Multiple pesticide residues and risk assessment of Dendrobium officinale Kimura et Migo: a three-year investigation.

Dendrobium officinale Kimura et Migo (D. officinale) is a traditional Chinese medicine homologous to food, and its safety has attracted considerable attention. Pesticide residues are critical indicators for evaluating the safety of D. officinale. This study investigated the levels of 130 pesticides in 137 stem samples and 82 leaf samples from five main production areas of D. officinale in Zhejiang Province, along with the associated risk of dietary exposure for the population between 2019 and 2021. Forty-five pesticides were detected in 171 samples, of which pyraclostrobin had the highest detection frequency. Multiple residues were detected in 52.56% of the stem samples and 54.88% of the leaf samples, and one stem sample contained up to 18 pesticides. Here, the level of difenoconazole in three samples (two stem samples and one leaf sample) was higher than the maximum residue limit (MRL) in China. Considering the possible health risks related to pesticide residues, a risk assessment of human exposure to pesticides via the intake of D. officinale stems and leaves was evaluated, indicating negligible short-term, long-term, and cumulative risks to human health. However, considering the high detection rate of unregistered pesticides, the supplementation of pesticide registration information on D. officinale should be expedited, and MRLs should be established to ensure food and drug safety.

Assessment of health risks associated with pesticide and heavy metal contents in Fritillaria thunbergii Miq. (Zhe Beimu).

Fritillaria thunbergii Miq. (Zhe Beimu, F. thunbergii) is widely cultivated in China's Zhejiang province, and pesticides and heavy metals are two major factors affecting its quality and safety. A total of 106 F. thunbergii samples from six main production areas were analyzed for 76 pesticides and four heavy metal content (As, Cd, Hg, and Pb). The pesticide detection rate of the samples was 66.98%; overall, the pesticide residues were very low, and residue levels ranged from 0.010 to 0.231 mg kg-1. The detection rates of As, Cd, Hg, and Pb were 95.3%, 100%, 76.4%, and 100%, respectively. A risk assessment of human exposure to pesticides and heavy metals via intake of F. thunbergii was performed, and the results revealed that the pesticide residues and heavy metal content detected in F. thunbergii does not pose a potential risk to human health, either in the long or short term. The exposure assessment showed that the levels of pesticides and heavy metals in F. thunbergii were safe for human consumption. These results provide useful information on F. thunbergii consumption.

Residue behavior and risk assessment of imidacloprid applied on greenhouse-cultivated strawberries under different application conditions.

A risk assessment for imidacloprid applied on strawberries under different conditions was performed after residue determination using the quick, cheap, effective, rugged, and safe (QuEChERS) method. The application conditions were varied according to the applied dosage, addition of a plant oil or organosilicon surfactant, water volume, and sprayer type. The degradation dynamics of imidacloprid on strawberries followed first-order kinetics. At applied doses of 30-60 g a.i. ha-1, the half-lives of imidacloprid were 2.89-3.46, 1.98-3.65, and 2.57-2.77 days after application without a surfactant or with a plant oil or organosilicon surfactant, respectively. For water volumes of 112.5, 225, 450, 675, and 900 L ha-1, the half-lives of imidacloprid applied in the presence of the plant oil surfactant were 3.30, 7.70, 5.33, 7.70, and 6.30 days, respectively. The half-lives after application with a knapsack mist duster, electric sprayer, and manual sprayer were 2.16, 5.77, and 7.70 days, respectively. The health risk assessment revealed risk quotients less than 1 in all cases, indicating that the application of imidacloprid poses a low health risk to humans after a pre-harvest interval of 10 days under our application conditions. The risk assessment results can provide reference data for setting a reasonable maximum residue limit for imidacloprid on strawberries in China.

Degradation of three fungicides following application on strawberry and a risk assessment of their toxicity under greenhouse conditions.

The health risk to humans of pesticide application on minor crops, such as strawberry, requires quantification. Here, the dissipation and residual levels of three fungicides (pyraclostrobin, myclobutanil, and difenoconazole) were studied for strawberry under greenhouse conditions using high-performance liquid chromatography (HPLC)-tandem mass spectrometry after Quick, Easy, Cheap, Effective, Rugged, and Safe extraction. This method was validated using blank samples, with all mean recoveries of these three fungicides exceeding 80%. The residues of all three fungicides dissipated following first-order kinetics. The half-lives of pyraclostrobin, myclobutanil, and difenoconazole were 1.69, 3.30, and 3.65 days following one time application and 1.73, 5.78, and 6.30 days following two times applications, respectively. Fungicide residue was determined by comparing the estimated daily intake of the three fungicides against the acceptable daily intake. The results indicate that the potential health risk of the three fungicides was not significant in strawberry when following good agricultural practices (GAP) under greenhouse conditions.