5. Discussion
When priority agents have been identified in environmental management, policy makers usually begin to seek
for risk sources. River runoff and anthropogenic activities are believed to be the main pollution sources in China
seas
[46]
. Table 4 shows water discharge and particle heavy metals in main rivers around Bohai Sea
[47]
.
Table 4 Water discharge and particle heavy metals in rivers around Bohai Sea
Water discharge (billion
Particle metal concentration (ng/g)
m
3
/a)
Cu Pb Cd
Liaohe River 9.4
50.7 144 üü
Shuangtaizihe River 43.0
38.1 82.0 0.85
Luanhe River 48.7
54.9 68.7 0.91
Yellow River 44.3
26.7 16.4 0.18
Data source: [47]
To further illustrate the influence of anthropogenic activities to Bohai Sea, background information for heavy
metals in sediments was found
[48]
. It is noticeable that it took more than 100 years for Pb to increase an extent of
2.43 mg/kg while to rise with extra 1.91 mg/kg just took 14 years (Table 5). A faster increase for Cd was also found
with a rate about 0.01 mg/kg.a during the last 16 years, in contrast to 0.0004 mg/kg.a one century ago.
Table 5 Comparative concentrations of heavy metals in sediments of Bohai Sea
Cu Hg Pb Cd
Background concentration in 1883
(mg/kg, or ×10
-6
)*
22.10 —— 13.96 0.088
Concentrations in 1983-1985 (mg/kg,
or ×10
-6
)*
25.75 —— 16.39 0.123
Concentrations in 1999 (mg/kg, or
×10
-6
)^
—— 0.057 18.30 0.273
Input amount (ton/a)^ —— 10.4 612.6 79.5
Data source: * [48]. Arithmetical value. [47]
Another proof comes from a comparative research about mercury in upstream sediments of Haihe River (before
it passes through Tianjin city) and downstream (after traversing), which showed that industrial factories in Tianjin
had contributed a lot to the mercury content increase in river sediment
[49]
. And total mercury in mollusc bodies
sampled in Bohai Sea showed that almost all individuals were contaminated and sample taken in Huludao had the
highest mercury concentration (Table 6)
[50]
. Jing Wang et al. / Procedia Environmental Sciences 2 (2010) 1632–1642 1639
Table 6 Mercury concentration scales in mollusc bodies
Concentration
(ng/g wet weight)
Provinces Coastal waters of cities
Gastropods Bivalve
Yingkou 60.5
15.0~43.2
Liaoning Huludao 53.1~453.0 19.9~99.3
Dalian 39.3~109.5 11.1~30.9
Qinhuangdao 41.7~53.4 11.0~19.7
Hebei
Tang’gu 11.3~42.7 6.7~51.3
Yangkou 32.0~96.1 10.7~68.4
Shandong
Penglai 62.2~138.7 19.7~194.2
Data source: [50]
There are evidences showing that Bohai Sea has been suffered from heavy metal pollution and anthropogenic
activities have greatly speeded up this environmental problem.
Seafood pollution of heavy metals was becoming serous in Bohai Sea. To carry out human health risk
assessment, it is suggested
[28]
that both seafood consumption rate and tolerable daily intake should be counted in.
Tolerable daily intake is the maximum amount of chemicals that ordinary human body can take in one day. And
level of concern is the quotient of tolerable daily intake divided by daily seafood consumption rate
[28]
, which is the
PNEC in human health risk assessment. Risk quotient is got by dividing measured concentration in seafood to the
level of concern.
RQ=
LOC
MEL(orPEL)
;
LOC=
CR
TDI
Due to lack of consumption rate and measured body level for metals, human risk assessment did not be carry out
in this paper.
5. Discussion
When priority agents have been identified in environmental management, policy makers usually begin to seek
for risk sources. River runoff and anthropogenic activities are believed to be the main pollution sources in China
seas
[46]
. Table 4 shows water discharge and particle heavy metals in main rivers around Bohai Sea
[47]
.
Table 4 Water discharge and particle heavy metals in rivers around Bohai Sea
Water discharge (billion
Particle metal concentration (ng/g)
m
3
/a)
Cu Pb Cd
Liaohe River 9.4
50.7 144 üü
Shuangtaizihe River 43.0
38.1 82.0 0.85
Luanhe River 48.7
54.9 68.7 0.91
Yellow River 44.3
26.7 16.4 0.18
Data source: [47]
To further illustrate the influence of anthropogenic activities to Bohai Sea, background information for heavy
metals in sediments was found
[48]
. It is noticeable that it took more than 100 years for Pb to increase an extent of
2.43 mg/kg while to rise with extra 1.91 mg/kg just took 14 years (Table 5). A faster increase for Cd was also found
with a rate about 0.01 mg/kg.a during the last 16 years, in contrast to 0.0004 mg/kg.a one century ago.
Table 5 Comparative concentrations of heavy metals in sediments of Bohai Sea
Cu Hg Pb Cd
Background concentration in 1883
(mg/kg, or ×10
-6
)*
22.10 —— 13.96 0.088
Concentrations in 1983-1985 (mg/kg,
or ×10
-6
)*
25.75 —— 16.39 0.123
Concentrations in 1999 (mg/kg, or
×10
-6
)^
—— 0.057 18.30 0.273
Input amount (ton/a)^ —— 10.4 612.6 79.5
Data source: * [48]. Arithmetical value. [47]
Another proof comes from a comparative research about mercury in upstream sediments of Haihe River (before
it passes through Tianjin city) and downstream (after traversing), which showed that industrial factories in Tianjin
had contributed a lot to the mercury content increase in river sediment
[49]
. And total mercury in mollusc bodies
sampled in Bohai Sea showed that almost all individuals were contaminated and sample taken in Huludao had the
highest mercury concentration (Table 6)
[50]
. Jing Wang et al. / Procedia Environmental Sciences 2 (2010) 1632–1642 1639
Table 6 Mercury concentration scales in mollusc bodies
Concentration
(ng/g wet weight)
Provinces Coastal waters of cities
Gastropods Bivalve
Yingkou 60.5
15.0~43.2
Liaoning Huludao 53.1~453.0 19.9~99.3
Dalian 39.3~109.5 11.1~30.9
Qinhuangdao 41.7~53.4 11.0~19.7
Hebei
Tang’gu 11.3~42.7 6.7~51.3
Yangkou 32.0~96.1 10.7~68.4
Shandong
Penglai 62.2~138.7 19.7~194.2
Data source: [50]
There are evidences showing that Bohai Sea has been suffered from heavy metal pollution and anthropogenic
activities have greatly speeded up this environmental problem.
Seafood pollution of heavy metals was becoming serous in Bohai Sea. To carry out human health risk
assessment, it is suggested
[28]
that both seafood consumption rate and tolerable daily intake should be counted in.
Tolerable daily intake is the maximum amount of chemicals that ordinary human body can take in one day. And
level of concern is the quotient of tolerable daily intake divided by daily seafood consumption rate
[28]
, which is the
PNEC in human health risk assessment. Risk quotient is got by dividing measured concentration in seafood to the
level of concern.
RQ=
LOC
MEL(orPEL)
;
LOC=
CR
TDI
Due to lack of consumption rate and measured body level for metals, human risk assessment did not be carry out
in this paper.
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