Occurrence and Profile Characteristics of the Pesticide Imidacloprid, Preservative Parabens, and Their Metabolites in Human Urine from Rural and Urban China

Abstract

Knowledge of human exposure to imidacloprid, the most extensively used insecticide, and para-hydroxybenzoic acid esters (parabens), the most extensively used preservative, is insufficient. In this study, 295 urine samples collected from subjects in rural and urban areas in China were analyzed for imidacloprid and four parabens (namely, methyl paraben, ethyl paraben, propyl paraben, and butyl paraben) as well as their major metabolites (namely, 6-chloronicotinic acid (6-ClNA) and para-hydroxybenzoic acid (p-HB)). Imidacloprid was detected in 100% of the urine samples from rural Chinese subjects and 95% of the urine samples from urban Chinese subjects. Concentrations of urinary imidacloprid detected in rural Chinese subjects (geometric mean (GM) = 0.18 ng/mL) were slightly higher than those detected in urban Chinese subjects (GM = 0.15 ng/mL) when the effect of pesticide spraying was excluded. However, concentrations of urinary imidacloprid detected in rural adults increased significantly in the subsequent days of pesticide spraying (GM = 0.62 ng/mL), which could return to the normal levels within 3 days. In contrast, concentrations of urinary parabens detected in rural Chinese subjects (GM = 6.90 ng/mL) were lower than that in urban Chinese subjects (GM = 30.5 ng/mL). In addition, the metabolism characteristics of imidacloprid to 6-ClNA and parabens to p-HB were discussed preliminarily.

Comparative studies of aerobic and anaerobic biodegradation of methylparaben and propylparaben in activated sludge

“…Benzoic acid is recognized as a nonspecific marker of parabens (Ye et al, 2006). In the present study, p-hydroxybenzoic acid, the reported common metabolite of all paraben esters Wang et al, 2015;Moos et al, 2015;Wang and Kannan, 2016), was not detected in the samples upon GC-MS analysis, while we did not detect the metabolite in the MP and PP controls as well. Therefore, it is possible that p-hydroxybenzoic acid was further oxidized to benzoic acid by mixed microbes during the rapid aerobic degradation process.…”

Mammalian Susceptibility to a Neonicotinoid Insecticide after Fetal and Early Postnatal Exposure

“…While the concentrations of neonicotinoids to which humans are exposed to has not been thoroughly established, studies quantitating neonicotinoids in human urine have reported a wide range of values 42 – 45 . In humans, IMI is metabolized in the liver to 6-chloronicotinic acid, 5-hydroxy-imidacloprid, 4,5-dihydroxy-imidacloprid and other metabolites 43 , 44 , while about 10–20% is excreted unchanged in the urine over several days subsequent to exposure 45 . However, it is difficult to compare human urine levels with our results in organ tissues.…”

A worldwide survey of neonicotinoids in honey

“…Neonicotinoids are taken up by plants and transported to all organs, including flowers, thus contaminating pollen and nectar as well as any fluid produced by the plant (3). There are increasing concerns about the impact of these systemic pesticides, not only on nontarget organismsespecially pollinators such as honey bees (4)(5)(6) and wild bees (7,8), as well as in other terrestrial and aquatic invertebrates (9, 10)-but also on vertebrates (11)(12)(13)(14), including humans (15,16). Impacts on such a broad range of organisms ultimately also affect ecosystem functioning (17).…”