Physico Chemical Analysis of Water in Aquaponds In Devaguptam Village in Allavaram Mandal, Dr. B. R. Ambedkar Konaseema Dist. A. P., India

Abstract

The seasonal variations of physico chemical parameters of water quality in Aquaculture ponds are investigated in may (2023) to (2024) April season in Devaguptam village, Allavaram mandal in the Dr B.R. Ambedkar Konaseema District, Andhra Pradesh. India. Aquaculture productivity is strongly influenced by the quality of water, which is determined by various physic-chemical parameters. The present study aims to evaluate the seasonal variations of water quality parameters including pH, Temperature, Turbidity, Alkalinity, Carbonates, Bicarbonates, Salinity, Total hardness, Calcium, Magnesium, Potassium, Dissolved Oxygen (DO), Free Co2, Total Dissolved solids (TDS), Nitrates, Nitrites and Ammonia. Monthly water samples was collected from the study area over a 12-month period and analyzed using standard methods. The data was statistically assessed to understand how seasonal changes influence pond water quality.

Keywords

Introduction

Seasonal Variations in pH:

pH ranged between 7.2 in May and 8.38 in April, with an annual average of 7.82. The water remained slightly alkaline throughout, which is ideal for aquaculture. The higher values in summer are due to intense photosynthetic activity, while lower values in early monsoon (May–July) may be due to increased carbon dioxide from organic decomposition. The pH values ranged from 7.2 (May) to 8.38 (April) with a mean of 7.82 ± 0.20. A higher pH was observed during pre-summer (April), possibly due to increased photosynthetic activity and reduced CO? solubility at higher temperatures. Pre-monsoon (march-may) pH is 7.68-8.38 it is higher pH values during this period can be link to increased sunlight and phytoplankton photosynthesis, which consumes CO2 and raises pH. This condition generally favors fish and shrimp growth if pH remains below 8.5. Monsoon (June – September) ph is 7.71 – 8.02. it Moderate pH values may be due to dilution from rainfall and inflow of freshwater, which buffers alkalinity. These stable conditions are suitable for aquaculture species with minimal stress risk. Post-Monsoon (October – January) pH is 7.51-7.96 Slight decline in pH, possibly due to reduced photosynthesis, decomposition of organic matter, and higher CO? levels. While still within optimal limits, close monitoring is essential to prevent acidification stress.  Summer (February – April) pH is 8.04 – 8.38. Elevated pH during summer months may result from high photosynthetic activity and evaporation, leading to concentration of salts. While beneficial for most species, excessively high pH can cause ammonia toxicity.

Seasonal variations in Temperature:

Temperature was fairly stable, ranging from 28–32°C (mean 29.75°C). This range is considered optimum for fish and prawn culture, as it supports metabolic activity and growth without causing thermal stress. Temperature varied between 28°C (July, March) and 32°C (April) with a mean of 29.75 ± 1.09°C. Monsoon (March – May) temperature is 28 – 30 is gradual temperature increase before monsoon promotes higher feeding activity and growth rates. Still within optimal range, but monitoring is needed in late May to avoid stress. Monsoon (June – September) temperature 28 – 31, Rainfall and cloud cover stabilize temperatures, reducing heat stress. Suitable for stable pond conditions and healthy growth. Post-Monsoon (October – January) temperature 29 – 30, Temperatures remain moderate, supporting good feed conversion efficiency and reduced risk of disease outbreaks. Summer (February – April) temperature 28 – 32, Highest temperatures in April may lead to reduced dissolved oxygen and increased ammonia toxicity. Proper aeration and water exchange are necessary to maintain fish and shrimp health.

Seasonal Variations in Turbidity:

Turbidity levels recorded during the study area ranged from a minimum of 28 NTU (February and April) to a maximum of 40 NTU (October and November). Increased turbidity during rainy months is linked to surface runoff and suspended particles, which may limit light penetration for photosynthesis. Turbidity ranged from 28 NTU (Feb, Apr) to 40 NTU (Oct, Nov) with a mean of 32.4 ± 3.95 NTU. Pre-Monsoon (March – May) Turbidity 28 – 32 is Moderate turbidity supports optimal phytoplankton growth and provides a balanced natural food base for fish and shrimp. Monsoon (June – September) turbidity 30 – 35 is Slight increase in turbidity due to rainfall and runoff introducing suspended solids into ponds. Still within tolerable limits for cultured species. Post-Monsoon (October – January) 30 – 40 is Highest turbidity recorded (40 NTU) in October and November due to sediment resuspension and nutrient-rich inflow from catchment areas. Requires monitoring to avoid reduced light penetration and oxygen production. Summer (February – April) 28 – 32 is Lowest turbidity observed, leading to high light penetration and increased photosynthetic activity. Beneficial for natural food production but may promote excessive algal blooms if nutrients are high.

Seasonal Variations in Alkalinity:

Alkalinity fluctuated between 110 mg/L (May) and 272 mg/L (January), with a mean of 145.5 mg/L. This indicates good buffering capacity of pond water, which helps maintain pH stability. Bicarbonates were the major contributors to alkalinity, ranging from 112–272 mg/L, while carbonates were detected only occasionally (4–16 mg/L). Higher alkalinity during winter suggests reduced utilization of carbonates by plankton. The alkalinity ranged from 110 mg/L (May) to 272 mg/L (Jan) with a mean of 145.5 ± 41.61 mg/L. Pre-Monsoon (March – May) Alkalinity range 127 – 172 Moderate alkalinity provides good buffering capacity, ensuring stable pH and supporting phytoplankton growth. Monsoon (June – September) alkalinity range 116-156 is Slight reduction due to dilution from rainfall and freshwater inflow. Lower buffering capacity requires monitoring to prevent sudden pH drops. Post-Monsoon (October – January) 128 – 272 is Highest values observed in January may be due to evaporation and mineral concentration, improving pH stability but exceeding the ideal range (>200 mg/L). Summer (February –April) 128- 172 stable and moderate alkalinity supports healthy pond ecosystems and optimal nutrient cycling.

Seasonal Variations in Carbonates:

Pre-monsoon (march – may) 0 – 4 Low carbonate levels, except for May (4 mg/L). Buffering is mainly supported by bicarbonates. Monsoon (June – September) 0 – 4 Very low values due to dilution from rainfall and freshwater inflow, stable pH depends on total alkalinity. Post monsoon (October – January) 0 No detectable carbonate levels, total alkalinity remained adequate for pH stability. Summer (February – April) 4 – 16 Highest value recorded in April (16 mg/L) likely due to evaporation and liming practices, improving buffering capacity during high-temperature months. Carbonates were mostly absent, except in May, Sep, Feb, and Apr where values (4–16 mg/L) were recorded. carbonates, averaging values 2.333 ± 4.46 mg/L.

Seasonal variations in bicarbonates:

Winter Season (December–February) Bicarbonate concentrations were at their highest, with a peak of 272 mg/L in January. This elevated level can be attributed to reduced photosynthetic activity, lower biological uptake, and minimal rainfall dilution. The colder temperatures also slow down microbial decomposition, leading to greater accumulation of carbonate and bicarbonate ions in the water. Summer Season (March–May) Concentrations ranged from 128 mg/L in April to 148 mg/L in May. Higher evaporation rates during summer can concentrate bicarbonates, increased algal photosynthesis and carbonate precipitation can offset this effect. Southwest Monsoon (June–September) The lowest concentrations were recorded during this season, with 112 mg/L in September. Heavy rainfall and surface runoff dilute the ionic content of pond water, while increased water exchange and suspended solids from inflows can alter carbonate chemistry. Post-Monsoon (October–November) Levels rose again to 128–148 mg/L, reflecting a recovery phase after monsoon dilution. Reduced rainfall, combined with increased evaporation and gradual re-establishment of primary production, leads to replenishment of bicarbonates. Bicarbonates varied between 112–272 mg/L, averaging 148 ± 43.58 mg/L, contributing significantly to total alkalinity.

Seasonal Variations in Salinity:

 Salinity varied seasonally between 6 ppt (June, Feb) and 11 ppt (May, April). The higher values in summer are attributed to evaporation, while the lower values in monsoon are due to dilution from rainfall and freshwater inflows. Salinity fluctuated between 6 ppt (June, Feb) and 11 ppt (May, April) with a mean of 8.83 ± 1.72 ppt. Higher salinity during summer (May, Apr) is attributed to increased evaporation and lower freshwater inflow. Summer (March–May) Salinity levels were at their peak during this period, with the highest values recorded in April (11 ppt) and May (11 ppt). The elevated salinity during summer is primarily due to high temperatures, enhanced evaporation rates, and minimal freshwater inflow, resulting in concentration of salts in the culture water. Monsoon (June–September) A marked reduction in salinity was observed, with the lowest value of 6 ppt in June. The drop in salinity during monsoon months is attributed to heavy rainfall and surface runoff, which introduce freshwater into the ponds and estuarine systems, causing dilution of salts. Post-Monsoon (October–November) Salinity remained moderately high (7–10 ppt) during this period, reflecting a balance between residual freshwater inflows and tidal mixing from adjacent brackish or marine waters. Winter (December–February) Moderate to low salinity values were recorded, with 6 ppt in February representing one of the annual minimal. Lower evaporation rates, combined with occasional winter rainfall or groundwater seepage, contributed to these reduced values.

 Seasonal Variation of Total hardness:

Total hardness showed variation, from 2520 mg/L (June) to 5270 mg/L (May). Similarly, Calcium (368–880 mg/L) and Magnesium (388–746 mg/L) concentrations were higher in summer months, reflecting evaporation and concentration of salts. These ions are essential for shell formation in prawns and fish bone development, thus beneficial for aquaculture. Values ranged from 2520 mg/L (June) to 5270 mg/L (May) with a mean of 4134 ± 80.78 mg/L. Pre-monsoon (March–May) Hardness is high due to evaporation and limited rain dilution. Monsoon (June–September) Hardness decreases because of heavy rainwater dilution. Post-monsoon/Winter (October–February) Moderate hardness, influenced by reduced rainfall, gradual mineral accumulation, and stable water conditions. Hardness is primarily due to dissolved calcium and magnesium salts, showing seasonal differences linked to water exchange and evaporation. Magnesium ranged from 388 mg/L (June) to 746 mg/L (May), mean 584 ± 116.06 mg/L.

Seasonal Variations of Calcium:

Calcium varied between 368 mg/L (June) and 880 mg/L (May), mean 691 ± 178.4 mg/L. Summer (March–May) Calcium levels during summer were moderate, ranging from 440 mg/L in May to 848 mg/L in April. Increased evaporation in the pre-monsoon period likely led to a gradual rise in calcium levels towards April. Monsoon (June–September) A noticeable drop in calcium concentration occurred in June (368 mg/L), the lowest of the year, due to dilution from heavy rainfall and runoff. Levels then increased steadily through July (836 mg/L) and September (728 mg/L) as rainfall intensity reduced and water exchange stabilized. Post-Monsoon (October–November) Calcium concentrations showed recovery, with values of 460 mg/L in October and 792 mg/L in November, possibly due to reduced dilution and increased mineral leaching from surrounding soils. Winter (December–February) The highest calcium values were recorded in this season (868 mg/L in December and 768 mg/L in January), reflecting low precipitation, minimal water inflow, and higher evaporation rates, all of which concentrate dissolved minerals in pond water. February showed a decline to 508 mg/L, indicating possible increased water exchange before the onset of summer.

Seasonal Variations of Magnesium:

Magnesium ranged from 388 mg/L (June) to 746 mg/L (May), mean 584 ± 116.06 mg/L. Summer (March–May) Magnesium concentrations in summer were relatively high, ranging from 435 mg/L in May to 726 mg/L in April. This increase before the monsoon may be attributed to evaporation-driven concentration and limited freshwater inflow. Monsoon (June–September) The onset of the monsoon in June resulted in the lowest magnesium level (388 mg/L), likely due to dilution from heavy rainfall. however, a sharp peak was observed in July (736 mg/L), the highest value recorded, possibly caused by soil mineral leaching and increased runoff from surrounding catchment areas. Levels then stabilized in August (517 mg/L) and September (573 mg/L). Post-Monsoon (October–November) Magnesium levels remained fairly stable, with 539 mg/L in October and 575 mg/L in November, reflecting a balance between reduced rainfall dilution and steady mineral input from soil and sediments. Winter (December–February) Magnesium concentrations during winter were moderate, with 583 mg/L in December and 537 mg/L in January, followed by a decrease to 427 mg/L in February, likely due to partial water exchange or management practices in aquaculture ponds.

Seasonal Variations in Potassium:

Potassium ranged between 35–55 mg/L, except in May where it was absent. Potassium supports phytoplankton productivity and thus indirectly contributes to natural food availability in ponds. Potassium levels were absent in May but ranged up to 55 mg/L (Sep, Apr). Mean concentration was 46.36 ± 6.06 mg/L, essential for primary productivity. Pre-monsoon season (March–May) Potassium levels ranged between 35–55 mg/L, with a minimum in May (35 mg/L) and a higher value in April (55 mg/L). The variability during this period can be linked to evapo concentration in summer months and dilution from occasional pre-monsoon showers. (June–September) Potassium values gradually increased from 40 mg/L in June to the seasonal peak of 55 mg/L in September. The progressive rise is likely due to runoff from surrounding soils rich in potassium minerals and enhanced decomposition of organic matter brought in by monsoon inflows. Post-monsoon season (October–January) Concentrations remained moderate, between 40–50 mg/L, indicating stable conditions with minimal dilution or concentration effects. The reduced rainfall and moderate evaporation rates may have contributed to this stability. Winter season (February) Potassium dropped to 35 mg/L, marking one of the lowest annual values. Lower decomposition rates, reduced biological activity, and absence of significant inflow may explain this decline.

Seasonal Variations in Dissolved Oxygen:

DO varied between 4.8 mg/L (Oct, Dec) and 6.1 mg/L (Apr) with a mean of 5.46 ± 0.44 mg/L. Pre-Monsoon Season (March–May) DO values were relatively high, with April recording the maximum value of 6.1 mg/L, followed by May at 5.7 mg/L. The elevated concentrations during this period can be attributed to increased photosynthetic activity due to higher sunlight intensity, reduced cloud cover, and moderate water turbulence, enhancing oxygen diffusion. Monsoon Season (June–September) DO levels showed a slight decline, with June recording one of the lower values at 4.9 mg/L, while July to September remained stable around 5.8 mg/L. The decrease in early monsoon is likely due to increased water temperature, higher organic load from runoff and reduced light penetration caused by turbidity, which limits photosynthetic oxygen production. Post-Monsoon Season (October–February) This period displayed mixed trends. The lowest DO concentrations (4.8 mg/L) were recorded in October and December, possibly due to decomposition of organic matter accumulated during the monsoon and increased microbial respiration. In February recorded a relatively higher value (5.9 mg/L), likely due to lower temperatures and enhanced oxygen solubility.

Seasonal Variation of Total Dissolved solids:

The Total Dissolved Solids (TDS) values in the study area exhibited seasonal variations. The highest TDS concentration (715 mg/L) was recorded in July (monsoon season), possibly due to surface runoff carrying dissolved salts and organic matter into the aquaculture pond. Conversely, the lowest TDS value (424 mg/L) was observed in February (winter season), which may be attributed to reduced evaporation and lower external inputs. These fluctuations in TDS are crucial as they directly influence water quality, osmoregulation in aquatic organisms, and the overall productivity of the aquaculture system. TDS ranged from 424 mg/L (Feb) to 715 mg/L (July) with a mean of 532.67 ± 78.46 mg/L.The Total Dissolved Solids (TDS) values recorded at the study area ranged from 424 mg/L (February) to 715 mg/L (July), showing distinct seasonal fluctuations influenced by rainfall, evaporation, and management practices in the aquaculture ponds. Summer (March–May) TDS values are 528 mg/L (March), 484 mg/L (April), 454 mg/L (May). TDS was moderate during summer. Higher evaporation rates in summer can increase dissolved ion concentration, but water exchange and management practices may dilute the effect. Monsoon (June–September) TDS values are 468 mg/L (June), 715 mg/L (July), 575 mg/L (August), 575 mg/L (September) TDS reached its maximum in July (715 mg/L). This increase is attributed to surface runoff carrying salts, minerals, and organic matter into the ponds. Monsoon inflows enrich the pond water, causing higher dissolved solids. Post-Monsoon (October–December) TDS values are 505 mg/L (October), 574 mg/L (November), 574 mg/L (December). TDS remained consistently high in this season, due to residual salts and nutrients left after monsoon and reduced flushing of pond water. Winter (January–February) TDS values are 443 mg/L (January), 424 mg/L (February). The lowest TDS (424 mg/L) was recorded in February. Cooler temperatures reduce evaporation, and limited agricultural runoff contributes to a dilution effect, resulting in lower TDS values.

Seasonal Variations of Nitrates:

Summer Season (March–May) During summer, nitrate levels were relatively low, with the minimum value (0.04 mg/L) recorded in May. The low concentration may be due to minimal surface runoff, high water evaporation rates, and active uptake of nitrates by phytoplankton and aquatic vegetation. Monsoon Season (June–September) Data gaps were observed in June, July, and September, but in August nitrate levels increased to 0.12 mg/L. This rise is likely due to nutrient-rich runoff from agricultural fields during rainfall, enhancing the nutrient load in the pond water. Post-Monsoon Season (October–November) Nitrate concentrations remained moderate, with values of 0.06 mg/L in October and 0.10 mg/L in November. This may be due to residual nutrient input from post-monsoon flows and moderate biological uptake. Winter Season (December–February) Nitrate levels were lowest in December (0.04 mg/L) but sharply increased in February (0.20 mg/L), representing the peak value in the study. This sudden rise may be attributed to the accumulation of organic matter during cooler months and reduced phytoplankton uptake due to lower temperatures. Pre-Monsoon (March–April) No data was available for March, but April showed a moderate nitrate value of 0.12 mg/L, possibly due to gradual nutrient accumulation before the onset of rains.

Seasonal Variation of Nitrite:

Nitrite concentrations in the study area remained below detectable limits (N) during most months of the year, including May, June, July, August, September, October, November, December, January, March, and April. This indicates that the aquatic environment maintained effective nitrogen cycling and biological filtration throughout these periods, minimizing the risk of nitrite accumulation.

Seasonal Variation of Ammonia:

January, February, March, and April. mean 0.097 ± 0.05 mg/L. Slightly elevated values in Feb and Nov suggest agricultural runoff.  Ammonia concentrations in the study site exhibited notable seasonal variation. The highest values (0.3 mg/L) were recorded during August, October, and November, suggesting a possible increase in organic matter decomposition and reduced nitrification efficiency during late monsoon and early winter months.

CONCLUSION:

The present study demonstrates that the physicochemical parameters of aquapond water at the Devaguptam village in Allavaram Mandal, Dr B.R. Ambedkar konaseema District, Andhra Pradesh, India., showed clear seasonal variations driven by climatic factors such as rainfall, evaporation, and biological activity. pH remained slightly alkaline (7.2–8.38), ideal for aquaculture.  Temperature was stable (28–32°C). supporting growth without thermal stress. Turbidity fluctuated moderately, enhancing plankton growth but requiring monitoring in post-monsoon months. Alkalinity and bicarbonates ensured buffering capacity, maintaining pH stability. Salinity followed seasonal cycles, with summer maxima and monsoon minima, but remained within tolerable limits for brackish water aquaculture. Hardness, calcium, and magnesium were abundant, supporting shell and bone development in cultured species. Dissolved oxygen mostly stayed above 5 mg/L, though care is needed during decomposition-rich months. Nutrients (nitrates, nitrites, ammonia) were generally low, indicating minimal eutrophication and safe conditions for culture operations [1].

ACKNOWLEDGEMENTS

Authors thank to Department of Environmental sciences for provided Research and Community Service, Acharya Nagarjuna University, Guntur.

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