• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.110-115
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• 2010

The aim of this study is to investigate the exposure assessment of Korean consumers to five neonicotinoid pesticides in fruit vegetables cultivated in Korea, using a probabilistic approach. We used five neonicotionid pesticides residues(acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) data in fruit vegetables reported by Rural Development Administration for the 2009 monitoring programme. Total exposure of five neonicotinoid pesticides for Korean consumer ranged from 0.087 to 0.236 ${\mu}g$/kg/day at the $95^{th}$ percentile. The $95^{th}$ percentile values of total exposure of five neonicotinoid pesticides by probabilistic approach were lower than those by deterministic approach, although mean values of total exposure by probabilistic approach were similar with those of total exposure by deterministic approach. Total exposure to acetamiprid residue may be mainly due to the exposure to acetamiprid through the consumption of strawberry. Also, acetamiprid residues in strawberry were considered as much more contributory factor to total exposure of acetamiprid than consumption data of strawberry. This contributory properties of acetamiprid were similar with those of all other neonicotinoid pesticides, excluding thiacloprid.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.221-227
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• 2016

This study was conducted to investigate residual organochlorine pesticides in green house soil and green perilla leaves. Extraction and clean-up method were developed using the modified QuEChERS method for residual organochlorine pesticides (ROCPs) in soil and green perilla leaves. Recovery and limit of quantitation (LOQ) of ROCPs in greenhouse soil and green perilla leaves were 76.3-113.4 and 79.4-107.3%, 0.03-0.24 and $0.33-0.50{\mu}g/kg$, respectively. Detected ROCPs in greenhouse soil were dieldrin and endosulfan sulfate, the residue were 1.6-9.2 and $22.0-87.8{\mu}g/kg$, respectively. But two pesticides in all green perilla leaf samples were not detected. These results showed that ROCPs residue in greenhouse soil was lower than the level of bioaccumulation occurring.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.38-47
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• 2011

This study focused on health risk assessment via multi-routes of As exposure to establish a target cleanup level (TCL) in abandoned mines. Soil, ground water, and rice samples were collected near ten abandoned mines in November 2009. The As contaminations measured in all samples were used for determining the probabilistic health risk by Monte-Carlo simulation techniques. The human exposure to As compound was attributed to ground water ingestion. Cancer risk probability (R) via ground water and rice intake exceeded the acceptable risk range of $10^{-6}{\sim}10^{-4}$ in all selected mines. In particular, the MB mine showed the higher R value than other mines. The non-carcinogenic effects, estimated by comparing the average As exposure with corresponding reference dose were determined by hazard quotient (HQ) values, which were less than 1.0 via ground water and rice intake in SD, NS, and MB mines. This implied that the non-carcinogenic toxic effects, due to this exposure pathway had a greater possibility to occur than those in other mines. Besides, hazard index (HI) values, representing overall toxic effects by summed the HQ values were also greater than 1.0 in SD, NS, JA, and IA mines. This revealed that non-carcinogenic toxic effects were generally occurred. The As contaminants in all selected mines exceeded the TCL values for target cancer risk ($10^{-6}$) through ground water ingestion and rice intake. However, the As level in soil was greater than TCL value for target cancer risk via inadvertent soil ingestion pathway, except for KK mine. In TCL values for target hazard quotient (THQ), the As contaminants in soil did not exceed such TCL value. On the contrary, the As levels in ground water and polished rice in SD, NS, IA, and MB mines were also beyond the TCL values via ground water and rice intake. This study concluded that the health risks through ground water and rice intake were greater than those though soil inadvertent ingestion and dermal contact. In addition, it suggests that the abandoned mines to exceed the risk-based TCL values are carefully necessary to monitor for soil remediation.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.473-477
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• 2013

This study was performed to evaluate the acute contact and oral toxicity of plant extracts (neem, sophora and derris) against Honeybee (Apis mellifera L.). As a result of acute contact toxicity test, $LD_{50}$ of neem and derris extracts were more than 100 ${\mu}g/bee$ while $LD_{50}$ of sophora extracts were 1.7 ${\mu}g/bee$. In case of acute oral toxicity test, $LD_{50}$ of neem and derris extracts were more than 100 ${\mu}g/bee$ while $LD_{50}$ of sophora extracts were 1.7 and 0.3 ${\mu}g/bee$. In conclusion, it is evaluated that neem and derris extracts are practically nontoxic while sophora extracts are highly toxic.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.21-24
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• 2010

In recent years, many agricultural scientists are studying on eco-friendly farming methods. Among of lots of the methods, the natural insecticides are highly motivated and interested due to their safety and biodegradable issues, and readily available source of bioinsecticides. In this study, the crude extract of custard apple (Annona reticulata L.) seed and its three fractions which were separated based on polarity indexes were examined for their insecticidal activities against Myzus persicae Sulzer and Nilaparvata lugens S.. The crude extract (Aceton/MeOH) showed strong insecticidal activities against both insects at 3.00 mg/mL ($LD_{50}$=0.45mg/mL for M. persicae S. and 1.42 mg/mL for N. lugens S.). Furthermore, simple fractionation with hexane, chloroform, and water lead to increase three-folds insecticidal activity on chloroform fraction ($LD_{50}$=0.13mg/mL for M. persicae S. and 1.14 mg/mL for N. lugens S.). The results suggest that A. reticulata extracts might be used to control for M. persicae effectively.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.106-113
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• 2020

BACKGROUND: Bumblebees have been shown to be very effective pollinators for most greenhouse tomatoes. Neonicotinoid insecticides are one of the most widely used pesticides in tomato crops in Korea. METHODS AND RESULTS: This study was carried out to investigate the toxicity of four neonicotinoid insecticides (clothianidin, dinotefuran, imidacloprid and thiamethoxam) to bumblebees based on the OECD guidelines (No.246, 247). The 48 hr LD₅₀ (㎍ a.i. /bumblebee) values in the acute contact toxicity tests were determined as follows: clothianidin, 0.467; dinotefuran, 3.741; imidacloprid, 3.967; and thiamethoxam, 0.747. The 48 hr LD₅₀ values in the acute oral toxicity tests were determined as follows: clothianidin, 0.005; dinotefuran, 0.056; imidacloprid, 0.325; and thiamethoxam, 0.018. The acute contact and oral toxicity of the test insecticides to bumblebees from most to least toxic was clothianidin > thiamethoxam > dinotefuran > imidacloprid. CONCLUSION: This study provided the basic toxicological data of neonicotinoid insecticides for bumblebees. In the near future, acute toxicity and mixture toxicity of other pesticides to bumblebees could be determined using this method.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.240-245
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• 2015

The monitoring of soil fertility changes in orchard is very important for agricultural sustainability. Field monitoring was performed to evaluate the soil chemical properties of 140 orchard (23 sites for sandy loam, 88 sites for loam, 28 sites for silt loam, and 1 site for loamy fine sand) in Gyeongnam province every 4 years from 2002 to 2014. Soil chemical properties such as pH, electrical conductivity, amount of organic matter (OM), available phosphate ($P_2O_5$), lime requirement (LR), exchangeable potassium (K), calcium (Ca), magnesium (Mg), and sodium were analyzed. The amount of OM, exchangeable K, Ca, and Mg were significantly increased as cultivation year increases. The frequency distribution within optimum range of subsoil chemical properties in 2014 was 34.3% for pH, 35.0% for OM, 17.1% for available $P_2O_5$, 22.9% for exchangeable K, 15.7% for exchangeable Ca, and 22.1% for exchangeable Mg. In addition, the available $P_2O_5$ and exchangeable calcium were excess level with portions of 69.3% and 48.6%, respectively. The soil chemical properties in the topsoil and subsoil showed that soil pH was significantly higher in sandy loam soil than those from the loam and silt loam soils. The OM, exchangeable K, Mg, and LR of loam soil were higher than those from the sandy loam soil. These results indicated that a balanced management of soil chemical properties as affected by soil texture can improve the amount of fertilizer applied for sustainable agriculture in orchard field.

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.350-351
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• 2008

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.171-174
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• 2009

The black soldier fly larvae are able to decompose various organic wastes such as livestock manures and food wastes. We tested whether the quality of the insect derived compost, i.e. larval feces, was comparable to that of a commercial fertilizer. The results show that the chemical composition and the growth rate of cabbages grown on the insect derived compost are virtually identical to those on the commercial fertilizer. Therefore the insect derived compost will be an ideal substitute to commercial fertilizers.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.464-472
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• 2014

The Codex Committee of Contaminants in Food (CCCF) has been discussing a new standard for arsenic (As) in rice since 2010 and a code of practice for the prevention and reduction of As contamination in rice since 2013. Therefore, our current studies focus on setting a maximum level of As in rice and paddy soil by considering bioavailability in the remediation of As contaminated soils. This study aimed to select an appropriate single chemical extractant for evaluating the mobility of As in paddy soil and the bioavailability of As to rice. Nine different extractants, such as deionized water, 0.01 M $Ca(NO_3)_2$, 0.1 M HCl, 0.2 M $C_6H_8O_7$, 0.43 M $HNO_3$, 0.43 M $CH_3COOH$, 0.5 M $KH_2PO_4$, 1 M HCl, and 1 M $NH_4NO_3$ were used in this study. Total As content in soil was also determined after aqua regia digestion. The As extractability of the was in the order of: Aqua regia > 1 M HCl > 0.5 M $KH_2PO_4$ > 0.43 M $HNO_3$ > 0.2 M $C_6H_8O_7$ > 0.1 M HCl > 0.43 M $CH_3COOH$ > deionized water > 1 M $NH_4NO_3$ > 0.01 M $Ca(NO_3)_2$. Correlation between soil extractants and As content in rice was in the order of : deionized water > 0.01 M $Ca(NO_3)_2$ > 0.43 M $CH_3COOH$ > 0.1 M HCl > 0.5 M $KH_2PO_4$ > 1 M $NH_4NO_3$ > 0.2 M $C_6H_8O_7$ > 0.43 M $HNO_3$ > 1M HCl > Aqua regia. BCF (bioconcentration factor) according to extractants was in the order of : 0.01M $Ca(NO_3)_2$ > 1 M $NH_4NO_3$ > deionized water > 0.43 M $CH_3COOH$ > 0.1 M HCl > 0.43 M $HNO_3$ > 0.2 M $C_6H_8O_7$ > 0.5 M $KH_2PO_4$ > 1 M HCl > Aqua regia. Therefore, 0.01 M $Ca(NO_3)_2$ ($r=0.78^{**}$) was proven to have the greatest potential for predicting As bioavailability in soil with higher correlation between As in rice and the extractant.