Characteristics of Hydro-Geochemictry and Its Zoning in Hai Duong Urban Area

VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 
131 
Characteristics of Hydro-geochemictry and Its Zoning 
in Hai Duong Urban Area 
Nguyen Van Dan1,*, Hoang Van Duy2, Van Thuy Linh3, Tran Duy Hung4 
1Hydrogeological Association of Viet Nam, 10 Tran Cung, Cau Giay, Hanoi, Vietnam 
2Northern Division for Water Resources Planning and Investigation, 10 Tran Cung, Hanoi, Vietnam 
3Institute of Resources, Environment and Sustainable Development (IRED), 
114 Tran Duy Hung, Hanoi, Vietnam 
4Department of Water Resources Management, 10 Ton That, Thuyet, Cau Giay, Hanoi, Vietnam 
Received 07 December 2018 
Revised 14 December 2018; Accepted 14 December 2018 
Abstract: Hai Duong urban area consists of Hai Duong city and its vicinity, covering an area of 
about 500 km2, located in the center of the Red River Delta with three main aquifers: qh, qp and n. 
The (qp) and (n) aquifers have significant amount of water potential, meaning that they can be 
sources for public water supply, but poor water quality that can limit the meaning of water supply. 
Highlights of water quality are: high level of total dissolved solid, iron content, manganese and 
nitrogen compounds. In all three aquifers water is saline in most of the area, accounting for 22% to 
64% of the area. The risk of salinity intrusion can be happened in all aquifers. For the (qp) aquifer, 
forecast to 2030, under current water exploitation conditions, salinity intrusion rates may range from 
2.7 to 9.3 m per year. In the study area, there are three types of hydro-geochemistry: Type I - All 
layers of water in the section are fresh; Type II - Top (qh) is fresh, (qp) and (n) aquifers are salinity, 
in which the (qp)is more salty than the (n) layer and the V-type is saline water in (qh) and (qp) 
aquifers, in the (n) aquifer water is fresh. The I type is normal of hydro-geochemistry; The V type 
is inverseof hydro-geochemistry due to (n) aquifer which its recharge is far from. In the II type there 
are both normal and invers of hydro-geochemistry due. 
Keywords: Water quality, aquifer, hydro-geochemical zoning, salinity intrusion. 
Studying hydro-geochemical characteristics 
and its distribution is very important for 
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determining the purpose of water use and the 
origin of groundwater formation. However, in 
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N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 132 
our country this research is often associated with 
the general study of groundwater. One of the 
special researches on hydro-geochemical 
analysis is the work of Nguyen Van Dan [4], 
after evaluating the overall hydro-geochemical 
characteristics of coastal areas from Mong Cai to 
Ha Tien, He made a zoning map for the hydro-
geochemistry, which is basics for forecasting for 
the presence of fresh groundwater in some 
coastal offshore areas 
In Hai Duong area, the hydro-geochemistry 
is rather complicate, the research results showed 
that there is intercalation between fresh water 
layer and saline water layer in the profile 
requires intensive research. Based on the water 
resource investigation and assessment report, the 
Hai Duong urban geological survey report and 
the recent survey on water protection in Hai 
Duong urban area in period 2014-2018, Hoang 
Van Duy [2] had the thesis for Master of science 
in the research on hydro-geochemistry. This 
article, publishes the results of Hoang Van Duy's 
research. And on the other hand, there is 
showing additional research results on the basis 
of application of integrated methods, system 
analysis, GIS and numerical modeling methods 
to simulate conditions, process and prediction of 
salinity intrusion with specialized softwares such 
as GMS, Modflow, MT3D... 
1. Introduce the research area 
The study area covers the whole acreage of 
Hai Duong city and part of the area of the 
districts of Nam Sach, Thanh Ha, Cam Giang, 
Gia Loc (Hai Duong province), Van Lam, My 
Hao (Hung Yen province), Thuan Thanh, Gia 
Binh (Bac Ninh province) located in the center 
of the Northern Delta, Area of about 
500km2(Figure 5) has a relatively flat 
topography with a height of 2-6 m, has tropical 
monsoon climate, the year is divided into two 
distinct seasons. The cold season coincides with 
the rainy less season from November to April of 
the following year, the hot season coincides with 
the rainy season from May to October with 80% 
of the annual rainfall. Average annual rainfall is 
1533mm. In the rainy season, the rainfall is 
much higher than the evaporation is the 
"moisture redundancy" period; In the dry season, 
evaporation is greater than rainfall, which is the 
period of "moisture shortage" (Figure 1). 
The research area has a system of dense 
rivers including big rivers such as Thai Binh, Pha 
Lai, Duong, Kinh Thay... Northwest - Southeast 
direction and have hydrological regime that 
repeats the rain regime: Flood season from May 
to October, The dry season from November to 
April next year. 
Due to the phasing of the sediment, the 
researchers divided into three aquifers: holes of 
Holocene sediment layer, denoted by (qh), holes 
of Pleistocene sediment layer, denoted by (qp), 
and the fractured - holes aquifer of Neogene 
sediment layer, denoted by (n). Between them 
are clay formations, sandy silt permeability weak 
(Figure 2).
Figure 1. The annual precitationand evaporation at Hai Duong station. 
N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 133 
Figure 2. Hydrogeological section across the study area. 
Holocene (qh) aquifer the no pressure layer 
on the top of the sectio ... T: 2015/BTNM with 32 parameters. 
However, as the research was only general, only 
18 parameters were identified and focused only 
on the (qp) aquifer because of significant water 
supply results as shown in table 1. 
There are 9 parameters in excess of QCVN 
09-MT: 2015 with the following comments: 
- The pH was determined in 37 samples with 
results ranging from 4.5 to 8.16, average 6.5, of 
which one sample, accounting for 2.7% 
exceeding the allowed standard with a maximum 
value of 8.16. 
- TDS was determined in 37 samples with 
results ranging from 129 to 4793, an average of 
1207 mg/ l, of which 9 samples, accounting for 
24%, exceeded the allowed standard with a 
maximum value of 4793 mg/l, exceeding 3.2 
times. 
- Total iron was determined in 25 samples 
with results ranging from 0.1 to 41.53, an 
average of 7.32 mg/l, of which 20 samples, 
accounting for 40%, exceeded the permitted 
standard with the maximum value of 41.53 mg 
/l, exceeding 8.3 times. 
- NO3 nitrate was determined in 9 samples 
with results ranging from 6.1 to 28.3, an average 
of 14.56 mg/l, of which 5 samples, accounted for 
55%, exceeded the allowed standard with the 
maximum value of 28.3 mg/l, exceeded 1.9 
times. 
- Nitrite NO2 was determined in 9 samples 
with results ranging from 0.008 to 4.5, an 
average of 0.52 mg/l, of which one sample, 
accounting for 11%, exceeds the allowed 
standard with a value of 4.5 mg/l, exceeding 4.5 
times. 
- NH4+ ammonium was determined in 9 
samples with results ranging from 0.62 to 3.4, an 
average of 1.5 mg/l, of which 4 samples, 
accounting for 44%, exceeding the allowed 
standard with the maximum value of 3.4 mg/l, 
exceeding 3.4 times. 
- Mn was determined in 10 samples with 
results ranging from 0.14 to 3mg/l. There are 7 
samples, accounting for 70% exceeded the 
permitted standard with a maximum value of 3 
mg / l, exceeding 6 times. 
N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 136 
Table 1. Evaluation of water quality in (qh) aquifer 
Order number Parameters 
Number 
of 
samples 
Characteristic value 
Unit 
QCVN 
09-MT : 
2015 
Number 
of sample 
exceeding 
the 
standard 
Proportion 
% 
Min Max Average 
1 pH 37 4.5 8.16 6.50 5.5 - 8.5 1 2.7 
2 TDS 37 129 4793 1207.87 mg/l 1500 9 24.32 
3 Cl- 37 22.16 2680.02 615.02 mg/l 250 21 56.75 
4 SO42- 37 1.2 67.5 14.72 mg/l 400 
5 NO3- 9 6.1 28.3 14.56 mg/l 15 5 55.56 
6 NO2- 9 0.008 4.5 0.52 mg/l 1 1 11.11 
7 NH4+ 9 0.62 3.4 1.53 mg/l 1 4 44.44 
8 Total Iron 25 0.1 92 16.46 mg/l 5 11 44.00 
9 As 10 0.0007 0.17 0.01925 mg/l 0.05 1 10 
10 Hg 10 0.0002 0.002 0.0009833 mg/l 0.001 
11 Cr 10 0.0005 0.02 0.0037 mg/l 0.05 
12 Cd 10 0.0004 0.001 0.0008 mg/l 0.005 
13 Pb 10 0.001 0.006 0.0018333 mg/l 0.01 
14 Cu 10 0.001 0.007 0.0034286 mg/l 1 
15 Zn 10 0.015 0.322 0.0574 mg/l 3 
16 Mn 10 0.138 3 1.4264 mg/l 0.5 7 70 
17 CN- 10 0.001 0.005 0.002 mg/l 0.01 
18 Phenol 10 0.001 0.01 0.006075 mg/l 0.001 
- As was determined in 10 samples with 
results ranging from 0.0007 to 0.17, an average 
0.01925 mg/l, of which one sample, accounting 
for 10%, exceeds the permissible standard with 
a value of 0.17 mg/l, exceeding 3.4 times. 
The combined results show that outstanding 
water quality issues are TDS, iron, manganese, 
and nitrogen compounds. TDS increase, the 
researchers found that the seawater was formed 
during seawalls that had been salted during 
geologic seasons but was now at risk of 
salinisation due to water exploited. The rest of 
the increase is the expression of contaminated 
water, where the origin of contamination of 
nitrogen compounds, Nguyen Van Dan and 
Nguyen Thi Dung [3] argue that mainly due to 
human activities; The origin of iron and 
manganese pollution, Nguyen Kim Ngoc [1] 
due to nature. 
3.3. Situation of groundwater salinity intrusion 
Salty situation of groundwater. The 
combined results in section 3.1 above show that 
all aquifers in the study area are saline (TDS> 
1000mg/l) The area is quite large, accounting for 
22% of (qh) aquifer and 40% of (n) aquifer and 
64% of (qp) aquifer. 
Forecast for salinity intrusion of (qp) 
aquifer. For the prediction of groundwater 
salinity intrusion(qp), Hoang Van Duy [2] 
constructed the groundwater model using 
MODFLOW- MT3DMS software to determine 
the material movement in the mining conditions. 
Results showed that, by 2030, the fresh area of 
the (qp) aquifer was narrowed down. The 
boundary between salty and fresh is moved 
towards the mining area from 40 to 140 m 
compared to the current rate of 2.7-9.3 m/ year 
(Table 2) 
N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 137 
Table 2. The speed of movement of boundary between salty and fresh in (qp) aquifer 
Order 
number 
Study site Move direction 
Movement prediction results 
Distance, m Speed, m/year 
1 
VinhTuy- BinhGiang 
-Hai Duong 
Southeast-Northwest 
140 9.3 
2 
Cam Son- Cam Giang 
-Hai Duong 
Northeast-Southwest 
88 5.9 
3 
Ho town –ThuanThanh 
– BacNinh 
South-North 
40 2.7 
The results of this study show that 
groundwater (qp) in the study area is likely to be 
salinized, It is necessary to continue to observe 
and study measures to prevent salinity intrusion 
in the following directions: study rational 
exploitation solutions, building walls at the 
boundary between salty and fresh, Construction 
of artificial additions to underground water or 
salt water pumps near the boundary between 
salty and fresh 
4. Division and zoning of hydro-geochemistry 
4.1. Hydro-geochemistry division vertically 
Hydro-geochemistry division is the change 
in the mineralization of groundwater in the 
geological section from the top down [4]. 
Decreasing of TDS is normal of hydro-
geochemistry. Increasing of TDS is invers of 
hydro-geochemistry 
I. K. Zaixev [1, 4] has divided into three 
main zones: Zone A contains fresh water (TDS 
<1g/l); Zone B contains saltwater (TDS 1 - 
35g/l); Zone C contains salt water (TDS> 35g/ 
l). 
N. I. Tonstikhin [1, 4] has divided into 6 
types of hydro-geochemical sections as shown in 
Figure 4. 
According to research results of Nguyen Van 
Dan [4] many regions in our country, including 
research areas, do not have zone C. Based on the 
variation of the two zones A and B, it is possible 
to divide the study area into 3 types of hydro-
geochemistry sections: I, II and V to map the 
zoning of the hydro-geochemistry. 
4.2. Zoning of hydro-geochemistry 
The study area is divided into 3 regions with 
different hydro-geochemistry zoning 
corresponding to the above three types of hydro-
geochemistry sections. On the zoning map, the 
symbol of the region is taken from the hydro-
geochemical type (Figure 5). 
Figure 4. Types of hydro-geochemical sections according to N.I.Tonstikhin 
N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 138 
Figure 5. Map of hydro-geochemical zoning in Hai Duong urban area 
Zone I: all aquifers contain in section fresh water 
Zone II: the (qh) aquifercontains fresh water, (qp) aquifer and (n) all contain saltwater 
Region V: (qh) and (qp) contain saltwater, (n) aquifer contains fresh water 
Zone I: In the cross section, all aquifers 
contain fresh water, distributed in My Hao and 
Van Lam districts of Hung Yen province; Thuan 
Thanh of Bac Ninh Province and part of Cam 
Giang District of Hai Duong Province. There are 
3 aquifers: (qh), (qp) and (n) which contain fresh 
water. 
Zone II: In the top down cross section, (qh) 
aquifer contains fresh water, (qp) and (n) 
aquifers all contain saltwater distributed in 
Luong Tai district of Bac Ninh province and part 
of Cam Giang district, Nam Sach district, Hai 
Duong province, in this case, mineralization of 
(qp) aquifer is greater than (n)the aquifer. 
Region V: In the section, (qh) and (qp) 
aquifers contain saltwater, (n)the aquifer 
contains fresh water, distributed in part of Hai 
Duong City and Thanh Ha District of Hai Duong 
Province. 
Zone I: has a type of normal hydro-
geochemistry, have top-down recharge. Zone V 
hasinvers of of hydro-geochemistry, (n) aquifer 
have remote power supply similar to the Hai Hau 
area of Nam Dinh province, but where is the 
recharge zone? It must be researched. Zone II 
has both normal and invers of hydro-
geochemistry, the (n) the aquifer has both remote 
and top-down. 
5. Conclusion 
- In Hai Duong city, there are 3 aquifers 
:(qh), (qp) and (n), of which (qp) and (n) aquifers 
are meaningful centralized water supply. 
- Water quality characteristics of all three the 
aquifers are high in TDS, iron, manganese and 
nitrogen compounds, of which the salinity of the 
three aquifers is 22 to 64% of the aquifer area. 
TDS be increased means ancient sea water was 
washed salty, there is currently a risk of 
salinization due to unreasonable exploitation; 
high content of iron, manganese, and nitrogen 
compounds indicate contaminated water; 
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N.V. Dan et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 34, No. 4 (2018) 131-139 139 
 - The aquifers are at risk of salinization, 
which is predicted by the numerical model of 
reservoir (qp) aquifer until 2030. Under the 
current mining conditions, the rate of salinity 
intrusion can reach from 2.7 to 9.3 m / year; 
- The study area has 3 zone corresponding to 
3 types of hydro-geochemistry: Zone I - All 
aquifers in the transect contain fresh water; Zone 
II - The top aquifer contains fresh water, 2 
aquifers below contain saltwater and zone V- 2 
upper aquifers containing saltwater, aquifer 
below contain fresh water. Zone I has a type of 
normal hydro-geochemistry, Zone V has 
hasinvers of of hydro-geochemistryand Zone II 
has both types hasinvers of hydro-
geochemistry./. 
References 
[1] Nguyen Kim Ngoc et al. (2005). Geochemical 
chemistry: Transportation Publishing House 
Company Limited. Hanoi 2005, pp. 32-38 and 106-
108. 
[2] Hoang Van Duy (2017). Study on the hydro-
geochemical characteristics of Hai Duong urban 
area, Master thesis, Archives of University of 
Mining and Geology, pages 40-96. 
[3] Nguyen Van Dan, Nguyen Thi Dung (2004). 
Groundwater contamination in Hanoi, Journal of 
Geology A / 280-1-2 / 2004, Hanoi 2004, pp. 48-57. 
[4] Nguyen Van Dan et al. (2015). Geological, 
hydrological and geochemical features of coastal 
areas in Vietnam, Journal of Marine Science and 
Technology, 334-340, Hanoi, pp. 334-340. 
Đặc điểm thủy địa hóa và tính phân đới của chúng 
khu vực đô thị Hải Dương 
Nguyễn Văn Đản1, Hoàng Văn Duy2, Văn Thùy Linh3, Trần Duy Hùng4 
1Hội Địa chất Thủy văn Việt Nam, Số 10, Trần Cung, Cầu Giấy, Hà Nội, Việt Nam 
2Liên đoàn Quy hoạch và Điều tra Tài nguyên nước miền Bắc, Số 10, Trần Cung, Hà Nội, Việt Nam 
3Viện Tài nguyên, Môi trường và Phát triển bền vững, 114 Trần Duy Hưng, Cầu Giấy, Hà Nội, Việt Nam 
4Cục Quản lý Tài nguyên nước, 10 Tôn Thất Thuyết, Cầu Giấy, Hà Nội, Việt Nam 
Tóm tắt: Khu vực đô thị Hải Dương bao gồm thành phố Hải Dương và phụ cận với diện tích khoảng 
500 km2, nằm ở trung tâm Đồng bằng Bắc Bộ có 3 tầng chứa nước chính là (qh), (qp) và (n). Mức độ 
chứa nước của tầng (qp) và (n) khá phong phú có ý nghĩa cung cấp nước tập trung, song chất lượng 
nước kém và không đồng đều đã làm hạn chế ý nghĩa cung cấp nước. Những vấn đề cần cần quan tâm 
về chất lượng nước khu vực nghiên cứu là độ tổng khoáng hóa (TDS), hàm lượng sắt, mangan và các 
hợp chất nito của nước tăng cao. Phần lớn diện tích của 3 tầng chứa nước đều bị mặn với diện tích từ 22 
đến 64% tổng diện tích phân bố tầng chứa nước. Tầng chứa nước (qp) có thể bị nhiễm mặn, dự báo đến 
2030, tốc độ nhiễm mặn theo chiều ngang có thể đạt từ 2,7 đến 9,3 m/năm. Khu vực nghiên cứu có 3 
kiểu mặt cắt thủy địa hóa: kiểu I- tất cả các tầng chứa nước trong mặt cắt đều chứa nước nhạt; kiểu II- 
tầng (qh) trên cùng chứa nước nhạt; tầng (qp) và (n) bên dưới chứa nước mặn, trong đó nước của tầng 
(qp) mặn hơn tầng (n) và kiểu V- tầng (qh) và (qp) bên trên chứa nước mặn, tầng (n) bên dưới chứa 
nước nhạt. Kiểu I có tính phân đới thủy địa hóa thuận; kiểu V có tính phân đới nghịch; Kiểu II có cả 
tính phân đới thủy địa hóa thuận và nghịch. 
Từ khóa: Chất lượng nước, nhiễm mặn, phân đới thủy địa hóa, tầng chứa nước.