Pollution characteristics and non-dietary human cumulative risk assessment of neonicotinoids in vegetable greenhouse soils: a case study in Shandong Province, China

PurposeThe benefits associated with the conventional use of neonicotinoids on greenhouse vegetables have lasted for several decades. Extensive use of neonicotinoids could result in their accumulation in the soils, thereby potentially threatening human health through ingestion, dermal contact and inhalation. This study aimed to clarify the pollution characteristics and non-dietary human cumulative risk of neonicotinoids in vegetable greenhouse soils.Materials and methodsA total of 283 soil samples were collected from celery, cucumber, pepper and tomato greenhouses across Shandong Province in China and analysed for nine widely used neonicotinoids. Furthermore, the potential health risks for both adults and children were assessed.ResultsAmong all the soil samples, imidacloprid, clothianidin and thiamethoxam were the top three detected neonicotinoids, with detection frequencies of 96.82–99.65%. The three neonicotinoids had higher average concentrations in the soils, with average concentrations of 27.55–157.64 µg/kg. All the soil samples contained at least two neonicotinoids, but most of the detected residues were at low levels with concentrations ranging from 0.02 to 1816.67 µg/kg. The levels of total neonicotinoids (calculated based on a relative potency factor method) in tomato and pepper soils were statistically higher than those in cucumber and celery soils. Although the exposure risk to children was far higher than that to adults, the health risk assessment for each neonicotinoid or total neonicotinoids was within the established safe limits (hazard index range, 1.07 × 10−10 to 1.95 × 10−3, < 1). Despite the low health risk, potential hazards of exposure to neonicotinoid-contaminated soils should be continuously assessed due to the low-dose adverse effects and potential accumulation in human tissues.ConclusionsOur findings indicate that attention should be given to the neonicotinoids in vegetable greenhouse soils due to their ubiquity and toxicokinetic characteristics.