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Heavy metals pollution is a notable threat to environment and human health. This study evaluated the potential ecological and health risks of heavy metals (Cu, Cr, Cd, Pb, Zn, Ni, and As) and their accumulation in a peanut-soil system based on 34 soil and peanut kernel paired samples across China. Soil As and Cd posed the greatest pollution risk with 47.1% and 17.6% of soil samples exceeding the risk screen levels, respectively, with 26.5% and 20.6% of the soil sites at relatively strong potential ecological risk level, respectively, and with the geo-accumulation levels at several soil sites in the uncontaminated to moderately contaminated categories. About 35.29% and 2.94% of soil sites were moderately and severely polluted based on Nemerow comprehensive pollution index, respectively, and a total of 32.4% of samples were at moderate ecological hazard level based on comprehensive potential ecological risk index values. The Cd, Cr, Ni, and Cu contents exceeded the standard in 11.76, 8.82, 11.76 and 5.88% of the peanut kernel samples, respectively. Soil metals posed more health risks to children than adults in the order As > Ni > Cr > Cu > Pb > Zn > Cd for non-carcinogenic health risks and Ni > Cr ≫ Cd > As > Pb for carcinogenic health risks. The soil As non-cancer risk index for children was greater than the permitted limits at 14 sites, and soil Ni and Cr posed the greatest carcinogenic risk to adults and children at many soil sites. The metals in peanut did not pose a non-carcinogenic risk according to standard. Peanut kernels had strong enrichment ability for Cd with an average bio-concentration factor (BCF) of 1.62. Soil metals contents and significant soil properties accounted for 35–74% of the variation in the BCF values of metals based on empirical prediction models. • Soil As and Cd had high ecological pollution risk, especially for As. • The Cd, Cr, Ni, and Cu contents exceeded the standard in several peanut kernel samples. • The soil As caused non-cancer risk index and soil Ni and Cr posed carcinogenic risk at some sites. • The metals in peanut did not pose a non-carcinogenic risk. • Soil metal contents and soil properties well predicted metal bio-concentration factor. [ABSTRACT FROM AUTHOR]

Aflatoxin B 1 (AFB 1) is a prominent food contaminant known for its high toxicity. Rapid, low-cost, and sensitive detection of AFB 1 is an urgent demand for food safety risk control. In the traditional enzyme-linked immunosorbent assay (ELISA) method for AFB 1 detection, horseradish peroxide (HRP) is high-cost and possesses poor environmental stability. In this study, a direct competitive single-atom nanozymes (SAzymes) -linked immunosorbent assay was developed based on Fe-N-C SAzymes. The proposed methods exhibited excellent sensitivity, rapid detection, fabrication, and low cost. Under the optimal conditions, the limit of detection of the new assay was 3.3 pg mL−1, with a quantitative relationship between 0.0084 and 0.358 ng mL−1. In addition, the developed method presented good recoveries in spiked samples, ranging from 84.50% and 103.75%, with coefficients of variation below 10%. Furthermore, the developed detection method showed good consistency (R2 = 0.9852) with the reference method, liquid chromatography/mass spectrometry (LC-MS/MS). To our knowledge, this is the first report about single-atom nanozymes-based ELISA for AFB 1 determination. This work provides a feasible strategy for the rapid and sensitive detection of food contaminants using SAzymes. • A Fe-N-C single-atom nanozyme-linked immunosorbent assay was developed. • Aflatoxin B 1 (AFB 1) could be detected within 50 min. • The results are reliable and sensitive. • The method was successfully applied to quantification of AFB 1 in peanut samples. [ABSTRACT FROM AUTHOR]

Gold nanocages/fluorinated graphene (AuNCs/FG) nanocomposite modified glassy carbon electrode (GCE) was developed, and it was applied to detect selenium by square wave anodic stripping voltammetry (SWASV). The proposed method was applied successfully for the determination of selenium in agricultural food (tea, rapeseed sprouts, peanut) and environmental (tap water and lake water) samples. • Synthesized a gold nanocages/fluorinated graphene nanocomposite. • A novel electrochemical method was developed for the detection of selenium. • This method exhibited wide linear range, low LOD, excellent selectivity, and in good agreement with AFS. • This electrochemical method was successfully applied to selenium determination in agricultural food and environmental samples. Selenium is one of the most attractive nutrient elements for antioxidant, anticancer and immunomodulatory effects, which is obtained from the agricultural food and environment. Herein, a gold nanocages/fluorinated graphene (AuNCs/FG) nanocomposite modified glassy carbon electrode (GCE) was fabricated for the electrochemical determination of selenium by square wave anodic stripping voltammetry. Under the optimal parameters, a wide linear relationship between peak current of selenium on AuNCs/FG/GCE and selenium concentration was observed between 0.002−5.0 mg/L. The method exhibited a low detection limit of 0.27 μg/L. The proposed method was applied successfully for the determination of selenium in agricultural food (tea, rapeseed sprouts, peanut) and environmental (tap water and lake water) samples. The results showed that the average levels of selenium were 0.04−0.27 mg/kg and not detectable, in agricultural food and water, respectively. Therefore, this method has great potential for the monitor of selenium in food and environmental samples. [ABSTRACT FROM AUTHOR]