Ecological and health risks of polycyclic aromatic hydrocarbons in the sediment core of Phayao Lake, Thailand

Abstract

Polycyclic aromatic hydrocarbons (PAHs) in sediment cores from Phayao Lake were investigated in terms of their concentration, distribution, and potential effects on the environment and human health. The concentration of Σ16PAHs ranged from 77.6 to 1251.1 ng g-1. Additionally, low molecular weight PAHs (two or three fused aromatic rings) were dominant, indicating that the main source of PAHs is the incomplete combustion of organic sources. The toxic equivalent quantities (TEQs) of 16 PAHs varied from 2.67 to 155.09 ng g-1, with an average of 38.29 ± 46.69 ng g-1. Furthermore, the TEQs of 9 known carcinogenic PAHs averaged 20.77 ± 30.63 ng g-1. B[a]P had the highest TEQ, followed by D[a,h]A and B[k]F, with values of 16.93 ± 25.49, 13.89 ± 15.37 and 2.12 ± 3.64, respectively. The RQ(NCs) of ∑PAHs (RQ∑PAHs(NCs)) ranged from 1.65 × 10-4 to 6.27 × 10-1 with an average value of 1.18 × 100 ± 1.52 × 100. Moreover, RQ(NCs) was less than 1 for individual PAHs, indicating a minor risk. However, RQ(MPCs) was less than 1 for individual PAHs, indicating a moderate risk. The results showed a significant incremental lifetime cancer risk (ILCR) from sediment-bound PAHs with dermal absorption, followed by ingestion and inhalation, as the prevalent route of exposure. The measured ILCR values of all PAHs were less than 10-6 for both adults and children, which were lower than the baseline value, indicating that each PAH poses a low risk of cancer to humans. This study provides information for control and preventive actions to limit future PAH pollution in Phayao Lake.

Health Risk Assessment of PAHs from Estuarine Sediments in the South of Italy

“…The total concentrations of PAHs were obtained using the sum of the calculated toxic equivalents for each compound in relation to BaP. BaPeq were calculated according to Equation (3) [ 52 ]: where C s represents the average concentration of an individual PAH.…”

Application of Positive Matrix Factorization for Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAH) in the Adriatic Sea, and the Evaluation of PAH-Related Carcinogenic Risks

“…Carcinogenic potential related with sediment PAH concentrations were calculated as summed toxic equivalent quantity for 9 EPA PAH compounds that are classified as known carcinogens, as well as for all 16 EPA PAH enlisted by USEPA as priority pollutants in the environment [14,[18][19][20]. Toxic equivalent factors used for calculation of BaP equivalent toxicity for 16 EPA PAHs are given in Table 1.…”

“…Various approaches have been developed to assess the environmental risk associated with PAH, of which the use of Sediment Quality Guidelines (SQGs) and bioassays have been the most widely used [15,16]. Laboratory experiments have been conducted on a variety of marine animals, including microorganisms, algae, invertebrates, fish and marine mammals [11,13,17], and the results served as the basis for the carcinogen classification system for PAH and mixtures of PAH, and for the development of the Toxic Equivalent (TEQ) method for PAH-related environmental risk assessment [13,[17][18][19][20]. This method assumes that all carcinogenic PAH are equitoxic to benzo[a]pyrene and that the carcinogenic effect of a complex PAH mixture can be calculated as the sum of the effects of the individual PAH compounds [17,20].…”

“…This method assumes that all carcinogenic PAH are equitoxic to benzo[a]pyrene and that the carcinogenic effect of a complex PAH mixture can be calculated as the sum of the effects of the individual PAH compounds [17,20]. Although this approach may lead to overestimation or underestimation of the effects of PAH due to the inhibitory/synergetic properties of PAH compounds when present as a complex mixture, the TEQ method has been used in many studies to assess the PAH-related environmental risk [18][19][20].…”