Distributions of the triazine herbicides in the surface seawater of Laizhou Bay

Abstract:

Many studies have been conducted to investigate the pollution status of herbicides in rivers and groundwater; however, the pollution status of seawater is still unclear. In the present study, we established an ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry (MS)method to determine 13 triazine herbicides and atrazine-desethyl in seawater. Samples were collected from the surface seawater of 43 stations in Laizhou Bay, China, filtrated and purified through the HLB solid phase extraction cartridges and separated by AcquityTM UPLC HSS C18 column (2.1 mm×100 mm, 1.8 μm), and then the analytes were confirmed and quantified using MS/MS system in multiple reaction modes. Only atrazine, prometryn, propazine, ametryn and atrazine’s metabolite atrazine-desethyl were detected, and the detection rates and average concentrations were 100% (31.3 ng/L), 97.7% (6.49 ng/L), 51.2% (1.57 ng/L), 100% (12.4 ng/L), and 93.0% (9.14 ng/L), respectively. The concentrations of the triazine herbicides in the bay were higher than those in the bay-mouth, which may be due to the different seawater exchange rates and terrigenous inputs. The concentrations in the western stations were higher than those in the eastern stations. The concentration of atrazine was significantly correlated with the concentration of atrazine-desethyl (R=0.336, n=43, P=0.034). The risk entropy of atrazine was less than 0.01 in all stations, and the ecological risk can be neglected theoretically.