Research on Sterols pollution in the water of Kim Nguu River, Ha Noi
| Meeting | VIWC2026 |
| Topic | OS4: Water quality and Aquaculture |
| Author | Quynh To Xuan | Toan Vu Duc |
| Organization | Trade Union University | Research of Organic Matter (ROOM), Environmental and Life Science Research Laboratory, Thuyloi University, Vietnam. |
| ID | 2023.1676263169 |
Content
1. Introduction
Sterols are special forms of steroids (also known as steroid alcohols - polycyclic alcohols), with a hydroxyl group at position-3 and a skeleton derived from cholestane.
Figure 1.1: Molecular structure of Sterol
Sterol substances disrupt metabolic activities in the natural environment such as stimulating natural hormone synthesis and plant sterol synthesis. These substances also cause endocrine disorders in humans. The monitoring and evaluation of sterols also partly helps to assess the pollution level of the environment.
Kim Nguu River is one of Hanoi\'s wastewater drainage rivers, receiving a large volume of wastewater daily from human activities. Therefore, the evaluation of sterols in the water of Kim Nguu river partly helps to identify the source of the waste so that appropriate measures can be taken.
2. Methods
2.1 Methods of investigation and data collection
Six water samples were taken along the length of the Kim Nguu River. Because Kim Nguu River is Hanoi\'s wastewater drainage river, the source of discharge to the river is quite complicated, so each sampling location has its own characteristics for that area\'s waste source.
2.2 Sampling method
Surface water samples were collected in April 2017, samples were taken according to TCVN 6663-3-2008- Guidelines for sampling in rivers. The distance between samples is from 800 to 900m. Surface water samples were collected and analyzed at the Environmental Laboratory of the Institute of Environment - Vietnam Academy of Sciences.
2.3 Methods of sample analysis.
Water samples were analyzed according to the procedure of Kadokami et al. (Kadokami et al., 2009). Add 30g of anhydrous NaCl to 500ml of water sample and shake well. Add 100 ml of Dichloromethane to the solution and shake well for 10 min, then filter the extract through a filter funnel with anhydrous Na2SO4 . Repeat this process 2 more times, each time with 50ml of Dichloromethane. Concentrate the solution after filtration with a rotary vacuum evaporator. Next, the solution was cleaned with an activated silica gel column. After cleaning, continue to concentrate the solution obtained by the rotary vacuum evaporator to a solution volume of about 5 ml. Blow N2 gas until the solution is 1ml . Analyzed on GC-MS-MS-SRM 9TSQ Quantum XLS, Thermo Fisher Sicentific, USA)
Figure 2.1: Sampling diagram of Kim Nguu river water
3. Results
3.1 Evaluation of Sterol contamination in the sediments of the Kim Nguu river
Through analysis, 8 sterols were found in the water. The highest concentration of sterols found in water was Coprostanol (1991.2 µg/ L ), the location with the highest concentration of sterols in water was M2 (2663.35 µg/L). This is the sampling location at Lac Trung Bridge where wastewater is received from Thanh Nhan Hospital, Hanoi Lung Hospital and Hanoi Oncology Hospital. In addition, location M2 is also a place to receive wastewater from old residential areas . The location with the lowest concentration of sterols is at location M6 , this is the location of Yen So conditioning reservoir where wastewater has been treated through Yen So wastewater treatment plant. This demonstrates the plant\'s treatment effect on Sterols . The concentration of sterols decreases in the order M 2 < M 3 < M 4 < M 5 < M 1 < M 6 .
Table 3.1 Concentrations of Sterols in Kim Nguu River Water
| TT | Sterols | Concentration (mean±SD) |
| 1 | Cholestane | 0.18 - 2.55 (1.24 ± 0.82) |
| 2 | Coprostanol | 14.4 – 654 (331.86 ± 259.24) |
| 3 | Cholesterol | 10.1 – 502 (280.91 ± 215.81) |
| 4 | Cholestanol | 0 – 613 (110.28 ± 247.04) |
| 5 | beta-Sitosterol | 2.69 - 75.4 (44.04 ± 30.11) |
| 6 | Epicoprostanol | 10.6 – 602 (281.53 ± 230.49) |
| 7 | Coprostanone | 5.71-231 (128.78 ± 97.14) |
| 8 | Campesterol | 0.82 – 36 (20.75 ± 15.85) |
3.2 Evaluation of the percentage of sterols
Of the 8 sterols found in the water of the KimNguu River, the concentration of Coprotanol was the highest (accounting for 27.66%), followed by the concentration of Epicoprostanol (23.47%) and Cholesterol (23.42%). These high percentage sterols are all sterols of animal origin, and these sterols are commonly found in municipal wastewater.
3.3 Evaluation of the emission source of Sterols
With the ratios of Coprostanol/(Coprostanol+Cholestanol), (Coprostanol+Epicoprostanol)/ (Coprostanol+ Epicoprostanol+ Cholestanol), if > 0.7 is an indication of pollution due to wastewater, < 0.3 is not contaminated (Jobling, S. et al, 2006) (Gagne,F. el al, 2001). If the ratio is in the range of 0.3 - 0.7, it is wastewater pollution with natural sterol sources. From the analysis results, all sterols in the water were contaminated at all sampling locations. Specifically, the source of pollution at locations M 2 and M3 is the combined pollution of both wastewater and natural sterols, the remaining locations are caused by wastewater pollution.
The ratio of Coprostanol/Cholesterol and Coprostanol/(Cholesterol+Cholestanol) is the ratio that represents the source of pollution, man-made or natural. It is found that for water, all positions are >1 and >0.06, showing that the main source of pollution comes from wastewater, which is raw untreated wastewater. Especially with the ratio of Coprostanol/Cholesterol. This is the rate of human fecal contamination. It can be seen that at all sampling sites are contaminated with human feces. This is the clearest proof that Kim Nguu River is Hanoi\'s wastewater drainage river. Wastewater discharged into rivers is mostly raw and untreated wastewater.
The ratio of Coprostanol/Epicoprostanol and Epicoprostanol/Coprostanol is also the ratio of pollution to the discharge source. If this ratio is > 1.5, then there is pollution and the source of pollution is caused by humans. found that in the water of the Taurus River, all locations are at the threshold of possible contamination. Locations where many people live and work have high concentrations because of sterol pollution from human activities and activities.
4. Conclusion
Through analysis, it was found that 8 Sterols exist in the water of Kim Nguu River. The concentration of Sterols in the water is 208.76 - 7276.63 µg/Kg. The concentration of sterols was high in locations with a lot of people\'s living activities (M 2 ) and lowest in Yen So conditioning reservoir when the water was treated.
Among the sterols found in the water of Kim Nguu river, Hanoi, the 3 sterols with the highest percentage are Coprotanol, Epicoprostanol and Cholestrol. These 3 sterols are all plant-derived sterols, and are the sterols that are abundant in municipal wastewater.
The proportion of sterols after analysis, most of the waste source locations are due to untreated raw water, this is also a reasonable result because Kim Nguu river is the drainage river of Hanoi.
Acknowledgement
This study was carried out within the framework of the strong research group (ROOM) and Environmental and Life Sciences Research Laboratory, University of Water Resources. The authors would like to thank ROOM team, Environmental and Life Sciences Research Laboratory, University of Water Resources for providing support during the research process.
5. REFERENCES
- Kadokami, et al., “Survey on 882 Organic Micro-Pollutants in Rivers throughout Japan by Automated Identification and Quantification System with a Gass Chromatography-Mass Spectrometry Database”. Journal of Evironmental Chemistry vol.19(3), pp. 351-360, 2009
- Jobling, S., et al ., “Predicted exposures to steroid estrogens in UK rivers correlate with widespread sexual disruption in wild fish populations”. Environ. Health Perspect , vol. 114, pp. 32-39, 2006.
- Gagne, F., et al ., “Evidence of coprostanol estrogenicity to the freshwater mussel Elliptio complanata”. Environ. Pollut ., vol 115, pp. 97-106, 2001.
