Open AccessA Study on PAHs in the surface soil of the region around Qinghai Lake in the Tibet plateau: evaluation of distribution characteristics, sources and ecological risks
Author(s) -
Zhongdi Zhang,
Yadi Zhu,
Tianjie Shao,
Ruojin Wang,
Zongyan Chen,
Peiru Wei,
Zhiping Xu,
Dongze Li,
Lijuan Fu,
Feier Wang
Publication year - 2021
Publication title -
environmental research communications
Language(s) - English
Resource type - Journals
ISSN - 2515-7620
DOI - 10.1088/2515-7620/abf3d9
Subject(s) - pollution , environmental science , environmental chemistry , phenanthrene , pyrene , extraction (chemistry) , soil test , fraction (chemistry) , plateau (mathematics) , soil contamination , soil water , chemistry , ecology , soil science , biology , mathematical analysis , mathematics , organic chemistry , chromatography
In order to evaluate the pollution and ecological risks of polycyclic aromatic hydrocarbons (PAHs) in the soil around the Qinghai Lake, 89 surface soil samples were collected in May 2019. After ultrasonic extraction and purification of silica gel-alumina-anhydrous Na 2 SO 4 chromatographic column, GC-MS was used to test and analyze 16 kinds of monomer PAHs under priority control of USEPA in the samples, so as to study the distribution characteristics, sources and ecological risks. The results are shown as follows: (1) The total amount of 16 kinds of PAHs in the soil of the study area was 169.00 ∼ 638.94 μ g·kg −1 , with an average of 318.37 μ g·kg −1 . The PAHs are dominated by dicyclic and tricyclic aromatic hydrocarbons, accounting for 40.89%∼70.73% of the mass fraction of PAHs, with an average of 49.22%, and phenanthrene accounts for the highest mass fraction. (2) The percentage of sampling points that exceeded the standard (200 μ g·kg −1 , which represents the upper limit of ‘no pollution’) was 87.6%, dominated by mild pollution(200 ∼ 600 μ g·kg −1 ). The soil pollution in the west and south of the Qinghai Lake is relatively lighter than the north of the Qinghai Lake. (3) The toxicity equivalent concentration of TEQ BaP for pyrene ranged from 8.19 to 42.35 μ g·kg −1 , with an average of 18.82 μ g·kg −1 . The ecological risk assessment results based on toxicity equivalent concentration and risk quality standard method showed that there was a low risk of PAHs in soil in this study area, and only a few areas exceeding the target reference value, mainly concentrated in the northern area of Qinghai Lake. (4) The results of source analysis by ratio method and principal component analysis method show that PAHs in the surface soil of the region around the Qinghai Lake come mainly from the combustion of oil and biomass.