Beijing Research Center for Agriculture Standards and Testing, Beijing, 100097, China.
Beijing Research Center for Agriculture Standards and Testing, Beijing, 100097, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Environ Pollut. 2020 Feb;257:113499. doi: 10.1016/j.envpol.2019.113499. Epub 2019 Oct 30.
Production of chrysanthemum (Dendranthema grandiflora) in greenhouses often requires intensive pesticide use, which raises serious concerns over food safety and human health. This study investigated uptake, translocation and residue dissipation of typical fungicides (metalaxyl-M and fludioxonil) and insecticides (cyantraniliprole and thiamethoxam) in greenhouse chrysanthemum when applied in soils. Chrysanthemum plants could absorb these pesticides from soils via roots to various degrees, and bioconcentration factors (BCF) were positively correlated with lipophilicity (log K) of pesticides. Highly lipophilic fludioxonil (log K = 4.12) had the greatest BCF (2.96 ± 0.41 g g), whereas hydrophilic thiamethoxam (log K = -0.13) had the lowest (0.09 ± 0.03 g g). Translocation factors (TF) from roots to shoots followed the order of TF > TF > TF. Metalaxyl-M and cyantraniliprole with medium lipophilicity (log K of 1.71 and 2.02, respectively) and hydrophilic thiamethoxam showed relatively strong translocation potentials with TF values in the range of 0.29-0.81, 0.36-2.74 and 0.30-1.03, respectively. Dissipation kinetics in chrysanthemum flowers followed the first-order with a half-life of 21.7, 5.5, 10.0 or 8.2 days for metalaxyl-M, fludioxonil, cyantraniliprole and thiamethoxam, respectively. Final residues of these four pesticides, including clothianidin (a primary toxic metabolite of thiamethoxam), in all chrysanthemum flower samples were below the maximum residue limit (MRL) values 21 days after two soil applications each at the recommended dose (i.e., 3.2, 2.1, 4.3 and 4.3 kg ha, respectively). However, when doubling the recommended dose, the metabolite clothianidin remained at concentrations greater than the MRL, despite that thiamethoxam concentration was lower than the MRL value. This study provided valuable insights on the uptake and residues of metalaxyl-M, fludioxonil, cyantraniliprole and thiamethoxam (including its metabolite clothianidin) in greenhouse chrysanthemum production, and could help better assess food safety risks of chrysanthemum contamination by parent pesticides and their metabolites.
温室菊花生产通常需要大量使用农药，这引起了人们对食品安全和人类健康的严重关注。本研究调查了典型杀菌剂（甲霜灵-M 和氟唑菌酰胺）和杀虫剂（虫螨腈和噻虫嗪）在土壤中施用于温室菊花时的吸收、迁移和残留消解情况。菊花植物可以通过根部不同程度地从土壤中吸收这些农药，生物浓缩因子（BCF）与农药的亲脂性（log K）呈正相关。高亲脂性的氟唑菌酰胺（log K=4.12）具有最大的 BCF（2.96±0.41 g g），而亲水性的噻虫嗪（log K=-0.13）具有最低的 BCF（0.09±0.03 g g）。从根部到地上部的迁移因子（TF）顺序为 TF>TF>TF。具有中等亲脂性（log K 分别为 1.71 和 2.02）和亲水性噻虫嗪的甲霜灵-M 和虫螨腈表现出相对较强的迁移潜力，TF 值在 0.29-0.81、0.36-2.74 和 0.30-1.03 范围内。菊花花朵中的消解动力学遵循一级动力学，甲霜灵-M、氟唑菌酰胺、虫螨腈和噻虫嗪的半衰期分别为 21.7、5.5、10.0 或 8.2 天。两次推荐剂量（分别为 3.2、2.1、4.3 和 4.3 kg ha）土壤施药后 21 天，所有菊花花朵样品中的这四种农药（包括噻虫嗪的主要毒性代谢物氯噻啉）残留均低于最大残留限量（MRL）值。然而，当推荐剂量加倍时，尽管噻虫嗪浓度低于 MRL 值，但代谢物氯噻啉的浓度仍高于 MRL 值。本研究提供了关于甲霜灵-M、氟唑菌酰胺、虫螨腈和噻虫嗪（包括其代谢物氯噻啉）在温室菊花生产中的吸收和残留的有价值的见解，并有助于更好地评估母体农药及其代谢物对菊花污染的食品安全风险。
