For verification of this paper, please visit on http://www.socialresearchfoundation.com/researchtimes.php#8

The quality of water is of vital concern for mankind since it is directly linked with human welfare. It is a matter of history that faecal pollution of drinking water caused water-borne diseases which wiped out entire populations of cities. At present, the menace of water borne diseases and epidemics still looms large on the horizons of developing countries. Polluted water is the culprit in all such cases. The major sources of water pollution are domestic waste from urban and rural areas, and industrial wastes which are discharged into natural waterbodies. Man-made activities have caused environmental degradation. We have degraded lands, destroyed forests at suicidal rates, thrown tonnes of toxic waste into rivers indiscriminately and poured toxic chemicals into the seas. Furthermore, we discharged green-house gases into the atmosphere leading to climatic changes. The net result is: we are surrounded by pollution in our daily lives—we breathe, we drink, we eat pollution.[1,4]

The Ganga River being the major river in India is concerned with the domestic, agricultural and industrially discharged from various sources. The LULC (Land Used and Land Cover) study carried out on this river involving collecting water samples show that expansion of built-up and agricultural lands is causing a reduction in true cover and water bodies. As Kolkata city continues to expand, the water quality is a matter of concern in the river and surrounding areas. The findings indicate that across the buffer zone LULC changes to a significant amount. A growing trend in the built-up area covering the Hooghly river is attributed to an increase in population. In addition, an expansion of agricultural areas at the expense of water body, leading to concern about the impact of Chemical fertilizer on the  water quality.

The study highlights the need for suatainable land use practices to preserve the rivers eco-system and maintain water quality.

The study has demonstrated the impact of changes in land use and land cover(LULC) and population growth on water quality. Localities in the vicinity of Dakshineswar, Shibpur and Garden Reach are particularly vulnerable to water quality detorioration due to LULC changes and increase in population density. The results revealed that areas experiencing significant LULC changes and population growth, exhibit poorer water quality.

The significance of a chemical analysis depends to a large extent on the sampling programme. An ideal sample should be one which is both valid and representative. These conditions are met by collection of samples through a process of random selection. This ensures that the composition of the sample is identical to that of the water body from which it is collected and the sample shares the same physico-chemical characteristic with the sampled water at the time and site of sampling.

The relevant factors for any sampling program are

(a)   Frequency of sample collection

(b)   Total number of samples

(c)    Size of each sample

(d)   Sites of sample collection

(e)   Method of sample collection

(f)    Data to be collected with each sample,  and

(g)   Transportation and care of samples prior to analysis.

For analysis of natural and waste water, two principal types of sampling procedures are employed:

1.     Spot or grab samples are discrete portions of water samples taken at a given time. A series of grab samples, collected from different depths at a given site, reflect variations in constituents over a period of time. The total number of  grab samples should satisfy the requirements of the sampling programme.

2.     Composite samples are essentially weighted series of grab samples, the volume of each being proportional to the rate of flow of the water stream at the time and site of sample collection. Samples may be composited over anytime period, such as 4,8 or 24 hours, depending on the purpose of analysis. Such composite samples are useful for determining the average condition which, when correlated with flow, can be used for computing the material balance of a stream of water body over a period of time.

It may be stated, in general, that it is more meaningful to analyse a large number of separate samples taken at different times and different locations than to compile and analyse a single representative sample.

Separate samples must be collected for chemical and biological analysis since the sampling and preservation techniques are quite different. For accurate analysis, it is desirable to allow a short-time interval between sampling and analysis. As a matter of fact, temperature, pH and dissolved gases (D.O) must be determined in the field and as quickly as possible after sampling.[1]

Water Quality Parameters and Standards

The parameters for water quality characterization are listed in Table-T-1The permissible limits, as laid down by the United States Public Health drinking water standards (USPH) and Indian Standard Institution (ISI) are listed for comparison. This refers to domestic water supplies for drinking water (Table-T-1). The ISI values, available for only a few parameters, are much higher than those for USPH, obviously for no good reasons.

Table-T-1 Showing Water Quality Parameters and Standards By USPH & ISI

Variation of pH and D.O.

From Tables it is observed that pH of the water samples collected from different blocks of Bardhaman district (both for the pre-monsoon and post-monsoon seasons) are within almost neutral region (6.0 - 8.0)[Table I]. The D.O. (ppm) on the other hand varies over a wide range (2.5 for BWN (GW)6 to 10.6 for BWN (SW)13[Table I]. The higher value of D.O. signifies a good quality water for the Ganga surface water while the tap water of Parulia Bazar, Purbasthali is not upto the satisfactory level [the permissible level of D.O. in drinking water > 5]. The intermediate level of D.O. of other water samples are of moderated qualities. The pH of the water samples of Hooghly district, lower, are within normal level (6.0 - 1.5)[TableIII] . The Damodar river water of this district is again found to be having highest D.O. content both for this pre-monsoon (10.2 ppm) and post-monsoon season (10.0 ppm)[same table]. The other sources of water are having permissible level of D.O. content (6.1 ppm 8.2 ppm). The pH of the Birbhum district with samples are normal. The D.O. content of this district is seen to be alarmingly low (2.7 ppm) for Maureswari-1[Table V] from a densely populated bus stand sample and can be concluded to be of poor quality-water .

Variation of Conductivity and TDS

The conductivity value (2ms) for the Bardhaman district varies from 0.240 for the tube well sample from Bhatar bazar to as high as 0.876 for a tube well sample of Dihat more, Katwa – II[Table II]. In general it is found that in both cases of ground water and surface water the magnitude of conductivity is lowered to some extent from the premonsoon season onto the postmonsoon season[Table II ].This can be attributed to the dilution effect. The TDS values (2ppt) on the other hand is seen to be very low (0.234) for the Ganga river, Kalna Municipality so also only 0.271 for the same river water sample at Katwa [same tables]. The TDS values for the ground water samples are on the higher range, upto 0.678 (2 ppt). This trend is very much distinct for the premonsoon (Table II), as well as for the post monsoon samples. This observed behaviour can again be due to higher extent of dilution of the dissolved solids in surface water in comparison to when that is confined in ground water.

Similar pattern of behaviour is observed in case of conductivity data (2ms) for the district Hooghly. The lowest value here is seen for the Damodar river (Pursurah) sample (0.298) for the pre-monsoon and (0.253) for the post-monsoon sample Table II . The highest magnitude here is observed for HOOG (GW)3 sample, that is for a ground water (TW) sample which is again lowered in case of the corresponding post-monsoon season results. This trend in behaviour is again manifested in the TDS (2ppt) values - only 0.165 for the HOOG (SW), and 0.137 for the pre-monsoon and post-monsoon seasons respectively. The higher values in case of ground water samples is again prominent here [(0.561) and (0.489) respectively]. In case of Birbhum district, however, we could not collect the premonsoon samples. Here also we find the same trend in behaviour for both the parameters of conductivity (2ms) and TDS (2 ppt), viz., 0.124 andO.079 respectively for the Maurakshi river sample, Table V. Here the highest values of these parameters occur for a ground water sample Birm (GW)2 with magnitudes of 0.75 and 0.49 respectively.

This general behaviour may be due to higher extent of dilution of the different ions in case of a river sample than that of a ground water sample.

Occurrence of Arsenic

In case of Bardhaman district we have found arsenic to occur in case of the Ganga river at Katwa burning ghat both for the pre-monsoon (0.125 ppm) and post-monsoon (0.105 ppm) seasons. At Kalna, Table II  however, downstream with respect to Katwa, arsenic was absent for the Ganga river water sample. This amount of arsenic is twice the permissible level of 0.05 ppm (ISI). Among the other ground water samples one location at Purbasthali- II block [BWN (GW)6] was found to contain 0.04 ppm of As in a tap water sample only in the pre-monsoon season. Another ground water (TW) sample BWN (GW)1 from Bhatar bazar bus stand was found to contain As both during the pre-monsoon (0.025 ppm) and post-monsoon (0.02 ppm) seasons. The BWN (GW)9 sample from Purbasthali - I block was found to contain 0.025 ppm of As at a depth of 70 ft. TW whereas for the TW samples from the same location at higher depths (250 ft and 300 ft) had negligible As content. The Purbasthali block was earlier reported to contain As by several workers.[2,7]. The presence of As in the shallow TW in comparison to the deeper ones may be due to the higher extent of dilution at the lower acquifer containing ground water. For the Hooghly district the blocks Khanakul - 1 and Khanakul - II were affected by ground water As contamination as is evident from the two TW samples HOOG (GW)4 and HOOG(GW)5 having As contents of 0.088 and 0.04 ppm respectively for the pre-monsoon season and 0.062 and 0.032 ppm respectively for the post-monsoon season Table V. The other parts of Hoohgly district are safe as far as arsenic occurrence is concerned.

Fig.1; Pictorial representation of occurrence of arsenic in different parts of West Bengal.

 

Variation of total hardness and chloride

The total hardness of different samples were found to vary from 8 to 228 (mg/L) both for the Burdwan and Birbhum districts. The chloride content was found to be within 355 to 1385 (mg/L) for samples collected from different locations both for Burdwan and Birbhum districts with a higher range for the Birbhum district. The only sample from Tilpara barrange of Mourakshi river was found to contain an abnormally high value of chloride i.e., 1,17,203 (mg/L)[ Table VI].[2,5]

Table I: pH and D.O. Data of Bardhaman District ()Premonsoon

GW = Ground Water, SW = Surface Water, TW = Tube Well

Table II: Conductivity, TDS and Arsenic data (Premonsoon) of Bardhaman district

Table III : pH and D.O. data of Hooghly district (Premonsoon)

Table IV : Conductivity, TDS and Arsenic data (Premonsoon) of Hooghly district

Table V : pH, D.O., Conductivity and TDS data of Birbhum district (Postmonsoon)

Table VI: Total hardness and Chloride data(Postmonsoon) of Birbhum district

1. De Anil K., Environmental Chemistry, Seventh Edition. New Age Int. Pub., pg 248 (2010).
2. Das Tanmoy, Water Quality of Bardhaman Circle, West Bengal, Periodic Research, August 2014.
3. Savarimuthu X., M.M. Hira-Smith, Yuan Y., Von Ehrenstein, Das, S. Ghosh, N., Mazumder D.N.G & Smith A.H., Seasonal Variation of Arsenic-Concentration In Tubewells In West Bengal, India, J. Health, Population and Nutrition, 24, 277(2006).
4. De A.K and De Arnab Kumar,Environment & Ecology
5. Das Tanmoy, Water its Qualitative and Quantitative Acceptability. ENVIRONICA, 5, 40 (2007).
6. Das D., Samanta G., Mandal B.K., Roy Chowdhury T., Chanda C.R., Chowdhury P.P, Basu G.K. and Chakraborti D., Arsenic in groundwater in six districts of West Bengal, India, Environmental Geochemistry and Health. 18, 5- 15 (1996).
7. Chatterji A., Das D. and Chakroborti D., A study of groundwater contamination by arsenic in the residential area of Behala, Calcutta due to industrial pollution, Environmental Pollution, 80, 57-65 (1993).
8. Ghosh Tathgata and Rolee Kanchan, SpatioTemporal Pattern of Groundwater Arsenic Concentration in Thick Unconfined Acquifer of Murshidabad District, West Bengal. India, Universal J. of Environmental Research and Technology. 1, 311-319 (2011).
9. Mandal B.K. & Suzuki K.T., Arsenic Round The World: A Review. Talanta. 58, 201-235 (2002).
10. Adimalla, N., Dhakate, R., Kasarla, A., Taloor, A.K., 2020. Appraisal of groundwater quality for drinking and irrigation purposes in Central Telangana, India. Groundw. Sustain. Dev. 10, 100334.
11. Salehi, S., Chizari, M., Sadighi, H., Bijani, M., 2018. Evaluation des utilisateurs des eaux souterraines pour l’agriculture en Iran: un biais environnemental culturel. Hydrogeol. J. 26, 285–295.
12. Ahmad, S., Umar, R., Arshad, I., 2019. Groundwater quality appraisal and its hydrogeochemical characterization — Mathura City, Western Uttar Pradesh. J. Geol. Soc. India 94, 611–623.
13. Janardhana Raju, N., Shukla, U.K., Ram, P., 2011. Hydrogeochemistry for the assessment of groundwater quality in Varanasi: a fast-urbanizing center in Uttar Pradesh, India. Environ. Monit. Assess. 173, 279–300.
14. Singh, U.K., Kumar, M., Chauhan, R., Jha, P.K., Ramanathan, A.L., Subramanian, V., 2008. Assessment of the impact of landfill on groundwater quality: a case study of the Pirana site in western India. Environ. Monit. Assess. 141, 309–321.
15. Adimalla, N., 2019. Controlling factors and mechanism of groundwater quality variation in semiarid region of South India: an approach of water quality index (WQI) and health risk assessment (HRA). Environ. Geochem. Health 8. 16. Margat, J., van der Gun, J., 2013. Groundwater around the World A Geographic Synopsis. CRC Press Taylor & Francis Group.
17. Howard, K.W.F., Isralilov, R.G. (Eds.), 2001. Current Problems of Hydrogeology in Urban Areas. Urban Agglomerates and Industrial Centres NATO Science Series.
18. Chaudhry, A.K., Kumar, K., Alam, M.A., 2019. Mapping of groundwater potential zones using the fuzzy analytic hierarchy process and geospatial technique. Geocarto Int. 0, 1–22.
19. Anbarasu, S., Brindha, K., Elango, L., 2019. Multi-influencing factor method for delineation of groundwater potential zones using remote sensing and GIS techniques in the western part of Perambalur district, southern India. Earth Sci. Informatics.
20. Ghorbani Nejad, S., Falah, F., Daneshfar, M., Haghizadeh, A., Rahmati, O., 2017. Delineation of groundwater potential zones using remote sensing and GIS-based data-driven models. Geocarto Int. 32, 167–187.
21. Hao, Q., Xiao, Y., Chen, K., Zhu, Y., Li, J., 2020. Comprehensive understanding of groundwater geochemistry and suitability for sustainable drinking purposes in confined aquifers of the wuyi region, central north china plain. Water (Switzerland) 12, 1–25.
22. Ozdemir, A., 2011. Using a binary logistic regression method and GIS for evaluating and mapping the groundwater spring potential in the Sultan Mountains (Aksehir, Turkey). J. Hydrol. 405, 123–136.
23. Xiao, Y., Yin, S., Hao, Q., Gu, X., Pei, Q., Zhang, Y., 2020. Hydrogeochemical appraisal of groundwater quality and health risk in a near-suburb area of North China. J. Water Supply Res. Technol. AQUA 69, 55–69.
24. Xiao, Y., Liu, K., Hao, Q., Li, J., Zhang, Y., Cui, W., Pei, Q., 2021. Hydrogeochemical Features and Genesis of Confined Groundwater and Health Perspectives for Sustainable Development in Urban Hengshui, North China Plain 2021
25. Yin, S., Xiao, Y., Han, P., Hao, Q., Gu, X., Men, B., Huang, L., 2020. Investigation of groundwater contamination and health implications in a typical semiarid basin of North China. Water (Switzerland) 12.
26. Samuel Che. N.Batt.S.Chineijem Okpara,E. Obuwaeadamilare Olagbaju,P.Escher Fayani,O.Mathuthu M. An assessment of Land Use and Land Cover changes and its impact on the surfacewater Quality of the Crocodile river catchment, South Africa in River Deltas research-Recent Advances, In Tech open; Rijoke, Croatia,2022 [ Google Scholar] [Cross-Ref.]
27. Vermo,S; Verme,R.K. Tiwary;Patel,N;Murthy,S. Relationships between Land use/Land cover Pattern and Surface Water Quality in Damodar River Basin, India,Glob.J.Appl.Environ.Sci,2012,2,107-121[ Google Scholar]
28. Shukla A.L,Ojha,C.S.Z Mijie,A;Buylaert.W, Pathak S,Garg.R.D,Shukla,S.S-Population growth,Land Use and Land Cover transformation and Water Quality.Nexus in the upper Ganga River Basin,Hydrol.EarthSyst.Sci,2018,22,4745-4770.
29. Assessing the Impact of Land Use and Land Cover changes on the Water Quality of River Hooghly,West Bengal,India, A case study by Ghritho Goswami,Samar Mandal,Sudip Basack,Rishika Mukherjee and Moseskarakerezian Hydrology,2023,10(3)71.