Yihua Liu

Pesticides in persimmons, jujubes and soil from China: Residue levels, risk assessment and relationship between fruits and soils.

Extreme and uncontrolled usage of pesticides produces a number of problems for vegetation and human health. In this study, the existence of organophosphates (OPs), organochlorines (OCs), pyrethroids (PYs) and fungicides (FUs) were investigated in persimmons/jujubes and their planted soils, which were collected from China. One OP (dimethoate), three OCs (DDT, quintozene and aldrin), six PYs (bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) and two FUs (triadimefon and buprofezin) were found in 36.4% of persimmons and 70.8% of jujubes, with concentrations from 1.0 μg/kg to 2945.0 μg/kg. The most frequently detected pesticides in the two fruits were fenpropathrin in persimmons and cypermethrin in jujubes, with the detection frequencies of 30.0% and 22.7%, respectively. The residues of 4.5% (persimmon) and 25.0% (jujube) of samples were higher than the maximum residue limits (MRLs) of China. Compared with the fruits, more types of pesticides and higher residues were observed in their planted soils. The most frequently detected pesticides were HCH in persimmon soil and DDT in jujube soil, with the detection frequencies of 10.9% and 12.7%, respectively. For the tested samples, 39.1% of fruit samples and 63.0% of soil samples with multiple residues (containing more than two pesticides) were noted, even up to 8 residues in fruits and 14 residues in soils. Except for cyhalothrin, the other short-term risks for the tested pesticides in the fruits were below 10%, and the highest long-term risk was 14.13% for aldrin and dieldrin. There was no significant health risk for consumers via consumption of the two fruits.

Residue levels and risk assessment of pesticides in nuts of China

The pesticide residue levels of three nuts (chestnut, walnut, pinenut) collected from seven main producing areas of China were investigated. Twenty-nine pesticides, including organophosphates (OPs), organochlorines (OCs), pyrethroids (PYs) and two fungicides (triadimefon and buprofezin) were analyzed by gas chromatography (GC). Four OPs (acephate, dimethoate, chlorpyrifos and parathion-methyl) were found in 11.4% samples, with the concentrations of 19.0 µg kg(-1) to 74.0 µg kg(-1). Six OCs (DDT, HCH, endosulfan, quintozene, aldrin and dieldrin) were found in 18.2% samples, with the concentrations of 2.0 µg kg(-1) to 65.7 µg kg(-1). Among OCs, p,p-DDE and α-HCH were the dominant isomer for DDT and HCH. Five PYs (fenpropathrin, fenvalerate, cypermethrin, bifenthrin and cyhalothrin) were found in 15.9% samples, with the concentrations of 2.5 µg kg(-1) to 433.0 µg kg(-1). Fenpropathrin was the most frequently detected pesticide. In addition, triadimefon and buprofezin were detected only in two samples. For the tested nuts, 25.0% samples with multiple residues (containing more than two pesticides) were noted, even up to 9.1% samples with five pesticide residues. The residue of 15.9% samples was higher than the maximum residue limits (MRLs) of China. The short-term risks for the tested nuts were below 1.2%, and the highest long-term risk was 12.58%. The cumulative risk (cHI) for the tested pesticides were 8.43% (OPs), 0.42% (OCs), 12.82% (PYs) and 0.15% (fungicides), respectively. The total cHI was 21.82%. There was no significant health risk for consumers via nuts consumption.

Time-dependent movement and distribution of chlorpyrifos and its metabolism in bamboo forest under soil surface mulching.

The dissipation and distribution of chlorpyrifos (CHP) granule formulation in bamboo forest under soil surface mulching conditions (CP) and noncovered cultivation conditions (NCP) from soil to product were investigated. In the CP treatment, the CHP granule with slow-release effect leached from the topsoil to the subsoil. Conversely, the CHP was fixed in the topsoil (0-5 cm layer) in the NCP treatment, and no obvious leaching effect could be observed. The residue of CHP could be found in bamboo shoots from CP treatment, mainly at the bottom part (5 cm length). CHP could be degraded into 3,5,6-trichloro-2-pyridinol (TCP) in the soil and bamboo shoots. In addition, the straw used as the mulching material with higher OM and pH had some regulatory role in changing the pH and OM characteristics of the soil. Thus the straw could indirectly affect the adsorption and degradation behavior of CHP and TCP in the soil.

Optimization of a One‐Step Method for the Multiresidue Determination of Organophosphorous Pesticides in Camellia Oil

UNLABELLED Due to the widespread use and potential toxicity of organophosphorous pesticides (OPs), multiresidue monitoring of OPs in camellia oil has become increasingly important. A simple, rapid, and effective matrix solid-phase dispersion extraction for the determination of 15 organophosphorous pesticides in camellia oil is described. Related important factors influencing the extraction efficiency, such as type of sorbent material, eluting solvent, and ratio of sample/sorbent were studied and optimized. The best results were obtained using 0.5 g of camellia oil, 1.5 g of white carbon black as dispersant sorbent, and 5 mL of acetonitrile: ethyl acetate (2:1, V/V) as eluting solvent. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries ranged between 76.7% and 102.9% with relative standard deviation values from 2.9% to 13.7% at 2 concentration levels (10 and 100 μg/kg). The method limit of detection at or below the regulatory maximum residue limits for the pesticides was achieved. PRACTICAL APPLICATION A simple, rapid, and effective method for multiresidue determination of organophosphorous pesticides in camellia oil was developed. The sample preparation could finish in 5 min.

Environmental behaviors of phoxim with two formulations in bamboo forest under soil surface mulching.

Phoxim (emulsifiable concentrate (EC) and granules (G)) has been widely used in bamboo forests. The persistence and magnitude of phoxim residues in the crop and soil must be investigated to ensure human and environmental safety. The environmental behaviors of the two formulations were investigated in a bamboo forest under soil surface mulching conditions (CP) and non-covered cultivation conditions (NCP). The half-lives of phoxim in soil under the two conditions in soil were 4.1-6.2days (EC) and 31.5-49.5days (G), respectively. Phoxim in EC could be leached from the topsoil into the subsoil. A minimized leaching effect was observed for G under NCP. Inversely, an enhanced leaching effect was observed for G under CP. The G formulation resulted in more parent compound (in bamboo shoots) and metabolite (in soil) residues of phoxim than in the case of EC, especially under CP conditions. In addition, the intensity and duration of the formulation effect on soil pH adjustment from G were more obvious than that from EC. Results showed that the environmental behaviors (distribution, degradation, residue) of phoxim in the bamboo forest were significantly influenced by the type of formulation. The prolongation effect from phoxim G might cause persistence and long-term environmental risk. However, bamboo shoot consumption could be considered relatively safe after applying the recommended dose of the two phoxim formulations.

Multielemental Analysis of Camellia Oil by Microwave Dry Ashing and Inductively Coupled Plasma Mass Spectrometry

A simple and practical method is reported for the determination of Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb in camellia oil by inductively coupled plasma-mass spectrometry (ICP-MS). Camellia oil was treated using microwave dry ashing at 380 degree Celsius for carbonization and 550 degree Celsius for ashing in a 110 minute procedure. The operational conditions of the dynamic reaction cell with ammonia as the reaction gas were optimized to minimize interferences. The recoveries and the relative standard deviations of optimized method were between 85.6 and 98.4 percent and 1.1 and 5.5 percent, respectively. The detection limits for Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb were 31, 48, 0.6, 4, 22, 0.4, 0.6, 0.9, 3, and 1 micrograms per kilogram, respectively. The developed method has significant potential for the determination of metals in edible oils.

The Fate of Organophosphorus Pesticides during Camellia Oil Production

The purpose of this study was to investigate the fate of organophosphorus pesticides (OPs) during camellia oil production process, from camellia fruit to the final oil product. The results showed that the OPs were mainly distributed in the peel of camellia fruit, basically above 40% after the pesticide application of 7 d (P < 0.05). A small amount of OPs could enter into the seed and convert to crude camellia oil, with the concentration of 19.5 to 548.2 mg/L. In addition, metabolites of OPs (25.7 to 768.9 mg/L) could be detected in the crude camellia oil. Moreover, the refining process (degumming, deacidfying, bleaching) had a significant effect on the removal of OPs from the crude camellia oil (P < 0.05), and the effect was related to the octanol-water partition constant (LogP) of pesticide. The larger the LogP, the more stable the OPs were during refining process. The final refined camellia oil was found to have no detectable levels of OPs metabolite.

Toxic and essential elements in five tree nuts from Hangzhou market, China

ABSTRACT In this study, a total of 35 tree nut samples of walnut, pecan, pine seed, hickory nut and torreya were obtained from 5 farm product markets in Hangzhou, China, and investigated for essential (Cr, Mn, Fe, Mo, Cu, Zn, Se and Sr) and toxic (Al, As, Cd and Pb) elements by inductively coupled plasma–mass spectroscopy. Mean elemental concentrations of different tree nuts were in the following ranges: Cr 0.26–0.78 mg kg–1, Mn 42.1–174 mg kg–1, Fe 33.7–43.9 mg kg–1, Mo 0.11–0.48 mg kg–1, Cu 10.3–17.6 mg kg–1, Zn 21.6–56.1 mg kg–1, Se 0.015–0.051 mg kg–1, Al 1.44–37.6 mg kg–1, As 0.0062–0.047 mg kg–1, Cd 0.016–0.18 mg kg–1 and Pb 0.0069–0.029 mg kg–1. The estimated provisional tolerable daily intake of Al, As, Cd and Pb was much lower than the provisional tolerable daily intake.

Identification of Geographical Origin of Honeysuckle (Lonicera Japonica Thunb) by Discriminant Analysis Using Rare Earth Elements

ABSTRACT Honeysuckle was collected from four locations in China: Pingyi, Shandong Province; Julu, Heibei Province; Dongkou, Hunan Province; and Fengqiu, Henan Province. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for the rare earth elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Y to characterize geographical traceability. The accuracy of the entire procedure was verified by the analysis of a citrus leaves standard reference material GBW10020. The classification of honeysuckle was carried out based on rare earth elements composition by a radar plot and linear discriminant analysis. Honeysuckle from the regions was easily distinguished by radar plots. Furthermore, linear discriminant analysis based on concentrations of rare earth elements provided more than 98% accuracy for predictions using leave-one cross-validation. Thus, rare earth elemental concentrations combined with the use of multivariate statistical techniques allows the evaluation of the geographical origin of honeysuckle. This method provides significant potential in differentiating the geographical origin of various plants.