[Show abstract][Hide abstract] ABSTRACT: In this study, a multiresidue analytical method for the detection of 37 pesticides in a soil matrix was developed and validated. The soil sample was fortified with a known quantity of pesticides at two different concentration levels (0.1 and 0.01 µg/g) and the analytes were extracted via a liquid-solid extraction method. The pesticides were separated on an HP5 capillary column and were analyzed with a gas chromatograph coupled to a nitrogen-phosphorous detector (GC-NPD). Method validation was accomplished with good linearity (r(2) = 0.994-0.999) within a considerable range of concentrations. Satisfactory recoveries (70.5-110.4%) were obtained with 32 pesticides at both spiking concentration levels, whereas five pesticides-dimepiperate, buprofezin, prometryn, pirimicarb, and fludioxonil-were recovered at relatively low levels (43.6-61.8%). The applicability of the method was demonstrated by analyzing field samples collected from 24 different sites around Yeongsan and Sumjin rivers in the Republic of Korea. No residues of the selected pesticides were detected in any of the samples. The developed method could be employed as a simple and cost-effective method for the routine detection and analysis of 37 pesticides in soil samples.
[Show abstract][Hide abstract] ABSTRACT: In a continuation of our earlier work, a multiresidual analytical method using 48 frequently used neutral pesticides in a water matrix was developed and validated in this study. The samples were extracted with dichloromethane and the pesticides were analyzed via GC-NPD followed by confirmation with GC-MS. Good linearity was detected over a concentration range of 0.01-1.0 microg/mL with correlation coefficients (r(2) ) in excess of 0.982. The recoveries were measured between 70.7 and 111.4% for the majority of the targeted pesticides with relative standard deviations (RSDs) of less than 20%. The LODs and LOQs were in ranges of 0.1-2 and 0.33-6.6 microg/L, respectively. A total of 66 water samples were collected from different locations in Yeongsan and the Sumjin River, Republic of Korea, and were analyzed in accordance with the developed method. None of the water samples were determined to contain any of the targeted pesticides. The method has been shown to be simpler, faster, and more cost-effective than the method established by the Environmental Protection Agency (EPA).
[Show abstract][Hide abstract] ABSTRACT: Uptake and release of nutrients from ponds used for lotus cultivation were measured in ponds under short-term (1 yr) cultivation with compost application (pond I) and under long-term (20 yr) cultivation without compost application (pond II). Total inflow loads of TN (irrigation water, rainfall and compost) during lotus cultivation period in ponds I and II were 72.3 and 34.3kgha−1 182day−1, respectively. TN removal rates in ponds I and II were 77.3 and 49.8% of total inflow load, respectively. Major removal mechanisms of TN were attributed to microbial processes and uptake by lotus. The total outflow loads (infiltration and runoff) of TN during the lotus cultivation period were 13.9kgha−1 182day−1 (19.2% of total inflow TN load) for pond I, and 11.3kgha−1 182day−1 (32.9% of total inflow TN load) for pond II. For TP the total inflow loads (irrigation water, rainfall and compost) during lotus cultivation in ponds I and II were 80.8 and 1.9kgha−1 182day−1, respectively. TP removal rates in ponds I and II were 84.9 and −274.1% of total input, respectively. Phosphorus removal was attributed to lotus uptake and soil adsorption. The total outflow loads (infiltration and runoff) of TP during lotus cultivation period were 10.1kgha−1 182day−1 (12.5% of total inflow TP load) for pond I, and 6.6kgha−1 182day−1 (355.6% of total inflow TP load) for pond II. TN and TP in runoff from pond I (with compost) was higher than that in pond II (without compost), showing that TN and TP in runoff were strongly influenced by compost addition. Therefore, in order to satisfy established water-quality standards, the amount of compost used in lotus cultivation should be evaluated.
[Show abstract][Hide abstract] ABSTRACT: The principal objective of the present study was to develop a multiresidue analytical method for 62 pesticides in a soil matrix. Soil samples were fortified with known quantities of pesticides at two different concentration levels (0.1 and 0.01 microg/g) and the analytes were extracted via a liquid-solid extraction method. The pesticides were separated on an HP5 capillary column and were detected by gas chromatography coupled to an electron capture detector (GC-ECD). The method was validated, considering its good linearities (r(2) = 0.978-0.999), specificity and recovery characteristics. Recoveries were found between 70.3 and 113.4% for all pesticides except edifenphos (67.5%) and dichlobenil (69.5%) spiked at a 0.1 microg/mL concentration level and 74.5-117% except ethalfluralin (63.3%) and dichlobenil (51.9%) spiked at a concentration of 0.01 microg/mL. The developed method could be utilized as a simple and cost-effective method for the routine analysis of 62 pesticides in soil samples.
[Show abstract][Hide abstract] ABSTRACT: Germanium (Ge) is a rare heavy metal and is known to toxic to plants at high level. However, there is little evidence about the Ge effect on plant growth. Here, we investigated the effect of inorganic (GeO2) and organic (Ge-132) germanium on lettuce growth by treatment with various concentrations of GeO2 and Ge-132. Under GeO2 treatment, lettuce growth was not much inhibited at 2.5 mg/L concentration and then significantly inhibited at 5 mg/L concentration. However, under Ge-132 treatment, lettuce growth was not much inhibited by concentrations up to 10 mg/L. Relative fresh weight of lettuce at 2.5, 5, 10 and 25 mg/L concentrations was 99, 76, 65 and 35% in GeO2 treatments and was 105, 99, 97 and 75% in Ge-132 treatments, respectively. In GeO2 treatments, Ge was highly accumulated in the roots at concentration below 10 mg/L and in the shoots at concentration above 25 mg/L. However, Ge was primarily accumulated in the roots at all Ge-132 concentrations. Accumulated Ge amounts of plants under GeO2 treatment were 0.72 mg/ g DW in roots and 0.27 mg/ g DW in shoots at a 10 mg/L concentration. At a 50 mg/L concentration of GeO2, the Ge content was 0.77 mg/g DW in roots and 1.58 mg/g DW in shoots, respectively. Based on our results, inorganic germanium is more toxic for lettuce growth than organic germanium. Upper critical toxic levels for lettuce growth were 2.5 to 5 mg/L concentrations in GeO2 treatments and 10 to 25 mg/L concentration in Ge-132 treatments, respectively.
Journal of the Korean Society for Applied Biological Chemistry 01/2009; 52(4). DOI:10.3839/jksabc.2009.069 · 0.69 Impact Factor