Concentration and risk assessment of nonylphenol in three types of drinking water sources in Hubei Province

Background Nonylphenol (NP) is a typical phenolic endocrine disruptor, and there are significant differences in NP concentration in different regions and water types.

Objective To investigate the concentration of NP in three types (river, lake, and reservoir) of water sources in Hubei Province, and assess its ecological risk and population health risk.

Methods Fifteen sampling points were set up at four river water sources (Liangtingshan Waterworks, Baishazhou Waterworks, Dijiao Waterworks, and Zongguan Waterworks), one lake water source (Liangzi Lake), and one reservoir water source (Fushui Reservoir). Water samples were collected from the 15 sampling points in June 2019 (wet season), October 2019 (level season), and December 2019 (dry season), respectively. The NP concentration in water samples was detected using ultra-high-performance liquid chromatography-tandem mass spectrometry, and the differences in NP concentration among groups were compared using variance analysis. The ecological risk and the health risk of NP were evaluated using risk quotient (RQ) and non-carcinogenic risk index (NCRI), respectively.

Results The detection rate of NP was 100%, with an average concentration of (18.10±15.00) ng·L⁻¹ (5.45-92.71 ng·L⁻¹). The average concentrations of NP during the level, wet, and dry seasons were (11.52±5.31) ng·L⁻¹, (23.86±22.08) ng·L⁻¹, and (18.93±9.51) ng·L⁻¹, respectively, and the maximum concentrations were 24.62 ng·L⁻¹, 92.71 ng·L⁻¹, and 42.38 ng·L⁻¹, respectively. The variance analysis showed no statistical difference in the NP concentration in the samples from rivers, lakes, and reservoirs in different periods (P>0.05). Only the water samples from the water source serving the Zongguan Waterworks showed an RQ (0.19) greater than 0.1 during the wet season, indicating a moderate risk. The RQ values of other water samples were all less than 0.1, indicating an overall relatively low ecological risk. The highest NCRI values during the level, wet, and dry seasons were 0.1459, 0.5492, and 0.2511, respectively, all less than 1, indicating an acceptable health risk level.

Conclusion The NP concentrations in all water sources in this study are at a relatively low level, which poses an acceptable risk level to human health.