Polycyclic Aromatic Hydrocarbons in Costal Sediments and Indian Halibuts of Asaluyeh, Kangan, Khark, Emam Hasan and Bushehr Coasts, Iran: Distribution Pattern and Health Risk Assessment

A total 20 sediment and 20 Indian halibut samples were sampled from Asaluyeh, Kangan, Khark, Emam Hasan and Bushehr coast, Bushehr province, Iran for studying distribution and health risk assessment of polycyclic aromatic hydrocarbons (PAHs). PAHs were analyzed using HPLC. The mean (cid:0) PAHs concentrations in sediment and Indian halibut samples were 6.894 ± 1.4301 and 14.807 ± 7.486 mg/kg, respectively. There was a signicant positive relationship (P < 0.05) between (cid:0) PAHs, 2–3 ring compounds, and 4 ring compounds in the sediments and Indian halibut samples. (cid:0) PAHs concentration in sediments and Indian halibuts was higher in Asaluyeh area followed by Khark area. The values of PAHs pollution in the Bushehr province coastline were low to very high. The toxic equivalent quotient (TEQ), excess cancer risk (ECR), and the incremental lifetime cancer risk (ILCR) were applied for health risk assessment. Based on TEQ calculation, DA was a good marker in assessing PAHs related to health risk. DDI values for ∑ PAHs and ∑ CPAHs (carcinogenic PAHs) were also highest in Asaluyeh and Kangan, respectively. ILCR values for sediments in 10% of all stations and cumulative ECR values for Indian halibuts in all studied areas exceeded the USEPA acceptable level thus suggesting a potential cancer risk. Thus, regular monitoring of PAHs pollutants in the coastlines of Bushehr province is recommended. of Indian halibuts in Asalouyeh and Kangan leads to exposure to PAHs and CPAHs, respectively. The calculated ILCR due to the PAHs in sediments showed which ingestion and dermal contact exposure are dominant for adults and child with potential cancer risk from sediments present in 10% of all stations. The collective values of ECR in adults exposed to PAHs from Indian halibut consumption also indicated that excess cancer risk in all studied areas exceeded the USEPA acceptable level. Thus, PAHs regular monitoring at the studied ecosystems is recommended.


Risk Assessment
The dietary daily intake (DDI) values of PAHs via Indian halibut eating were assessed for adults with an average weight (70 Kg) using Eq. (1) (Tongo et al. 2017).
DDI (mg/day) = Ci × IFR (1) The toxicity and carcinogenic ability of the high molecular weight PAHs compared to BaP were determined by toxic equivalent quotient (TEQ). This quotient is related to the valence of any congener for create modi cation in DNA of human. The BaP carcinogenic equivalent (TEQ) for the individual PAHs in sediment and sh samples was calculated by Eq.
Where Ci = concentration of the individual PAHs in the sampling sediments and Indian halibuts (mg/kg dw), and TEFn = toxic equivalence factor for individual PAHs.
The incremental lifetime cancer risk (ILCR) evaluates exposure health risk from PAHs according to USEPA standard. The major pathways for human exposure to sediments PAHs are include (a) inhalation, (b) ingestion, and (c) dermal contact, with the age categories of children (1-11 years) and adults (18-70 years).
The excess cancer risk of PAHs from Indian halibut consumption was calculated using Eq.

Analysis of Data
The SPSS-23 software was applied to the statistical analyses of results. The results were presented as the average ± standard deviation (SD). The correlation between data was tested with Pearson's correlation coe cient and analysis of variance (ANOVA). The level of P<0.05 was signi cant.

Distribution Pattern of PAHs
PAHs concentrations evaluated in the coastal sediment and Indian halibut samples of Bushehr province have been summarized in A considerable positive relationship was found between the total PAHs concentration with compounds 2-3 rings, and 4 rings in the sediments and the edible part of Indian halibuts in the studied stations (Fig. 3).

Risk Assessments
The carcinogenic potential of the eight compounds of PAHs generally noted as possible human carcinogens have been reported in Table 3. The results showed that BaP carcinogenic equivalent (TEQ) in sediment and Indian halibut samples varied from 0 mg/kg to 7.999 mg/kg with a medium concentration of 0.804±2.338 mg/kg and 0.290 mg/kg to 3.562 mg/kg with an average concentration of 1.673±1.545 mg/kg, respectively.
The Indian halibut is consumed in Bushehr province; therefore, it is necessary to calculate dietary daily intake (DDI) of PAHs due to Indian halibut consumption for human health risk evaluation. The DDI amounts of individual PAHs at Indian halibuts for an adult population are summarized in Table 5. These values were obtained from 0-0. This study has determined the potential carcinogenic risk caused by the exposure of human with PAHs in surface sediment and Indian halibut samples. The potential cancer risk values of PAHs in sediments for adults and children have been summarized in Table 4. The results showed that both ILCRDermal and ILCRIngestion were signi cantly higher than ILCRInhalation.
The excess cancer risk (ECR) in adults exposed to PAHs from Indian halibut consumption was also investigated. The ECR values in different areas are presented in Table 5. These values were compared with the receivable instructions value of USEPA.

Distribution Pattern of PAHs
As observed in Table 3, the individual PAHs were distributed in various stations with different patterns. This difference in distribution of PAHs compounds may be a function of the amount and the nature of inputs in each station. In addition, factors such as organic carbon content, structure, diameter of sediment particles, and water solubility are effective in the distribution and abundance from PAHs at sediments and Indian halibut (Nikpour and Ghanemi 2012).
According to Fig. 2, concentration of PHAs is high in studied regions. The high PAHs concentrations in these areas can possibly be because of proximity of sampling stations to gas re neries and discharge of re nery sewage as well as urban sewage into the marine ecosystem. On the Khark Island, a great volume of oil is also loaded daily to export; thus, large amount of PAHs are imported into the sea due to oil spills and leakages. The lowest PAHs concentration was detected at Bushehr stations. Being away from ports and municipal areas and the absence of direct discharges may be the main reasons for these stations remaining cleaner than others.

Risk Assessments
According to  (Fig. 4). Thus, the TEQ values obtained for DA in this study showed that this congener may create a higher probable cancer risk for those which might be exposed to sediments and Indian halibuts in studied coastal areas.
The results of DDI values for PAHs in the present study demonstrate that Indian halibut consumption in Asalouyeh and Kangan leads to exposure to PAHs and CPAHs, respectively, thus endangering human health. Accordingly, regular monitoring of PAHs in the marine ecosystems of studied areas is recommended.
As shown in Table 4, both ILCRDermal and ILCRIngestion were signi cantly higher than ILCRInhalation, suggesting that respiration of sediments PAHs through mouth and nose are less than through other exposure methods. According to instructions for carcinogen risk evaluation, ILCR values of 10 -6 -10 -4 indicate potential cancer risk, while the feasible safety was obtained with an ILCR value of 10 -6 or less and an ILCR values higher than 10 -4 (Liao and Chiang 2006). In this study, 90% of all stations had cancer risk values less than 10 -6 , indicating safety cancer risk. On the other hand, 10% of cancer risk values in all stations ranged within 10 -6 -10 -4 , indicating potential cancer risk, thus warranting immediate attention.
Accordingly, if the level of ECR (age ≥ 70 year) is equal to 10 −6 , the risk level is acceptable, but ECR equal to or greater than 10 −4 has a serious risk. In the present research, the ECR values for every individual PAH except for DA were less than threshold value of USEPA (10 −6 ) ( The collective values of ECR in adults exposed to PAHs from Indian halibut consumption also indicated that excess cancer risk in all studied areas exceeded the USEPA acceptable level. Thus, PAHs regular monitoring at the studied ecosystems is recommended.

Declarations Con ict of interest
Authors have no con icts of interest to declare.

Funding information
This study has received no fund.     Aver 5.09*10 -6 9.87*10 -11 6.34*10 -6 1.14*10 -5 3.97*10 -6 3.08*10 -10 7.05*10 -6 1.10*10 -5 Emam Hasan  The studied areas and sampling locations (a) Assaluyeh, (b) Kangan, (c) Khark, (d) Emam Hasan, and (e) Bushehr stations Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.

Figure 2
Regional differences between PAHs at sediment and Indian halibuts Share of single PAHs for carcinogenic potencies in sediment (a) and Indian halibuts (b) samples