Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 19 Impact of toxic heavy metals on the Condition Index of Cirrhinus mrigala Abhijit Mitra1, *, Sana Ahmed2,#, Subra Bikash Bhattacharyya2,α, Sitangshu Roy2.β, Prosenjit Pramanick2,$, Nabonita Pal2,¥, Ricardo Gobato3,§ and Sufia Zaman2,¤ 1 Department of Marine Science, University of Calcutta, 35 B.C. Road, Kolkata 700019, India. Department of Oceanography, Techno India University, West Bengal, EM 4 Salt Lake, Sector V, Kolkata 700091, India. 3 Green Land Landscaping and Gardening, Seedling Growth Laboratory, 86130-000, Parana, Brazil. 2 To cite this article: Abhijit Mitra, Sana Ahmed, Subra Bikash Bhattacharyya, Sitangshu Roy, Prosenjit Pramanick, Nabonita Pal, Ricardo Gobato, and Sufia Zaman. “Impact of toxic heavy metals on the Condition Index of Cirrhinus mrigala”, Parana Journal of Science and Education. Vol. 8, No. 8, 2022, pp. 19-29. DOI: tiny.cc/PJSE24476153v8i8p019-029 Received: October 24, 2022; Accepted: October 29, 2022; Published: November 1, 2022. Abstract The paper presents evidence that dissolved toxic heavy metals like cadmium, lead, and chromium pose significant adverse impact on the overall average Condition Index (CI) of Cirrhinus mrigala, a commercially important freshwater finfish consumed in India. This index serves as a better proxy to ambient environmental health of the species compared to the existing Fulton’s condition equation. Observations of fish culture related hydrological parameters such as surface water temperature, surface water pH, Dissolved Oxygen (DO), dissolved nitrate, dissolved phosphate, and dissolved silicate during the culture period of 5 months exhibit significant positive relationships with the overall average CI (exception is silicate), which indicate the growth of the fish species as functions of these variables.. Keywords: Cirrhinus mrigala, Dissolved toxic heavy metals, Condition Index (CI), Hydrological parameters, correlation coefficient. *Email: [email protected] (Corresponding Author) α Email: [email protected] $ Email: [email protected] § Email: [email protected] # Email: [email protected] Email: [email protected] ¥ Email: [email protected] ¤ Email: [email protected] β Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 20 1. Introduction India is the 3rd largest fish producing country in the World and contributes about 7% of the total global fish production. The country sustains around 10% of the global fish biodiversity and is one of the 17-mega biodiversity rich countries. It has been documented that approximately 14 million people are engaged in fisheries and several other fish related activities. Andhra Pradesh is the largest fish producing state in the country followed by West Bengal and Gujarat. About 70% of the India’s fish production comes from inland waters, out of which nearly 65% is sourced from aquaculture. In the domain of inland aquaculture production Indian major carps are the most cultured freshwater fish followed by exotic carps, minor carps, catfish and trout. In many of the aquatic ecosystem of the country, toxic heavy metals are frequently encountered that originates from the adjacent landmasses as runoff. These metals retard the growth of the cultured species and subsequently impact the CI value of the species. The present paper aims to highlight the impact of dissolved cadmium, lead and chromium along with other relevant parameters, on the growth of Cirrhinus mrigala with the primary objective to evaluate the suitability of the environment for the growth of the species. The suitability of an aquatic ecosystem for the growth and survival of the species depends on several relevant hydrological parameters like surface water temperature, surface water pH, dissolved oxygen and dissolved nutrients (like nitrate, phosphate and silicate). However, in recent times impact of toxic heavy metals on fish growth has become a vital issue due to rapid industrialization, urbanization, and unplanned tourism activities. Reports of bioaccumulation of heavy metals in fish tissues have been reported in several literatures and preferably in the state of West Bengal [1-5]. On this background the present research focuses on the oscillation of the overall average Condition Index (CI) of Cirrhinus mrigala in response to dissolved cadmium, lead and chromium that are highly toxic in nature. 2. Materials and Methods 2.1 Study area Diamond Harbour (22°11'4.2''N; 88°11'22.2''E) is a region adjacent to Indian Sundarbans, the designated World Heritage Site [6-9]. The region has large number of freshwater ponds where species like Labeo rohita, Catla catla, and Cirrhinus mrigala etc. are cultured. In this pilot project, 6 freshwater ponds of approximately 10 ft depth were selected for culturing Cirrhinus mrigala for a period of 5 months (March 2022 to August, 2022). The ponds are basically rainwater harvested ponds but owing to the presence of the Hooghly estuary surrounding the region, salinity intrusion results to a very mild salinity around 1.0 to 1.5 psu in the culture ponds. 2.2 Pond preparation The selected ponds were dewatered with pump and the bottom was sun- dried for one month to allow excavation of the bottom mud and to complete digging of the experimental ponds; thus, aquatic weeds and unwanted fauna were removed. The embankments of the ponds were repaired and constructed. After testing soil pH, liming was done at a dose of 250kg/ha that helps to maintain good ambient water quality. Stocking of the fish was done ~1/m2. 2.3 Monitoring of dissolved toxic heavy metals in water Analysis of dissolved cadmium, lead and chromium of the six cultured ponds were done simultaneously along with the analysis of selected hydrological parameters. Before analysis, each water sample was collected and stored in clean TARSON bottles and was filtered through a 0.45 µm Millipore membrane. The filtrate was treated with diethyl dithiocarbamate and extracted in carbon tetrachloride [10]. The extract was evaporated to dryness and the residue was mineralized with 0.1 ml of concentrated nitric acid. Analytical blank was prepared and treated with the same reagents. Analyses were done in duplicate by direct aspiration into AAS (PerkinElmer Model: 3030) equipped with a HGA-500 graphite furnace atomizer and a deuterium background corrector. The AAS was used to determine the dissolved heavy metal concentrations as it is the most widely used method of trace element analysis in environmental materials such as water, soil and tissues [11]. 2.4 Monitoring parameters of selected hydrological Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 21 Analysis of 21 physic-chemical variables like surface water temperature, surface water pH, dissolved oxygen (DO), and dissolved nutrients (nitrate, phosphate and silicate) were carried out in every month for all the 6 selected ponds as per the standard method [12]. 𝐾= ̅ℎ = Average weight of cultured fishes during 𝑊 harvesting; ̅𝑠 = Average weight of cultured fishes during 𝑊 stocking; Monthly estimation of CI of the cultured species was carried out using the expression of Fulton [13]: ̅ 𝑊 𝑥102 (𝑇𝐿)3 (2) where 2.5 Monitoring of Condition Index (CI) and overall average CI 𝐾= ̅𝑠 ̅ℎ − 𝑊 𝑊 𝑥 102 ̅̅ )3ℎ − (̅̅ ̅̅ )3𝑠 (̅̅ 𝑇𝐿 𝑇𝐿 ̅̅ )ℎ =Average total length of cultured fishes (̅̅ 𝑇𝐿 during harvesting; (1) ̅̅ )𝑠 =Average total length of cultured fishes (̅̅ 𝑇𝐿 during stocking. ̅ is the average weight (g) where K is the CI, 𝑊 and 𝑇𝐿 is the average total length (cm) 3. Results 3.1.CI The overall average CI of the cultured species is a modification of the index of Fulton [13] and was computed using C- language as per the expression: The CI being a function of weight and length of the cultured species were computed for 150 days (5 months) at an interval of 30 days for all the 6 selected ponds (Tables 1 – 3). Table 1: Weight (g) of Cirrhinus mrigala in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 53 49 55 54 58 51 30th 125 121 127 126 129 125 May th 60 213 204 218 215 222 206 June 90th 315 306 321 316 323 310 July 120th 410 398 417 411 421 400 th 509 499 515 511 517 502 April August 150 Source: Authors. Table 2: Length (cm) of Cirrhinus mrigala in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 19.18 19.22 20.07 20.46 20.74 19.77 30 th 24.21 24.83 24.44 25.49 24.02 24.12 May 60 th 28.60 28.62 28.31 27.99 28.39 28.28 June 90th 31.37 31.07 31.67 31.20 31.74 31.73 July 120 th 34.03 34.25 34.33 33.84 34.44 33.75 August 150th 36.23 36.33 36.60 36.51 36.65 36.06 April Source: Authors. Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 22 Table 3: Condition Index (CI) of Cirrhinus mrigala in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 0.75 0.69 0.68 0.63 0.65 0.66 30th 0.88 0.79 0.87 0.76 0.93 0.89 60 th 0.91 0.87 0.96 0.98 0.97 0.91 June 90 th 1.02 0.96 1.01 1.04 1.01 0.97 July 120th 1.04 0.99 1.03 1.06 1.03 1.04 th 1.07 1.04 1.05 1.05 1.05 1.07 April May August 150 Source: Authors. 3.3 Hydrological parameters The relevant hydrological parameters like surface water temperature, surface water pH, DO, dissolved nitrate, phosphate and silicate were monitored simultaneously during length-weight observation periods to find the impacts of these variables on the CI of the cultured species, Tables (4 – 9) and Figures (1 - 6). Table 4: Surface water temperature (°C) in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 32.9 32.8 33.0 32.9 32.8 32.6 April 30th 32.9 32.9 33.1 32.9 33.0 32.7 May 60th 33.1 33.0 33.2 33.1 33.0 32.7 June 90 th 33.5 33.0 33.4 33.2 33.1 32.8 July 120th 33.6 33.1 33.5 33.4 33.2 33.0 th 33.8 33.2 33.6 33.5 33.4 33.1 August 150 Source: Authors. Figure 1: Pond-wise variation of mean surface water temperature during the culture period. Surface water temperature ( °C) 34 33.8 33.6 33.4 Day 1 33.2 Day 30 33 Day 60 32.8 Day 90 32.6 Day 120 32.4 Day 150 32.2 32 Pond1 Source: Authors. Pond 2 Pond3 Pond4 Pond5 Pond6 Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 23 Table 5: Dissolved Oxygen (ppm) in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 5.02 5.19 5.23 5.98 5.70 5.80 30 th 5.12 5.44 5.55 5.99 5.83 5.91 May 60 th 5.34 5.63 5.61 6.01 5.90 5.99 June 90th 5.68 5.71 5.68 6.10 5.98 6.13 July th 120 5.72 5.80 5.80 6.17 6.05 6.19 August 150th 6.01 5.96 5.93 6.20 6.11 6.22 April Source: Authors. Figure 2: Pond-wise variation of mean Dissolved Oxygen (DO) during the culture period. 7 Dissolved Oxygen (ppm) 6 Day 1 5 Day 30 4 Day 60 3 Day 90 2 Day 120 1 Day 150 0 Pond1 Pond 2 Pond3 Pond4 Pond5 Pond6 Source: Authors. Table 6: Surface water pH in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 7.14 7.22 7.28 7.29 7.20 7.18 30 th 7.18 7.24 7.29 7.30 7.21 7.20 May 60 th 7.23 7.26 7.30 7.30 7.23 7.24 June 90th 7.24 7.27 7.31 7.31 7.27 7.25 July th 120 7.26 7.28 7.32 7.32 7.30 7.26 August 150th 7.30 7.29 7.33 7.34 7.31 7.30 April Source: Authors. Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 24 Figure 3: Pond-wise variation of mean surface water pH during the culture period. 7.4 7.35 Day 1 7.25 Day 30 7.2 Day 60 7.15 Day 90 7.1 Day 120 7.05 Day 150 pH 7.3 7 Pond1 Pond 2 Pond3 Pond4 Pond5 Pond6 Source: Authors. Table 7: Dissolved nitrate (µgatl-l) in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 17.86 24.55 25.30 20.49 18.20 18.23 April 30 th 18.33 24.98 25..85 23.18 19.85 19.44 May 60th 19.44 25.10 26.30 24.30 20.71 20.55 June 90 th 20.33 26.34 27.66 26.14 22.45 21.67 July 120th 21.68 28.63 28.13 27.10 22.68 23.68 th 29.40 31.04 30.77 28.14 23.16 24.10 August 150 Source: Authors. Figure 4: Pond-wise variation of mean Dissolved Nitrate (µgatl -1) during the culture period. 35 Nitrate (µgat/l) 30 Day 1 25 Day 30 20 Day 60 15 Day 90 10 Day 120 5 Day 150 0 Pond1 Source: Authors. Pond 2 Pond3 Pond4 Pond5 Pond6 Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 25 Table 8: Dissolved phosphate (µgatl-l) in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 2.05 4.05 2.66 3.46 4.55 3.96 30th 2.10 4.15 2.85 3.99 4.61 3.98 60 th 2.11 4.30 3.83 4.02 4.66 4.05 June 90 th 2.65 4.60 4.13 4.13 4.79 4.60 July 120th 3.68 4.83 5.02 4.65 4.88 4.73 th 4.64 5.11 5.06 4.86 5.02 4.99 April May August 150 Source: Authors. Figure 5: Pond-wise variation of mean Dissolved Phosphate (µgatl-1) during the culture period. 6 Phosphate (µgat/ l) 5 Day 1 4 Day 30 3 Day 60 Day 90 2 Day 120 1 Day 150 0 Pond1 Pond 2 Pond3 Pond4 Pond5 Pond6 Source: Authors. Table 9: Dissolved silicate (µgatl-l) in 6 selected ponds at Diamond Harbour. Month Day Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 March 1st 78.26 77.41 78.04 77.62 78.66 76.30 April 30 th 78.19 77.48 78.12 77.46 78.44 76.38 May 60th 78.31 77.51 77.81 77.60 78.41 76.21 June 90th 78.13 77.40 77.90 77.64 78.58 76.30 July th 120 78.21 77.41 78.13 77.25 78.49 76.16 August 150th 78.33 77.51 77.97 77.34 78.56 76.24 Source: Authors. Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 26 Figure 6: Pond-wise variation of mean Dissolved Silicate (µgatl -1) during the culture period. 79 78.5 Silicate (µgat/l) 78 Day 1 77.5 Day 30 77 Day 60 76.5 Day 90 76 Day 120 75.5 Day 150 75 74.5 Pond1 Pond 2 Pond3 Pond4 Pond5 Pond6 Source: Authors. 4. Discussion The research has attempted to develop the overall average Condition Index (CI) of the fishes in all the 6 ponds by considering the weights and lengths during their stocking and harvesting, the results of which are depicted in Figures (7 – 12). Figure 9: Overall average CI of Cirrhinus mrigala in Pond 3. Figure 7: Overall average CI of Cirrhinus mrigala in Pond 1. Source: Authors. Figure 10: Overall average CI of Cirrhinus mrigala in Pond 4. Source: Authors. Figure 8: Overall average CI of Cirrhinus mrigala in Pond 2. Source: Authors. Source: Authors. Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 27 Figure 11: Overall average CI of Cirrhinus mrigala in Pond 5. and weight ̅ = 𝑊 ̅ℎ − 𝑊 ̅𝑠 𝑊 (3) are the foundations of the overall average CI of fishes and provide better insights on the wellbeing of the cultured species in context to the ambient environment. These expressions are also useful to evaluate Cost Benefit Analysis (CBA) at ease as is Equation (3) the actual indicator of profit margin. The output generated from the correlation coefficient computation highlights few relevant points, Table (10). Source: Authors. Figure 12: Overall average CI of Cirrhinus mrigala in Pond 6. i. The overall average CI of C. mrigala is directly proportional (p < 0.01) to the surface water temperature, irrespective of the ponds ii. The surface water pH and DO also pose significant positive impacts on the overall average CI of the cultured species (p < 0.01). iii. The overall average CI of the cultured species is positively correlated with dissolved nutrients like nitrate and phosphate for all the ponds (p < 0.01), but with dissolved silicate there exists insignificant correlation. iv. It is a matter of great concern that CI of the cultured fish species is inversely related to dissolved cadmium, chromium, and lead (p < 0.01), which indicates that the productivity of the pond is adversely impacted by dissolved toxic heavy metals that will decrease the profitability margin. Source: Authors. The computation was done using C- Language and the values indicate the suitability of the pond for the cultured species as per the sequence Pond 1 (1.321) > Pond 2 (1.278) > Pond 6 (1.271) > Pond 3 (1.252) > Pond 4 (1.222) > Pond 5 (1.216). The authors feel that increment of total length ̅̅ ̅̅ = (̅̅ ̅̅ )ℎ − (̅̅ ̅̅ )𝑠 𝑇𝐿 𝑇𝐿 𝑇𝐿 Table 10: Correlation coefficient (r) computed between overall average CI and selected environmental variables. Combination Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 CI × SWT 0.9289 0.9605 0.8947 0.8641 0.8382 0.8744 CI × pH 0.9546 0.9955 0.9099 0.7465 0.7721 0.9077 CI × DO 0.951 0.9890 0.9602 0.8053 0.9039 0.9461 CI × Nitrate 0.7364 0.8561 0.7766 0.9392 0.9103 0.9276 CI × Phosphate 0.8007 0.9504 0.8897 0.8287 0.7621 0.8234 Parana Journal of Science and Education (PJSE) – v.8, n.8, (19-29) November 1, 2022 ISSN: 2447-6153 https://sites.google.com/site/pjsciencea 3 CI × Silicate -0.0639 0.1526 -0.2424 -0.4165 -0.5334 -0.4648 CI × Cd -0.9579 -0.9780 -0.7639 -0.8416 -0.9921 -0.9697 CI × Cr -0.9367 -0.8557 -0.9718 -0.7905 -0.5539 -0.8629 CI ×Pb -0.9672 -0.7441 -0.7982 -0.9268 -0.8598 -0.9508 Source: Authors. 5. Conclusions We have provided in the paper an overall average Condition Index of the cultured fish species as per the equation (2) is a better indicator of profitability as change of fish biomass or gain in weight during the culture period is directly reflected. [5] A. Mitra, S. Zaman, P. Pramanick, “Blue Economy in Indian Sundarbans: Exploring Livelihood Opportunies”, published by Springer, DOI: https://doi.org/10.1007/978-3-031-07908-5, eBook ISBN 978-3-031-07908-5, XIV, 403 (2022). The correlation coefficient carried out between the overall average CI and dissolved toxic heavy metals reflect the adverse impacts of dissolved toxic heavy metals on fish growth, but direct correlations exist between the overall average Condition Index and hydrological parameters like surface water temperature, surface water pH, Dissolved Oxygen, and dissolved nutrients (except with silicate). The results have significant implications in terms of water quality management of the culture pond, which plays pivotal role in boosting / accelerating fish growth. [6] P. Pramanick, S. Zaman, D. Bera, A. 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