QUALITY AND SUITABILITY OF GROUND WATER FOR DRINKING PURPOSES IN THE WESTERN FRINGE (PERI-URBAN) OF KHULNA CITY, BANGLADESH

Study Team: Coordinator Professor Dilip Kumar Datta, Ph.D Environmental Science Discipline, Khulna University, Khulna-9208 Supervisor Masudur Rahman Assistant Professor, Environmental Science Discipline, Khulna University, Khulna-9208. Research Intern Md. Muhyminul Islam B.Sc. Student, Environmental Science Discipline, Khulna University, Khulna-9208 with Khondakar Arifuzzaman MS Graduate, Environmental Science Discipline, Khulna University, Khulna-9208

Project

Water Security in Peri-Urban South Asia: Adapting to Climate Change and Urbanization

December 2011

ABSTRACT

This study has conducted to assess the quality and suitability of groundwater for drinking purpose in peri-urban area of Khulna City which is situated in the south-western part of coastal Bangladesh. To complete this research work, 20 ground water samples of 10 shallow aquifers and 10 deep aquifers, were collected from 5 different sampling spots which are located on the both banks of the Mayur River. The analysis reveals that the chemical composition of the groundwater in this area is variable, with electrical conductance ranging from 813 to 9800 µs/cm. The pH values range from 7.02 to 8.44. Most of the groundwater is weakly alkaline. Higher value of electrical conductivity (EC) and concentration of sodium ion suggest that water quality of shallow aquifer in this locality is quite unsatisfactory and exceeds the standard guideline value of drinking water of DoE, Bangladesh and WHO. But the major parameters concentration of deep aquifers meets the both standards and is quite satisfactory in respect to drinking purposes.

1. INTRODUCTION

1.1 Background of the Study

The quality of drinking water is a powerful environmental determinant of the health of a community. The problem of the quality of water resources in general, and groundwater resources in particular, is becoming increasingly important in both industrialized and developing nation. In developing countries like Bangladesh the essential concerns as regards water resources are their quantity, availability and suitability. Nevertheless, experience in the more highly developed industrial nations tells us that it is necessary, or at least desirable, to adopt modernization that is compatible with the environment, that is, that will have a sustainable impact. When aiming for environmental sustainability, groundwater and surface water play a leading role because they are of fundamental importance to all living things (Fiorucci, 2007).

Although water is the most frequently occurring substance on earth, lack of safe drinking water is more prominent in the developing countries. Groundwater is the main source of water supply throughout the world. Due to increasing world population, extraction of groundwater is also increasing for irrigations, industries, municipalities and urban and rural households day by day. During dry season extensive withdrawal of groundwater for irrigation purpose is lowering the water table in the aquifer and also changing the chemical composition of water quality (for different aquifer chemistry) (Saha et al.,2007).

Land use has significant impacts on ground water quality. Typical observed changes include increased nitrate concentrations and detection of pesticides in agricultural areas (Burkhart and Kolpin, 1993; Anderson, 1993; Keeney and DeLuca, 1993; Bauder et al., 1993; Cain et. al, 1989), increased nitrate concentrations and pesticide detections in residential areas (Anderson, 1993; Geron et al., 1993; Eckhardt and Stackelberg, 1995), and increased nitrate concentrations and volatile organic compound (VOC) detections in commercial and industrial areas (Eckhardt and Stackelberg, 1995) compared to undeveloped land use settings (Haycock and Pinay, 1993; Anderson, 1993). Some mega or big-cities are allocated near shore or the groundwater resources are underlain by salt waters. In these cases excessive groundwater abstraction may force salt water to move either laterally or vertically into the freshwater, so deteriorating groundwater quality. (Megic et al., 2004). The Khulna City Corporation (KCC) in southwest Bangladesh lies on young Holocene-Recent Alluvium of the Ganges deltaic plain in north and Ganges tidal plain in south. The area is composed of coarse to very fine sand, silt and silty clay up to a depth of 300m with peaty soil and calcareous as well as non-calcareous soil at the top (Roy et al., 2005). Vulnerability of coastal aquifers due to saline water intrusion and other anthropogenic pollution is one of the major environmental hazards restricting availability of fresh water in most coastal cities of the world. KCC is one such city where the aquifers are subjected to

marine influence due to intense anthropogenic pressure from within and outside the region (Datta and Biswas, 2004). And within the KCC areas, only 30% of households are under piped water supply, where the rest are self-managed and many of the people face extreme water crisis. For this reason all the peri-urban dwellers along the both banks of the Mayur River are totally dependent on the GW (ground water) sources for drinking and other household purposes. So quality assurance for groundwater has become the most prior concern in this fringe of the KCC. 1.2 Objectives of the study To monitor the physico-chemical and biological characteristics of the GW of the

western fringe of the KCC area; and

To determine the health risk of GW by assessing its suitability for drinking purpose.

2. MATERIALS AND METHODS 2.1 Component One: Problem Identification Groundwater is the only reliable water resource for human consumption throughout the different parts of the country. Moreover when aiming for environmental sustainability, ground-water plays a leading role because it is of fundamental importance to all living things. So it is urgent to monitor and determine the quality and characteristics of the ground water in an area where the community people are mostly dependent on this source of water. 2.2 Component Two: Study Area Selection Studies for the assessment of the GW quality in the KCC area have already been done but particularly in this western fringe are not still done. Virtually there is a possibility of ground water pollution by the polluted water of Mayur River as the aquifers along the banks might be recharged by river water also. The communities living on the banks of this river are directly dependent on groundwater sources for their drinking purposes. For this reason assessing of the quality and suitability of the ground water for drinking purposes in this area study is now a matter of urgency. 2.3 Component Three: Collection of Water Sample 2.3.1 Selection of the sampling locations The study was conducted on the both banks of the Mayur river. The samples were collected from 5 different sampling locations of the both banks of the Mayur river from Rayer-Mahal to Sachibunia at an approximately same distance of 2 Km.

Table 2.1: Sampling Locations

No. of spots

Sampling Locations

Co-ordinates Longitude(N) Latitude(E)

01. Rayermahal 22°49´58´´ 89°31´08´´ 02. Shonadanga 22°48´58´´ 89°32´11´´ 03. Gollamari 22° 48´06´´ 89°32´26´´ 04. Mohammadnagar 22° 48´00´´ 89°32´33´´ 05. Sachibunia 22°47´05´´ 89°32´22´´

Fig 2.1: Sampling locations (on the both banks of the river)

2.3.2 Number and frequency of water samples From each sampling location ground water samples will be collected for 4 times at an interval of 2 months from August, 2011 to May, 2012. Each sampling location includes 2 deep-tube wells and 2 shallow tube wells on each bank of the river and 1surface water sample from the middle of the river. 2.3.3 Collection methods 2.3.3.1 For physico-chemical analysis It is the most important part of the present study for the degree of accuracy of analytical results. Every possible precaution was taken to obtain a representative sample. Water samples were collected in 1 L plastic bottles. The bottles were washed 6-7 times with household water and then 2-3 times with distilled water and again entering 1-2 ml of 95-98% industrial sulfuric acid with water (for free foreign chemicals in bottles) in to every bottles and sealed well and preserved for one night. After one night preservation, every bottle was properly washed with shaking by water again 6 or 7 times. Then the bottles were dried in room temperature. Before collection the tube well water was pumped out for at least 5 minutes so that the sample could represent the ground water from which the well is fed. The bottle was then sealed by the tapes. Aeration during sampling was avoided as far as possible. From each bank of the river groundwater samples were collected from the tube-wells which are within 150 feet radial distance from the river.

Fig 2.2: Distance of the sampling tube-wells from the river

2.3.3.2 For microbiological analysis The water samples will be collected during the post monsoon using sterile 250ml sized glass sampling bottles. Samples will be transported to the laboratory in ice for analysis. 2.3.4 Present status of water sample collection Water samples for 3 times (shown in red colour) have already been collected and other samples will be collected in the following months (shown in white colour).

Table2.2: Time of sample collection

2.4 Component Four: Analysis of Water Sample

2.4.1 Parameter selection To measure quality of the collected sample the following tests were performed in respect to health hazard in the ground water of the study area.

Table 2.3: Selected Physico-chemical and Biological parameters for analysis

No. Types Parameters No. Parameters a. Physical i. Temperature

ii. pH iii. EC (Electric Conductivity) iv. TDS v. DO

b. Chemical Cations i. Na+ ii. K+ iii. Ca2+ iv. Mg2+

Anaions i. Cl- ii. HCO3- iii. SO42- iv. PO43- v. NO3- vi. H4SiO42-

c. Biological i. Total Bacterial Counts (TBC) ii. Total Coliform Counts (TCC)

2.4.2 Analytical procedures

For physical, chemical and biological analysis of those water samples a number of sophisticated instruments were used and following established world recognized analytical methods were followed (Table 2.4).

Table 2.4: The methods/instruments, book references used to measure the parameters

2.4.2 Present status of water sample analysis Groundwater and surface water samples of two times have already been analyzed and third samples are being analyzed in the laboratory following the above (Table 2.4) methods or instruments.

Parameters Unit Methods /Instruments References Temperature o

C Centegrade Mercury Thermometer Ramesh and Anbu, 1996 And APHA, 1992

pH - Microprocessor pH meter (HANNA instruments, pH

211) EC µs/c

m TDS meter (H1-9635, portable water proof Multirange Conductivity/TDS meter, HANNA)

TDS ppm TDS meter (H1-9635, portable water proof Multirange Conductivity/TDS meter, HANNA)

Salinity ppt Salinity meter DO mg/l DO meter Ca2+ mg/l Titrimetric method Ramesh

and Anbu, 1996 And APHA, 1992

Mg2+ mg/l Titrimetric method Cl- mg/l Titrimetric method Na+ ppm Flame photometric method K+ ppm Flame photometric method HCO3- mg/l Potentiometric method PO43- ppm Ascorbic acid method (Thermospectronic, UV-visible

Spectrophotometers, Helios 9499230 45811) NO3- ppm Ultraviolet spectrophotometric screening method

(Thermospectronic, UV-visible Spectrophotometers, Helios 9499230 45811)

SO4

2- ppm Turbidimetry method

3. RESULTS AND DISCUSSION

3.1 Results of the Study

The quality of groundwater is assessed by analyzing the composition of the groundwater and

the mechanism which govern its chemistry. The chemical composition of groundwater

samples in the study area are shown in the following tables (Table 3.2 and Table 3.4).

Table 3.1: Physical parameters of samples in the month of August, 2011 (Sample: 01)

Note: S₁R₁= Sample of Reyermahal, S₁S₁= Sample of Shonadanga, S₁G₁= Sample of Gollamari S₁M₁= Sample of Mohammadnagar, S₁C₁= Sample of Sachibunia. * Red Color marks exceed the recommended limit for drinking water.

Sample ID Type of Tubewells

EC (μs)

TDS (gm/L) pH DO (mg/l)

Temp ( C)

F1 F2 S₁R₁ Deep 1300 0.909 0.649 8.19 1.5 25.4 S₁R₂ Deep 1060 0.743 0.531 8.08 1.3 25.4 S₁R₃ Deep 1093 0.764 0.546 7.11 1.0 25.4

S₁S₁ Shallow 2720 1.90 1.50 7.12 1.7 25.6 S₁S₂ Deep 1020 0.713 0.510 7.91 1.8 25.5 S₁S₃ Deep 846 0.592 0.423 8.07 1.3 25.6 S₁S₄ Shallow 2210 1.55 1.262 7.06 0.9 25.7

S₁G₁ Deep 960 0.671 0.480 8.16 1.7 25.7 S₁G₂ Shallow 880 0.616 0.440 7.95 1.8 25.5 S₁G₃ Shallow 1068 0.747 0.534 7.02 1.4 25.7 S₁G₄ Deep 8150 5.69 4.07 8.30 1.5 25.5

S₁M₁ Deep 837 0.586 0.419 8.11 1.3 25.7 S₁M₂ Shallow 8910 6.19 4.42 7.18 1.9 25.6 S₁M₃ Shallow 7830 5.43 3.89 7.14 2.0 25.7 S₁M₄ Deep 804 0.564 0.403 7.82 1.6 25.7

S₁C₁ Deep 944 0.661 0.472 7.93 1.5 25.9 S₁C₂ Shallow 9800 6.80 4.86 6.94 2.1 25.8 S₁C₃ Deep 972 0.680 0.486 8.04 1.5 25.8 S₁C₄ Shallow 6650 4.64 3.32 7.12 2.1 25.9

Table 3.2: Chemical composition of Groundwater in the month of August, 2011 (Sample: 01)

* Red Color marks exceed the recommended limit for drinking water.

Sample ID

Type of Tubewells

Depth (feet)

Cations (meq/l) Anions (meq/l) Na+ K+ Ca 2+ Mg2+ Cl - NO3

- SO42- PO4

3- S₁R₁ Deep 960 11.04465 0.08545 0.3992 0.3948 2.500111 0.06148 0.1063 0.0153715 S₁R₂ Deep 1050 18.1569 0.05968 0.1996 0.3454 1.000044 0.04447 0.0267 0.0144612 S₁R₃ Deep 960 5.63934 0.07901 0.3493 0.2961 1.500066 0.04847 0.0446 0.0136647

S₁S₁ Shallow 250 19.57935 0.40119 1.5469 2.0235 14.50064 0.16981 0.1263 0.0501687 S₁S₂ Deep 1200 17.01894 0.03390 0.1497 0.2961 1.000044 0.03946 0.0924 0.0264088 S₁S₃ Deep 1050 7.06179 0.05968 0.1497 0.3454 1.000044 0.03496 0.0247 0.0109338 S₁S₄ Shallow 260 19.662 0.38830 1.3972 1.8755 10.50046 0.17482 0.0586 0.0353763

S₁G₁ Deep 1200 9.26376 0.02746 0.1497 0.098712 2.500111 0.02145 0.0586 0.0260675 S₁G₂ Shallow 120 6.5076 0.04034 0.1996 0.246 1.500066 0.15450 0.1063 0.0274117

S₁G₃ Shallow 200 57.85065 0.45274 3.5429 4.5407 64.00284 0.06614 0.0247 0.0308248

S₁G₄ Deep 950 13.70424 0.02746 0.1996 0.1480 1.000044 0.06864 0.0824 0.0311879

S₁M₁ Deep 960 12.03906 0.08545 0.1497 0.3948 1.500066 0.01244 0.0586 0.0074064 S₁M₂ Shallow 150 60.1953 0.05323 4.0419 6.0707 76.50326 0.01736 0.0824 0.0057917 S₁M₃ Shallow 255 42.15585 0.04679 3.493 2.9613 64.50272 0.01736 0.0366 0.0126189 S₁M₄ Deep 1050 7.59858 0.10478 0.3992 0.5429 2.000089 0.00644 0.0207 0.0070650

S₁C₁ Deep 1100 7.63077 0.08545 0.2994 0.4442 4.500200 0.01695 0.0864 0.0149163 S₁C₂ Shallow 215 58.90553 0.45274 4.2415 7.3046 85.50366 0.05989 0.0466 0.0167369 S₁C₃ Deep 1200 9.6222 0.09189 0.2994 0.4442 2.500111 0.02395 0.0884 0.0083167 S₁C₄ Shallow 185 53.8008 0.39474 5.1896 6.8604 50.00222 0.10367 0.0366 0.0137568

Table 3.3: Physical parameters of samples in November, 2011 (Sample: 02)

Note: S₁R₁= Sample of Reyermahal, S₁S₁= Sample of Shonadanga, S₁G₁= Sample of Gollamari, S₁M₁= Sample of Mohammadnagar and S₁C₁= Sample of Sachibunia. * Red Color marks exceed the recommended limit for drinking water.

Sample ID Type of Tubewells

EC (μs)

TDS (gm/L) pH DO (mg/l)

Temp ( C)

F1 F2 S₁R₁ Deep 1250 0.875 0.625 8.19 1.5 28 S₁R₂ Deep 986 0.688 0.492 8.08 2.0 28.2 S₁R₃ Deep 1055 0.738 0.527 7.11 2.9 28.6

S₁S₁ Shallow 2380 1.65 1296 7.12 1.5 28.7 S₁S₂ Deep 907 0.635 0.454 7.91 1.8 28.8 S₁S₃ Deep 779 0.546 0.391 8.07 2.0 29.0 S₁S₄ Shallow 2060 1.50 1.158 7.06 1.1 29.1

S₁G₁ Deep 899 0.628 4.9 8.16 2.0 29.1 S₁G₂ Shallow 985 0.689 0.492 7.95 2.2 29.2 S₁G₃ Shallow 7450 5.20 3.72 7.02 1.8 29.2 S₁G₄ Deep 974 0.682 0.488 8.30 2.1 29.3

S₁M₁ Deep 821 0.573 0.409 8.11 2.2 28.2 S₁M₂ Shallow 8900 6.22 4.43 7.18 2.1 28.1 S₁M₃ Shallow 7920 5.53 3.95 7.14 1.1 28.2 S₁M₄ Deep 788 0.552 0.395 7.82 1.5 28.3

S₁C₁ Deep 900 6.30 0.450 7.93 1.2 28.0 S₁C₂ Shallow 9720 6.78 4.84 6.94 1.2 28.1 S₁C₃ Deep 865 0.605 0.430 8.04 2.0 28.0 S₁C₄ Shallow 6090 4.25 3.04 7.12 1.2 28.2

Table 3.4: Chemical composition of Groundwater in the month of November, 2011 (Sample: 02)

Sample ID

Type of Tube wells

Depth (feet)

Cations (meq/l) Anions (meq/l) Na+ K+ Ca 2+ Mg2+ Cl - NO 3- SO42- PO43- HCO3-

S2R₁ Deep 960 14.2593 0.163238 0.2994 0.3948 0.50002 0.01967 0.07872 0.016265 10.500007 S2R₂ Deep 1050 13.70424 0.125267 0.0998 0.39484 1.00004 0.01310 0.0595 0.016402 10.234407 S2R₃ Deep 960 14.53683 0.153113 0.2495 0.44420 1.50006 0.01524 0.09148 0.014889 10.234407

S2S₁ Shallow 250 18.14472 0.752908 1.3473 2.36908 15.5005 0.01228 0.12150 0.029060 15.493286 S2S₂ Deep 1200 10.37388 0.092358 0.0998 0.19742 1.00004 0.01507 0.12150 0.016681 8.0033681 S2S₃ Deep 1050 5.37834 0.127798 0.1497 0.24678 3.50015 0.00589 0.05188 0.013927 7.2065682 S2S₄ Shallow 260 29.667 0.752908 1.3972 2.02359 11.0004 0.01163 0.07625 0.029747 15.227686

S2G₁ Deep 1200 10.92894 0.084764 0.0998 0.14806 2.00008 0.00736 0.08510 0.02097 7.6406082 S2G₂ Shallow 120 6.21093 0.102484 0.1497 0.24678 1.50006 0.00310 0.10423 0.033874 9.2782478 S2G₃ Shallow 200 64.35825 0.879480 3.3932 4.9356 60.5025 0.01360 0.07447 0.011179 15.306686 S2G₄ Deep 950 13.14918 0.087296 0.0998 0.19744 0.50002 0.00802 0.12549 0.019326 10.234407

S2M₁ Deep 960 8.7087 0.163238 1.1976 0.69098 1.50006 0.00359 0.08085 0.009525 6.9940883 S2M₂ Shallow 150 79.6224 0.135393 3.5429 6.36692 76.5032 0.00195 0.14887 0.008425 10.287527 S2M₃ Shallow 255 65.7459 0.13033 3.2435 4.34332 69.0030 0.00195 0.03834 0.018603 14.484006 S2M₄ Deep 1050 5.9334 0.201210 0.2994 0.49356 1.50006 0.00146 0.06172 0.007737 6.3035284

S2C₁ Deep 1100 4.26822 0.170833 0.1996 0.39484 2.50011 0.00408 0.07625 0.017228 8.0033681 S2C₂ Shallow 215 112.926 0.879480 4.2914 7.15662 86.0038 0.00736 0.03447 0.018056 10.924967 S2C₃ Deep 1200 2.32551 0.173364 0.3493 0.39484 2.50011 0.00753 0.07660 0.011176 7.6846481 S2C₄ Shallow 185 31.05465 0.790880 4.5908 7.30468 46.5019 0.01294 0.07235 0.026309 21.124005

3.2 DISCUSSION OF THE STUDY

Drinking water quality in respect to consumer health safety refers to that water which is free from any potential health hazard to the consumers. To assess the suitability of groundwater for drinking purposes, in this study two standards, namely the WHO (World Health Organization) and Bangladesh standards were considered to compare with the analyzed data (Table: 3.1 & Table: 3.2) for different parameters.

3.2.1 Description of the Physical parameters

Temperature has no health significance (EPA, 2001) and generally, it is climatologically influenced (in the absence of thermal discharges). Temperatures in all samples were within the standard both in August and November, 2011.

The pH, physical characteristic of all waters or solutions, has no health significance except that extreme values will show excessive acidity or alkalinity, with organoleptic consequences (EPA, 2001). pH in all samples were within the both standard (Table 3.1 and Table 3.3).

Electrical conductivity (EC), which has no direct significance on health, reflects mineral salt content of water (EPA, 2001). EC values of all deep-tubewells were within the standards in the month of August and November, 2011 except S2R1 which exceeded the range in the month of November. But all the shallow aquifer groundwater samples exceeded the standards both in August and November, 2011. DO is the natural characteristic of clean waters. The value of DO in all samples was within the standard both in August and November, 2011.

3.2.2 Description of the Chemical Parameters

Sodium is also an essential dietary requirement and the normal intake is as common salt (sodium chloride) in food; daily consumption may amount to 5 grams or more. The main reason for limiting is the joint effect which it exercises with sulphate but too excessive intake can cause hypertension (EPA, 2001). All samples except S₁R₃, S₁Rs, S ₁S₃, S₁Ss, S₁G₂, S₁Gs, S₁M₄, S₁Ms, S₁C₁ and S₁Cs exceeded both the WHO and Bangladesh standard in August and November, 2011. The highest value of sodium may be due to intrusion of saline water into the aquifer system.

Table 3.5: Chemical composition of Groundwater in the month of August, 2011 (Sample: 01)

Note: Red colored values show the exceeding standards for drinking water.

Sample ID

Type of Tubewell

Depth (feet)

Cations (mg/L) Anions (mg/L)

Na+ K+ Ca 2+ Mg2+ Cl - NO3- SO4

2- PO43- SiO2

S₁R₁ Deep 960 253.9 3.342 8 4.8 88.625 3.81174 5.11 0.486594 17.1112 S₁R₂ Deep 1050 417.4 2.334 4 4.2 35.45 2.75706 1.2844 0.457778 2.9848 S₁R₃ Deep 960 129.64 3.09 7 3.6 53.175 3.00522 2.14516 0.432564 3.6824 S₁S₁ Shallow 250 450.1 15.69 31 24.6 514.025 10.5282 6.0664 1.58812 2.1128 S₁S₂ Deep 1200 391.24 1.326 3 3.6 35.45 2.44686 4.44052 0.835988 4.0312 S₁S₃ Deep 1050 162.34 2.334 3 4.2 35.45 2.16768 1.18876 0.346116 4.9032 S₁S₄ Shallow 260 452 15.186 28 22.8 372.225 10.8384 2.81464 1.11986 17.8088 S₁G₁ Deep 1200 212.96 1.074 3 1.2 88.625 1.33014 2.81464 0.825182 3.1592 S₁G₂ Shallow 120 149.6 1.578 4 3 53.175 9.579 5.11 0.86772 7.3448 S₁G₃ Shallow 200 1329.9 17.706 71 55.2 2268.8 4.10085 1.18876 0.97578 18.8552 S₁G₄ Deep 950 315.04 1.074 4 1.8 35.45 4.25595 3.96232 0.987272 4.5544 S₁M₁ Deep 960 276.76 3.342 3 4.8 53.175 0.77178 2.81464 0.234454 4.0312 S₁M₂ Shallow 150 1383.8 2.082 81 73.8 2711.92 1.0764 3.96232 0.18334 21.9944 S₁M₃ Shallow 255 969.1 1.83 70 36 2286.52 1.0764 1.7626 0.39946 12.5768 S₁M₄ Deep 1050 174.68 4.098 8 6.6 70.9 0.39954 .99748 0.223648 4.0312 S₁C₁ Deep 1100 175.42 3.342 6 5.4 159.525 1.05096 4.1536 0.472186 4.5544 S₁C₂ Shallow 215 1354.15 17.706 85 88.8 3030.97 3.7131 2.2408 0.529818 21.4712 S₁C₃ Deep 1200 221.2 3.594 6 5.4 88.625 1.48524 4.24924 0.26327 3.1592 S₁C₄ Shallow 185 1236.8 15.438 104 83.4 1772.5 6.42735 1.7626 0.43548 12.5768

Standards WHO 200 - 75-200 30 250 50 250 5 - BD 200 12 75 30-35 150-600 10 400 6 -

Remark S₁R₃, S₁S₃, S₁S₄, S₁C₁, S₁M₄, S₁G₂ are within standards

All deep tube-well samples

satisfy the standards

Without S₁C₄, S₁C₂

& S₁M₂ others satisfy

standards

Most of the

samples satisfies

the standards

Most of the samples

satisfy the standards

All samples

are within standards

All samples

are within standards

All samples are within standards

Table 3.6: Chemical composition of Groundwater in the month of November, 2011 (Sample: 02)

Note: Red colored values show the exceeding standards

Sample ID

Type of Tubewell

Depth (feet)

Cations (mg/L) Anions (mg/L) SiO2 (mg/L) Na+ K+ Ca 2+ Mg2+ Cl - NO3

- SO42- PO4

3- HCO3-

S₁R₁ Deep 960 327.8 6.384 6 4.8 17.725 1.21952 3.7814 0.514888 640.635 17.1112 S₁R₂ Deep 1050 315.04 4.899 2 4.8 35.45 0.81272 2.8625 0.519242 624.43 2.9848 S₁R₃ Deep 960 334.18 5.988 5 5.4 53.175 0.94493 4.394 0.471348 624.43 3.6824 S₁S₁ Shallow 250 417.12 29.445 27 28.8 549.47 0.76187 5.836 0.91992 945.289 2.1128 S₁S₂ Deep 1200 238.48 3.612 2 2.4 35.45 0.93476 5.836 0.52806 488.308 4.0312 S₁S₃ Deep 1050 123.64 4.998 3 3 124.075 0.36524 2.492 0.44087 439.693 4.9032 S₁S₄ Shallow 260 682 29.445 28 24.6 389.95 0.72119 3.6624 0.94169 929.084 17.8088 S₁G₁ Deep 1200 251.24 3.315 2 1.8 70.9 0.45677 4.0877 0.66404 466.175 3.1592 S₁G₂ Shallow 120 142.78 4.008 3 3 53.175 0.19235 5.0066 1.07231 566.092 7.3448 S₁G₃ Shallow 200 1479.5 34.395 68 60 2144.72 0.84323 3.5772 0.3539 933.904 18.8552 S₁G₄ Deep 950 302.28 3.414 2 2.4 17.725 0.49745 6.0276 0.611792 624.43 4.5544 S₁M₁ Deep 960 200.2 6.384 24 5.0 53.175 0.22286 3.8835 0.301542 426.729 4.0312 S₁M₂ Shallow 150 1830.4 5.295 71 77.4 2711.92 0.12116 7.1507 0.26671 627.671 21.9944 S₁M₃ Shallow 255 1511.4 5.097 65 52.8 2446.05 0.12116 1.8415 0.588906 883.71 12.5768 S₁M₄ Deep 1050 136.4 7.869 6 6 53.175 0.09065 2.9646 0.24494 384.596 4.0312 S₁C₁ Deep 1100 98.12 6.681 4 4.8 88.625 0.25337 3.6624 0.545366 488.308 4.5544 S₁C₂ Shallow 215 2596 34.395 86 87 3048.7 0.45677 1.656 0.5716 666.563 21.4712 S₁C₃ Deep 1200 53.46 6.78 7 4.8 88.625 0.46694 3.6793 0.35379 468.862 3.1592 S₁C₄ Shallow 185 713.9 30.93 92 88.8 1648.42 0.80255 3.4751 0.83284 1288.835 12.5768

Standards WHO 200 - 75-200 30 250 50 250 5 200 - BD 200 12 75 30-35 150-600 10 400 6 - -

Remark S₁S₃, S₁G₂, S₁C₁ , S₁M₁, S₁M₄, S₁C₁ are within standards

All deep tube-well samples satisfy the standards

Without S₁C₄, & S₁C₂ others satisfy standards

Most of the samples satisfies the standards

Most of the samples satisfy the standards

All samples are within standards

All samples are within standards

All samples are within standards

All samples exceeded the standards

Potassium has no significant health effects except at gross level (EPA, 2001). All samples except S₁C₂, S₁C₄, S₁G₃, S₁S₄, and S₁S₁ exceeded both the WHO and Bangladesh standard in August and November, 2011.

High levels of calcium may be beneficial and waters which are rich in calcium (and hence are very hard) are very palatable. This element is the most important and abundant in the human body and an adequate intake is essential for normal growth and health. The presence of the element in a water supply is beneficial to health because it helps to reduce the heart disease (EPA, 2001). All values Without S₁C₄, S₁C₂ & S₁M₂ were within the standard (Table 3.5 and Table 3.6).

Magnesium is the second major constituent of hardness and it generally comprises 15-20 per cent of the total hardness expressed as CaCO3. Its concentration is very significant when considered in conjunction with the sulphate and it has indirect effects on health (EPA, 2001).The shallow water sample of S₁C₄, S₁M₂, S₁M₃, S₁C₂, S₁G₃ exceeded both the WHO and Bangladesh standard in August and November, 2011. From the reconnaissance survey it was evident that, consumers were suffering from eczema due to use of excess hard water. A suggested explanation relative to hard water is that increased soap usage in hard water results in metal or soap salt residues on the skin (or on clothes) that are not easily rinsed off and that lead to contact irritation (WHO, 2010).

Chloride does not pose a health hazard to humans and the principal consideration is in relation to palatability (EPA, 2001). Without S₁C₄, S₁C₂, S₁M₂, S₁M₃, S₁G₃ others satisfied the Bangladesh standard while most of the samples are exceeding the WHO standard (Table 3.5 and Table 3.6).

Excess sulphate has a laxative effect, especially in combination with magnesium and/or sodium (EPA, 2001). The values were within the standard (Table 3.5 and Table 3.6).

Most importantly, high nitrate levels in waters to be used for drinking will render them hazardous to infants as they induce the "blue baby" syndrome (methaemoglobinaemia) (EPA, 2001). The values were within the standard (Table 3.5 and Table 3.6). Phosphorus occurs widely in nature in plants, in micro-organisms, in animal wastes and so on. It has no significance on health (EPA, 2001). The values were within the standard (Table 3.5 and Table 3.6). Silica is not a water pollutant but excess of silica in groundwater indicates the active degradation of silicate minerals (Appelo and postma, 1993). The silica content of natural water is usually 1-30 ppm. In the study area the concentration of silica varies from 2.9848 mg/L (S₁R₁) to 21.4712 mg/L (S₁M₂) (Table 3.5 and Table 3.6).

4. CONCLUSION

In the present study, the groundwater quality and its chemical composition have been made to characterize the water in the shallow and deep aquifer in respect to community health in the western peri-urban fringe of Khulna city. The groundwater shows a very variable chemical composition, e.g. electrical conductance ranges from 813 to 9800 µs/cm. However, the chemical quality of the water with respect to sodium ion concentration at most sampling points exceeds the WHO and Bangladesh drinking water standards. Magnesium ion concentration in respect to carbonate hardness is high in shallow aquifers. The water is therefore not suitable for laundry. This study confirms that major chemical parameters of groundwater in Khulna meets the Bangladesh and WHO standard and reflect the suitability of drinking and domestic purposes. However, continuous assessment and monitoring is needed to verify the temporal as well as special variability of the groundwater resources in Khulna for water security and public health.

ACKNOWLEDGEMENTS This study is a part of the research project titled “Water Security in Peri-Urban South Asia: Adapting to Climate Change and Urbanization” supported by the International Development Research Centre (IDRC). We are grateful to Professor M.S. Khan, Professor, Institute of Water and Flood Management (IWFM) of Bangladesh University of Engineering and Technology (BUET) for giving the opportunity in joining with this research project and conducting this study. Thanks are given to IDRC for their support in the development of the study. We are particularly indebted to Dr. Dilip Kumar Datta, Professor and Head, Environmental Science Discipline, Khulna University, Khulna for his continuous invaluable assistance during the study.

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Appendix-A

Unit of analysis

mg/l = milligrams per litter sample.

ppm = parts per million, by weight of the sample.

mmol/l = millimoles per litter sample (millimolarity).

meq/l = milliequivalents per litter sample. .

µ s/cm = micromhos per centimeter.

N = normality, equivalents per litter.

EC = electrical conductivity, µs/cm (µ mho/cm), EC ≈ 100 meq (anions or cations)/l.

pH = - log[H+], the log of H+activity.

Appendix-B

Table B.1: Drinking Water Standards of DoE, Bangladesh and WHO

Sl. Water quality parameter Unit Bangladesh standard WHO standard 01 pH - 6.5-8.5 7-8.5 02 EC (Electrical Conductivity) µ s/cm - - 03 TDS (Total Dissolved solids) mg/L 1000 1000 04 Sodium (Na+) mg/L 200 200 05 Potassium (K+) mg/L 12 06 Calcium (Ca2+) mg/L 75 75-200*

07 Magnesium (Mg2+) 30-35 50-150*

08 Chloride (Cl-) 150-600* 200-600 09 Bicarbonate (HCO3

-) - - 10 Dissolve silica (H4SiO4

2-) - 11 Phosphate (PO4

3-) 6 12 Sulphate (SO4

2-) 400 250 13 Fluoride (F-) 1 0.5-1 *DoE= Department of Environment

Appendix-C

Fig C.1: Community people collecting water

Fig C.2: Surrounding condition of a tubewell

Fig C.3: Field analysis of water sample (myself)

Fig C.3: Field analysis of water sample with my friend