Sediments were sampled from different surface water bodies in Tianjin coastal area, China, and persistent organic pollutants (POPs) including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were measured using GC/MS or GC/ECD. The purposes were to investigate the concentration levels of the POPs and to assess their ecological risks. The results showed that all the 16 priority PAHs were detected from the 10 sediments sampled with the total concentrations of the 16 PAHs ranging from 274.06
Persistent organic pollutants (POPs) are organic compounds resisting degradation through chemical, biological, and photolytic processes in the environment. They can bioaccumulate through food webs from the environment and pose a risk of causing harmful effects to the ecosystem and human health according to animal experiments and epidemiological studies [
Tianjin is located in the west side of Bohai Bay and the center of the circular Bohai Belt. Depending on its rich natural resources and solid industrial base, Tianjin has become one of the most active and potential regions in economic development in China. Particularly, the development and opening up of the Tianjin coastal area has been fit into the National Eleven Five program and development strategy. However, with the development of economy and urbanization, Tianjin, especially the coastal area, faces increasing environmental problems that cause harm to the health of residents and the development of the city. Researches show that the surface soils in Tianjin coastal area have been widely polluted by PAHs, with the mean value of the total concentration of the 16 priority PAHs
Sediment-associated POPs are known to exhibit narcotic effects in benthic organisms, and they also have been implicated in the development of tumors in bottom-feeding fish and in the induction malformation, loss of fertility, or immuno deficiency in many organisms [
In this study, surface sediments were sampled from different surface water bodies in Tianjin coastal area. The concentrations of POPs including PAHs, OCPs, PCBs, and PBDEs were measured and sources of the POPs were analyzed. Based on the toxicity data of benthic organisms, the ecological risks of POPs were assessed. The purposes were to investigate the concentration levels of PAHs, OCPs, PCBs, and PBDEs in the surface sediments of Tianjin coastal area and to determine their ecological risks.
In January 2009, surface sediments were sampled from 10 locations in Tianjin coastal area, as shown in Figure
Plot of sediment sampling locations in Tianjin coastal area. b1: mouth of Hai River; b2: Dagu waste discharge river; b3: mouth of Dagu waste discharge river; b4: offshore river; b5: Du waste discharging river; b6: Bei waste discharging river; b7: offshore sea; b8: Yinghe reservoir; b9: mouth of yongding new river; b10: Beitang waste discharging river.
Before analysis, the sediment samples were frozen dried and ground to pass through a 70 mesh metal sieve. Physicochemical properties including pH, available nitrogen (available-N), available phosphate (available-P), and total organic carbon (TOC) of the sediments were analyzed. For the pH, 5 g of each of the dried and sieved samples was thoroughly mixed with 25 mL distilled water and shaken for 3 h in a shaker; the turbid liquid was centrifuged at 5000 rpm for 10 min (
Microwave-assisted extraction was applied to extract the POPs from the dried and sieved sediments. For each sample, 5 g of the sediment and 50 ng of each of the surrogate standards (naphthalene-
For quality analysis and quality control, reagent and procedure blanks were included in the measurements. Concentrations of the studied POPs in the blanks were below the detection limits, and recoveries of the objective compounds in the blanks spiked with the standards ranged from 60% to 128%. For all the sediment samples, the recoveries of the surrogates were
The reagents acetone, n-hexane, and dichloromethane (analytical grade, Beijing Reagent, China) were purified by distillation before use. Silica gel (100–200 mesh, Qingdao Marine Chemical, China) was baked at 450°C for 4 h and activated at 130°C for 16 h prior to use. The surrogate standards, internal standards, and working standards (guarantee grade) were purchased from J&K Chemical, USA.
Based on the toxicity data of the benthic organisms, the threshold and probable effect concentrations (TEC and PEC) derived from consensus-based sediment quality guidelines for the analytes were used to assess the ecological risks of PAHs, OCPs, and PCBs in the studied sediments [
Based on the toxicity data of benthic organisms [
Physicochemical properties of the 10 sediment samples were measured and shown in Table
Physicochemical properties of the sampled sediments.
Label |
Location |
pH |
Available-N (mg/L) | Available-P (mg/L) | TOC (%) |
---|---|---|---|---|---|
b1 | Mouth of Hai River | 6.1 | 88.55 | 24.12 | 4.83 |
b2 | Dagu waste discharge river | 8.3 | 326.48 | 16.49 | 3.18 |
b3 | Mouth of Dagu waste discharge river | 7.1 | 104.34 | 19.11 | 4.69 |
b4 | Offshore river | 7.5 | 58.91 | <0.10 | 2.65 |
b5 | Du waste discharging river | 8.1 | 104.72 | 30.97 | 1.47 |
b6 | Bei waste discharging river | 7.6 | 75.85 | 27.65 | 3.25 |
b7 | Offshore sea | 6.9 | 26.57 | 25.96 | 1.45 |
b8 | Yinghe reservoir | 7.0 | 41.97 | 6.26 | 1.78 |
b9 | Mouth of Yongding new river | 8.1 | 58.14 | 37.01 | 1.53 |
b10 | Beitang waste discharging river | 6.9 | 59.68 | 7.78 | 1.94 |
The 16 priority PAHs were all detected in the 10 sediment samples, as shown in Table
Concentrations of PAHs in the sampled sediments (
PAH | b1 | b2 | b3 | b4 | b5 | b6 | b7 | b8 | b9 | b10 |
---|---|---|---|---|---|---|---|---|---|---|
Naphthalene | 771.09 | 657.56 | 582.06 | 126.68 | 90.56 | 145.79 | 75.69 | 85.16 | 76.97 | 226.21 |
Acenaphthylene | 41.77 | 15.16 | 24.72 | 10.66 | 4.19 | 7.83 | 4.08 | 42.83 | 3.91 | 13.99 |
Acenaphthene | 344.24 | 77.51 | 51.62 | 51.00 | 22.86 | 33.48 | 33.98 | 21.09 | 27.04 | 358.71 |
Fluorene | 245.17 | 79.40 | 129.82 | 208.65 | 27.88 | 81.69 | 40.79 | 37.79 | 28.04 | 255.55 |
Phenanthrene | 289.16 | 103.49 | 312.03 | 54.23 | 37.76 | 215.01 | 56.15 | 83.57 | 31.26 | 134.74 |
Anthracene | 52.72 | 15.59 | 60.03 | 10.54 | 4.86 | 41.23 | 9.69 | 29.46 | 6.08 | 27.11 |
Fluoranthene | 6.72 | 68.19 | 256.16 | 93.34 | 32.67 | 275.56 | 55.69 | 326.82 | 32.44 | 2.41 |
Pyrene | 239.06 | 55.64 | 272.13 | 77.43 | 24.52 | 220.19 | 46.16 | 194.15 | 27.22 | 78.34 |
Benzo(a)anthracene | 71.86 | 7.18 | 42.41 | 15.08 | 3.66 | 75.73 | 3.35 | 34.37 | 3.04 | 30.47 |
Chrysene | 77.46 | 17.62 | 117.84 | 13.90 | 7.22 | 171.90 | 12.73 | 84.18 | 7.56 | 36.50 |
Benzo(b)fluoranthene | 194.85 | 16.85 | 83.22 | 25.53 | 15.83 | 106.85 | 21.32 | 84.79 | 13.95 | 86.15 |
Benzo(k)fluoranthene | 42.01 | 0.02 | 52.08 | 16.11 | 9.91 | 66.88 | 13.34 | 53.07 | 8.73 | 20.19 |
Benzo(a)pyrene | 90.40 | 6.72 | 105.78 | 6.29 | 3.82 | 136.30 | 7.44 | 30.10 | 4.27 | 36.76 |
Indeno(1,2,3-cd)pyrene | 78.22 | 2.23 | 59.36 | 6.37 | 2.65 | 130.04 | 6.30 | 17.85 | 2.89 | 38.89 |
Dibenzo(a,h)anthracene | 22.09 | 0.51 | 14.32 | 1.33 | 0.54 | 5.64 | 1.21 | 2.98 | 0.65 | 9.57 |
Benzo(ghi)perylene | 89.83 | 2.71 | 52.93 | 4.84 | 2.72 | 94.66 | 4.97 | 11.19 | 0.01 | 1.28 |
| ||||||||||
|
2656.64 | 1126.39 | 2216.51 | 721.98 | 291.63 | 1808.79 | 392.88 | 1139.40 | 274.06 | 1356.86 |
It is generally believed that PAHs of different sources have different structures and compositions, and therefore characteristic ratios of some PAHs could be used to characterize the sources [
It was found that TOC was positively correlated with
Relationship between TOC and total PAHs in the studied sediments.
The concentrations of OCPs, PCBs, and PBDEs were generally low in the studied sediments except in the Dagu waste discharging river. Figures
Concentrations of total OCPs in the studied sediments.
Concentrations of total PCBs in the studied sediments.
Concentrations of total PBDEs in the studied sediments.
There was no significant correlation between TOC values and the concentrations of halogenated POPs in the sediment (
The ecological risks of PAHs, OCPs, PCBs, and PBDEs in the studied sediments were assessed on basis of the toxicity data of benthic organisms. Relatively high risks were observed for PAHs, particularly LMW-PAHs. At each sampling location, at least one LMW-PAH had concentration over its TEC, and in several locations (b1, b2, b3, and b10), the concentrations of naphthalene and/or acenaphthene exceeded their PEC values, indicating adverse ecological effects to benthic organisms. Tables
Threshold effect concentration hazard quotients (TEC-HQ) for PAHs*.
PAH | TEC ( |
b1 | b2 | b3 | b4 | b5 | b6 | b7 | b8 | b9 | b10 |
---|---|---|---|---|---|---|---|---|---|---|---|
Naphthalene | 176 |
|
|
|
0.72 | 0.51 | 0.83 | 0.43 | 0.48 | 0.44 |
|
Acenaphthylene | 5.87 |
|
|
|
|
0.71 |
|
0.69 |
|
0.67 |
|
Acenaphthene | 6.71 |
|
|
|
|
|
|
|
|
|
|
Fluorene | 77.4 |
|
|
|
|
0.36 |
|
0.53 | 0.49 | 0.36 |
|
Phenanthrene | 204 |
|
0.51 |
|
0.27 | 0.19 |
|
0.28 | 0.41 | 0.15 | 0.66 |
Anthracene | 57.2 | 0.92 | 0.27 |
|
0.18 | 0.08 | 0.72 | 0.17 | 0.51 | 0.11 | 0.47 |
Fluoranthene | 423 | 0.02 | 0.16 | 0.61 | 0.22 | 0.08 | 0.65 | 0.13 | 0.77 | 0.08 | 0.01 |
Pyrene | 195 |
|
0.29 |
|
0.40 | 0.13 |
|
0.24 |
|
0.14 | 0.40 |
Benzo(a)anthracene | 108 | 0.67 | 0.07 | 0.39 | 0.14 | 0.03 | 0.70 | 0.03 | 0.32 | 0.03 | 0.28 |
Chrysene | 166 | 0.47 | 0.11 | 0.71 | 0.08 | 0.04 |
|
0.08 | 0.51 | 0.05 | 0.22 |
Benzo(b)fluoranthene | 240 | 0.18 | 0.00 | 0.22 | 0.07 | 0.04 | 0.28 | 0.06 | 0.22 | 0.04 | 0.08 |
Benzo(k)fluoranthene | 150 | 0.60 | 0.04 | 0.71 | 0.04 | 0.03 | 0.91 | 0.05 | 0.20 | 0.03 | 0.25 |
Benzo(a)pyrene | 200 | 0.39 | 0.01 | 0.30 | 0.03 | 0.01 | 0.65 | 0.03 | 0.09 | 0.01 | 0.19 |
Indeno(1,2,3-cd)pyrene | 33 | 0.67 | 0.02 | 0.43 | 0.04 | 0.02 | 0.17 | 0.04 | 0.09 | 0.02 | 0.29 |
Dibenzo(a,h)anthracene | 170 | 0.53 | 0.02 | 0.31 | 0.03 | 0.02 | 0.56 | 0.03 | 0.07 | 0.00 | 0.01 |
| |||||||||||
|
1610 |
|
0.70 |
|
0.45 | 0.18 |
|
0.24 | 0.71 | 0.17 | 0.84 |
*Numbers in bold indicate TEC-HQ > 1.
Possible effect concentration hazard quotients (PEC-HQ) for PAHs*.
PAH | PEC ( |
b1 | b2 | b3 | b4 | b5 | b6 | b7 | b8 | b9 | b10 |
---|---|---|---|---|---|---|---|---|---|---|---|
Naphthalene | 561 |
|
|
|
0.23 | 0.16 | 0.26 | 0.13 | 0.15 | 0.14 | 0.40 |
Acenaphthylene | 128 | 0.33 | 0.12 | 0.19 | 0.08 | 0.03 | 0.06 | 0.03 | 0.33 | 0.03 | 0.11 |
Acenaphthene | 88.9 |
|
0.87 | 0.58 | 0.57 | 0.26 | 0.38 | 0.38 | 0.24 | 0.30 |
|
Fluorene | 536 | 0.46 | 0.15 | 0.24 | 0.39 | 0.05 | 0.15 | 0.08 | 0.07 | 0.05 | 0.48 |
Phenanthrene | 1170 | 0.25 | 0.09 | 0.27 | 0.05 | 0.03 | 0.18 | 0.05 | 0.07 | 0.03 | 0.12 |
Anthracene | 845 | 0.06 | 0.02 | 0.07 | 0.01 | 0.01 | 0.05 | 0.01 | 0.03 | 0.01 | 0.03 |
Fluoranthene | 2230 | 0.00 | 0.03 | 0.11 | 0.04 | 0.01 | 0.12 | 0.02 | 0.15 | 0.01 | 0.00 |
Pyrene | 1520 | 0.16 | 0.04 | 0.18 | 0.05 | 0.02 | 0.14 | 0.03 | 0.13 | 0.02 | 0.05 |
Benzo(a)anthracene | 1050 | 0.07 | 0.01 | 0.04 | 0.01 | 0.00 | 0.07 | 0.00 | 0.03 | 0.00 | 0.03 |
Chrysene | 1290 | 0.06 | 0.01 | 0.09 | 0.01 | 0.01 | 0.13 | 0.01 | 0.07 | 0.01 | 0.03 |
Benzo(b)fluoranthene | 13400 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Benzo(k)fluoranthene | 1450 | 0.06 | 0.00 | 0.07 | 0.00 | 0.00 | 0.09 | 0.01 | 0.02 | 0.00 | 0.03 |
Benzo(a)pyrene | 3200 | 0.02 | 0.00 | 0.02 | 0.00 | 0.00 | 0.04 | 0.00 | 0.01 | 0.00 | 0.01 |
Indeno(1,2,3-cd)pyrene | 135 | 0.16 | 0.00 | 0.11 | 0.01 | 0.00 | 0.04 | 0.01 | 0.02 | 0.00 | 0.07 |
Dibenzo(a,h)anthracene | 3200 | 0.03 | 0.00 | 0.02 | 0.00 | 0.00 | 0.03 | 0.00 | 0.00 | 0.00 | 0.00 |
| |||||||||||
|
22800 | 0.12 | 0.05 | 0.10 | 0.03 | 0.01 | 0.08 | 0.02 | 0.05 | 0.01 | 0.06 |
*Numbers in bold indicate PEC-HQ > 1.
At six locations (b2, b5, b7, b8, b9, and b10), the concentrations of heptachlor epoxide exceeded the TEC value. In the Dagu waste discharging river (b2), the concentrations of heptachlor epoxide and
In the 10 sediments sampled from different surface water bodies in Tianjin coastal area, the 16 priority PAHs were all detected and the mean value of
There were relatively high risks for PAHs in the studied sediments. At each sampling location, at least one LMW-PAH had concentration over its TEC, and in several locations, the concentrations of naphthalene and/or acenaphthene exceeded their PEC values. In the Dagu waste discharging river, relatively high risk for OCPs and slight risk for PCBs were observed. In the other locations, the risks for the halogenated POPs were rare.
This research was supported by the National Nature Science Foundation of China (40871214, 41030529, and 40830746). The authors are grateful to Ms. Yu Liu and Ms. Bingjun Meng in the Laboratory for Earth Surface Processes for their assistances in the sample analyses.
The authors declare they have no conflict of interests.