A reliable analytical method for the simultaneous determination of famoxadone and oxathiapiprolin dissipation kinetics, as well as the metabolites of oxathiapiprolin (IN-E8S72 and IN-WR791) in tomato and soil was developed. We studied the dissipation of famoxadone and oxathiapiprolin in tomatoes grown using different kinetic curves in the area of Beijing in 2015 and 2016. Our results show that the most suitable model for two fungicides in 2015 and 2016 was first-order kinetic and second-order kinetic with the half-lives 3.4 to 5.2 and 2.4 to 3.0 days, respectively. In addition, we applied the dynamic plant uptake model dynamiCROP and combined it with results from the field experiments to investigate the uptake and translocation of famoxadone and oxathiapiprolin in the soil-tomato environment. Modeled and measured results of two years fitted well with R2 values ranging from 0.8072 to 0.9221. The fractions of famoxadone and oxathiapiprolin applied during tomato cultivation that are eventually ingested by humans via residues in crop harvest were finally evaluated and found to be in the range of one part per thousand, that is one gram intake per kg applied.

Mycotoxins seriously threaten the quality of maize seriously around the world. A total of 426 samples of maize kernel from northeast and northwest China were analyzed in this study. Ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was performed to analyze the mycotoxin contamination of maize samples. The results showed that it was contaminated by mycotoxins in maize. The average contamination levels of fumonisins, deoxynivalenol, aflatoxins, zearalenone, ochratoxin A, T-2 and HT-2 were 937, 431, 22, 27, 2 and 12 μg/kg, respectively. Concentration of mycotoxins in some samples exceeded their limit, but most were still at safe levels. The contamination level of FBs and DON were most significative. The proportion of mycotoxins exceeding the maximum limit standard was in the following order: 8.0%, 8.0%, 7.0%, 1.6%, 1.4% and 0.0%. The contamination of mycotoxins in maize varies from region to region.