1. Executive Summary
1.1 .Overview of study
This is a study that
relate to the land contamination of a brickwork factory to the land (include soil
and underground water nearby). The purpose of this study is to investigate how the
facilities and the daily work of factory to contaminate the soil and underground
water nearby, the contamination of soil and underground water will decrease the
environment quality of surrounding places. For this site, because the northern boundary
of the site has been designated as nature conservation importance, it is
possible that the production process and sewage discharge will be generate a
level of influent to that nature conservation importance.
This project will be
involving the surveying of land contamination inside the site and at the
location near the site by measure the concentration of chemical substances at
different depth. Apart from the measure the chemical concentration of land,
this study has also need to review the daily work and the facilities inside the
brickwork factory base on brickwork factory is the main pollution source to the
land surrounded. To show the land contaminate situation, site process of
producing a conceptual model is a must in this study to identify the possible
areas of land contamination and the pollution linkage (the way of pollutant
from pollution source to receptors). On the other hand, investigation of land
contamination influent to human health and environment quality are also the
scope of this study.
1.2. Legal Context
1.2.1. Risk Based Remediation Goals for
Contaminated Land Management[1]
Object
|
Aims
|
Benefit
|
a guideline about the protection the health of human which will
impact by land contamination by chemical, and this guideline can be the
elevation criteria of land contamination for most of the land in Hong Kong
|
to protect the health of human which are expose in the land
contamination environment.
|
can determine a designation level of land contamination by a
digitization chemical concentrate. On the other hand, this goal is also a remind to government to treat the contaminated
land, preserve the environment quality and human health
|
the limitation criteria about the 54 concern chemical concentration that contain on the ground soil in
different types include VOCs, metals etc.
|
1.2.2.
Guidance Note for Contaminated Land Assessment and Remediation[2]
Object
|
Aims
|
indicated that no matter the remediation after
contamination or contamination possible case in the future, like land
contamination generate by construction work conduct in the future
|
to provide a clear guidance about the
methodology to conduct site assessment, and suggest the remedial measure to
clean the contaminated area to relate stakeholders for reference
|
project proponent needs to determine that it is
necessary to conduct contamination assessment or not to minimize the
pollution.
|
2.
Site Conceptual Model
[1] Department, E. P., 2007. Guidance
Manual for Use of Risk Based Remediation Goals or Contaminated Land Management,
Hong Kong: Environmental Protetion Department.
[2] Department, E. P., 2007. Guidance
Note for Contaminated Land Assessment, Remediation, Hong Kong:
Environmental Protection Department.
3.
Sampling Strategy and Laboratory Techniques
3.1. Sampling Strategy
In the sampling location
choosing strategy, this project has been chosen 2 kinds of strategies-- the
sampling location that are surrounding the brickwork factory and sampling at
the location that have the high risk in environment quality after polluted by
chemical substances. The main reason is it is believe that sampling at the
position that near the factory (pollution source) can be reflect the actual
situation of land contamination, the concentration of hazard chemical in the
underground soil at the position near the pollution source will be higher than
the position that have a distant to pollution source, based on the chemical
substance will be adsorb by soil or groundwater when the chemical substances
are diffuse. In addition, chosen the location that have the high risk in
environment quality after polluted by chemical substances like Rowletch Burn
which impact by the surface water from green end of the site is a good
opportunity to show how high level of chemical substances generate from factory
influent, destroy the environment quality of those area. Although the chemical
substances concentration may be decrease through the process of, but the risk
of land pollution of those area is still appearing. In addition, after reviewing
the underlying strata of those sampling locations, the location with thin made
ground must be choose as the sampling location because of the high risk of land
contamination if the made ground is thin.
3.2. Window Sampling
Window Sampling are
applied in this project, to detect the chemical concentration of the
underground soil at the location near the brickwork factory. Window sampling is
a technique that utilize a metal tube to take the soil sample and view the soil
sample by layer. The advantage of Window Sampling is these techniques can let
the sampler to view the soil contamination situation immediately at the same
time. In addition, Window Sampling is also a low-cost land contamination
sampling method and utilize Window Sampling can sampling at different position
in one day, it is convenient if it is necessary to getting the data
immediately. But utilize Window Sampling can only detect the land contamination
in a shallow depth, it cannot detect the contamination at deep position, let
the sampling result not comprehensive.[1]
For the aspect of
sampling design, it is mention above that the sampling location will be choose
at the location with thin made ground and near the pollution source and possible
to contaminate by pollution source will be the sampling location choosing
strategy of sampling design. For the aspect of the depth of sampling, the
strategy will be trying to be sampling at soil layer at 4 sampling location
near factory and 10mto 50m at the north of the site, the reason will be
consider that chemical will be penetrate to underground soil layer at a short
time when the chemical still not yet to spread out of the site. On the other
hand, chemical substances may spread to surface water or underground water and
then go out of the site through water flow, after the chemical substances
penetrate to the soil layer, the chemical substances may spreading continue, so
it is necessary to sampling at the different layer at the north of the site (the
possible location of pollution by factory discharge).
For the aspect of substances
that will analyze for, metal is the main object to analyze, and other types of
chemical like VOCs, SVOCs etc. are also the object of analyze in this sampling
base on the producing work and daily operation of brickwork factory will
generate a large among of hazard chemical substances and it is possible that those
substances will be penetrate to underground and spread to surrounding
environment.
4.Results
4.1. Result in Chart
Analyte
|
Soil organic matter
|
Arsenic
|
Cadmium
|
Chromium
|
Copper
|
Lead
|
Mercury
|
Nickel
|
Selenium
|
Zinc
|
Phenols
|
Benzene
|
Toluene
|
Ethylbenzene
|
Total xylenes
|
|
Units
|
%
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
mg/Kg
|
|
WS1
|
Mean
|
4.933333
|
5
|
0.2
|
17.333333
|
244
|
95
|
0.4
|
24.66667
|
<0.3
|
249.33333
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
Medium
|
5.6
|
5
|
0.2
|
10
|
243
|
89
|
0.3
|
23
|
<0.3
|
234
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
maximum
|
5.6
|
5
|
0.2
|
34
|
288
|
123
|
0.9
|
34
|
<0.3
|
345
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
percentage of concentration measured to
RBRGs Limit
|
2.5%
|
0.03%
|
0.5-1.7%
|
2.01-2.88%
|
3.2-5.4%
|
<0.3-2.3%
|
0.17-0.34%
|
0.003%
|
1.69-3.45%
|
<0.05%
|
<0.1%
|
<0.1%
|
<1.2%
|
8.1%
|
||
WS2
|
Mean
|
2.56
|
6
|
0.3
|
18
|
71
|
70
|
<0.5
|
32
|
0.4
|
112
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
Medium
|
2.56
|
6
|
0.3
|
18
|
71
|
70
|
<0.5
|
32
|
0.4
|
112
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
maximum
|
2.56
|
6
|
0.3
|
18
|
71
|
70
|
<0.5
|
32
|
0.4
|
112
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
percentage of concentration measured to
RBRGs Limit
|
3.15
|
0.04%
|
0.9%
|
0.71%
|
3%
|
<1.3%
|
0.32%
|
0%
|
1.12%
|
<0.05%
|
<0.1%
|
<0.1%
|
<1.2%
|
<8.1%
|
||
WS3
|
Mean
|
5.164
|
6
|
0.433333
|
21.6
|
38.6
|
98.6
|
<0.5
|
29
|
<0.3
|
279
|
1
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
Medium
|
5.47
|
6
|
0.4
|
21
|
34
|
67
|
<0.5
|
28
|
<0.3
|
102
|
1
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
maximum
|
7.91
|
8
|
0.6
|
26
|
70
|
264
|
<0.5
|
45
|
<0.3
|
1011
|
1
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
percentage of concentration measured to
RBRGs Limit
|
2-4%
|
0.03-0.09%
|
1-1.3%
|
0.19-0.7%
|
0.7-11.5%
|
<1.3%
|
0.13-0,45%
|
<0.003%
|
0.6-10.11%
|
0.005-0.01%
|
<0.1%
|
<0.1%
|
<1.2%
|
<8.1%
|
||
WS4
|
Mean
|
1.763333
|
4.333333
|
<0.2
|
24.333333
|
17
|
12.33333
|
,0.5
|
26.33333
|
<0.3
|
44.333333
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
Medium
|
1.77
|
4
|
<0.2
|
26
|
17
|
11
|
<0.5
|
25
|
<0.3
|
44
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
maximum
|
2.13
|
5
|
<0.2
|
26
|
18
|
15
|
<0.5
|
30
|
<0.3
|
50
|
<0.5
|
<0.01
|
<0.01
|
<0.01
|
<0.01
|
|
percentage of concentration measured to
RBRGs Limit
|
2-2.5%
|
<0.03%
|
1-1.3%
|
0.16-0,18%
|
0.5-0.65%
|
<1.3%
|
0.24-0.3%
|
<0.003%
|
0.39-0.5%
|
<0.05%
|
<0.1%
|
<0.1%
|
<1.2%
|
<8.1%
|
[1] GEOCON, n.d. GROUND
INVESTIGATIONS. [Online]
Available at: http://www.geoconsiteinvestigations.com/gi-contractor/ground-investigation
Available at: http://www.geoconsiteinvestigations.com/gi-contractor/ground-investigation
Sampling Name
|
average
|
maximum
|
|||||||||
Analyte
|
10M
|
1st
|
20M
|
30M
|
40M
|
50M
|
Far Bank 1
|
Far Bank 2
|
Sediment
|
||
cr
|
35.2
|
36.8
|
31.2
|
31.4
|
36.8
|
37.4
|
60
|
86.7
|
33.5
|
43.2
|
86.7
|
co
|
43.3
|
51.1
|
38.1
|
31.6
|
42.7
|
47.3
|
49.6
|
47.9
|
40
|
43.5
|
51.1
|
ni
|
31.3
|
31.1
|
38.7
|
38.6
|
33.2
|
38.8
|
47.3
|
47.1
|
61.8
|
40.9
|
61.8
|
cu
|
60.8
|
82.3
|
61.9
|
62
|
50.5
|
45.2
|
141.4
|
148.5
|
57
|
78.8
|
148.5
|
zn
|
270.3
|
353.6
|
293.5
|
310
|
276.7
|
255.7
|
571.2
|
640.7
|
189.6
|
351.3
|
640.7
|
as
|
7.6
|
8
|
6
|
6.7
|
7.3
|
5.8
|
8.6
|
10.9
|
10.8
|
8.0
|
10.9
|
mo
|
4.4
|
6.4
|
5.2
|
5
|
4.9
|
4.2
|
9.5
|
9.7
|
3.6
|
5.9
|
9.7
|
cd
|
1.1
|
0.9
|
1.2
|
0.9
|
0.4
|
0.8
|
0.3
|
0.8
|
1
|
0.8
|
1.2
|
sn
|
9.6
|
17.8
|
11.1
|
8.7
|
6.6
|
5.1
|
26.6
|
27.5
|
38.5
|
16.8
|
38.5
|
sb
|
10.6
|
13.5
|
12.9
|
9.4
|
5.6
|
3.5
|
11.6
|
10.2
|
6
|
9.3
|
13.5
|
ba
|
5445
|
4076
|
5368
|
3430
|
1223
|
876.5
|
901.3
|
946.7
|
2276
|
2726.9
|
5445
|
hg
|
2.1
|
2.1
|
2.1
|
2.2
|
1.9
|
2
|
2.1
|
2.2
|
2.3
|
2.1
|
2.3
|
pb
|
117.1
|
199.8
|
120.6
|
127.4
|
99.4
|
87.1
|
327.5
|
332
|
109.5
|
168.9
|
332
|
4.2. Result Description
The survey were conduct
at 13 positions inside and outside the site, those surveying positions are
involved different kinds of chemcial substances and measuring depth. The result
has been shown in the table and graph above.
For the aspect of Window
Sampling result at WS1, it shows that Zinc is the main chemical substances
contain in the underground base on Zinc have the highest concentrate in maximum
and average concentration (345mg/kg in 1.6-1.8m, 249.3 mg/kg in average) among
all the chemical substances. Higher than other substances with at least 2.2% in
average. It shows that Zinc are more appear at least 19.8% It shows that Zinc
are more appear at WS1. For the aspect of WS2, at same as WS1, Zinc is also the
chemical substances that have the highest concentration in the underground. The
maximum and average concentration of Zinc at WS2 are 112mg/kg in average, it is
higher than other substances with at least 57.7%. In addition, Copper and Lead
are also the main contamination source at WS2, two chemical substances have the
nearest concentration with 71 and 70mg/kg in average. It shows that Zinc are
the main contamination source at WS2, and the mining work is conduct nearby.
For the aspect of WS3, also as same as WS1 and WS2, Zinc are the highest
concentration chemical substances. The maximum and average concentration of
Zinc in WS3 are 279mg/kg and 1011mg/kg in 0-0.3m, it is higher than other
substances with at least 183% in average. For the aspect of WS4, PAHs become
the highest concentration chemical substances in the underground of WS4 with
maximum and average concentration of PAHs are 232mg/kg in 1.6-2.6m and 146
mg/kg respectively with percentage 364% at least, it shows that the chemical
substances in the underground of WS4 are concentration to one type of chemical
substances are 232mg/kg and 146 mg/kg respectively. It is higher than other
chemical with 231.8%, it shows that PAHs have the higher level of impact to underground
soil and water of WS4.
To view by the
percentage to RBGR limit, Lead and Zinc measure at WS3 has the highest
percentage with 0.7-11.5% to 0.6-10.11%, means that the land contamination by Lead
and Zinc at WS3 are closest to excess, although the
percentage
of concentration measured to RBRGs Limit are not high but still have the risk
of land contamination impact to human health and environmental quality.
For the aspect of survey
result of 10M-Sediment, it shows that Ba is the highest concentration among
survey point 10M to Sediment, and also in the average concentration. In survey
result in 10M-Sediment, the highest concentration of Ba was measured at 10M
with 5445b mg/kg and 2726.9 mg/kg for average concentration. Then Zinc is the
second highest concentration among all the chemical measured with average and
maximum concentration 351.7 and 640.7mg/kg
5.
Discussion and Recommendations
5.1 Land Contamination at factory site
To view the potential
pollution sources, in window sampling, it is mentioned that the land
contamination situation of WS1 and WS3 are more serious than WS2 and WS4,
become the main pollution source of factory. For the aspect of WS3, the
position of WS3 is located near the LPG storage tank and unsurfaced quarry
plant storage area which contain mobile fuel bowser. Quarry plant storage area
is a unsurfaced land area, chemical like hydrocarbon which generate by LPG leaking
based on it is more easy to infiltrate to underground soil when contact with
rainwater because the underground soil do not influence of site drainage to
land contamination, at WS3, the potential groundwater pollution source will be
from the green at the north of the site to Rowletch Burn, before the water
discharge to the river Rowletch Burn, water will reduce the suspended soil
through settlement system catch pit, on the other hand, a part of the water
discharge will be contain on site, means that discharge water will not spread
out of the site, so the measurements mention be reduce the groundwater
pollution at WS3 and surrounding area at a certain level.
At
WS1, it is located at clay stockpiles, as same as WS3, the area of clay stockpiles
is also an unsurfaced land, it is estimate that the land contamination situation
is similar to WS3, the metal like Chromium, Cadmium, Copper etc. may be penetrate
to underground soil and diffuse to underground soil at the surrounding
environment. According to site conceptual model. To view the underground water
pollution of WS1, the location of WS1 is near the settlement pond, the
settlement pond is a pond that contain waste water that contain clay particles,
it is sure that the waste water will pass through the underground of WS1 which
is shown in conceptual model. The land contamination
risk from chemical substances and waste water to human health and environment
quality are appear. [1]
5.2. Land Contamination at the
north of the site
The land contamination at the north of the site are
associated with land contamination at factory site because the chemical like
metal have the character of spreading that has mentioned above, the land
contamination at the north of the site are also facing the risk of health
damage and destroy the environment quality. According to the result, Ba at 10M
is the highest concentration chemical substances with 5445 mg/kg, and the
second highest concentration chemical is Zinc with 189.6-640.7. According to
the conceptual model. The source of Ba and Zinc will be from the waste water
discharge and land contaminants spreading by groundwater, because the location
of 10M to Sediment are far from the pollution source, it is possible that the
land contamination is from another place. For the relationship between land
contamination to underlying strata, the underlying strata with thin made ground
will be have higher risk of land contamination. According to the cross-section
underlying strata model, borehole 4,5,6 have the thinnest made ground, the
potential land contamination source is from metal and waste oil penetrate above
the ground, although some of the chemical substances will be obstruct by made
ground, but there are still have high risk in underground soil contaminate by
hazard substances of metal and waste oil.
5.3. Health Impact of land contamination
The pollutants of land contamination
in case mention above are mainly come from metal. Copper and Chromium are the
chemical mention above and both will cause health risk to people who work or
live near copper process smelter. The illness case from contact with copper for
a long time can be divide into slight to serious, headache, stomachaches,
diarrhea at best, damage the liver and kidney and death at worst. Copper
poisoning can cause hepatic cirrhosis, brain damage etc. [2],[3]
For the aspect of Chromium, excess
to adsorb Chromium are carcinogenic, people who exposure under Chromium are
possible to get lung cancer, liver cancer and kidney cancer, for more serious,
Chromium will cause people to death. In addition, the hazard of Chromium to
health can view by its oxidation state, Chromium in hexavalent form is toxic,
excess to adsorb hexavalent form Chromium can be get the illness relate to
throat, bronchus and Respiratory tract like wheezing and bronchospasms.
5.4. Environment Impact of land contamination
For the aspect of Copper, Copper is a metal that cannot easy
to break down, so Copper will accumulate in the soil, it has very low survival
opportunities of vegetations if the soil accumulates numerous of Copper, the
vegetation coverage will be decrease in those places. Although Copper are
attaches by organic matter and minerals when it is going into underground soil
and release to groundwater, but Copper will travel for a long distance by
surface water, so Copper still have a risk to water pollution of surrounding
environment.[4],[5]
5.5. Recommendations
5.5.1. Cover System
The purpose to utilize
Cover System in land contamination recommendation is to block the way of
contaminators to pollute the receptors (soil and water), the obvious benefit of
Cover System is remove the risk of chemical substances generated penetrate to underground
soil and water to protect human health and environment quality like provide a
suitable medium for vegetation to growth. For the aspect of material utilize as
Cover System, natural soil material, clay etc. is the common material utilize,
and the most effective material are membranes concrete and soils mixed with
cement or bentonite because those have the character of decrease the
permeability, to be a barrier between underground soil or water and
contaminators above the ground, prevent cross-contamination of two things..It
is sure that this is a cheaper method among all the recommendations base on this
method just need to add a low permeability material although a low permeability
material But the problem of cover system
is cover system still not yet to solve the problem of original contamination
source underground, because cover system just solve the problem of
contamination from contamination source above the ground to underground, and
the underground contamination source still not yet remove, contamination source
will continue to spread the hazard substances to pollute the underground soil
and water.
5.5.2. Vertical barrier systems
Vertical barrier systems are a system to focus on both soil
and groundwater contamination include fresh water, salt water. The operation
principle of Vertical barrier systems is to build a vertical underground wall
to trap the horizontal flow of contaminants at underground water and soil,
prevent the horizontal diffusion of contaminants at underground soil and water.[6],
the hazard chemical substances contain at underground water are block by the
board of vertical barrier systems, so the land contamination at underground
water can be obstruct. For the aspect of cost compare to Cover System, this
method may be more expensive base on this method involve to build an underground
wall, dig an underground hole and build a pump house, the construction fee is
expensive than utilize cover system. But the effective is higher than utilize
cover system because this method is focusing on solve the underground
pollution, involve take away the contaminated water let contaminated water
cannot spread to underground water layer to increase the pollution rate and
build a wall to isolate the polluted and unpolluted to avoid underground soil
pollution.
[2] LENNETH,
n.d. Copper - Cu Chemical properties of copper - Health effects of copper -
Environmental effects of copper. [Online]
Available at: https://www.lenntech.com/periodic/elements/cu.htm
[Accessed 10 11 2019].
Available at: https://www.lenntech.com/periodic/elements/cu.htm
[Accessed 10 11 2019].
[3] LENNTECH, n.d. Chromium
- Cr Chemical properties of chromium - Health effects of chromium - Environmental
effects of chromium. [Online]
Available at: https://www.lenntech.com/periodic/elements/cr.htm
[Accessed 10 11 2019].
Available at: https://www.lenntech.com/periodic/elements/cr.htm
[Accessed 10 11 2019].
[4]LENNETH, n.d. Copper - Cu Chemical
properties of copper - Health effects of copper - Environmental effects of
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