Detailed evaluation of physicochemical properties and microbial activities of Hanna Lake and Spin Karez

As

Arsenic

B

Boron

Ba

Barium

Ca

Calcium

Cd

Cadmium

CFU

Colony forming unit

Co

Cobalt

Cr

Chromium

Cu

Copper

DO

Dissolved oxygen

EC

Electrical conductivity

E-coli

Escherichia coli

Fe

Iron

GPS

Global Positioning System

ICP-MS

Inductivity coupled plasma mass spectroscopy

K

Potassium

Mg

Magnesium

Mg/L

Milligrams per litre

Mn

Manganese

Mo

Molybdenum

Na

Sodium

NEQS

National Environmental Quality standards

Ni

Nickel

NTU

Nephelometric turbidity unit

Pb

Lead

PCRWR

Pakistan Council of Research and Water Resources

pH

Power of hydrogen

PHED

Public Health Engineering Department

Se

Selenium

TC

Total coliforms

TDS

Total dissolved solids

TH

Total hardness

WHO

World Health Organization

Zn

Zinc

μS/cm

micro-Siemens per centimeter

A key element that is essential to supporting life on our planet is water. It is not only necessary for the continued existence of every living being but also it can to create a conducive habitat for life to flourish (Westall & Brack 2018). As the population in the cities and the municipal areas are increasing with each passing day, so is the need to attain fresh potable water to accommodate the public (Liyanage & Yamada 2017). Since water is one of the basic amenities of life, its supply is even more adamant. The precipitation in the Quetta region is very low, and the nature of the atmosphere is mostly dry throughout the year (Khan et al. 2013). The water table of Quetta is about 2,000 feet below the ground level, and according to one study, it is decreasing even more by about 4.5 feet every year. Due to the scarcity of fresh water, the ratio of waterborne diseases is increasing with each passing day (Durrani et al. 2018).

The water from Hanna Lake is not suitable for drinking purposes because the concentration of coliforms is high (Aziz et al. 2013). The microbial parameters including total coliform, total fecal coliforms, and total fecal streptococci in Hanna Lake were higher than the permissible limits of the WHO in 2016 (Aamir et al. 2017). Among the most well-known diseases associated with consuming feces-contaminated food and water are cholera diarrhea and typhoid (Osiemo et al. 2019). People get most of the diseases from recreational places from microbial organisms, and about 80% of people in the United States get Giardia disease by swallowing the water from these places, and these organisms in water create the symptoms of cramps and nausea (Gyamfi et al. 2012; Yoder et al. 2012), as Hanna and Spin Karez are also used for recreational purposes so there is a high chance of getting diseases such as skin infections, diarrhea, cholera, and many more. Spin Karez is about 8 miles east of Quetta city and is currently used for watering the trees and plants in the Quetta Cantonment area. The stagnant water in both lakes is the major cause of the increasing waterborne diseases among the public. The sources of water contamination are agricultural and industrial pollutants, and soil conditions, and these are further classified as organic and inorganic microorganisms meaning microbial and physio-chemical parameters in higher concentrations cause water undrinkable (Panhwar et al. 2022). Heavy metals concentration increases in lakes due to anthropogenic activities and the consumption of heavy metals become a threat to the lake's living organisms and to people who eat these living organisms (Sibal & Espino 2018). In this research, the results of each sample will be compared with the guidelines and standards set by the WHO and National Environmental Quality Standards (NEQS). The entry of the chemicals into the fresh water contaminates it, and water becomes unsuitable for drinking purposes and poses a threat to human health. The lack of fresh water supply has greatly increased the number of patients in the city. The underground water is mostly contaminated, according to a study in 2020 (Rasheed et al. 2021). Seventy-six water samples were collected from different sources in Baluchistan, and of those 76 samples, 57% were polluted with total coliforms, E. coli, fluoride, chloride, TDS, and hardness. The public is not aware of the contaminants in the water, due to which people are exposed to waterborne diseases, and many young children are affected by this which also increases the risk of inappropriate mental growth of the kids (Ahmed et al. 2020). Physio-chemical parameters including temperature and turbidity are also linked to the lake ecosystem. This will be a comprehensive study of the water quality of both the reservoirs and the physio-chemical and microbial parameters that are affecting it. To measure multiple elements in water samples, the Varian 820 ICP-MS (inductively coupled plasma mass spectroscopy) coupled with a Varian SPS 3 auto-sampler was employed (Louie et al. 2012). Direct nebulization ICP-MS was used to measure the total chromium and selenium concentrations in the test samples (Bednar et al. 2009). ICP-MS can be used to trace a wide range of elements, including both metals and nonmetals. In the present study, the Perkin Elmer NexION 350Q model of ICP-MS was used to measure the concentrations of various elements in water samples in a very sensitive and precise manner. The water sample was inoculated onto a growth medium that had already been sterilized and hardened, and the colonies that emerged on its surface were counted (Yasin et al. 2015). To evaluate bacterial colonies in water samples, the current study utilized bacterial culture grown on Recipe Rapid E-coli 2 agar.

The average annual precipitation and average annual snowfall of Quetta are about 260 and 560 mm, respectively, and the highest annual precipitation was 928.9 mm in 1982 (Durrani et al. 2021). The elevation of the city is about 1,676 m from the sea level. The shape of the city is like a bowl. Both the lakes are surrounded by mountains. During the winter season, snow melts in the mountains, and the water is stored in the lakes. Most of the water volume is stored in the lakes in January and February because of greater precipitation, i.e., 60 and 50 mm, respectively (Durrani et al. 2021). Hanna Lake is located about 13 km from Quetta city and was built to save water in the British era. The latter is the main spot for recreational activities for families and get-togethers. Quetta City is groundwater dependent, and the annual precipitation is inadequate. With the continuous increment in the population and the depletion of groundwater, the city is facing great challenges (Dawood et al. 2021). Soon the city will no longer rely on groundwater because the discharge is more than recharge and the volume of water will be decreasing with time (Kakar et al. 2020).

The aim of this study is to examine the physicochemical and microbial properties of Hanna Lake and Spin Karez to determine their suitability as sources of potable water. Furthermore, the study aims to create awareness among the local populace and stakeholders regarding the significance of clean water and the hazards associated with consuming contaminated water. Previously, no significant research has been conducted on the Spin Karez. This study represents the first comprehensive investigation of this body of water. While there have been some earlier attempts to examine the physio-chemical and microbial parameters of Hanna Lake, this current research represents a more detailed study that covers both the Spin Karez and the Hanna Lake. The study includes 25 physio-chemical parameters and microbial colonies for both lakes, which have not been investigated before.

Quetta is the largest city and capital of Baluchistan Province. The city is located at 30.1798^o N, 66.9750^o E. The sources of drinking water here are groundwater as well as surface water. Surface water is contaminated with coliforms, pesticides, and toxic metals (Leghari et al. 2011). The city is currently experiencing groundwater depletion and a daily decline in the water table level; as a result, the tube wells that were not properly planned are also drying up (Khan et al. 2013).

Turbidity (nephelometric turbidity unit (NTU)), pH, dissolved oxygen (DO) (mg/l), and total hardness (mg/l) were measured with a turbidity meter, pH meter, DO meter, and total hardness meter, and the other chemical parameters like Mg (mg/l), Na (mg/l), K (mg/l), B (mg/l), Ba (mg/l), Se (mg/l), and Ca (mg/l), in addition with heavy metals including Pb (mg/l), Cd (mg/l), Ni (mg/l), Fe (mg/l), Zn (mg/l), Cr (mg/l), Co (mg/l), Cu (mg/l), As (mg/l), Mo (mg/l), and Mn (mg/l), were measured using the ICP-MS model (NexION 350Q, Perkin Elmer) (Kéri et al. 2018), a sensitive instrument having detection limit particles per trillion for many elements measurement.

The bacterial colonies were observed on Recipe Rapid E-coli 2 agar (Gelose). Medium was prepared and then sterilized in an autoclave for 15 min at 121 °C, and then cooled in Petri dishes until it forms a soft gel, which supports a filter paper contaminated with microbes, and these Petri dishes were kept in an incubator for 24 h before examining bacterial colonies.

Water pollution is a result of the activities caused by humans intentionally or unintentionally. Physical pollution is caused by the heat of the waste in water, mining sites, construction sites, eroded lake banks, and many other factors. Chemical pollution is caused due to the waste carried from factories, farms, and cities, while biological pollution is caused by animal wastes, human wastes, and the decay of organic matter in water. These kinds of pollution can harm human health, and that is why it is necessary to find the concentration of these pollutants in drinking water. This study assessed the water quality of Hanna and Spin Karez lakes, and water parameter concentration of Hanna Lake was different from that of Spin Karez.

The rate of water solubility is determined by EC and the conductivity of water tends to increase when it is heated. The amount of dissolved salts also affects the conductivity of water, and the higher the concentration of dissolved salts, the higher will be the conductivity. The presence of phosphate, chloride, and nitrate would increase the EC of the lake water because of a sewage system failure (Bhateria & Jain 2016). The concentration of dissolved ions also affects the EC of water. The EC of the samples collected from Hanna Lake was observed to be 537.4 μS/cm on average (Table 1), and 7 out of 10 samples have EC more than 500 μS/cm, which is more than permissible limits and the samples from Spin Karez had a conductivity of about 758.9 μS/cm on average (Table 1), and all the samples have EC more than 500 μS/cm, which is more than permissible values. These values are not under the guidelines established by the WHO (Meride & Ayenew 2016) and NEQS (Daud et al. 2017).

The suspended particles in the lake water, such as plant debris, silts, organic and inorganic matters, and clay, causes cloudiness or muddy nature. The turbidity of Hanna Lake in all samples was within the WHO limits with a mean value of 4.17 NTU (Table 1), while the turbidity in Spin Karez in all samples was above the WHO limits with a mean value of 9.5 NTU (Table 1). Because of the higher turbidity range in samples of Okara, the color of the water changed to light yellow or brownish (Sunday et al. 2014). The samples collected from Hanna Lake were colorless, while the samples from Spin Karez were slightly cloudy.

The solubility of water and the rate of organic activity are heavily influenced by temperature (Adbarzi et al. 2020). The temperature of the samples collected in the winter season from Hanna Lake was 14.6 °C on average, and the samples from Spin Karez were about 14.77 °C (Table 1) within permissible limits. Cold water is mostly preferred because warm water helps the growth of microorganisms.

In both lakes, TDS values were within the WHO standards having a mean value of 275.3 mg/l in Hanna Lake and 291.6 mg/l in Spin Karez (Table 1).

For aquatic organisms, the amount of DO is very important. Numerous chemical reactions in water and its products are also influenced by DO. Algae growth is aided by the high DO content of the water, which in turn raises the biological oxygen demand (Thompson et al. 2022). The Hanna Lake and Spin Karez DO averages were approximately 9.06 mg/l and 8.86 mg/l, respectively, which is more than the acceptable limit of 6.5–8 mg/l.

Ca causes hardness when present in water. The guidelines provided by the WHO are as follows: below 60 mg/l is soft, 60–120 mg/l is moderately hard, 120–180 mg/l is hard, and above 180 mg/l is very hard (Kozisek 2020). The water obtained from Hanna Lake had Ca of about 31.5 mg/l, and water samples taken from Spin Karez had about 43.5 mg/l of Ca within permissible levels.

Mg generally has a very slow reactivity, but the amount of DO affects it. The average Mg content found in the samples from Hanna Lake was about 7.9 mg/l, while the samples from Spin Karez had an Mg content of 10.3 mg/l, which lies inside the guidelines provided by the WHO (<50 mg/l).

The total amount of dissolved Ca⁺² and Mg⁺² in water is referred to as the total hardness. On average, the total samples collected from Hanna Lake lie around 158 mg/l, and the samples collected from Spin Karez were about 185 mg/l, which is well under the limit of <500 mg/l.

The average range of Na concentration in the samples was determined to be approximately 4–5 mg/l, and the concentration of Na in both lakes was within the permissible standard range. Noting that excessive amounts of Na might have negative impacts on human health, including hypertension and cardiovascular illnesses, it is important to analyze the Na content in water samples.

Potassium is a necessary mineral that is required for many body processes such as controlling heartbeat, preserving fluid balance, and supporting neuron and muscle functions. Although potassium is important, the body only needs a little quantity of it to function properly, and too much may be hazardous (Meride & Ayenew 2016). Average potassium values in Hanna Lake and Spin Karez are 4.6 and 4.3 mg/l, respectively.

Boron (B) enters the surface water by dumping wastewater or recharging through an underground water source. The average concentration of B observed from samples collected from Hanna Lake was 0.0636 mg/l and the average concentration of B observed from samples from Spin Karez was about 0.0637 mg/l on average. These are well under the guidelines established by WHO and NEQS.

This element enters drinking water through the recharge of underground water and industrial waste. The WHO specifies 1.3 mg/l as the acceptable limit. Ba observed on the samples collected from Hanna Lake is about 0.0147 mg/l and that on the samples collected from Spin Karez is about 0.0464 mg/l, which is significantly under the suggested maximum.

It is a rare element that is used as a trace component in packaged food that is produced in factories. The minimum amount of Se allowed by the WHO is 0.01 mg/l. The Hanna Lake and spin Karez samples have Se of 0 mg/l.

Heavy metals in water are higher as a result of anthropogenic activities such as mining, fertilizers, and the release of industrial wastes into the water (Dranga et al. 2017). Heavy metal concentrations are higher in surface water samples from Quetta city's dams, lakes, and ponds according to a study by Leghari et al. (2011), while the current study has found that heavy metals values were within the range set by the WHO.

If they get into the water, Pb, Cd, and Cr are harmful substances that can harm the kidneys and brain as well as cause serious health problems (Eldaw et al. 2020). According to the WHO guidelines, Cr metal in a specified range is required in drinking water to maintain nutrition and maintain normal human glucose metabolism (Mughal et al. 2022).

Heavy metals typically have lower concentrations in water than in the bed of lakes or sediments (Hou et al. 2013; Gülcü-Gür & Tekin-Özan 2015). Metals like Pb, Zn, Ni, Fe, and Cu were found in higher concentrations along the lake's shores and lower concentrations in the lake's center. This could be due to bioaccumulation (Sheikh et al. 2014).

Ni is carcinogenic if intake is more than the allowable limit, while Zn has not much effect on health, and the concentration of Ni and Zn may increase from the stainless-steel fittings and the pipes (Meride & Ayenew 2016). Iron, a naturally occurring metal found in the earth's crust (Eldaw et al. 2020), aids in the delivery of oxygen to our blood.

To increase the production of red blood cells, a certain amount of Co is required; however, a concentration that is higher than the allowed limit is harmful to human health. (Zakir & Ihsanullah 2009). Cu concentrations in water rise as a result of pesticide use and industrial waste (Gyamfi et al. 2012). Ar can be found in the environment in both organic and inorganic forms, and consuming more than the allowed amount can cause lung and bladder cancer (Pál et al. 2022).

Molybdenum comes from mining areas and Cu and tungsten byproducts. Weathering can occasionally raise Mn levels in water in mountainous areas (Eldaw et al. 2020).

The results of heavy metals concentration of all the samples that were taken from Hanna and Spin Karez met the WHO and NEQS guidelines, as shown in Table 2.

The aim of the study is to shed insight into Hanna Lake and Spin Karez's water quality. The results show that several parameters, including DO, EC, Ca, and turbidity, have concentration levels that are higher than the WHO and NEQ standards, rendering the water unfit for human consumption. The poor condition of Quetta's water distribution system exacerbates the depletion of water resources. The results of the study hold significance for both public health and environmental science. The effect of climate change and mountain erosion on the water quality in the area has not been thoroughly examined. Future studies could examine the link between these elements and the criteria governing Hanna Lake's and Spin Karez's water quality. In addition, it is proposed that quick action is required to solve Quetta's problems with water delivery and quality.

The draft was written by ZA and MB. The data were gathered by MBA, MSA, MB, and ZA. The data were interpreted by ZA and SP. SSH used the ICP-MS technique, SP, ZA, and MB cultured the bacteria, and SP and HS supervised this research work.

The staff of the Public Engineering Lab and Surveying Lab at NUST Baluchistan Campus, as well as the U.S.-Pakistan Center for Advanced Studies in Water (USPCAS-W), MUET Jamshoro, for assisting us with heavy metals detection, are sincerely appreciated by the authors.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.