IJERD – International Journal of Environmental and Rural Development (2014) 5-2

Research article
erd

Metals and Nutrient Seasonal Variations in the NamphongRiver NE Thailand and Land Use Practices
TATIANA KOMAROVA*
Queensland Health Forensic and Scientific Services (QHFSS), Inorganic Chemistry Division,
Coopers Plains, Brisbane, Australia
Email: Tatiana_Komarova@health.qld.gov.au

CHULEEMAS BOONTHAI IWAI
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand

ATCHARAPORN SOMPARN
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand

NATSIMA TOKHUN
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand

BARRY NOLLER
The University of Queensland, Centre for Mined Land Rehabilitation (CMLR), Sustainable
Minerals Institute, Brisbane, Australia
Received 17 January 2014

Accepted 2 May 2014(*Corresponding Author)

Abstract The Namphong river catchment in NE Thailand, part of the Mekong River
catchment, has agro-industrial activities, dry land farming, rice cultivation and river cageaquaculture. Most utilize irrigation while larger industrial activities extract groundwater.
The tropical wet and dry seasons cause variation in river flow. Potential effects of water
quality may arise annually from constituents introduced by agricultural and other practices.
Nutrients are added to soil to improve agricultural production and directly to the river incage aquaculture from fish feed. The seasonal variations were considered from heavy
metals (cadmium, copper, iron, manganese, lead and zinc) and nutrients in the NamphongRiver during one annual cycle and their relationships to water quality. Water samples werecollected from 10 sites along the Namphong River in January 2012 (dry season mean flow
8 sec/m) and 9 sites in September 2012 (wet season mean flow 28 sec/m). Labile metals
estimated by the Diffusive Gradient in Thin Films (DGT) technique showed no toxicity toaquatic biota. Most metals showed concentration and location consistency in both seasons.
Iron and manganese in pulp mill discharge and vegetable cultivation downstream showed
high concentrations in September indicating a groundwater or saturated soil seepage
source from reducing conditions. Nutrients decreased by half from January to September;
total N was higher at upstream sites in January while nitrate and orthophosphate were notsignificant and pH and electrical conductivity were consistent for both seasons. Hardness
and alkalinity increased in September and were highest in pulp mill discharge indicating agroundwater source. Total and suspended solids were affected by wet season runoff.
Variations in metals and nutrients in January and September were attributed to differencesin Namphong River flow and from seasonality and agricultural activities. Large agroindustries, particularly pulp, contributed the highest concentrations of nutrients and metals
to the river.
Keywords metals, nutrients, seasonal, variations, river flow, land use practicesⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2014) 5-2

INTRODUCTION
The Namphong River in the NE part of Thailand is within a sub-catchment of the Mekong River(Fig. 1). The Namphong River flows to the Chi River and via the Mun River to the Mekong River.
Below Ubolratana Dam, there are extensive agro-industry and farming activities along theNamphong River. The wet-dry agricultural activities use irrigation from dam storage and some
supplementary groundwater supply. A key question is: what are the effects of seasonal variations ofheavy metals and nutrients in the Namphong River and their relationships to other water quality
parameters associated with agro-industry and farming activities. The prevailing tropical wet anddry seasons cause variation in river flow. The background water quality is influenced by water
seepage through geological strata and soil before entry to the main river channel. Nutrients areadded to soil to improve agricultural production and in river cage aquaculture are transferred
directly from fish feed to the river water. Potential effects are therefore possible from constituents
added to river water during the annual cycle that may arise from heavy metals and nutrients
introduced by agricultural, aquaculture, urban discharges from Khon Kaen to tributaries and otherpractices.
OBJECTIVE
This study aimed to understand the effects of seasonal variations of heavy metals and nutrients in
the Namphong River during one cycle and their relationships to other water quality parameters
associated with land use practices comprising agro-industry and small-scale farming activities
along the Namphong River, a sub catchment of the Mekong River located in NE Thailand. The
study compares water quality data with existing water quality criteria during one annual wet-dry
season cycle.
METHODOLOGY
Water samples were collected from 10 sites along the Namphong River in 19-23 January 2012 and9 sites 20-24 September 2012 (Fig. 1). Site C is on a small tributary less than a few km to theNamphong River from the pulp and paper mill (Fig. 1.C). Water quality parameters including
heavy metal and nutrient concentrations were measured using standard techniques (APHAAWWA-WEF, 1998). Concentrations of labile metals were estimated by the Diffusive Gradient inThin Films (DGT) technique (Komarova et al. 2012, 2013). The DGT accumulates labile metal
species in waters (Davison and Zhang, 1994; Davison et al. 2000; Zhang and Davison, 1995; Zhang
and Davison, 2000). The DGT technique incorporating passive sampling gives an integrated
concentration measurement (Davison and Zhang 1994) and was previously described formeasurement of labile metal forms in water and predicting their toxicity to aquatic biota(Komarova et al. 2012, 2013).
The DGT passive samplers were deployed to accumulate labile heavy metals at the 10 sites(Fig. 1) and were used to measure labile metal forms in waters at sub-nanogram per liter levels.
Passive samplers are defined as human-made devices where sample collection is completely
passive (Komarova et al. 2012). Measurements were made of pH, electrical conductivity (EC),temperature, dissolved oxygen (DO) concentration in river water using field equipment. Active(direct) sampling was employed to collect water samples (1L) before and after DGT deployment at
each site in January and September for total dissolved solids (TDS), suspended solids (SS), total
alkalinity (mg/L CaCO3), hardness (mg/L CaCO3), nutrients [total N and P, nitrate (NO3-) andortho-phosphorus (P)] and dissolved organic carbon (DOC). All measurements on the active water
samples were undertaken in the field or at the Division of Land Resources and Environment,
Department of Plant Sciences and Agricultural Resources, Faculty of Agriculture, Khon Kaen
University. Following deployment, DGTs were sent by air courier to the Queensland HealthForensic and Scientific Services (QHFSS), Inorganic Chemistry laboratory at Coopers Plains,
Australia, for the extraction of the heavy metals from the gel and analysis by inductively-coupledⒸ ISERD

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plasma mass spectrometry (ICPMS). The time-averaged concentration of dissolved heavy metal
species in the bulk solution, C, is then calculated using the DGT equation derived from Fick’s firstlaw of diffusion (Komarova et al. 2012, Zhang and Davison, 1995).

Fig. 1 Location of study site in the Mekong River basin NE Thailand (Maps A and B) andsampling sites along the Namphong River (Map C)
Sites A – Ubolratana Dam; B – fish cage (in-river cage aquaculture for Tilapia production); C – pulp/paper industrial
plant (discharge via small tributary to main river); sugar industrial plant; C2 cucumber culture; C3 corn culture; Dovegetables culture; D vegetable culture and paddy fields; E vegetables culture; and F – vegetables culture, residential
discharge to Chi River just upstream from confluence with Namphong River

Water quality was assessed by comparison with the Water Quality Standards of the Pollution
Control Department, Ministry of Natural Resources and Environment, Thailand and the protectionof the aquatic ecosystem of the Australian ANZECC/ARMCANZ (2000) decision tree process forassessing heavy metal toxicity in water. Site-specific trigger values for metals were calculated byusing a correction for hardness (mg/L CaCO3) to the default ANZECC/ARMCANZ (2000) heavy
metal guideline value. Aquatic metal toxicity decreases with increasing water hardness as soluble
metal is precipitated. The metal concentrations in labile or bioavailable forms (DGT technique) andmetals in particulate and insoluble colloidal fractions were also measured following filtration(<0.45µm membrane) and were shown to be much higher compared with the bioavailable fractionsof metals in Namphong river water (Komarova et al. 2013).
RESULTS AND DISCUSSION
Tables 1 and 2 give average water quality and nutrient data for January and September at the 10
sampling sites (Fig.1). The Namphong River mean flow was 3.6 times lower in January (dry season
mean flow 8 sec/m) compared with September (wet season mean flow 28 sec/m). Table 3 gives
average labile metal concentration data using DGTs [cadmium (Cd), copper (Cu), iron (Fe),manganese (Mn), lead (Pb) and zinc (Zn)] for each sampling period at the 10 sampling sites.
The water quality shows little difference in pH, DO and DOC between January and September.
Temperature was lower in January (mean 24 0C) compared with September (mean 32 0C) (Tables 1
and 2). Mean EC (TDS) in January was 65% of September and indicated wet season flushing ofsalts or groundwater contribution to the river; both alkalinity and hardness showed the same feature.
Mean SS in January was 51% of September indicating wet season runoff of solids and anⒸ ISERD

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association with EC. DOC was higher in September showing the effect of runoff or biologicalactivity in the river. Total N in January and September were similar but in January the contribution
from upstream was higher and was subsequently diluted moving further downstream. Nitrate waslower in September indicating dilution with wet season flow. Total (not shown) and ortho-P wereboth similar in January and September but localized additions to river water were apparent. Water
quality standards for Thailand (Tables 1 and 2), excepting SS, were not exceeded.
Table 1 Seasonal variations of water quality in the Namphong River
Sampling site

pH
Jan
7.4

Sep
7.4

EC(µS/cm)
Jan
Sep
94
116

Temp (0C)Jan
Sep
23.0 31.9

DO (mg/L)
Jan
Sep
6.28 5.20

SS (mg/L)
Jan
Sep
53
213

TDS (mg/L)
Jan
Sep
46
59

A. Ubolratana
B. River cage
7.7
7.4
86
106
23.0 32.3 5.45 5.78
80
274
47
52
aquaculture
1790
C. Pulp mill
8.2
8.4
1250
1040
25.0 31.7 5.88 4.60
1067
672
508
C1.Sugar mill
7.8
7.4
97
143
25.0 32.8 5.29 5.18
360
314
52
62
C2.Cucumber
7.9
7.5
80
154
23.0 32.2 7.65 6.20
107
264
47
76
C3. Corn
7.7
7.4
99
122
23.0 32.7 7.31 5.62
80
290
51
61
Do.Vegetable
7.9
7.3
102
164
25.0 32.6 5.46 5.20
133
210
55
80
D. Vegetable/
7.9
7.4
106
191
25.0 33.1 5.75 5.44
120
287
55
95
paddy field
E. Vegetable
7.7
7.5
109
171
25.0 33.4 5.54 5.05
150
244
57
84
F. Vegetable
7.8
7.4
110
181
25.0 30.8 5.47 4.72
150
317
57
89
Note: Water Quality Standards Pollution Control Department, Ministry of Natural Resources and Environment, Thailand
Freshwater animal Temperature (0C) 23-32, pH 5-9, Dissolved Oxygen (mg/L) 3 min., Suspended solids (mg/L) 25 max.

Table 2 Seasonal variations of water quality and nutrient content in the Namphong River
Hardness(mg/L CaC03)
Jan

Sep

Jan

Sep

Jan

Sep

Jan

Sep

A. Ubolratana

18

64

684

2.3

4.6

23

10

1.8

1.2

B. River cageaquaculture31

Sampling site

65

DOC
(mg/L)

Total N
(mg/L)

NO3(mg/L)

Alkalinity(mg/L
CaC03)
Jan
Sep

Ortho-P /Total P (mg/L)
Jan
0.04/
0.34

Sep
0.004/
0.40

0.05/
0.002/
0.36
0.26
0.22/
0.024/
C. Pulp mill
131
190
227
1289
2.3
22.5
28
8
2.5
0.5
1.31
2.6
0.05/
0.002/
C1.Sugar mill
24
59
70
532
3.4
3.7
19
11
3.1
1.1
0.39
0.25
0.04/
0.008/
C2.Cucumber
29
74
69
613
1.9
5.3
23
12
2.9
1.4
0.37
0.88
0.04/
0.008/
C3. Corn
12
65
67
412
1.8
4.0
12
10
2.0
1.1
0.33
0.94
0.04/
0.007/
Do.Vegetable
18
70
65
839
1.3
4.1
13
12
1.9
1.1
0.35
0.72
D. Vegetable/
0.04/
0.006/
23
55
69
549
3.6
6.2
12
12
3.0
1.0
paddy field
0.33
0.64
0.04/
0.006/
E. Vegetable
30
61
61
377
2.9
5.9
12
10
2.2
0.8
0.36
0.53
0.03/
0.006/
F. Vegetable
30
65
66
499
3.1
3.2
7
9
2.4
1.2
0.36
0.68
Note: Water Quality Standards Pollution Control Department, Ministry of Natural Resources and Environment, Thailand
protecting Water Source Class 3 (applies to Namphong River). NO3-N 5 mg/L; Effluent Standard B Point Source Total
TKN (mg/l) 35, Total N (mg/L) 410, Total P (mg/L) 0.5.
63

66

745

1.9

8.8

26

11

2.8

1.0

The labile metal DGT concentrations for Cd, Cu, Pb and Zn are very low and do not exceed
the Water Quality Standard Class 3 (Table 3). Comparison of Cd, Cu, Pb and Zn labile
concentrations against the ANZECC/ARMCANZ (2000) criteria adjusted for hardness (Table 3)
indicates that these metals are not likely to be toxic to aquatic biota in the Namphong River.
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Table 3 Seasonal variations of labile metal concentrations using DGT (passive) sampling(average of before and after DGT sampling for 19-23 January and 20-24 September
2012, respectively)
Sampling site

Cd (µg/L)
DGT conc.
JanSep

Cu (µg/L)
DGT conc
Jan
Sep

Fe (µg/L)
DGT conc
JanSep

Mn (µg/L)
DGT conc
Jan
Sep

Pb (µg/L)
DGT conc
Jan
Sep

Zn (µg/L)
DGT conc
Jan
Sep

A. Ubolratana
B. River cageaquaculture
C. Pulp mill

0.021

0.00

0.39

0.37

0.68

1.19

9.17

0.032

0.00

2.96

3.86

0.021

0.01

0.30

0.40

2.43

4.03

6.76

27.9

0.024

0.00

2.75

2.90

0.020

0.00

0.24

0.41

34.3

31.5

269

106

0.049

0.00

2.16

4.08

C1.Sugar mill

0.021

0.00

0.22

0.02

2.19

1.39

13.0

8.62

0.026

0.00

2.08

2.04

C2.Cucumber

0.021

-

0.19

-

27.8

-

21.5

-

0.040

-

1.68

-

C3. Corn

0.021

0.01

0.23

1.71

15.5

35.2

20.6

66.7

0.042

0.05

3.82

6.08

Do.Vegetable
D. Vegetable/
paddy field
E. Vegetable

0.020

0.00

1.45

0.23

8.23

18.5

23.9

126

0.031

0.00

1.42

2.65

0.020

0.00

0.25

0.36

4.84

5.26

30.8

32.1

0.13

0.00

9.25

0.93

0.020

0.00

0.21

1.17

3.00

9.23

16.9

36.4

0.17

0.05

8.53

1.40

F. Vegetable

0.027

0.00

0.28

0.19

8.00

3.31

26.9

16.8

0.50

0.00

1.47

1.33

4.80

Note: Water Quality Standards Pollution Control Department, Ministry of Natural Resources and Environment, Thailand
protecting Water Source Class 3 (applies to Namphong River): Cd 5 µg/L (hardness <100 mg/L CaCO 3) or 50 µg/L
(hardness >100 mg/L CaCO3); Cu 100 µg/L, Pb 50 µg/L and Zn 1000 µg/L. Trigger value (µg/L) 95% of aquatic species
protection (adjusted for hardness) Cd (0.5 µg/L), Cu (3.5 µg/L), Fe (-), Mn (-), Pb (13.6 µg/L) and Zn (20.0 µg/L)(ANZECC/ARMCANZ, 2000).

The Mn and Fe DGT concentrations show high levels in the pulp mill effluent at Site C and atdownstream Namphong River Sites C2, C3 and Do (Fig. 1.C). Below Site Do labile Fe decreases tolevels similar to upstream while labile Mn decreases but remains higher than found upstream. It isclear that the source of labile Fe and Mn at and below Site C2 is different from Site C and thelocation of Site C2 is more than 20 km downstream from Site C (Fig 1.C). Thus there is a different
source of labile Fe and Mn at and below Site C2 which may be shallow seepage from watersaturated soil, including paddy fields as there is no increase in total alkalinity and hardness asobserved at Site C (Table 2). The Cu DGT concentrations are low but show some increase at Sites
C3 (September), Do (January) and Site (E) (September) (Fig. 1.C).
Wet season transfer of particulate and soluble constituents is a key feature of the water quality
data from this study. The industrial area (Sites C and C1 - pulp and sugar mills) was a major
potential source of contamination of the Namphong River associated with increased levels of labile
heavy metals in both sampling periods. The increase of total alkalinity, hardness and EC (Tables 1
and 2) for both periods confirms that groundwater was being used in the pulp mill (Site C). The
release of Cu and Pb in the Namphong River occurred in the area of rice and mixed vegetable
cultivation (Sites C3 - E) and was most likely related to extensive pesticide use (metals in thepesticides used such as carbamates). At Site F in the Chi River labile metal levels were low,
excepting for Fe and Mn, and were similar to the Namphong River at the upstream Site A (Fig 1.C).
The overall finding is that there is little effect on the water quality of the Namphong River
from upstream to downstream, from the extensive river cage aquaculture and vegetable farms, andpaddy fields and taking account of dilution removing observed additions of suspended solids andlabile metals from the major agro-industrial activities located upstream.
CONCLUSION
Variations in the levels of heavy metals and nutrients were observed in the Namphong River inJanuary and September 2012. These variations could be attributed to differences in river flow andassociated with seasonality and agricultural activities in the catchment. Although the industrial area
(pulp and sugar industries) is a major source of contamination of the Namphong River with heavy
metals, there is sufficient dilution from the Namphong River to give safe levels downstream forprotection of aquatic species. The outcome of this study will help to develop more focusedmonitoring of specific toxic heavy metals at particular locations on the Namphong River.
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ACKNOWLEDGEMENTS
The authors wish to thank the Integrated Water Resource Management Research and Development
Center in Northeast Thailand, Khon Kaen University, Thailand. We thank Clinical and Statewide
Services (CASS), Queensland (Australia) for the financial support and staff of Inorganic Chemistry
Division of QHFSS (Australia) for assistance with sample analyses and data interpretation. Aung
Naing Oo, Suraden Chason, and Pantakarn Wanciaen from Khon Kaen University assisted withfield work. Dharawan Noller prepared the maps.
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