Ecological of human health risk of total petroleum hydrocarbons and four metals in seawater of the southeastern Bohai Sea, China.

Abstract

To obtain systematic knowledge on the waterborne pollution status and ecological and human health risk of total petroleum hydrocarbons (TPHs) and metals in the southeastern Bohai Sea, seawater samples were collected in three seasons from 2014 to 2018. TPHs and mercury (Hg) levels were determined by ultraviolet spectrophotometry and cold atomic absorption spectrometry, respectively, and concentrations of copper (Cu), lead (Pb), and cadmium (Cd) were detected by anodic stripping voltammetry. Spatial distribution patterns indicated that these waterborne pollutants are mainly sourced from terrestrial inputs. Temporal variation showed that Pb contents decreased in the past five years, and summer exhibited higher concentrations of Hg, Cu, and Cd than spring and autumn. Spearman's rank correlation coefficients demonstrated that temperature correlated positively with Cu content, while dissolved oxygen, pH, and suspended particulate material correlated negatively with pollutant concentrations. While hazard quotient values were lower than 1 for TPHs, Hg, Pb, and Cd, the hazard quotient of Cu (4.88) was greater than 1, suggesting potential ecological risks of this element in seawater of the southeastern Bohai Sea. The total target hazard quotients of Hg, Cu, Pb, and Cd in seawater of the southeastern Bohai Sea were all lower than 1, which indicated that there was no noncarcinogenic risk caused by heavy metals in seawater of the southeastern Bohai Sea. However, the carcinogenic risk of Cd (1.54 × 10-5) was in the range of 10-6-10-4, which may lead to the occurrence of cancer. This study sounds an alarm for stricter control of metal emissions into this sea area.