Metal bioaccumulation in fishes and macro zooplankton in some lakes in Ha Noi - Pham Thi Hong

Vietnam Journal of Science and Technology 56 (2C) (2018) 96-103 METAL BIOACCUMULATION IN FISHES AND MACRO ZOOPLANKTON IN SOME LAKES IN HA NOI Pham Thi Hong1, *, Doan Thi Ngoc Anh1, Dao Thi Nha2, Dao Hoang Hai1, Hoang Thi Thu Huong1 1School of Environmental Science and Technology, Hanoi University of Science and Technology, 1 Dai Co Viet, Ha Noi 2Department of Environmental Engineering, Thuy Loi University, 175 Tay Son, Dong Da, Ha Noi *Email: hongtlu2016@gmail.com Received: 10 May 2018; Accepted for publication: 21 August 2018 ABSTRACT Ha Noi lakes are of great ecological interest, but they are suffering from many pollution sources, especially wastewater discharge. Aquatic organisms living, especially Oreochomic mossambicus and Labeo rohita cultured in polluted water for local consumption would pose a threat to human health. The research attempted to understand the metal accumulation in these two fish species and in Macro zooplankton (> 200 µm) living in lakes of Hanoi. Various metals showed different affinity to fish species and their tissues. Metal accumulation factors (BAF) in livers ranged from 4 to 23 is much higher than that in muscles ranged from 0.04 to 2.07. The variation of metal accumulation in fish statistically correlated to the temperature of water. Metal concentration in macrozoo plankton varied during the period of sampling. The results showed the increase in metal accumulation from lower to upper trophic levels in food webs. Keywords: bioaccumulation, aquatic organisms, heavy metal. 1. INTRODUCTION Constructing from low land level, Hanoi has many scenic lakes. Lakes in Ha Noi have become highly polluted due to rapid urbanisation and a long history of poor management [1]. Previous researches showed that Ha Noi lakes receiving a large volume of untreated waste water have created a highly metal contaminated sediment layer which would threaten to the aquatic ecosystem [2, 3]. In many lakes, fishes such as Oreochomic mossambicus and Labeo rohita are cultured for local consumption thus are causing a high risk to human health [4]. Among of the pollutants, metals such as arsenic, lead, copper, and zinc are considered as the principal pollutants of aquatic ecosystems due to their environmental persistence, toxicity, and high potential of accumulation in the food. Zooplankton and fish living in metal polluted aquatic bodies may absorb and accumulate these metals in different parts of their body. In the research about the metal accumulation in some fish species living in Ha Noi lakes, Le et al. found that, metals were highly accumulated in fishes’ muscle, but, the correlations of metal levels in fish to Metal bioaccumulation in fishes and macro zooplankton in some lakes in Ha Noi 97 those in water and sediments were weak [5]. In fact, many factors would affect on the accumulation of metal in fish like water characteristics and food and target tissues of fishes [6]. To our knowledge there have not yet researches in Ha Noi lakes related to clarifying about how metals were accumulated in different organs in fish living in Ha Noi lakes, metal accumulated in which organs relate to metal concentration in water and whether metal in zooplankton would influence on metals accumulated in fishes. In this study, the metal accumulations in different organs of were determined. The metal accumulation in macro zooplankton was also studied to understand the biomagnification of metal pollutants from zooplankton to fish spices. 2. MATERIALS AND METHODS 2.1. Water sampling and measurements Samples were collected from three main lakes in Ha Noi, i.e. Truc Bach, Linh Dam and Thu Le from fall 2017 to spring 2018. Water temperature was from 20 oC to 26.22 oC. The lakes were selected based on the similar function such as raising fishes, receiving domestic waste water from surrounding hold houses and being used for entertainment activities. The water sampling procedure and analysis followed the ISO 17025 standard. The sampling procedure followed the TCVN 5994:1995 (ISO 5667-4:1987) – Water quality – Sampling: Guidance on sampling in natural and artificial lakes. Field measurements included depth (m, ultrasonic device), water temperature (°C)), pH (pH Meter DREL/2010), Chemical analysis was performed for COD (SMWW 5220C ISO 6060:1989), BOD5 (SMWW 5210B, ISO 10707:1994), total nitrogen (SMEWW-4500-N :2012), total phosphorus (SMWW 4500-P E), chlorophyll-a (Chl-a) (SMWW 10200 H) and metals (As, Pb, Cu and Zn) (ICP-MS, ELEMENT, Finnigan MAT, EPA 200). 2.2. Zooplankton and fish tissues Zooplankton was collected in vertical tows in the centre of Truc Bach lake from 0.5 m above the bottom to the surface using a cone net (202-mm fraction mesh) for macro zooplankton following the sampling process description of Chen et al. [7]. The macro zooplankton were sorted by the Pasture pipets. The macroplankton contains adult cyclopida, clanoid, cladorecan and aquatic insects. The biomass samples were determined by filtering through polymer filter, cleaned by acid and dried at 60 oC and weight [7]. Plankton metal samples were digested for analyzed with a solution (2:1 nitric acid and hydrochloric acid), heated at 108 oC for 8-10 hours. After being digested, the samples were sent directly to analyze arsenic, cadmium, lead, and zinc. Fish were caught from the three main lakes during the sampling time. The selected species were Oreochomic mossambicus and Labeo rohita. These fish species are usually cultured in Ha Noi lakes and are consumed by local people. Collected fish were immediately preserved in an ice box, weighed and measured length in the laboratory. The fish tissue preparation and analysis were made according to the guideline of FAO [8]. Muscles, liver, and gills were taken out. All the samples after separating different organisms were rinsed with diluted H2SO4 and distilled water and stored in deep-frozen storage. Fish tissues were then ground and digested for analyzed with a solution (2:1 nitric acid and hydrochloric acid), heated at 100 oC for 8-10 hours until clear. For gill, we used perchloric acid. Metal concentrations in the prepared solutions were analyzed by ICP –MS as water samples. Pham Thi Hong, Doan Thi Ngoc Anh, Dao Thi Nha, Dao Hoang Hai, Hoang Thi Thu Huong 98 Bioaccumulation factors (BAF) were calculated for each metal in different fish species are defined as the ratio of the concentration of a metal in any tissue of an aquatic organism to its concentration in water (mean metal concentrations in tissues of an aquatic organism in µg/g)/ (mean total metal concentration in water in µg/l). The weight of the organism is presented on a wet weight and the unit of the BAF is l/g [9]. Biomagnification factors (BMF) is calculated as the ratio of a concentration of a substance in a predator (mg/kg)/ a concentration in the predator’s prey (mg/kg). The weight of the organism was presented on a dry weight followed the calculation:([mean metal concentrations of fish in mg/kg]/ [mean metal concentration of macro zooplankton in mg/kg]; Trophic state indices (TSIs) were calculated for the lakes using the equations described by: TSITP = 60-14.42 ln(48/TP); TSIChla = 9.81 ln (Chl-a) + 30.6; TSISD = 60 – 14.41 ln(SD); TSITN = 54.45+14.43 ln(TN); TSI = [TSITP+TSIChl+TSISD+TSITN]/4. where: Chl-a is chlorophyll a concentration (µg /l); TP is total phosphorus (µg/l); SD is water transparency measured by Secchi disk (m); TN is total Nitrogen. One-way ANOVA was used to compare metals between species in the single organ (significant values, p < 0.05). All statistical calculations were carried out with SPSS 20.0 for Windows. 3. RESULT AND DISCUSSION 3.1. Water characteristics in Ha Noi lakes The results showed that, the concentration of COD and BOD in Truc Bach lake and Thu Le lake, exceeded limitation value for freshwater quality according to the QCVN 08-MT: 2015/B1 (Table 1). Table 1. Water characteristics of Thu Le, Truc Bach, Linh Dam lakes. Lakes COD (mg/l) BOD (mg/l) Total P (mg/l) Total N (mg/l) Chlorophyll a (mg/m3) TSI Truc Bạch 30.5 ± 7.2 14.8± 1.2 0.97 ± 0.2 30.4 ± 6.6 201.1 ± 83.44 86.7 ± 0.93 Thu Le 36.6± 18.2 18.6± 0.8 0.3 ± 0.08 17.9 ± 1.9 89.6 ± 43.02 76.48 ± 0.88 Linh Dam 24.4± 9.2 5.1± 3.9 3.58 ±1.5 8.07± 0.9 50.2±27.69 77.04 ± 0.96 QCVN 08- MT:2015/B1 30 15 The total phosphorus and nitrogen concentrations were considered as key water quality parameters to monitor the trophic state in the three lakes. As can be observed, the eutrophic state was associated with the high TP values in all investigated lakes. According to Carlson’s trophic state index values and classification, the TSI of the three lakes which were higher 70, illustrated that Thu Le, Truc Bach and Linh Dam were classified as hypertrophic, especially the Truc Bach lake. The result also indicated that the concentrations of phosphorus and nitrogen in samples near the banks were higher than those were in the center of lakes. Therefore, it seems that the nutrient enrichment in the Truc Bach lake was correlated to wastewater discharge. Metal bioaccumulation in fishes and macro zooplankton in some lakes in Ha Noi 99 Table 2. Metal concentration in water of the Thu Le, Truc Bach, Linh Dam lakes. Metal Concentration (µg/l) Thu Le lake Truc Bach Linh Dam lake QCVN 38:2011 QCVN 08- MT:2015/A1 As 3.5 ± 1,76 22.49 ± 3.78 6.71 ± 1.78 20 10 Pb 0.17 ± 0.41 2.14 ± 3.32 0.96 ± 0.78 20 20 Zn 6.61 ± 5.51 51.24 ± 21.11 78.55± 5.78 500 Cu 1.56 ± 0.01 0.01 – 0.08 3.68± 2.78 200 100 Table 3. Metal concentrations in macro zooplankton in Truc Bach lake (µg/ g dry weight). The concentration of As in the Truc Bach lake was higher than the permissible limits of As concentration in water according to QCVN 38:2011 (National technical regulation on Surface Water Quality for protection of aquatic lives), the content of Cu and Pb in water body were lower than the limitation of metal level in QCVN 38:2011. Zn content in the three lakes was far under the metal limitation in water according to QCVN 08-MT: 2015/A1 (National technical regulation for surface water quality - Use for water supply purposes, conservation of aquatic fauna and flora) (Table 2). 3.2. Metal accumulation in macro zooplankton The metal concentrations (mg/kg dried wt) in macro zooplankton in Truc Bach lake has changed according to sampling time and the component of macro zooplankton species in each sample (cyclopida: clanoid: cladorecan: aquatic insects). Metal concentration (As, Cu and Zn) except Pb was highest in the samples taken in the end of March when the macro zooplankton samples consisted of the same proportion of each species, cyclopida: clanoid: cladorecan. The highest concentration were Pb (48.70 µg/ g dry weight) found in samples taken early in March when clanoid was the dominant species. It suggested that, clanoid uptakes highest Pb among macro zooplankton species and different zooplankton have different metal accumulation ability. There should be further study investigate this issue. In fact, Many factors would effect on the metal accumulation in zooplankton such as water characteristics like, temperature, DOC (dissolved Organic Carbon [10] and biological factors like age, sex and size [11]. However, our research could not find the relationship between metal concentration in water and metal accumulation in zooplankton. The reason could be the limitation of zooplankton amount in the samples. Another reason would be that, the clanoid accumulated metal from assimilating them from their food or by adsorbing them from water [12]. Therefore, the metal accumulated in Period of time As Pb Cu Zn 25/1/2018 159.98 9.41 11.06 101.61 5/3/2018 190.36 48.70 42.89 717.86 26/3/2018 657.90 27.40 303.95 1747.85 17/4/2018 348.50 15.08 111.26 1348.85 3/5/2018 272.87 24.68 148.40 1688.75 mean 325.92 25.05 123.51 1120.98 SE 178.58 13.48 102.44 627.52 Pham Thi Hong, Doan Thi Ngoc Anh, Dao Thi Nha, Dao Hoang Hai, Hoang Thi Thu Huong 100 zooplankton would come from their food. Unfortunately, due to the high concentration of suspended maters in water, we were not able to collect purified algae samples to detect metal concentration accumulated in algae 3.3. Metal accumulation in fishes Table 4. Concentrations of heavy metals (mg/kg wet wt) in some organs of fish species. Locati on Metal s Oreochmic mossambisus Labeo rohita Liver Gill Muscle Liver Gill Muscle Thu Le lake Cu 139.22 ± 30.85 15.64± 10.28 1.26 ± 1.12 51.26 ± 26.83 4.72±5.91 0.62± 0.53 Zn 39.94±19.77 39.72±12.5 12.8±3.89 56±30.11 67.65±12.87 15.21±6.95 Pb 5.96±8.44 0.76±0.47 0.25±0.05 0.6±0.04 0.56±0.15 0.26±0.07 As 11.9±7.22 12.86±10.2 5 4.55±3.31 7.18±0.58 14.9±3.6 4.45±2.14 Truc Bach lake Cu 34.37±32.33 1.26±0.99 1.79±1.47 18.49 ± 15.42 2.02±2.14 0.54 ±0.29 Zn 45.24±20.6 22.2±12.45 20.496 ± 10.34 40.86±12.4 6 108.43±46.4 5 13.5±2.99 Pb 0.69±0.17 2.16±3.49 0.53±0.24 0.75±.055 0.58±0.55 0.34±0.12 As 16.71±6.6 8.36±2.75 5.56±3.24 8.11±3.11 19.22±10.13 4.04±.39 Linh Dam lake Cu 1.2 ± 0.94 0..86 ± 0.57 0.71±0.02 17.46 ± 2.45 1.06±3..75 0.38±0.63 Zn 65.04±12.34 13.45±12.2 7.8±0.21 3.3 ±1.2 158±34.67 5.5±1.21 Pb 0.25±0.25 0.28 ± 0.31 0.15±0.02 0.13 ±0.02 0.22±0.07 0.09±0.01 Table 5. BAF values of metal accumulated in liver of fish species. Lakes Fish spices Cu Zn Pb As Truc Bach Labeo rohita 7.76 5.00 0.09 0.34 Oreochomic mossambicus 23.45 4.58 0.09 0.76 Thu Le Labeo rohita 6.93 13.58 0.13 2.58 Oreochomic mossambicus 14.93 4.23 0.51 2.83 Linh Dam Labeo rohita ND 0.05 0.00 0.42 Oreochomic mossambicus 0.58 1.52 0.01 1.38 ND: Not Detected metal in water. Our results showed that there was a statistical correlation between the temperature of water and the Zn concentration in muscle (p = 0.028), but not in the gill of fish (p = 0.41) which was different from the findings of Yang et al. [13]. The higher the temperature in water, the higher the Zn content in muscle. The reason could be that temperature relates to an increase in metabolic rate of fish [14] and it would influence the rate of excretory processes, an elimination poison mechanism of fish [13]. Current results did not demonstrate the relationship between tropic status and metal accumulation including Cu, Zn, Pb, As in gill of fish, the p-values were Metal bioaccumulation in fishes and macro zooplankton in some lakes in Ha Noi 101 0.85, 0.92, 0.34, 0.68, respectively. In another point, both the essential metals and the non- essential metals were accumulated at the lowest level in the muscle of fish. These results have the agreement with the finding of the previous study [15]. While the essential metals such as Cu and Zn had a tendency to concentrate in the liver, the non-essential metal, Pb and As accumulated mainly in gills. The main reason would link to their roles in metabolism. According to Roesijudi [16], Zn and Cu in hepatic tissues often bind to the proteins metallothioneins (MT) which are considered as an essential metal (like Cu and Zn) store to fulfil enzymatic and other metabolic demands. On the other hand, other non-essential metals such as Pb also accumulated highly in the liver. The reason would be that Pb binds to different kinds of transport proteins including metallothionein, transferrin, calmodulin, and calcium-ATPase which are relating to biosynthesis of liver [17]. Fish tends to accumulate As and Pb in the gills. Our findings showed, there was a close relationship between As concentration in water and that in the gills (significant values, p = 0.01< 0.05). Gills are the main route of metal ion exchange from water because they have a large surface area to rapidly facilitate the diffusion of metals. Therefore, the water is the main source of metal accumulated in the fish gills. This finding agreed with the conclusion of Moore and Ramamoorth [17, 18]. While gills had a wide range of Zn concentration, muscles showed a narrow range of the Zn content. Labeo rohita tend to accumulate Zn concentration higher in the liver compared to other species. Pb concentrations in gills of Oreochomic mossambicus was always higher than that in gills of Labeo rohita. Table 5 illustrated that Oreochomic mossambicus tend to accumulate As, Cd and Cu in liver higher than in Labeo rohita. The BAF values for fish among Truc Bach, Thu Le and Linh Dam showed that fish living in the aquatic body with higher metal concentration tend to accumulate metal higher. The BAF values in macrozooplankton varied according to their species. The result also illustrated that, there were no magnification of metal from macrozooplankton to fish (BMF < 1). The fish BMF for Zn and Cu was significantly greater than those for Pb, As. 3.4. Health-risk assessment for fish consumption In their research, Elnabris et al. claimed that muscle is not the active organ for metal transformation and accumulation [19]. However, as aquatic organisms live in the polluted water, the metal concentration would exceed the permissible limits for human consumption because of biomagnification through a food chain. Then, the metal itself would cause high risk to human health. To evaluate the health risk, the averages of the metal concentration in the muscle were compared with the maximum permissible limits consumption (MPL) for human established by Food and Agriculture Organization of the United Nations (FAO), World Health Organization (WHO) and Ministry of Health in Viet Nam (MOH) (Table 6). The results showed that concentrations of the essential metals such as Cu, Zn in muscle were under all the MPLs for human consumption. The Table 6 illustrated that Pb also caused low risk to human health. The content of As in muscles of fishes in all study lakes exceed the MPL required by the Ministry of Health in Viet Nam. The main sources of As in the water can be from the geological layers in Ha Noi. Other sources would come from the smelting of non- ferrous and burning fossil fuel to generate energy. In all samples, the As concentrations in the water sample taken near the bank were lower than in the sample taken at the central areas of the lake. Therefore, the main source of the As input into these lakes would mainly come from soil and sediment. The variation of As level in the sampling location near the lake bank illustrates that additional sources of As would be from outside like sewage input or overflow from street surface. Pham Thi Hong, Doan Thi Ngoc Anh, Dao Thi Nha, Dao Hoang Hai, Hoang Thi Thu Huong 102 Table 6. Comparing the metal accumulated in fishes to the limited metal levels of different organizations. Metal (µg/g wet wt) References Sources Cu Zn Pb As FAO (1983) 30 30 0.5 FAO [20] WHO 1989 30 100 2 Mokhtar[21] Viet Nam standard 30 100 0.2 2 MOH Oreochromis niloticus, Thu Le lake 1.26 14.42 0.26 4.55 Present study Oreochromis niloticus, Truc Bach lake 1.57 18.67 0.48 5.54 Present study Oreochromis niloticus, Linh Dam lake 0.71 7.8 0.15 1.17 Present study Labeo rohita, Thu Le lake 0.51 15.21 0.26 4.45 Present study Labeo rohita, Truc Bach lake 0.54 13.15 0.75 4.04 Present study Labeo rohita, Linh Dam lake 0.31 5.5 0.09 0.85 Present study 4. CONCLUSION Metal accumulated differently in liver, gill, and muscle. Among the fish’s organs, liver had highest metal concentration. The Zn accumulation in muscle significantly correlated to water temperature. There were no correlation between tropic status and the metal accumulation in fish’s organs. A variation of metal concentrations in macro zooplankton in the three lakes has changed according to time of sampling. The content of Pb and As in muscles of fishes cultured in study lakes were higher and MPL and may cause high risk to human health. Further study would be carried for other pollutants as well as other aquatic species living in urban lakes of Ha Noi. REFERENCES 1. Hoang T. H. T., Van A. D., and Nguyen H. T. T. - Driving variables for eutrophication in lakes of H anoi by data‐driven technique, Water and Environment J. 31 (2017) 176-183. 2. Ly N. N. - Ha Noi lakes report 2015, The Viet Nam Union of Science and Technology Associations Center for Environment and Community Research, 2015, pp. 15. 3. Kikuchi T., Hai H. T. and Tanaka S. - Characterization of heavy metal contamination from their spatial distributions in sediment of an urban lake of Ha Noi, Viet Nam, Journal of Water and Environment Technology 8 (2) (2010) 111-123. 4. CECR - Baseline Data for Ha Noi Lakes in Its Six Old Districts, Transportation Publisher, Ha Noi, 2010. 5. Le H. T. and Ngo H. T. T. - Cd, Pb, and Cu in water and sediments and their bioaccumulation in freshwater fish of some lakes in Ha Noi, Viet Nam, Toxicological & Environmental Chemistry 95 (8) (2013) 1328-1337. 6. El-Moselhy K. M., Othman A. I., El-Azem H. A., and El-Metwally M. E. A. - Bioaccumulation of heavy metals in some tissues of fish in the Red Sea, Egypt, Egyptian Journal of Basic and Applied Sciences 1 (2) (2014) 97-105. 7. Chen C. Y., Stemberger R. S., Klaue B., Blum J. D., Pickhardt P. C., and Folt C. L. - Accumulation of heavy metals in food web components across a gradient of lakes, Limnology and Oceanography 45 (7) (2000) 1525-1536. Metal bioaccumulation in fishes and macro zooplankton in some lakes in Ha Noi 103 8. Stirn J. - Manual of methods in aquatic environment research, Part 8, Ecological assessment of pollution effects (Guidelines for the FAO GFCM/UNEP Joint Coordinated Project on Pollution in Mediterranean), FAO fisheries technical paper 209 (1981) 1-190. 9. Arnot J. A. and Gobas F. A. - A review of bioconcentration factor (BCF) and bioaccumulation factor (BAF) assessments for organic chemicals in aquatic organisms, Environmental Reviews 14 (4) (2006) 257-297. 10. Sunda W. G., Tester P. A., and Huntsman S. A. - Effects of cupric and zinc ion activities on the survival and reproduction of marine copepods, Marine Biology 94 (2) (1987) 203- 210. 11. Langston W. and S. Spence - Biological factors involved in metal concentrations observed in aquatic organisms, Metal speciation and bioavailability in aquatic systems 3 (1995) 407-478. 12. Reinfelder J. R., and Fisher N. S. - The assimilation of elements ingested by marine copepods, Science 251 (4995) (1991) 794-796. 13. Yang H. N., and Chen H. C. - Uptake and elimination of cadmium by Japanese eel, Anguilla japonica, at various temperatures, Bulletin of environmental contamination and toxicology 56 (4) (1996) 670-676. 14. Jezierska B. and Witeska M. - The metal uptake and accumulation in fish living in polluted waters, in Soil and water pollution monitoring, protection and remediation, Springer (1996) 107-114. 15. Canli M. and Atli G. - The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and the size of six Mediterranean fish species, Asian Journal of Animal and Veterinary Advances 6 (3) (2002) 189-196. 16. Roesijadi G. - Metallothionein and its role in toxic metal regulation. Comparative biochemistry and physiology part C, Pharmacology, toxicology and endocrinology, 113 (2) (1996)117-123. 17. Zeitoun M. M. and Mehana E. - Impact of water pollution with heavy metals on fish health: overview and updates, Global Veterinaria 12 (2) (2014) 219-231. 18. Moore J. W. and Ramamoorthy S. - Heavy metals in natural waters: applied monitoring and impact assessment, Springer Science & Business Media, 2012. 19. Elnabris K. J., Muzyed S. K., and El-Ashgar N. M. - Heavy metal concentrations in some commercially important fishes and their contribution to heavy metals exposure in Palestinian people of Gaza Strip (Palestine), Journal of the Association of Arab Universities for Basic and Applied Sciences 13 (1) (2013) 44-51. 20. Nauen C. E. - Compilation of legal limits for hazardous substances in fish and fishery products, 1983. 21. Mokhtar M. B., Aris A. Z., Munusamy V., and Praveena S. M. - Assessment level of heavy metals in Penaeus monodon and Oreochromis spp. in selected aquaculture ponds of high densities development area, Eur. J. Sci. Res. 30 (3) (2009) 348-360.