Development and establishment of a QuEChERS-based extraction method for determining tembotrione and its metabolite AE 1417268 in corn, corn oil and certain animal-origin foods by HPLC-MS/MS.

In this study, we established a rapid and sensitive HPLC-MS/MS method for quantitative determination of tembotrione and its metabolite AE 1417268 (M5) in corn, corn oil, beef, pork, chicken, and eggs. Both analytes eluted from a C18 column within 6 min. The electrospray ionisation-positive mode was used for tembotrione, whereas the negative mode was used for M5. Acetonitrile was the extractant for all samples, and the addition of 2 g NaCl to each homogenised sample facilitated the extraction of the analytes into acetonitrile. The extracted analytes were further purified by the addition of 50 mg of C18 sorbent (25 mg GCB was also added to corn samples) for subsequent HPLC-MS/MS analysis. Satisfactory calibration-curve linearities (R2 ≥ 0.997) were obtained for the two analytes at concentrations of 1-500 µg/L. Mean recoveries in different matrices ranged from 73.7% to 110.4%, whereas intra-day and inter-day relative standard deviations were <15% for all concentrations of spiked analytes. The limit of quantification was 2 µg/kg for each analyte in all matrices. In food samples obtained from markets, residual tembotrione and M5 were all below the limits of quantification. These results confirm that the method is suitable for the routine monitoring of residual tembotrione and M5 in a variety of food matrices.

Application of Rice Grain Husk Derived Biochar in Ameliorating Toxicity Impacts of Cu and Zn on Growth, Physiology and Enzymatic Functioning of Wheat Seedlings.

Livestock and poultry manure containing high levels of copper and zinc have led to contamination of farmland and products which could have an impact on human health. Biochar is an inexpensive and efficient heavy metal absorbent. In the present study, we have used biochar to mitigate the effects of heavy metals on the growth of wheat seedlings. The study showed that the effects of heavy metals on wheat seedlings growth were mitigated by increasing exposure to biochar. Compared to the control group, the germination potential, germination rate, germination index and vigor index of wheat seedlings with supplemented biochar increased significantly. Moreover, the specific activity of catalase, peroxidase, superoxide dismutase decreased and chlorophyll contents increased, which promote wheat growth and suggests that the addition of biochar could reduce the effects of heavy metals on wheat seedlings.

[Influence of Four Kinds of PPCPs on Micronucleus Rate of the Root-Tip Cells of Vicia-faba and Garlic].

In order to determine the degree of biological genetic injury induced by PPCPs, the genotoxic effects of the doxycycline (DOX), ciprofloxacin (CIP), triclocarban (TCC) and carbamazepine (CBZ) in the concentration range of 12.5-100 mg · L⁻¹ were studied using micronucleus rate and micronucleus index of Vicia-fabe and garlic. The results showed that: (1) When the Vicia-faba root- tip cells were exposed to DOX, CIP, TCC and CBZ, micronucleus rates were higher than 1.67 ‰ (CK1), it was significantly different from that of the control group (P < 0.05), and the micronucleus index was even greater than 3.5; With the increasing concentrations of the PPCPs, the micronucleus rates first increased and then decreased. (2) When the garlic root tip cells were exposed to DOX, CIP, TCC and CBZ respectively, the micronucleus rates were less than those of the Vicia-faba, while in most treatments significantly higher than that of the control group (0.67‰). The micronucleus index was higher than 3.5 in the groups exposed to CIP with concentrations of 25, 50, 100 mg · L⁻¹ and TCC and CBZ with concentrations of 25 mg · L⁻¹; With the increase of exposure concentrations, the micronucleus rate showed a trend of first increasing and then decreasing as well. (3) Under the same experimental conditions, the cells micronucleus rates of the garlic cells caused by the four tested compounds were significantly lower than those of Vicia-faba. (4) The micronucleus index of the root tip cells of Vicia-faba and garlic treated with the four kinds of compounds followed the order of CIP > CBZ > TCC > DOX. These results demonstrated that the four compounds caused biological genetic injury to root-tip cells of Vicia-faba and garlic, and the genetic damage caused to garlic was significantly lower than that to Vicia-faba. The damages caused by the four kinds of different compounds were also different.

[Effects of nitrogen and phosphorus fertilizer on atrazine degradation and detoxification by degrading strain HB-5].

An atrazine-degrading strain HB-5 was used as a bacteria for biodegradation. Treatments of soil with nitrogen single, phosphate single and nitrogen phosphate together with HB-5 were carried out for degradation and eco-toxicity test; then, relationship between atrazine degradation rate and soil available nitrogen, available phosphorus were discussed. Atrazine residues were determined by HPLC; available nitrogen was determined with alkaline hydrolysis diffusion method; available phosphorus was determined with 0.5 mol/L-NaHCO3 extraction and molybdenum stibium anti-color method, and toxicity test was carried out with micronucleus test of Vicia faba root tip cells. The results showed that: After separately or together application, nitrogenous and phosphorous fertilizers could significantly accelerate atrazine degradation than soil with HB-5 only. On day 5, the order of atrazine degradation was ANP > AP > AN > A; 7 days later, no statistically significant differences were found between treatments. The available nitrogen and phosphorus level in soil reduced as the degradation rate increased in the soil. The soil of eco-toxicity test results indicated that the eco-toxicity significantly reduced with the degradation of atrazine by HB-5, and the eco-toxicity on treatments of soil with fertilizer were all below the treatments without fertilizer. On day 5, the order of eco-toxicity was ANP < AP < AN < A; 7 days later, all treatments were decreased in control levels. So, adjusting soil nutrient content could not only promote atrazine degradation in soil but also could reduce the soil eco-toxicity effects that atrazine caused. All these results could be keystone of atrazine pollution remediation in contaminated soil in the future.

[Effects of long-term fertilization on soil microorganism and its role in adjusting and controlling soil fertility].

To clarify the relationships between soil microorganisms and soil fertility under the condition of long-term fertilization, a 12-year fertilization experiment was installed on a fluvo-aquic soil, and the amount of soil microorganisms and the content of soil nutrients were determined and analyzed. The results showed that chemical fertilizers combined with organic manure could significantly improve soil fertility and increase the amount of soil microorganisms. Organic manure was obviously superior to corn straw in improving soil fertility. The correlation between soil microorganisms and soil fertility was significant. A positive correlation was found between the amount of bacteria and azotobacteria and the contents of organic matter, total N, alkalified N, total P and available P. The relationship between the amount of fungi and actinomycetes and the content of soil nutrients was not obvious.