• Journal of Environmental Health Sciences
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• v.19 no.1
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• pp.90-93
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• 1993

Increasing Public Concern : Pesticide residue is probably one of the fastest growing problems in regard to environmental contamination. Pesticide use in agriculture in this century has produced certain benefits, including a decrease in crop waste and an increase in crop yields and food quality. However, pesticide use also creates problems of having effects on the environment and remaining in food chain. The presence of pesticide residue in food, water, and soil has aroused public concern over potential health hazards. Despite information provided by national and private level agencies suggesting that food is safe, consumer groups worldwide are demanding assurance as to the safely of agricultural products.

• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.174-179
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• 2006

Chinese cabbage, Braccica campestris has long been consumed as a staple food for Koreans in various forms of fresh, salted, and fermented Kimchi. Cultivation of the crop under greenhouse has become a general practices to fulfill its off-seasonal consumer's demand. However, agricultural practices of the crop have always accompanied with heavy applications of pesticides caused by severe outbreaks of diseases and pose under warm and humid circumferences. Since dissipation patterns of pesticide residues in/on the crop under greenhouse conditions ate quite different from those in the open-air, changes of diazinon, O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphornthioate, in/on the Chinese cabbage applied by foliar spraying under greenhouse were studied. Diazinon 34% EC was applied with dilution of recommended and double dose to the crop. The shoots of crop were harvested immediately after this application and at regular intervals over a 10-day. After sample preparations, the diazinon residue was analyzed using gas chromatography equipped with electron capture detector (GC/ECD). Initially deposited amount of the chemical in/on the crop right after applications with recommended and double doses were 8.3 and 15.2 mg/kg, respectively. The residue levels after 10 days of application were 0.03 and 0.09 mg/kg with 1.3 and 1.5 days of half-life in/on the crop, respectively. In consequent 10 days of pre-harvest interval (PHI) for diazinon EC formulation in/on Chinese cabbage under greenhouse condition was fulfill maximum residue level set by Korea Food and Drug Administration (KFDA, 0.1 mg/kg).

• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.237-245
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• 2016

Background: Cyanazine is used as a pre-emergent herbicide once during the growing season to control weeds of many upland crops worldwide. This study aimed to establish a method to determined cyanazine residue levels in major medicinal crops by using high performance liquid chromatography-UV detection/mass spectometry (HPLC-UVD/MS). Methods and Results: Cyanazine residue was extracted with acetone from the raw products of four representative medicinal plants - Scutellaria baicalensis, Paeonia lactiflora, Platycodon grandiflorum and Angelica gigas. The extract was diluted with a large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. It was then purifined using optimized Florisil column chromatography. HPLC analysis conducted using an octadecylsilyl column allowed the successful separation of cyanazine from co-extractives of the samples, and the amount was sensitively quantified by ultraviolet absorption at 225 nm with no interference. The accuracy and precision of the proposed method were validated by conducting recovery experiments on each medicinal crop sample fortified with cyanazine at two concentration levels per crop in triplicate. Conclusions: The mean recoveries ranged from 91.2% to 105.3% for the four representative medicinal crops. The coefficients of variation were less than 10%, irrespective of the sample types and fortification levels. The limit of quantification of cyanazine was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method was performed by liquid chromatography/MS using selected-ion monitoring technique to clearly identify the suspected residue.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.492-497
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• 2005

In establishing legal limits of pesticide residues, various default values are employed to compensate for unavoidable variability in data. Because permissible errors in residue analysis reach ${\pm}30-40%$ RSD, maximum residue limits (MRLs) follow geometric progression. According to 5-yr period JMPR reports, variability factor (ratio of highest to median values) in field residue trials was 3.8-fold in 486 crop-pesticide combinations and round-up effort from highest residue to MRL was 1.5-fold, whereas regulatory margin (ratio of MRL to highest residue) used in Korea was 4.8-fold in 822 crop-pesticide combinations; Korean MRLs will be set at higher levels as compared with Codex limits if these margins are employed. Validation studies to compare and harmonize Korean and Codex MRLs of pesticide residues on food crops should be undertaken.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.1-7
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• 2011

Application of biochar to soils is proposed as a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. In addition to reducing emissions and increasing the sequestration of carbon, production of biochar and its application to soils will contribute improve soil quality and crop productivity. Objectives were i) to evaluate biochar productivity from crop residues using a low-cost field scale mobile pyrolyzer and ii) to evaluate characteristics of feedstocks and biochars from locally collected crop residues. Pyrolysis experiments were performed in a reactor operated at $400-500^{\circ}C$ for 3-4 hours using biomass samples of post-harvest residues of corn (Zea mays L.), cotton (Gossypium spp.), rice (Oryza sativa L.), sorghum (Sorghum bicolor L.) and wheat (Triticum aestivum L.). Feedstocks differed, but average conversion to biochar was 23%. Carbon content of biomass feedstock and biochar samples were 445 g $kg^{-1}$ and 597 g $kg^{-1}$, respectively. Total carbon content of biochar samples was 34% higher than its feedstock samples. Significant increases were found in P, K, Ca, Mg, and micro-nutrients contents between feedstock and biochar samples. Biochar from corn stems and rice hulls can sequester by 60% and 49% of the initial carbon input into biochar respectively when biochar is incorporated into the soils. Pyrolysis conversion of corn and rice residues sequestered significant amounts of carbon as biochar which has further environmental and production benefits when applied to soils. Field experiment with crop residue biochar will be investigated the stability of biochars to show long-term carbon sequestration and environmental influences to the cropping systems.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.95-100
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• 2022

BACKGROUND: This study was aimed to determine characteristics of residues of the soil-treated boscalid and pyraclostrobin within Hylomecon vernalis and to evaluate the risks from intake of the residual pesticides in the crop. METHODS AND RESULTS: The pesticides were treated to soils at two different concentrations, and the plant samples were collected 57 days after seeding. The samples were extracted using the QuEChERS extraction kit (MgSO₄ 4 g, NaCl 1 g). The quantitative methods for boscalid and pyraclostrobin were validated using linearity, recovery, and CV (coefficient of variation). Risk assessment of the pesticides was performed using Korea national nutrition statistics 2019. CONCLUSION(S): The residual levels of boscalid were 0.02-0.05 mg/kg (for the treatment at 6 Kg/10a) and 0.05-0.08 mg/kg (for the treatment at 12 Kg/10a), respectively. The residual concentrations of pyraclostrobin were below the LOQ. The amounts of pesticides were less than Maximum Residue Limits specified by the Korean Ministry of Food and Drug Safety. The maximum hazard indices of boscalid in chwinamul and amaranth for consumers were 0.0075% and 0.1525%, respectively, and it indicates that the risk of the pesticides from the crop is considered to be low.

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.05a
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• pp.88-89
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• 1996

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.612-613
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• 2006

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.45-55
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• 2005

This study was undertaken to find out necessary measures to improve the tolerance setting system of pesticide residues on food crops in Korea which is scientifically reasonable and harmonizable with international standards. Information on tolerance setting systems of pesticide residues by Codex Alimentarius Commission, Joint FAO/WHO Meeting of Experts on Pesticide Residues, USA, EU, Japan and Taiwan was collected and analyzed. On the basis of information in the above countries, necessary actions to be taken by the Korean regulatory authorities were recommended with respect to priority setting, maximum residue limits (MRLs) setting based on field residue data, group MRLs, minor crop problems, quantitation limit and dietary intake assessment.

• The Korean Journal of Pesticide Science
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• v.13 no.1
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• pp.13-20
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• 2009

Two insecticides, commonly used for Chinese cabbage, etofenprox and methoxyfenozide, were subjected to a field residue trial to evaluate safeties of the residues at harvest. The pesticides were sprayed onto the crop at recommended and double doses 10 days before the prearranged harvest and then sampling was done at 0, 1, 2, 3, 5, 7, 10, and 12 days after spraying. The amounts of pesticides residues in the crop were analyzed by chromatographic methods. Limits of detection (LODs) of both etofenprox and methoxyfenozide were $0.01mg\;kg^{-1}$ and mean recoveries were $96.76{\pm}2.67$ (CV=2.76%) and $95.84{\pm}2.57%$(CV=2.69%) in case of etofenprox and $103.26{\pm}3.21$ (CV=3.11%) and $94.50{\pm}1.35%$(CV=1.43%) in case of methoxyfenozide, respectively. Biological half-lives of etofenprox and methoxyfenozide were 3.2 and 3.5 days at the recommended dose and 2.7 and 3.5 days at the double dose, respectively. Initial residue levels of the pesticides at the recommended and double doses exceeded their MRLs, but final residue levels of the pesticides in the crop samples at harvest were less than their MRLs. The ratios of the EDI to ADI by intake the crop harvested 10 days after spraying were less than 4% of their ADIs, representing that residue levels of two pesticides at harvest were evaluated as safe.