Distribution of nonylphenol ethoxylates and nonylphenol in 4 formulations of abamectin and their migration from packing

The detection of nonylphenol ethoxylates (NPEOs) and 4-n-nonylphenol (NP) in abamectin pesticide formulations was conducted using high performance liquid chromatography-fluorescence method, and distribution characteristics of NPEOs and NP in 4 formulations: emulsifiable concentrate (EC), microemulsion (ME), emulsion in water (EW), suspension concentrate (SC) were analyzed. Solution migrations of NPEOs and NP from packing material (plastic) were detected by soaking the samples with methanol as an oil-based analog, and the sources of NPEOs and NP in pesticide formulations were analyzed. Results showed that the detection rate of NPEOs, NP, and both in the 4 formulations was 60.47%, 62.79%, 51.16%, respectively. The detection of NPEOs and NP in complexation agent was higher than that in a single agent. The mean and median value of NPEOs and NP in 4 formulations from high to low both were EC > EW > ME > SC. Among them, EC contained 6.83% of NPEOs and 8.41% of NP, both were the highest in the tested samples. Component of NPEOs was more than that of NP in EC, while both were used equally in EW. 2 h migrations of NPEOs and NP were 0.16-49.34 and 0.19-18.05 µg/cm², respectively, while the values after 30 days were 0.76-66.48 and 2.84-137.79 µg/cm², respectively. At the beginning of the experiment, migration of NPEOs was more stable than NP, but migration of the both were close at 15 d, which ranged from 46.64%-100.82% and 46.89%-102.03% of 30 d migrations. The highest contribution of NP from packing plastic was 2.568%, while it was 0.241% for NPEOs. 30 d contribution of NP was 1.66-107.51 times to that of NPEOs, and the contribution of NP from plastic bags was higher than that from plastic bottles. The results demonstrated that NP was used more often than NPEOs in the packing of pesticide, but additives during production was the main source of NPEOs and NP in pesticide.