Water Chemistry Variation In Langat River Biology Essay

Published:

This paper present the water chemistry of Langat River, Selangor, based on its major ion chemistry and its suitability for drinking and irrigation propose. This study was conducted on December 2010 while thirty sampling stations were chosen along the downstream of Langat River. Water samples were collected from each station respectively to assess the water quality. The physical and chemical variable selected were temperature, electrical conductivity (EC), total dissolved solids (TDS), salinity, dissolved oxygen (DO), pH and reduction-oxidation potential (Eh). Beside, major ions, (Ca, Na, Mg, K, HCO3, Cl, SO4 and NO3) were analysed by FAAS while trace elements (Al, As, Ba, Be, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se and Zn) were also analysed by ICP-MS in this study. Based on analyses of heavy metal, the concentration of heavy metals are varies at the different sampling station. The guideline verifies that most of heavy metals are below the permissible limit recommended by World Health Organization (WHO) and Ministry of Health (MOH) except for Al, Fe and Se. However, these concentrations are still in acceptable limit. The results show that Langat River is not suitable for drinking without treatment. The water samples also indicate that half of the stations were suitable for irrigation purpose while half are not based on calculated SAR, salinity hazard and magnesium hazard.

Lady using a tablet
Lady using a tablet

Professional

Essay Writers

Lady Using Tablet

Get your grade
or your money back

using our Essay Writing Service!

Essay Writing Service

Introduction

River ecosystems are one of the important assets based on their immense biological diversity. These regions are highly remarked with biological productivity and also high accessibility by which there are numerous interactions occurs in between different forms of plant and animal. River ecosystems are not only considerable sources of food for both human and animal consumption, as breeding ground and sanctuary for aquatic organism but also sink of contaminant. Nonetheless, the high economical value poses by this ecosystem makes its suitability for aquaculture activity, source of food for sustaining food security, recreation, nature tourism and genetic resources. These attractive values posed make them as magnet for world's population. Thus, people gravitate to this region and bring both development and contamination which bear a direct affect to this ecosystem. Rapid development had resulted in the increase of metals in various form released or leach into the environment which can cause severe damage to the ecosystem. The development activities in Malaysia involving manmade alterations of the river environment have also accelerated worsen the impacts of pollution leading to the deterioration of river environmental quality, depletion of river resources, public health risks and loss of bio-diversity. The natural resources and overall environment will become unhealthy once the water quality had depleted (Ujang et al., 2008).

Despite the importance of river ecosystem, the release of pollutants such as heavy metals into environment attributed to dense development has become an emerging issue to river ecosystem, food security, and its ecological balance. The accumulation of metals in the environment especially in river, lake, estuaries and marine sediment is due to the fact that they are elements and therefore cannot be broken down unlike organic pollutants that can be degraded to carbon dioxide and water (Khan et al., 2004; Gupta et al., 2001). When metals enter the environment, it will incorporated in soils with organic matter, Fe/Mn oxides, sulphides, and clay (Wang and Chen, 2000) thus forming several reactive components which is harmful to the environment. Certain metals which is a potent toxin enter into food chain through phytoplankton and been biomagnified in fish or other aquatic organisms (Andrew et al., 2004). As a result, foods from river are contaminated with metals and effect on human health risk. With the swift aquaculture and fishing activity, heavy metals has contributed to the degradation and destruction of this ecosystem, therefore a profound understanding on river ecosystem is indispensable especially for Malaysia who depends on the river activities for its production. It is vital for us to fully understand the threat posed to this area which can jeopardise it productiveness.

Langat River, the principal river draining densely populated and developed area of Selangor (Mokhtar et al., 2009; Sarmani, 1989). It has served about half of the population of Selangor by providing potable water to residents and also supplies water for manufacturing and agricultural production. In other hand, Langat River plays a significant role in ecology and other services such as recreational sites, habitats for fish and other aquatic wildlife, hydropower. Local people heavily use the river for drinking water supply, daily use, plantation and irrigation, and also commercial use. However, the Langat River is one of the most polluted rivers in the State of Selangor (DOE, 2009; Sarmani, 1989). In recent years, rapid industrialization and urbanization had led the development of infrastructure with expanding of population growth. Land areas within the basin especially from the middle to lower reaches of the river were widely exploitation in order to support dense development activities. The pollution loading into the Langat River were increases due to the poor land management practices along the river basin such as discharge of industry effluent and domestic sewage within the basin. This study was focused on the downstream of Langat River because the waste discharges of the river going downstream were increases as it receive discharges from upstream and tributaries which flow through the hub of industrial, residential and commercial areas within the basin. Thus provide important information on studying the interaction of heavy metals in water with environmental variables.

Lady using a tablet
Lady using a tablet

Comprehensive

Writing Services

Lady Using Tablet

Plagiarism-free
Always on Time

Marked to Standard

Order Now

The aim of this study was to determine the selected physico-chemical parameters and concentration and distribution of heavy metals in Langat River. The results of these water matrices were then compared with guidelines for drinking and irrigation purpose. The water quality variation obtained will later provide the baseline for future monitoring and tracking changes in water quality due to human activities within this basin.

Material and Methods

Site descriptions

The study area chosen was Langat River. The Langat River is located in the mid western part of Peninsular Malaysia involves two states viz. Selangor State and Negeri Sembilan. The basin lies within latitudes 2o 40'M 152" N to 3o 16'M 15"N and longitudes 101o 19'M 20" E to 102o1'M 10" E with total catchment area of approximately 1815 km2. Langat Dam and Semenyih Dam are two major impoundments that supply water to the entire basin while Semenyih River is the main tributary which than merges with Langat River. The main river course length is about 141 km and mostly situated around 40 km east of Kuala Lumpur. The river flows from the highhills in the north towards the plains and turning westward toward the coast of the state of Selangor (Mokhtar et al., 2009). The Langat River consist two estuaries in which one is located on the northeastern side and the river water flows into the straits of Selat Lumut and other is on southern side and it flows directly into the Straits of Malacca (Mokhtar et al., 2009). Langat River basin is underlain by schist and phyllite and granite rock formation of Permian age dominates. In the low flatlands close to the coast, Quartenary layers are deposited on the bedrocks (Taha, 2003; JICA and MGDM, 2002). Geologically, study area is sited on top of the river alluvium, that consists mainly of silt, clay and sand (Mohamed et al., 2009; Figure 1)

Malaysia has a climate which is equatorial and greatly influenced by two types of monsoon: the northeast from January to March and the southwest from April to November. Subsequently, weather at Langat River is much influenced by the southwest monsoon that blows across the Straits of Malacca. Therefore, the climate in the study area is characterized by high average and uniform annual temperatures, high rainfall, and high humidity. Langat River receives annual rainfall between 1521 and 2883 mm which is high as it influenced by the monsoon blows in the middle of November and January. The basin experiencing average temperature of 32°C and has a warm and humid climate around 80% annually. A summary of monthly rainfall from 2000 to 2009 for the study area are presented in Figure 2.

Figure 1: Map of sampling stations in Langat River

Figure 2: Monthly rainfall data for study area from 2000 to 2009

Field sampling and preservation

Thirty sampling stations were chosen within the study area (Figure 1) and the exact sampling locations are recorded by Global Positioning System (GPS) techniques (Table 1). The sampling was carried out on December 2010 which considered as northeast monsoon. Before sampling, all the laboratory apparatus and polyethylene bottle are pre-cleaned with acid washed by soaked overnight in 5% (v/v) nitric acid and rinsed thoroughly first with distilled water. This procedure is very crucial in order to ensure any contaminants and traces of cleaning reagent were removed before the analysis (APHA, 2005). It is performed in clean laboratory to minimize the potential risk of contamination. Polyethylene bottles were used for collecting water sample in order to avoid and minimize interference for heavy metal analysis. Afterward, the collected samples were stored in the ice box with approximately 4áµ’C to minimize the microbial activity in the water (APHA, 2005). During sampling, the polyethylene bottle were normalized with river water and then filled up with water running in the direction of flow. Triplicate samples were collected and homogenized from each sampling station in order to obtain an average value for the analysis. Each bottle was labelled with its corresponding sampling station and time of sampling was recorded. The water samples were kept in polyethylene bottles and brought back to laboratory in cool box (below 4°C).

Table 1: The coordinate of sampling station

Station

Latitude

Longitude

LY1

2°55'12.16"N

Lady using a tablet
Lady using a tablet

This Essay is

a Student's Work

Lady Using Tablet

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Examples of our work

101°25'49.98"E

LY2

2°54'18.20"N

101°25'04.93"E

LY3

2°53'24.43"N

101°24'48.25"E

LY4

2°52'31.16"N

101°25'33.20"E

LY5

2°53'25.51"N

101°25'40.92"E

LY6

2°54'26.50"N

101°25'39.71"E

LY7

2°53'53.38"N

101°26'33.14"E

LY8

2°53'28.28"N

101°27'08.59"E

LY9

2°51'59.68"N

101°26'23.10"E

LY10

2°52'28.37"N

101°26'37.31"E

LY11

2°48'14.80"N

101°24'26.80"E

LY12

2°50'23.60"N

101°24'51.70"E

LY13

2°52'47.50"N

101°27'06.00"E

LY14

2°53'23.10"N

101°28'23.60"E

LY15

2°52'32.20"N

101°28'46.40"E

LY16

2°51'19.50"N

101°28'55.00"E

LY17

2°51'10.70"N

101°30'53.50"E

LY18

2°49'51.30"N

101°31'37.50"E

LY19

2°48'47.60"N

101°30'40.40"E

LY20

2°48'47.30"N

101°31'33.50"E

LY21

2°48'41.20"N

101°32'15.20"E

LY22

2°49'08.00"N

101°33'02.10"E

LY23

2°49'04.80"N

101°33'50.30"E

LY24

2°49'00.30"N

101°34'34.20"E

LY25

2°48'41.40"N

101°35'03.80"E

LY26

2°47'56.40"N

101°35'22.30"E

LY27

2°48'04.80"N

101°36'04.10"E

LY28

2°47'43.50"N

101°36'19.60"E

LY29

2°47'27.38"N

101°36'33.42"E

LY30

2°47'25.20"N

101°36'51.40"E

Water analysis

In order to obtain an average value for the analysis, triplicate samples were collected and homogenized from each sampling station. Certain basic water quality parameters included in-situ parameters such as temperature, conductivity, total dissolved solids (TDS), salinity, oxidation-reduction potential (ORP), dissolved oxygen (DO) and pH were taken into account for measurement. The measurement of in-situ parameters were done immediately during each field work by using multi-parameters probe (Mettler Toledo) except temperature and DO measured using DO meter. The multi-parameters probe was calibrated before the measurements were taken. Besides, sensitive parameters such as bicarbonate (titration method using 0.02N HCl) and chloride (argentometric method using 0.0141N AgNO3) were analyzed on site using unfiltered samples accordance with the standard method procedure (APHA, 2005; HACH, 2003). Water samples were immediately filtered with 0.45μm cellulose acetate membrane filter after transported to the laboratory. This process is crucial to obtain dissolved metal which is always smaller than 0.45 µm and also avoiding the occurrence of clogging during analysis with spectrometry instrument. Each water sample is then transfer to into two polyethylene bottles. One bottle is preserved with acidified by HNO3 for determination of cations (Ca, Na, Mg and K) and trace elements (Al, As, Ba, Be, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se and Zn). In order to prevent precipitation of components such as metal oxides and hydroxides and to retard any biological activities, the samples were acidified to pH < 2. The other bottle of water sample is for subsequent analysis of sulphate (SurfaVer 4 method) and nitrate (NitraVer 4 method) analysis (APHA, 2005; HACH, 2003). For cations, the samples were analyzed for using Flame Atomic Absorption Spectrometry (FAAS, Shimadzu AA6800) method while trace metals were analyzed using Inductive Couple Plasma Mass Spectrometry (ICP-MS, Perkin Elmer ELAN DRC-e). Standard calibration solutions and blank sample were prepared with MilliQ water. These metals in the water will be expressed as milligram per liter (mg/L) for cation and microgram per liter (μg/L) for trace metals. Average values of three replicates were taken for each analysis.

Data analysis

Data analyses were conducted using the raw data obtained from the sample analysis by using software Statistical Package for Social Science (SPSS ver. 17) in order to do statistical analysis. Descriptive statistics, ANOVA and correlation coefficient analyses were calculated based on selected physic-chemical parameters and ions in river water within sampling stations and. These techniques provide useful generalization about water quality for both either physical parameter or heavy metal analysis in term of variability, graphical and description of similarities. The differences in water chemistry between stations also presented using graphical diagram such as ternary diagram and Wilcox diagram which illustrate the major ions constituent. All obtained results were compared with the permissible limit recommended by Ministry of Health (MOH, 2004) and World Health organization (WHO, 2004) for drinking water quality.

Results and Discussion

The mean values for the measured in-situ parameters and heavy metals concentrations in water samples obtained from different sampling stations are shown in Table 2. Table 3 shows the descriptive analyses for measured water matrices with interpret the results by compared with Drinking Water Quality Standard by World Health Organization (WHO, 2004) and the Malaysian National Standard for Drinking Water Quality (NSDWQ) by the MOH (2004).

Basically, pH is one of the most important parameter to show the water quality index in surface water although it has no direct impact on consumers. The surface water pH fluctuated between slight acidity and slightly alkalinity for most station of the study except for LY 1 which is in acidic condition. ANOVA (P<0.01) showed pH to be significantly different among the station and pH of Station 1 was significantly lower than the other stations. The surface water pH at Langat River was ranging from 4.79 to 7.48 between different stations and an average value of 6.67 (Table 3). The highest mean pH was 7.46±0.02 obtained at LY 11, while the lowest was 4.79±0.00 obtained from LY 1 which has highest Eh value (150.60 mV). The pH value express the concentration of hydrogen ion (H+) in water and it can be used to determine the water condition on presented on scale from 0-14 which 0-6 is acidic, 7 is neutral, and 8-14 is basic. The acidic condition of Langat River at certain stations may be influenced by the amount of dissolved carbon dioxide uptake by water plants due photosynthetic process which form carbonic acid or decaying of organic matter which form organic acid in water (Mokhtar et al., 2008; Gasim et al., 2007; Radojevic and Bashkin, 2006) and shown in Eq. 1 and Eq.2 below.

(Eq. 1)

(Eq. 2)

Basically, the content of H+ ions in natural water is mainly related to the quantitative ratio or carbonic acid and its ions. The high Eh value indicate that the water have tendency to gain of hydrogen ions between chemical species and becoming acidic. While, alkaline conditions at certain stations had indicates the presence of carbonate bedrock in river such as calcium or magnesium carbonate (Reza and Singh, 2010; Begum et al., 2009; Connell and Miller, 1984). The reaction between carbonate rock and water had contributed hydroxide (OH-) ions with mechanisms shown in Eq. 3 and Eq. 4 below. (Eq. 3)

(Eq. 4)

The temperatures of the water vary between different sampling stations ranging from 26.80 °C to 29.90°C. The temperature recorded among all sampling stations were more or less similar since the sampling was conducted during the weather is cloudy and drizzle at certain locations. Even thought temperature of water is not be as important as other variables, it has the profound effects on certain variables such as dissolved oxygen (DO). DO in this study was range between 1.50 to 5.40 mg/L among stations and it was noticed that with the increasing of temperature, the DO concentration was decreasing and concluded that the temperature is inversely control the solubility of oxygen in water. The DO in water sample was not only depending on physical process (temperature) but also chemical, biological and microbiological processes (Yang et al., 2007). According to Yayintaş et al. (2007), the low DO concentrations (<3 mg/L) in fresh water aquatics systems indicate high pollution level of the waters. In other words, the discharged of domestic wastes such as organic pollutant from community were also depleted DO.

Electrical conductivity (EC) value between different stations ranged from 0.09 to 37.40 mS/cm with average value 14.55 mS/cm while TDS values ranged from 42.40 to 18720.00 mg/L with average value 7287.71 mg/L. The different values of EC represent the relative difference of ion constituent in water between each station. Since EC is measurement that indicate the the ability of water sample to allow electric current to flow. Thus the higher value of EC is a good indicator of the presence of ions such as sodium, potassium, chloride or sulfate. In the other hand, TDS also said to be an good indicator on the present of dissolved ions such as inorganic salt and organic matter in water (Reza and Singh, 2010; WHO, 2004). There is a perfect relationship between EC and TDS (r=1.000, p<0.01; Figure 3) and it can concluded that the higher the dissolved salt content present in water, the higher the EC and TDS value obtained. The salinity values measured were varies and ranged from 0.05 to 23.70 ppt for different stations with a mean value 9.07 ppt. LY 3 had the highest salinity (23.57±0.12 ppt), as it was near to the estuary of the river. During tides, much dissolved inorganic salt such as halite, NaCl from ocean was mixed with river water and cause the salinity increase. This was due to the dissolution or dissociation of halite into free ions and dissolution of halite can be express as equation below.

(Eq. 5)

The dissolution process had increase the amount of dissolved ions present in water and thus the EC and salinity perfect and positive relationship (r=1.000, p<0.01; Figure 4).

Table 2: Mean value of in-situ parameter and major ions of the sampling stations at Langat River. (n=90)

Station

pH

Eh

Temp

EC

Sal

DO

TDS

Ca

K

Mg

Na

HCO3

Cl

NO3

SO4

LY 1

4.79

150.53

29.33

22.97

13.84

4.47

11486.67

80.25

35.01

758.00

6598.00

13.83

7830.91

1.47

235.00

LY 2

7.30

-6.50

29.77

36.83

23.30

5.00

18410.00

353.52

150.94

1164.77

9195.33

124.44

7714.27

0.97

1316.67

LY 3

7.39

-12.13

29.90

37.20

23.57

4.50

18616.67

355.80

161.36

1221.23

9745.33

122.00

7947.54

1.07

1025.00

LY 4

7.42

-14.17

29.90

36.43

23.00

4.97

18216.67

347.83

52.03

810.47

9763.67

119.56

2199.32

1.13

1316.67

LY 5

7.17

1.40

29.50

36.10

23.00

5.00

18223.33

343.26

128.19

1135.97

11034.67

134.20

7580.98

0.60

1300.00

LY 6

7.22

-1.63

29.27

35.80

22.77

4.27

18050.00

340.81

153.48

1188.30

10376.33

117.93

7464.35

0.50

1250.00

LY 7

7.21

-0.73

29.40

35.80

22.57

4.27

17903.33

334.13

144.19

1129.63

9851.67

123.63

7464.35

1.53

1250.00

LY 8

7.19

-0.17

29.37

35.50

22.33

3.90

17743.33

343.87

147.65

1141.57

8971.67

132.57

7331.06

0.63

1275.00

LY 9

6.92

17.23

29.23

23.00

13.84

4.10

11483.33

215.61

41.07

778.10

5283.67

117.12

5065.10

0.53

875.00

LY 10

7.12

4.70

29.17

31.37

19.51

4.60

15686.67

305.77

125.43

1023.63

11093.33

92.72

6681.26

0.70

1150.00

LY 11

7.46

-16.50

29.00

36.47

22.97

5.23

18186.67

336.59

135.89

1146.23

9395.00

122.00

7830.91

1.07

1275.00

LY 12

6.93

16.63

28.40

27.30

16.73

2.23

13643.33

254.10

73.00

896.90

9053.33

87.03

5548.28

2.23

975.00

LY 13

6.78

26.00

28.53

22.10

13.28

2.13

11143.33

200.10

31.78

623.30

4947.00

79.71

4515.27

1.80

1025.00

LY 14

6.66

33.47

28.70

17.78

10.47

2.27

8886.67

141.70

22.53

525.53

5158.33

54.49

4515.27

3.07

825.00

LY 15

6.33

55.87

28.20

0.30

0.14

2.57

149.07

5.09

2.83

5.36

77.24

10.57

67.31

5.23

23.00

LY 16

6.31

56.77

28.10

0.14

0.07

2.37

68.10

3.88

0.96

2.28

8.42

28.47

69.65

2.70

18.00

LY 17

6.30

55.40

27.70

0.12

0.06

2.17

62.57

3.67

0.81

1.78

11.45

19.52

22.99

3.07

16.00

LY 18

6.29

56.40

27.90

0.12

0.06

2.50

60.57

4.45

0.64

1.85

11.44

24.40

16.66

10.83

14.00

LY 19

6.36

53.17

27.90

0.12

0.06

2.17

61.70

6.34

0.62

1.59

11.80

30.91

24.33

6.20

14.00

LY 20

6.39

50.37

27.83

0.12

0.06

2.53

61.23

3.67

0.59

1.68

11.47

29.28

16.99

7.80

13.00

LY 21

6.40

49.20

27.40

0.10

0.05

2.03

51.73

6.95

2.48

1.07

8.42

29.28

15.33

3.57

11.00

LY 22

6.45

45.77

26.80

0.09

0.05

1.87

42.93

3.24

1.79

0.75

5.56

32.53

13.33

1.77

8.00

LY 23

6.40

49.30

27.00

0.09

0.05

1.50

46.10

3.07

1.97

1.02

8.11

29.28

13.33

6.17

9.00

LY 24

6.47

44.90

26.90

0.09

0.05

2.27

44.07

5.31

1.70

0.71

5.65

30.91

13.00

2.20

5.00

LY 25

6.47

44.73

27.10

0.09

0.05

3.30

44.23

3.84

1.79

0.75

5.24

10.57

14.33

2.00

7.00

LY 26

6.49

43.97

27.23

0.10

0.05

2.87

51.03

4.97

2.53

0.94

7.49

21.15

14.33

6.80

6.00

LY 27

6.52

41.70

27.10

0.10

0.05

2.50

50.03

4.49

2.25

0.82

6.91

27.65

11.66

12.10

9.00

LY 28

6.46

45.00

27.10

0.10

0.05

3.03

51.90

4.01

2.32

0.86

7.40

27.65

13.00

4.13

12.00

LY 29

6.42

47.97

27.10

0.11

0.05

2.77

52.83

4.66

2.26

1.05

6.70

33.35

13.33

2.63

2.00

LY 30

6.39

49.77

27.20

0.11

0.05

4.07

53.10

4.32

2.32

1.10

8.83

30.91

13.33

3.00

3.00

(Unit in mg/L except for Eh; mV, Temperature; °C, Conductivity; mS/cm, Salinity; ppt and pH)

Table 3: Descriptive analysis for selected water matrices at Langat River. (n=90)

Unit

Min

Max

Range

Mean±SD

WHO

MOH

pH

-

4.79

7.48

2.69

6.67±0.530

NA

6.5-9.0

Eh

mV

-17.60

150.60

168.20

32.95±33.170

NA

NA

Temp

°C

26.80

29.90

3.10

28.27±1.025

NA

NA

EC

mS/cm

0.09

37.40

37.32

14.55 ± 16.176

0.25

NA

Sal

ppt

0.05

23.70

23.65

9.07±10.175

NA

NA

DO

mg/L

1.50

5.40

3.90

3.25±1.143

NA

NA

TDS

mg/L

42.40

18720.00

18677.60

7287.71±8101.911

NA

1000

HCO3

mg/L

9.76

139.08

129.32

61.92±45.188

NA

NA

Cl

mg/L

10.00

8347.41

8337.41

3001.39±3409.882

250

NA

NO3

mg/L

0.50

12.10

11.60

3.25±2.965

50

NA

SO4

mg/L

2.00

1325.00

1323.00

508.78±570.223

250

250

Na

mg/L

5.21

11183.00

11177.79

4022.32±4543.159

200

200

Ca

mg/L

2.55

356.15

353.60

134.18±151.516

200

NA

K

mg/L

0.56

171.95

171.39

47.68±61.558

200

NA

Mg

mg/L

0.70

1230.70

1230.00

452.24±508.218

150

150

Al

µg/L

1.15

5191.70

5190.56

290.07±817.499

200

200

Ba

µg/L

<0.00006

30.71

30.71

7.14±7.319

700

700

Cd

µg/L

<0.00008

0.53

0.53

0.11±0.115

3

3

Cu

µg/L

0.57

81.02

80.45

28.16±29.703

2000

1000

Fe

µg/L

81.79

807.15

725.36

312.60±156.739

NA

300

Pb

µg/L

<0.00007

6.99

6.99

1.07±1.637

10

10

Mn

µg/L

<0.00017

640.07

640.07

87.14±119.604

400

100

Zn

µg/L

0.95

65.06

64.11

15.21±14.291

NA

3000

Co

µg/L

0.06

6.22

6.17

0.64±1.144

NA

NA

Be

µg/L

<0.001

1.10

1.10

0.13±0.226

NA

NA

As

µg/L

0.08

24.71

24.63

8.54±9.145

10

10

Cr

µg/L

0.32

4.67

4.35

1.13±0.906

50

50

Ni

µg/L

0.80

24.72

23.92

7.29±6.750

70

20

Se

µg/L

<0.00005

264.996

265.00

87.86±101.313

10

20

Table 4: Pearson correlation coefficient (r) between in-situ parameters and major ions. (n=90)

Figure 3: TDS versus EC plot for studied river water (n=90)

Figure 4: Salinity versus EC plot for studied river water (n=90)

Ion concentration and distribution

Metal concentrations in water are a good indicator of the degree of river contamination. These concentrations may come from natural factors other than anthropogenic input.

For major ions analysis, it is found that the concentration values of Na, Mg, Cl, and SO4 occur in high concentration compared to those Ca, HCO3, K and NO3. Ca, Mg, Na and K are known as major cations and it's constitute more than 30% of total element content of the earth's crust (Alloway, 1995). The concentration of major ions were found to be significantly higher (p<0.01) in the Langat River as dominant components. The major ions concentration from different sampling stations shows significant differences (p<0.05) among the sampling station. It means that their concentration may not only origin from weathering process but also other input sources such as ion exchange. From the analyses, the concentrations of Na, Mg, Cl and SO4 at Langat River are high from LY 1 to LY 14. Based on the ternary diagram (Figure 5), the major ion chemistry of Langat River in the study area were dominated by Na > Mg > Ca. The average concentration of Na is 4022.32 mg/L, Mg is 452.24 mg/L, while for Ca and K is 134.18 and 47.68 respectively. From the result, it was found that the correlation between Cl and Na were strong (r= 0.947, p<0.01) which describe the process of seawater intrusion. Due to the sampling locations which near to estuary area (LY 1 to LY 14), the possible source of these excess ions may due to intrusion of saline water which derived from the dissolution of inorganic salts principally sodium and magnesium salt from ocean which mix to the river water with the tide and subsequently occurs ion exchange (Appelo and Postma, 2005) as equation below.

(Eq. 6)

The average concentration of Cl and SO4 is 3001.39 and 580.78 mg/L respectively. These two ions are considered as major contributor to salinity in waters and acts as dominant anions in this study. The SO4 concentration increase with NaCl concentration with well correlated with Na (r=0.946, p<0.01), and Cl (r=0.883, p<0.01). Most of the time, the Cl ion are derived from dissolution of NaCl while SO4 are either attributed from weathering of pyrite (FeS2) or sulfate reduction. The water sampler are tend to undergo sulfate reduction process since the water samples collected were experience foul smell. Thus the reduction equation is as below.

(Eq. 7)

This process also contributes to HCO3- concentration. Table 4 illustrated the positive relationship between these two variables (r=0.955, p<0.01) in this study. The ionic composition of the water in Langat River is dominated by Mg followed by Ca. The concentration for Mg and Ca might be contributed from rock weathering and run-offs from surrounding watershed. Additionally, it was found that a high positive correlation was found between electrical conductivity with salinity, TDS and major ions except nitrate (Table 4), suggesting the large contribution of these elements to the river water chemical load.

Based on the percentage of trace metal distribution according to each station, it shows that Fe has the highest value followed by Al, Se, Mn, Cu, Zn and the rest of the measured metals (Figure 6). Fe and Al are one of the earth's most abundant metallic element and Al constitutes about 8% of the Earth's crust while Fe making up at least 5% of the earth's crust (WHO, 2003). The concentration of Al ranged from 1.15 to 5191.50 µg/L and the highest at LY 1. The major contributor of Al concentration was the water pH or water rich in organic matter. With arise in more acidic waters (pH <4 at LY1) can cause an increase in the dissolved aluminum content of the surrounding waters (ATSDR, 1992; WHO, 1997). The mechanism of aluminum oxide are present in acidic water was shows as below.

(Eq. 8)

In this study, the present of Fe may derive from the geological weathering and also other sources. Its high concentration can be observed through the color of water sample collected which is more reddish because when ferrous iron exposed to atmosphere, it will oxidizes to ferric iron and giving an objectionable reddish-brown color to the water (WHO, 2004). The average concentration of Se in this study are 87.86 µg/L. The possible source of Se are from the human activities and natural environment based on the geological charactheristic of this station that have many distribution of rock. For example, weathering of shales which contain substantial amount of Se and sulfide mineral. Cu occur as sulfide, that often contain Se and As. During weathering, such ore deposits can give rise to concentration of dissolved trace element. Se is often associated with heavy metal sulphides where it occurs as selenide (Se2-), or as a substitute ion for sulphur in the crystal lattice (Adriano, 1986). Electrolytic copper refining activity might contributed to the Se concentration which generated as a byproduct.

Figure 5: Ternary diagram for cation in water samples Langat River

Figure 6: Metal distribution accordingly to its sampling station

Suitability for drinking and general domestic use

All obtained results were compared with the permissible limit recommended by Ministry of Health (MOH, 2004) and World Health organization (WHO, 2004) for drinking water quality.

The average values of EC (14.55 mS/cm), TDS (7287.71 mg/L), Cl (3001.39 mg/L), SO4 (508.78 mg/L), Na (4022.32 mg/L) and Mg (452.24 mg/L) are higher than the guidelines for drinking water set by WHO and MOH (Table 3). Additional, water characteristic LY 1 to LY 14 exists with high salinity, EC, TDS and also Cl, could be regarded as saline water. Usually the excess value of these variables is no direct impact on consumer but it wills greatly affects the taste of water, thus it may be objectionable to consumers and has a significant impact on the users' acceptance of the water as potable. Overall, the heavy metals concentrations within the overall result analysed at Langat River were below the permissible limit recommended except for Al, Fe, and Se. Due to the ability of heavy metals to be bioaccumulation and biomagnifications of heavy metal, its concentration will directly affects the ecosystem of a river. The variation of Fe concentrations in this study were ranged between 81.79 to 807.15 µg/L which had exceeded the permissible limit (300 µg/L) set by MOH. However, Fe is not considered hazardous to health because Fe is an essential nutrition for human consumption. Only taste and appearance (metallic taste, offensive odor and reddish brown) of water are affected at concentrations based on health-based value. The high concentration of Al has been hypothesized as a risk factor for the development or acceleration of onset of alzheimer disease in human with daily uptake(WHO, 2004). The presence of Se in water samples was only detected in LY 1 to LY 21. The Se mean value are 87.86 µg/L which is 80% higher than the permissible limits recommeded by WHO (10 µg/L) and 40% higher than permissible limits recommeded by MOH (20 µg/L). Se is an essential element for humans, with a recommended daily intake of about 1mg/kg of body weight for adults (WHO, 2004). However, it should not exceed the safe limits or else it would be health hazard if it is taken into the body.

Suitability on irrigation

Within the Langat Basin are intensive with agriculture development. Irrigation water quality plays an important role on agriculture at Langat River and therefore, quality of irrigation water is of major concern. Previous study on classification of the quality of irrigation water based on sodium adsorption ratio (SAR), salinity hazard and magnesium hazard was done by Mokhtar et al. (2008) at Maliau Basin. The chemical composition of irrigation water should consider both the total quantity of the various ions included Na, Mg and Ca and the mutual proportion of Na to Ca and Mg occur. Hence, the important hydrochemical properties for determining irrigation water quality are SAR, salinity hazard and magnesium hazard.

SAR is a ratio of the sodium (detrimental element) to the combination of calcium and magnesium (beneficial elements) in relation to known effects on soil dispersibility. SAR was used to indicate the effect of relative cation concentration on Na accumulation in the soil (Glover, 1996). The SAR value is calculated using the equation (Glover, 1996):

(Eq. 9)

where [Na+], [Ca2+], and [Mg2+] are the concentrations in milliequivalents per liter (meq/L) of Na, Ca, and Mg ions in the water. The concentration of these three cations are determined by analysed using Flame Atomic Adsorption Spectrometry (FAAS) after filtered through a 0.45µm membrane filter paper and preserved with concentrated acid nitric (HNO3) as described by APHA (2005).

Magnesium hazard is used to evaluate the hazard potential of Mg ions to irrigation water. It can be calculated using the following equation:

(Eq.10)

Normally, the parameters used for measure water salinity are total dissolved solids (TDS) or electrical conductivity (EC). For salinity hazard, it was categorized as low-salinity water (<250 µS/cm), medium-salinity water (250-750 µS/cm), high-salinity water (750-2250 µS/cm) and very high-salinity water (>2250 µS/cm) (Nishanthiny et al., 2010; Mokhtar et al., 2008).

From the calculated value, water samples out of the 30 selected sampling stations at Langat River can be classified into two distinct groups in which Group 1 is suitable for irrigation purpose and Group 2 is not suitable for irrigation purpose. There are 50% of stations having low class on SAR, Mg hazard and salinity hazard which the water can be used for irrigation on almost all soils while other 50% have very high class of SAR value, Mg hazard and salinity which considered as unsatisfactory for irrigation purposes. This can be clearly observed in Wilcox diagram (Figure 7) and dendrogram cluster analysis (Figure 8), the water samples are obviously categorized into two different groups in which Group 1, LY 1 to LY 14, is considered not suitable for irrigation use and Group 2, LY 15 to LY 30, is classified as suitable for irrigation on most crops. The high Na content in LY 1 to LY 14 is the major factor that contributed to high value of SAR, salinity hazard and magnesium hazard. Even though Na occurs in most of freshwater, it was not considered as an essential nutrient for plant (Glover, 1996). Generally, the high concentration of Na was undesirable for irrigation purpose. Excess Na tends to seal the soil surface and produce soils with high exchangeable sodium levels. It will not only affect on soil structure but also pose toxic effect on plants by decreasing the hydraulic conductivity or permeability to water (Glover, 1996). The hydrochemical properties of stations in Group 1 is affected by the seawater intrusion due to the location of sampling station which is near to the estuary.

Figure: 7: Wilcox diagram of irrigation water accordingly to its sampling stations

Figure 8: Dendrogram groups of sampling station determined in Cluster Analysis based on suitability of irrigation

Conclusion

This study highlights potentially substantial effect on the drinking and irrigation purpose, especially on the downstream of basin. For assessing water quality using physico-chemical parameters, it was seen that the stations which located downstream and near to estuary have the higher range value than upstream with EC and TDS are exceeded the standard (WHO, 2004; MOH, 2004). The heavy metals concentration for Al, Fe and Se were found to be higher than the recommended permissible value (WHO, 2004; MOH, 2004). This findings showed that the hydrochemistry of Langat River was differentiate into two different type of water chemistry which may control by the hydrogeology factors such as weathering process and ion exchange process, apart from the pollution sources from domestic and industrial waste loading. Based on the above study, a useful information and a baseline for future monitoring along with continuous studies on the heavy metals concentrations in Langat River has provided regards to the results obtained.