of heavy metals by Koreans showed a decreasing trend from the 1980s to the 1990s. The average intakes offs and Hg were 6∼8% and those of Cd and Pb were 50∼80% of PTWI(provisional tolerable weekly intake), all of which were below the tolerance. As the extreme intakes of these metals may exceed the PTWI, a careful assessment for them may be necessary. Dietary intakes of Cd, Hg and Pb by Koreans lie in the mid-level among countries cited in the GEMS/Food monitoring data. As fishery foods are suspecious of contamination with Hg, Cd and As, and floods in general are with Pb, it is necessary to establish legal limits for these metals and monitor any progress of their contamination. Furthermore, overall assessment of exposure to heavy metals from all sources including floods, air, drinking water and occupation should be made in order to confirm the dietary risk factors and to assure the safety of food resources.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.126-132
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• 1981

Rice grains harvested from paddy fields around industrial areas of Kyongin, Iri, and Jeonju were taken and analysed the contents of heavy metals which were considered to be accumulated in those rice grains. Atomic absorption spectrophotometer was applied for analysis of heavy metals such as copper(Cu), zinc(Zn), lead(Pb) and cadmium (Cd) in unpolished rice grains. The content of Cu in rice grains harvested from Iri was the lowest, 2.94 ppm, while those from Seo-Myon, Shiheung-Gun was the highest, 3.65 ppm. The contents of Zn and Pb in rice grains were ranged 20.56~27.21 ppm and 0.38~0.53 ppm, respectively. Cd content were exceptionally lower than the regulated level, 1.0 ppm. The content of this metal detected in rice grains from Seo-Myon was the highest, 0.509 ppm, but those of other areas were much lower, ranged 0.040~0.136 ppm. The present concentrations of Cu, Zn, and Pb in rice grains were also lower than the expected level and below the maximum permissible concentrations.

• Analytical Science and Technology
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• v.23 no.3
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• pp.284-294
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• 2010

In this study, river water-based reference materials (RMs), NIER-I08RW and NIER-I09, for trace metal analysis were prepared and certified for Pb, Cd, Cr and Cu with evaluation of uncertainties. The RMs were confirmed to be homogeneous enough to be used as proficiency testing materials since within-bottle homogenieties of the RMs were lower than 0.3 times of targeted standard deviation of proficiency testing. The RMs were distributed to environmental testing laboratories for the proficiency testing and the variation of Z scores of the proficiency testing results were compared for different assigned values. The relative bias, $B_{relative}$, deviations between reference values and consensus values, were lower than ${\pm}$1 except for cadmium of NIERI08RW. The results showed both values were in a good agreement and only 2.9% of Z scores changed by using a different assigned values such as consensus and reference values.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.253-262
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• 2020

BACKGROUND: It has been reported that the nutritional composition of Locusta migratoria (Orthoptera: Acrididae) changes nutrients depending on the host plants. In this study, to confirm whether Locusta migratoria is an edible insect, the nutrients and harmful substances such as heavy metals and pathogens were analyzed and compared according to corn (LC) or wheat (LW) as host plants. METHODS AND RESULTS: All experimental methods mainly referred to AOAC (2004). The content of crude protein per dry weight was 77.3% in (LW), 1.1 times higher than 69.8% in LC. Crude fat was 6.5% in LW, 2.2 times less than LC 14.3%. Alpha-linolenic acid, which has the highest content among unsaturated fatty acids, was 1.2 times higher in LC (39.9%) than LW (32.5%). As a result of analysis of harmful substances by LC and LW, lead and cadmium among heavy metals were at levels suitable for heavy metal standards of edible insects, and arsenic was not detected in both groups. E. coli and Salmonella spp. were not detected in both groups. CONCLUSION: When comparing the overall nutrients composition of LW and LC, it was confirmed nutrients are different depending on the host plants, and the safety was proved.

• Journal of the Korean Chemical Society
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• v.40 no.12
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• pp.724-732
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• 1996

The organic precipitate flotation using Cu(II)-pyrrolidinedithiocarbamate complex as a coprecipitant was studied for the preconcentration and determination of trace Cd, Pb, Bi and Co in several water samples. Experimental conditions such as pH of solution, amounts of Cu(II) and ammonium pyrrolidinedithiocarbamate(APDC), stirring time, the type and amount of surfactant, etc. were optimized for the effective flotation of analytes. After 3.0 mL of 1,000 ${\mu}g/mL$ Cu(II) solution was added to 1.00 L water sample, the pH of the solution was adjusted to 2.5 with HNO3 solution. Trace amounts of analytes were coprecipitated by adding 2.0% APDC solution. And the precipitates were flotated onto the surface of solution with the aid of nitrogen gas and sodium lauryl sulfate. The floats were collected from mother liquor, and filtered through the micropore glass filter by suction. The precipitates were dissolved with 4 mL conc. HNO3, and then diluted to 25.00 mL with deionized water. The analytes were determined by graphite furnace atomic absorption spectrophotometry. This flotation technique was applied to the analysis of some water samples, and the 90 to 120% of recoveries were obtained from the spiked samples, this procedure could be concluded to be simple and applicable for the trace element analysis in various kinds of water.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.281-288
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• 2021

This study was conducted to analyze and compare the concentrations of heavy metals in 430 different products of 20 types of herbal medicines available in the domestic market in Korea by Graphite Furnace-Atomic Absorption Spectrometry (GF-AAS) and automated mercury analyzer. The accuracy for lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg) was in the range 92.67-102.56%, and the precision was 0.21-6.00 relative standard deviation (RSD%), which was in compliance with the Codex acceptable range. Furthermore, the Food Analysis Performance Assessment Scheme (FAPAS) quality control (QC) material showed a recovery range of 96.7-102.0% and 0.33-4.93 RSD%. The average contents (㎍/kg) of Pb, As, Cd, and Hg in herbal medicines were 254.9 (not detected (N.D.)-2,515.2), 171.0 (N.D.-2,465.2), 99.2 (N.D.-797.1), and 6.0 (N.D.-83.6), respectively. Based on the quantitative analysis results, the heavy metal contents of 20 types of herbal medicines distributed in Korea are within the acceptable range according to the standards issued by the Ministry of Food and Drug Safety (MFDS). By using the manufacturer of herbal products as the standard for QC, the Pb, As, Cd, and Hg contents were investigated in the packaging process just before distribution to determine the actual conditions of residual heavy metals in herbal medicines. Thus, these result may contribute to monitoring the QC of herbal medicines distributed in Korea and could provide basic data for supplying safe herbal medicines to the public.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.51-59
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• 2021

In this study we analyzed the elution rates of 11 metals from 82 metallic kitchen utensils purchased in the market. The elution frequency of the 11 types of metals was iron > aluminum > chromium, nickel > zinc > copper > lead > arsenic > antimony > stannum > cadmium. For metallic kitchen utensils, the elution rate of heavy metals was 7.3-93.9%, and the average elution concentration was 0.001-13.473 mg/L. The average elution concentration of heavy metals was ranged between none-detected (N. D.) to 30.473 mg/L for non-coated kitchen utensils and 0.000-10.005 mg/L for coated kitchen utensils. The average elution concentration of metals from domestic kitchen utensils ranged from 0.001-25.145 mg/L, and from 0.000-33.518 mg/L for imported kitchen utensils. In particular, aluminum was found to be high in domestic kitchen utensils while iron was high in imported kitchen utensils. The average elution concentration of heavy metals was N.D.-2.670 mg/L for stainless steel, N.D.- 31.575 mg/L for aluminum, and N.D.-307.737 mg/L for iron. The amount of transition to food after cooking was investigated.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.35-42
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• 2015

This study was performed for both evaluating the safety of other processed products and providing basic information for making the general standard for contaminants in the category of other processed products. We analyzed the contents of three heavy metals, thirty six anti-impotence drugs and their analogues, three anti-obesity drugs and their analogues, twenty eight steroid drugs and their analogues, collecting in Incheon Metropolitan City. Any illegal compound was not detected in those products. However the contents of lead, cadmium and mercury of those products were at the range of 0.001-13.390 mg/kg, 0.03-1.231 mg/kg and 0.001-0.650 mg/kg respectively. Because there are no standards of heavy metals against other processed products, we compared the analytical results with relevant standards of both S. Korea and foreign countries. As a result, two products exceeded the relevant standards of lead, and other two products exceeded the relevant standards of mercury. The relative hazards compared to PTWI of FAO/WHO (Codex), Seafoods-pajeonmix, Perilla seed powder exceeded PTWI standards 0.214. The compulsory standards of each food product are determined by the category of the products. Because there is no standard of heavy metals in the category of other processed products in S. Korea, any food products registered as other processed product by manufacturer are free with those standards. Abusing similar problems on the categorization of food products could cause consumers' health problem. To prevent these problems, detail regulations on the categorization of food products have to be introduced.