SpatialVariationsandPotentialRisksofHeavyMetalsin Seawater

Research ArticleSpatial Variations and Potential Risks of Heavy Metals inSeawater Sediments and LivingOrganisms in Jiuzhen Bay China

Xia Sun1 Bao-Shi Li 1 Xuan-Li Liu1 and Cheng-Xuan Li 23

1Marine Ecology Research Center e First Institute of Oceanography Ministry of Natural Resources of ChinaQingdao 266061 China2Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237 China3Key Laboratory of Science and Technology of Marine Ecological Environment e First Institute of OceanographyMinistry of Natural Resources of China Qingdao 266061 China

Correspondence should be addressed to Cheng-Xuan Li cxlifioorgcn

Received 18 October 2019 Revised 23 December 2019 Accepted 9 January 2020 Published 3 February 2020

Guest Editor Yuhe He

Copyright copy 2020 Xia Sun et alis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Coastal waters are polluted by heavymetals to varying degrees posing potential risks to marine ecology and human health InMay2006 the pollution levels sources and ecological risks of heavy metals (Cu Pb Zn Cd Hg and As) in seawater surfacesediments and living organisms were studied in Jiuzhen Bay in Fujian China is study identified Hg (026ndash072 microgL) and As(203ndash315 microgL) pollution in the seawater of Jiuzhen Bay In sediments heavy Pb pollution (946 microgg dw) was only detected at onestation at a level posing very serious potential risk while Hg pollution (0052ndash0087 microgg dw) was observed at three stations at alevel posing serious potential risk No heavy metal pollution was detected in sediments at other stationse concentrations of fiveheavy metals (Cu Zn As Cd and Pb) exceeded the corresponding National Quality Standards for oysters indicating heavypollution based on an ecological risk assessment In clams two heavy metals (Pb and As) exceeded the standards indicating lightpollution based on an ecological risk assessment No heavy metal pollution was found in fish or shrimps e heavy metals in theseawater and sediments of Jiuzhen Bay are mainly derived from the river discharges of Luxi and Wujiang Rivers although sewagedischarge along the coast of Jiuzhen Bay is another source of heavy metal pollution at some stations Given the pollution of Pb Hgand As in seawater and sediments at some stations within the bay the potential risks of Pb Hg and As in living organisms to boththe marine ecology and human health deserve increased attention

1 Introduction

Over the past 40 years because of rapid industrialization andeconomic development in China the problem of soil con-tamination by heavy metals has become increasingly serious[1] with large amounts of these soil pollutants being dis-charged into coastal and estuarine environments by riversand other pathways [2 3] Compared with other pollutantsheavy metals are persistent and have toxic as well as bio-accumulation effects which severely damage marine envi-ronments [4] erefore heavy metal contamination hasattracted much attention and become the focus of globalconcern in recent years Estuaries and coastal regions (suchas bays) are important components of coastal systems

receiving large amounts of heavy metals via riverine input[5ndash7]

Estuaries are zone of complex interaction betweenfluvial and marine ecosystems in which many critical en-vironmental processes including sediment depositionfresh water-salt water interaction delta accretion pollutantretention and material-energy exchanges occur Particu-larly the mixing of continental river water and marine saltwater usually leads to flocculation and accumulationprocesses of heavy metals [8] Although metal-aquochemistry is the main factor affecting the removal andtransformation of heavy metals sediment type also has amajor effect on transport and accumulation of heavymetals erefore the spatial patterns of heavy metals are

HindawiJournal of ChemistryVolume 2020 Article ID 7971294 13 pageshttpsdoiorg10115520207971294

closely related to sediment types [9] e spatial distri-butions of heavy metals are often consistent with those offine-grained sediments [10] Most heavy metals becomepart of the sediment through different biogeochemicalprocesses which trigger precipitation and deposition [11]Heavy metals do not behave conservatively and they arealso affected by changing physicochemical conditions suchas salinity pH and redox conditions [12] When sedi-mentary environments change the heavy metals in thesediment may be released back into the water body throughvarious processes of remobilization producing secondarypollution within the environment [13] erefore marinesediments are considered an important sink of heavymetals especially in coastal areas

Heavy metals in seawater and marine sediments can bedirectly absorbed by organisms and then accumulated andtransformed within their bodies Accumulation may bemagnified via the food chain thereby threatening the marineecosystem and human health [14ndash16] Zhao et al [17] re-ported that some seafood from Xiangshan Bay might posenoncarcinogenic risks to both adults and children Althoughconsumption of most common types of seafood fromXiamen markets does not pose a noncarcinogenic risk sometypes such as yellowfin bream (Sparus latus) oyster and theRed alga (nori Porphyra tenera) could form a carcinogenicrisk [18] e levels of five metals in marine fish and shellfishfrom China are generally low based on published dataHowever some findings suggest that there are health risksfrom exposure to Cd and As in some shellfish [19] Con-sidering the pollution of heavy metals in seawater andsediments in coastal areas the risk of heavy metal pollutionin seafood deserves greater attention

Jiuzhen Bay is located on the southern coast of Fujianbetween Gulei and Liursquoao Peninsulas It is a concavesemienclosed shallow bay forming an estuary Its coastline is4597 km in length with a total embayed area of 6964 km2e entire bay is occupied by an intertidal shoal except forits tidal channel e intertidal area accounts for about 80of the bay area e tidal inlet runs from the bayrsquos mouth tothe Luxi River outlet [20] Jiuzhen Bay has rich marinebiological resources and is an important marine aquaculturebase in Fujian e main aquaculture species are shellfishAlong the coast of Jiuzhen Bay there are multiple industriessuch as wind power generation shipbuilding placer miningseafood processing and shipping In addition the nearbyGulei Port Economic Development Zone is one of the sevenpetrochemical bases in Chinae pollutant discharges fromthese various industrial enterprises may be causing seriousenvironmental impacts on Jiuzhen Bay

Given the environmental and sedimentation charac-teristics of Jiuzhen Bay most of the heavy metals enteringJiuzhen Bay accumulate within the bay To date there hasbeen no research on the distribution and ecological risk ofheavy metals in seawater sediments or seafood of JiuzhenBay e purpose of this study was to (1) determine thecontents and distributions of various heavy metals in sea-water sediments and living organisms within the bay (2)analyze the sources of these heavy metals and (3) evaluatethe degree of heavy metal pollution using the single-factor

pollution index comprehensive index evaluation and po-tential ecological risk index

e data provided here will assist the local governmentto monitor the change in the heavy metal pollution status ofthis area and implement targeted control measures

2 Materials and Methods

21 Sample Collection A total of nine stations were inves-tigated during the survey of May 2006 as shown in Figure 1A GO-FLO water sampler (General Oceanics Inc MiamiFL USA) was used for sample collection Water only withinthe surface layer was collected at stations where waterdepths were less than 5m (A1 B1 and B2) while watersamples from surface (Sur) and bottom (Bot) layers werecollected at stations with water depths of 5ndash20m (B3 C1 C2and E1ndashE3)Water samples were preserved at minus 20degC for lateranalysis Sediment samples were collected using a grabbucket-type bottom sampler sediments from the 0ndash2 cmsurface layer were placed in a polyethylene sealing bag andpreserved at minus 20degC for later analysis

Biological samples were collected by trawling and strictcriteria were used to select adults of local representativebiological species for the study Specimens were preserved atminus 20degC for later analysis

22 Laboratory Analysis Six heavy metalsmdashCu Pb Zn CdHg and Asmdashin seawater sediments and living organismswere analyzed in this study

All water samples were filtered using a hybrid celluloseester Millipore filter which was dipped before filtering inacid e filtrate was acidified to pHlt 2 with HNO3 andstored in a Teflon bottle

Before analysis of the sediment samples they werefreeze-dried All large debris was removed followed bygrinding and sieving Dry sediment samples were dissolvedin an equimolar mixture of HF HNO3 and HClO4 having avolumetric ratio of 3 1 05 and then evaporated to drynesse samples were redissolved with aqua regia and threeparts of this metal solution were diluted with HNO3

Edible parts of living organisms were removed usingbiomedical stainless-steel implements smashed using astamping machine blended and dried in an oven allowingmoisture content to be calculated Dried biological sampleswere digested like sediments

Cu Pb Zn and Cd were analyzed using an Agilent 7500ainductively coupled plasma source mass spectrometer(Agilent Technologies Inc Santa Clara CA USA) while Hgand As were analyzed using an atomic fluorescent pho-tometer AFS200T (Skyray Instrument Inc Stoughton MAUSA)

Total nitrogen (TN) total phosphorus (TP) dissolvedinorganic nitrogen (DIN) dissolved inorganic silicon (DSi)and PO4 were measured using a spectrophotometricmethod while total organic carbon (TOC) redox potential(Eh) and pH were analyzed using K2Cr2O7 oxidation-re-duction volumetric method and potentiometer and acidmeter method respectively DIN is the sum of NO3

minus NO2minus

2 Journal of Chemistry

andNH4+ TN TP DIN DSi and PO4 were analyzed using a

flow injection analyzer (model Lachat-QC8000) Redoxpotential (Eh) and pH were determined using an acid meter(model pHS-3C)

23 Quality Control and Quality Assurance Laboratoryquality assurance and quality control methods were prac-ticed involving standard operating procedures calibrationusing standards and analysis of reagent blanks All sampleswere analyzed in parallel at proportions of 10 Qualitycontrol was ensured by measuring nationally certifiedstandard reference materials (GBW07314 GBW080042GBW080230 GBW080040 and GBW 10050) e differ-ences in the concentrations between the certified andmeasured values were lt5e recoveries of all metals werewithin the range of 85ndash99 e relative measurementerror was less than 10

24 Data Analysis and Evaluation Methods Pearson cor-relation analysis was used to quantify relationships amongheavy metals Data calculation and statistics were performedwith SPSS 170 statistical software (IBM Armonk NY USA)and Microsoft Excel (Microsoft Corp Albuquerque NMUSA) e figures in this paper were drawn with Surfer 8(Scientific Software Group Salt Lake City UT USA)

e single-factor index method was used to evaluateheavy metals in seawater using the formula below

Pi Ci times Sij (1)

where Pi is the heavy metal pollution index Ci is the con-centration value of a given heavy metal and Sij is thestandard value of a given heavymetale Type I Standard ofthe National Seawater Quality Standard (China) was used to

obtain standard values of heavy metals in seawater yieldingvalues for Cu (5 μgL) Zn (20 μgL) As (20 μgL) Cd (1 μgL) Hg (005 μgL) and Pb (1 μgL)

Biotoxicity or biological risks of heavy metals in sedi-ments were evaluated using the potential ecological riskindex proposed by the Swedish scholar Hakanson [21] usingthe formula below

Eir T

ir times C

ir T

ir times

Ci

Cin

RI 1113944n

i1E

ir

(2)

where Tri is the toxicity response coefficient of a heavy metaland those of Hg Cd As Cu Pb and Zn are respectively setas 40 30 10 5 5 and 1 [22 23] Ci

r is the pollution index of agiven heavy metal also called its enrichment coefficient Ci isthe measured concentration of the given heavy metal insediments Ci

n is the background value of the given heavymetal Ei

r is the potential ecological risk index of the givenheavymetal and RI is the total potential ecological risk indexrelated to multiple heavy metals e degrees of ecologicalrisk corresponding to Ei

r and RI values are given in Table 1e single-factor evaluation method and comprehensive

index evaluation method were combined to evaluate heavymetals in living organisms In this case the National QualityStandard was a bivalve referred to as the Type I Standard inMarine Biological Quality (China) (GB18421-2001) Stan-dard values for crustacea and fish are taken from previouslydetermined values from monitoring and evaluation of heavymetal pollution elements in offshore areas [24]

e formula for the comprehensive index evaluationmethod is given below

Pij

maxPi( 11138572

+ avePi( 11138572

2

1113971

(3)

where Pij is the comprehensive quality index Pi is the single-factor pollution index maxPi is the maximum value of thesingle-factor pollution index for a given living organism andavePi is the average value of the single-factor pollution indexof a given living organism

e degree of heavy metal pollution in marine livingorganisms that correspond to values obtained from thecomprehensive index method are given in Table 2

In this paper the bioconcentration factors (BCFs) andbiota-sediment accumulation factors (BSAFs) were calcu-lated to analyze the bioaccumulation of heavy metals fromseawater and sediments in living organisms e BCFs in-dicate the status of organisms enriched in heavy metals fromthe surrounding waters while the BSAFs evaluate theequilibrium relationship of heavy metal contents in benthicorganisms and sediments ie the indirect absorption ofheavy metals by benthic organisms from their living envi-ronments [25 26]

e calculations are defined as follows

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B2 B3

C1C2E1

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degE

degN

GuleiEconomic

DevelopmentZone

Port

Gulei P

enins

ula

Luxi

Wujiang

Jiuzhen Bay

Liursquoao

Penin

sula

Figure 1 Location of the Jiuzhen Bay study area and all samplingstations

Journal of Chemistry 3

BCF Cx

Csw

BSAF Cx

Cs

(4)

where Cx and Csw are the mean concentrations of a givenmetal in the organism and in seawater respectively while Csis the mean concentration of the metal in the sediment

3 Results and Discussion

31 Distribution Characteristics and Evaluation of HeavyMetal Pollution in Seawater

311 Distribution Characteristics of Heavy Metals inSeawater Heavy metal contents in seawater were measuredin samples from all stations within Jiuzhen Bay as shown inTable 3 Analysis of their vertical distributions show that theaverage values of heavy metalsmdashCd and Pbmdashin seawaterfrom the surface layer were higher than those in the bottomlayer while other heavy metal contents (Cu Zn As and Hg)in the surface layer were lower than those in the bottomlayer Zn concentrations in the bottom layer were twice thosein the surface layer

e overall horizontal distribution characteristics wereas followse distribution of heavy metals (Cu As and Hg)in the surface and bottom seawater layers were relatively

consistent both layers showing a decrease from the outer toinner parts of the bay with highest values within the bayrsquosmouth and outer areas ere was a distinct difference in thedistribution of Pb in the surface and bottom seawater layersAn area having a low Pb content occurred on the inner sideof the mouth e Pb content gradually increased in sur-rounding areas resulting in a high value at station B1 on thewest side of the bay In the bottom seawater layer high levelsof Pb were detected at stations B3 and C2 while Pb graduallydecreased from east to west An overall decrease from thebayrsquos mouth to outer areas was observed for Cd in both thesurface and bottom seawater layers with the highest valueswithin the mouth area e distribution of Zn varied greatlyin the surface and bottom seawater layers Although Zndisplayed a consistent trend like those of Cu As and Hg insurface seawater its concentration at station C2 in thebottom seawater layer was 123 microgL which was seven timesthat of surrounding stations Distributions of all six heavymetals within Jiuzhen Bay are shown in Figure 2

e contents of heavymetals in seawater measured in thepresent study were compared with historical data andstudies of other regions in China (Table 4) In comparisonwith historical data [20] the contents of Cu and Cd haveincreased markedly Except for the much higher contents ofHg and As the heavy metal contents determined in thepresent study were basically consistent with those of thesouthern Gulf of China [13 17 27ndash29] is comparisonindicates that heavy metal content of the seawater ofJiaozhou Bay was the highest among all documented bays[30]

312 Main Factors Affecting Dissolved Heavy Metal Dis-tributions in Seawater According to the correlation analysisbetween the heavy metals in seawater and environmentalfactors (Table 5) significant correlations were determinedbetween heavy metals (As Hg and Cu) and environmentalfactors (PO4 Si and DIN) (Rgt 0605 Plt 005 N 15)indicating certain similar sources of the substances In factthe sources of heavy metals (As Hg and Cu) in seawater areindeed similar to those of PO4 Si and DIN mainly beingriver water and domestic and industrial wastewater along thecoast of Jiuzhen Bay e distribution trend of heavy metals(As Hg and Cu) increased gradually from the mouth of thebay out to sea e higher concentrations at the mouth wereresults from the changes in environmental factors such assalinity and redox factors Specifically the heavy metalsadsorbed by suspended particles in the river water dissolvedout resulting in high contents of As Hg and Cu in theseawater at the mouth is is consistent with the conclu-sions of Zhang et al [31] in which study it was proposed thatthe content of heavy metals in the downstream of the YellowRiver was lower than that at the estuary and the content ofdissolved heavy metals was closely related to the adsorptionand desorption of heavy metals in suspended particles

In the seawater of bays and estuaries heavy metalcontent is affected by changes in environmental factors suchas salinity hydrodynamics pH redox and biological effects[32 33] e investigation sea area is located at the mouth of

Table 1 Degrees of potential risks corresponding to various valuesof the potential risk index (Eri) and total potential ecological riskindex (RI)

Range of potentialecological risk indexEi

r of a single heavymetal

Range of total potentialcomprehensive

ecological risk index RI

Degree ofpotential

ecological risk

Eir lt 40 RIlt 150 Low potential

ecological risk

40leEir lt 80 150leRIlt 300

Moderatepotential

ecological risk

80leEir lt160 300ltRIlt 600

Relativelysevere potentialecological risk

160leEir lt 20 RIge 600 Severe potential

ecological risk

Erige 320 mdashVery heavypotential

ecological risk

Table 2 Grades for the comprehensive quality index (Pij) evalu-ation of heavy metals in marine living organisms

Grade Comprehensive quality index Pij Pollution degreeGrade I Pijgt 3 Heavy pollutionGrade II 2ltPijle 3 Medium pollutionGrade III 1ltPijle 2 Light pollutionGrade IV Pijle 1 No pollution


Jiuzhen bay which is the mixing region of river water andseawater erefore the environmental factors vary signif-icantly posing different degrees of impact on different heavymetals which is the main reason for the poor correlationbetween heavy metals and environmental factors

e maximum value of Pb content in surface seawaterwas located at station B1 of shallow water which is con-sistent with the location of the high-value zone in thesediment indicating that the concentration of Pb in seawaterat station B1 was affected by the content of sediment Uponchanges of environmental conditions the equilibrium be-tween the overlying water and the sediment is brokenresulting in the migration of heavy metal pollutants from thesediment to the water body [12] e high value area of Pb inbottom seawater was at the east side of the tidal channel iethe Liursquoao Peninsula and the Liursquoao Port e population onthe Liursquoao Peninsula is mainly concentrated in Liursquoao TownLarge amount of sewage discharge from human domesticand industrial activities to the Jiuzhen Bay resulted in thehigh Pb content on the east side of the tidal channel emaximum concentration of Zn detected at the C2 station inbottom seawater was also caused by the discharge of do-mestic and industrial sewage from Liursquoao Town

e heavy metals in the seawater of the investigation areaaremainly originated from thewater of Luxi andWujiangRiveras well as the domestic and industrial wastewater along the coastof the Jiuzhen Bay Moreover the dissolution of heavy metalsfrom sediments is another source of heavy metals in seawater

313 Evaluation of Heavy Metal Pollution in SeawaterValues of the single-factor pollution indices of various heavymetals at each station are given in Table 6 and their re-spective ranges were Cu (067ndash127) Zn (045ndash613) As(102ndash158) Cd (024ndash050) Hg (529ndash1433) and Pb(025ndash054) Typically the single-factor pollution indices forboth Hg and As in Jiuzhen Bay were greater than 1 indi-cating that both metals exceeded the Type I National Sea-water Quality Standard at all stations Cu and Zn exceededthe type I standard at some stations at rates of 33 and 13respectively Neither Cd or Pb exceeded the type I thresholdAccording to average values of single-factor pollution in-dices for heavy metals their pollution degree wasHggtAsgtZngtCugt PbgtCd

32 Distribution Characteristics and Evaluation of HeavyMetal Pollution in Sediments

321 Distribution Characteristics of Heavy Metals inSediments Average heavy metal contents of sediments

within Jiuzhen Bay are given in Table 7 Pb had highestvalues in sediments along the northern coast and in thenorthwest part of the mouth of the bay they progressivelydeclined eastward A high value area of all five heavy metals(Cu Zn Cd Hg and As) occurred on the northeast side ofJiuzhen Bay Heavy metal distributions in sediments areshown in Figure 3

e heavy metal contents in sediments measured in thispresent study were compared with historical data andstudies of other regions (Table 8) Compared with historicaldata [20] Pb contents have increased markedly while otherheavy metal contents have remained unchanged In thispaper the heavy metal contents in sediments were lowerthan those of other marine areas and bays in China[10 17 28 36 37] except for Pb content which was muchhigher than in all other locations

322 Main Factors Affecting Heavy Metal Distributions inSediments According to our correlation analysis of heavymetals and environmental factors in the sediments (Table 9)a significant positive correlation was determined for Cu ZnCd Hg and As (Rgt 0737 Plt 005 N 9) is suggeststhese metals have the same mode of accumulation in surfacesediments of Jiuzhen Bay e main source of these heavymetals was land-based pollution Regarding the effect ofenvironmental factors the correlation coefficients for totalorganic carbon (TOC) TP total nitrogen (TN) and redoxpotential (Eh) with Cu Zn Cd Hg and As were all relativelyhigh showing strong correlations e reproduction ofplankton removes nutrients from fresh water inputsforming a large amount of organic suspended matter justlike the natural large-scale ecological beds resulting fromsewage treatment in Jiuzhen Bay [38] e heavy metalscombine with organic matter and remain suspended inwater mixing zones water before being precipitated ismay be the cause for the high value areas of all five heavymetals (Cu Zn Cd Hg and As) on both sides of the tidalchannel as well as the higher contents of heavy metals insediments within the mouth area compared with furtheroffshore

Based on a comparison of historical background values[20] the values of Pb in sediments were far higher than thoseof other heavy metals In terms of their distributions thecorrelations of Pb with other heavy metal elements werenonsignificant For example the Pb content at station B1 wastens of times more than those at other stations with seriouspollution indicating that increasing Pb content was relatedto pollution discharge from land areas on the west side of thebay

Table 3 Heavy metal contents in seawater layers of Jiuzhen Bay (μgL)

Heavy metal type Total average value (range) Average value at the surface layer (range) Average value at the bottom layer (range)Cu 482 (337sim633) 474 (337sim588) 494 (405sim633)Zn 220 (89sim123) 167 (115sim292) 301 (89sim123)As 270 (203sim315) 263 (203sim298) 279 (250sim315)Cd 034 (024sim050) 034 (024sim050) 032 (029sim035)Hg 046 (026sim072) 044 (026sim072) 050 (039sim067)Pb 037 (025sim054) 037 (025sim045) 036 (025sim054)


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Figure 2 Continued


e contents of Hg and As in the sediments at Futou Bayare higher than those at Jiuzhen Bay [36] related to thepolluted discharge from Gulei Peninsula Evaluation of the

seawater and sediments in Jiuzhen Bay shows that Hgpollution was heavier than other heavy metals suggestingthat Futou Bay may be another source of Hg

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034

03

03

(g)

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033031

(h)

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(i)

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032

(k)

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03 05

0504

(l)

Figure 2 Distributions (surface layer left panels bottom layer right panels) of various heavy metals in the seawater of Jiuzhen Bay (μgL)(a) Cu Sur (b) Cu Bot (c) Zn Sur (d) Zn Bot (e) As Sur (f ) As bot (g) Cd Sur (h) Cd Bot (i) Hg Sur (j) Hg Bot (k) Pb Sur (l) Pb Bot


323 Ecological Risk Evaluation of Heavy Metal Pollution inSediments Evaluation results of potential ecological risks ofheavy metals in sediments in the surface layer of Jiuzhen Bayare shown in Table 10 Ranges of the ecological risk index(Eri) for each heavy metal were Cu (054ndash1066) Zn(017ndash243) As (244ndash591) Cd (3ndash2597) Hg (58ndash1395)and Pb (63ndash5267) respectively e Eri values of Cu Zn Asand Cd in sediments were less than 40 at all stations rep-resenting a low degree of potential ecological risk In con-trast the maximum Ei

r value for Pb in sediments was 5267(station B1) which indicates a very serious potential

ecological risk e Eir values of Pb at all other stations were

less than 40 representing a low degree of potential ecologicalrisk e Ei

r values of Hg at three stationsmdashA1 B3 andC2mdashwere 838ndash1395 indicating a relatively high degree ofpotential ecological risk However the Ei

r values of Hg at allother stations were less than 40 representing a low degree ofpotential ecological risk at other sites According to theaverage Ei

r values of heavy metals potential ecological risksrelated to single heavy metals were ranked PbgtHggtCdgtCugtAsgtZn

e overall range of the potential ecological risk index(RI) was 189ndash5561 in the study area with a maximum valueof 5561 at station B1 indicating a relatively serious potentialecological risk e RI values of stations A1 and B3 were2224 and 1667 respectively indicating a moderate po-tential ecological riske RI values of all other stations wereless than 150 representing low to moderate potential eco-logical risks According to average RI values of all stationspotential ecological risks linked to sediments at each stationwere ranked B1gtA1gtB3gtC2gtB2gtC1gtE1gtE3gtE2

Table 7 Heavymetal contents and background values in sedimentsof Jiuzhen Bay (microgg dw)

Heavy metaltype

Average value(range)

Backgroundvalue Reference

Cu 86 (11ndash21) 98

[20]Zn 57 (9ndash134) 55Cd 0062 (0016ndash0139) 0056Pb 136 (11ndash946) 9As 63 (37ndash89) 15 [34]Hg 0028 (0004ndash0087) 0025 [35]

Table 6 Single-factor pollution indices for heavy metals in sea-water at all stations of Jiuzhen Bay

Station Layer Cu Zn As Cd Hg PbA1 Sur 067 082 102 038 529 042B1 Sur 087 093 127 036 752 045B2 Sur 084 057 118 024 543 025B2 Bot 081 054 125 035 901 029B3 Sur 091 065 141 032 759 040B3 Bot 094 045 135 032 771 054C1 Sur 094 065 122 036 943 029C1 Bot 102 079 143 035 1331 027C2 Sur 100 079 145 029 616 041C2 Bot 097 613 126 034 1195 053E1 Sur 094 065 137 037 1433 038E2 Sur 118 098 149 050 1007 043E2 Bot 092 047 152 030 901 025E3 Sur 117 146 144 029 1383 034E3 Bot 127 066 158 029 854 028Total average 096 110 135 034 928 037

Table 5 Matrix chart of correlation coefficients among the heavy metals in the seawater

As Hg Cu Pb Cd Zn PO4 DSi DINAs 1Hg 0364 1Cu 0812a 0464 1Pb minus 0176 minus 0040 minus 0080 1Cd minus 0045 0218 0059 0324 1Zn minus 0153 0315 0076 0485 0033 1PO4 minus 0755a minus 0734a minus 0605b 0078 minus 0129 minus 0108 1Si minus 0834a minus 0634b minus 0689a 0024 0080 minus 0187 0918a 1DIN minus 0813a minus 0667a minus 0665a minus 0004 0016 minus 0194 0943a 0985a 1aCorrelation is significant at the 001 level bCorrelation is significant at the 005 level

Table 4 Concentrations of heavy metals in seawater (microgl) in the present study compared to published data for other locations in China

Region Cu Pb Zn Cd Hg As ReferenceDongshan Bay China 121 166 111 0032 mdash mdash [13]Xiangshan Bay China 45 223 168 014 0061 26 [17]East of Qinzhou Bay China 063 mdash 84 428 00205 0845 [27]Maowei Sea China 56 27 484 038 0068 042 [28]Bihe Bay China 276 0655 1314 0088 0036 057 [29]Jiaozhou Bay China 210802 7574 8528 293 155 5261 [30]Data of history 040 033 0028 [20]Study area 482 037 220 034 046 270


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(e)

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65

(f )

Figure 3 Distributions of various heavy metals in sediments of Jiuzhen Bay (microgg dw) (a) Cu (b) Zn (c) Cd (d) Hg (e) Pb (f ) As


33 Heavy Metal Contents in Living Organisms and eirAssociated Ecological Risks

331 Heavy Metal Content Characteristics in LivingOrganisms Average heavy metal contents of representativeliving organisms from the study area are shown in Table 11Cu Zn and Cd contents were highly variable in differentkinds of living organisms Average Cu and Cd contents inoysters were 7319 μgg ww and 0748 μgg ww respectivelythese values were much higher than those in fish (023 μggww and 0001 μgg ww) e Zn content was highest inoysters (234 μgg ww) followed by those in shrimps(2561 μgg ww) and fish (547 μgg ww) e content of Hgwas highest in fish (0043 μgg ww) and lowest in clams(0008 μgg ww) e contents of Pb and As were highest inoysters with average values of 0361 μgg ww and 314 μggww respectively e lowest contents of Pb and As weredetected in shrimps with average values of 0008 μgg wwand 116 μgg ww respectively

Enrichment degrees of most heavy metals in shellfishwere higher than those in fish as reported by many previousresearchers [29 39 40] In this study the contents of fiveheavy metals (Cu Zn As Cd and Pb) in oysters were higherthan those in all other living organisms Two heavy metals(Cu and Zn) had high contents in shrimps but these rankedsecond to their contents in oysters e Hg contents in fishwere higher than those in other living organisms

332 Ecological Risk Evaluation of Heavy Metal Pollution inLiving Organisms Evaluation results of the single-factorpollution index (Pi) and comprehensive pollution index (Pij)

of heavy metals in living organisms are shown in Table 12e evaluation index (Pi) ranges of various heavy metalswere Cu (001ndash732) Zn (014ndash1170) As (015ndash314) Cd(0ndash374) Hg (008ndash050) and Pb (003ndash361) e single-factor pollution index of heavy metals varied significantly indifferent species of living organisms Although the heavymetal contents in fish and shrimps were all below the Na-tional Quality Standards those in mollusks greatly exceededthe standards Pb and As contents in clams were above thethreshold values of their standards while all heavy metals(except Hg) in oysters exceeded the standards e rankingof the pollution indices of heavy metals in oysters wasZngtCugtCdgtPbgtAsgtHg

e comprehensive pollution index (Pij) of heavy metalsin living organisms ranged from 013 to 900 Oysters dis-played the highest comprehensive pollution index beingclassified as heavily polluted is was followed by clamswhich were classified as lightly polluted Heavy metalcontents of fish and shrimps were not considered polluted

333 Analysis of Enrichment of Different Heavy Metals inLiving Organisms According to the BCF and BSAF values ofvarious organisms (Table 13) the rankings of enrichmentcoefficients of different heavy metals in seawater accordingto species were oysters CugtZngtCdgtPbgtAsgtHg clamsPbgtZngtCugtCdgtAsgtHg fish PbgtZngtHggtAsgtCugtCd and shrimps CugtZngtPbgtAsgtHggtCd Likewise therankings of enrichment coefficients of different heavy metalsin the sediments according to species were oystersCdgtCugtZngtHggtAsgt Pb clams CdgtAsgtHggtZngtCugtPb fish HggtAsgtZngtCugtCdgtPb and shrimps

Table 8 Concentrations of heavy metals in sediments (microgg dw) in the present study compared to published data from other locations inChina

Region Cu Pb Zn Cd Hg As ReferenceChangjiang Subaqueous Delta 2679 2655 9434 009 [10]Zhejiang-Fujian coastal 3398 3769 12926 008Xiangshan Bay China 368 385 1208 015 0106 1231 [17]Maowei Sea China 3037 3210 10884 032 007 1373 [28]Futou Bay China 354 142 258 0079 61 [36]Liaodong Bay China 1966 2264 702 022 0056 928 [37]Data of history 98 9 55 0056 [20]Jiuzhen Bay China 86 136 57 0062 0028 63 is study

Table 9 Matrix of correlation coefficients among heavy metals and environmental factors in sediments of Jiuzhen Bay

Hg Cu Pb Zn Cd As TOC TP TN EhHg 1Cu 0970a 1Pb minus 0151 minus 0158 1Zn 0978a 0983a minus 0129 1Cd 0971a 0988a minus 0155 0982a 1As 0737b 0850a 0155 0828a 0819a 1TOC 0883a 0921a minus 0163 0909a 0941a 0814a 1TP 0944a 0980a minus 0160 0945a 0957a 0811a 0839a 1TN 0924a 0966a minus 0063 0936a 0937a 0851a 0804a 0990a 1Eh minus 0877a minus 0914a 0171 minus 0944a minus 0923a minus 0858a minus 0858a minus 0863a minus 0874a 1aCorrelation is significant at the 001 level bCorrelation is significant at the 005 level TOC total organic carbon TN total nitrogen TP total phosphorus Ehredox potential


CugtHggtZngtAsgtCdgtPb e ranking of heavy metalcontents in living organisms was not consistent with that ofseawater or sediments is indicates that at low concen-trations the enrichment of heavy metals is not only relatedto the concentrations of heavy metals in seawater andsediments but also to many other factors

In oysters clams and shrimps the enrichment coeffi-cients of Cu Zn Cd and Pb were higher than those of Asand Hg is is because Cu and Zn are essential elements oflife thus they are actively absorbed by living organismserefore the ability of marine organisms to be enriched inCu and Zn was much higher than for nonessential metalelements [41] Notably the excretion of Pb and Cd is very

slow in most organisms Because shellfish are filter feedersand both Pb and Cd complexes in suspension and in thesediments were ingested by and enriched in shellfish [42]accounting for the high enrichment coefficients of Pb and Cdin oysters clams and shrimps

According to Table 13 the enrichment coefficient of Hgwas higher in fish than in shellfish is is caused by thehigher capacity of fish to absorb Hg through water and foodintake as well as physiological mechanisms that produce Hgenrichment within their bodies [43]

Studies have suggested that an enrichment coefficientgreater than 1000 indicates a potential cumulative problem[25] In the present study an enrichment coefficient greater

Table 12 Values of the pollution index (Pi) and comprehensive pollution index (Pij) for single-factor heavy metal pollution in various livingorganisms

Living organism PCu PZn PAs PCd PHg PPb AvePi PijOyster 732 1170 314 374 050 361 500 900Clam 015 054 241 016 016 189 088 182Fish 001 014 048 mdash 014 005 014 035Shrimp 008 017 015 mdash 008 003 008 013Average value 189 314 154 097 022 140 153 282

Table 13 Bioconcentration factors (BCFs) and biota-sediment accumulation factors (BSAFs) of various living organisms

Factor Living organism Cu Zn As Cd Hg Pb

BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054

Table 11 Heavy metal contents in various living organisms in Jiuzhen Bay (μgg ww)

Living organism Cu Zn As Cd Hg Pb ReferenceOyster 7319 234 314 0748 0025 0361

Investigation data in this paperClam 149 1077 241 0031 0008 0189Shrimp 766 2561 116 0005 0015 0063Fish 023 547 240 0001 0043 0097Bivalve mollusk 10 01 10 02 005 01 Marine biological quality (China) (GB18421-2001)Shellfish 100 20 80 20 020 20 [24]Fish 20 20 50 06 030 20

Table 10 e ecological risk index (Eir) and potential ecological risk index (RI) values for different heavy metals in sediments at all stations

within Jiuzhen Bay

Station ECu EZn EAs ECd EHg EPb RIA1 1066 243 473 2597 1395 391 2224B1 184 061 448 619 163 5267 5561B2 477 119 469 1341 394 189 823B3 961 201 591 2428 915 334 1667C1 120 040 361 422 102 119 316C2 923 171 544 1922 838 274 1468E1 116 064 339 375 93 94 276E2 068 017 300 300 58 63 189E3 054 024 244 553 61 66 215Average 441 104 419 1173 447 755 1415


than 1000 was found for Cu Zn and Cd in oysters and Cuand Zn in shrimps indicating serious accumulation of CuZn and Cd by oysters and shrimps in Jiuzhen Bay Althoughthe enrichment coefficients of Pb Hg and As were lowerthan 1000 the pollution levels of Pb Hg and As in seawaterand sediments were relatively high erefore the ecologicaland human health risks related to Pb Hg and As in themarine organisms of Jiuzhen Bay cannot be neglected

4 Conclusions

is study reported the contents distributions pollutionlevels and ecological risks of heavy metals (Cu Pb Zn CdHg and As) in seawater sediments and living organisms ofJiuzhen Bay e seawater was mainly polluted by Hg andAs while heavy Pb and Hg pollution was detected in sed-iments at a few stations e main sources of heavy metalpollution in the marine environments of Jiuzhen Bay arefrom surface runoff carried by the Luxi and Wujiang Riversand coastal discharges from local industriese enrichmentcoefficients of Cu Zn and Cd were high in oysters andclams According to the comprehensive pollution indexvalues the heavy metal pollution in oysters and clams wasclassified as heavy and light pollution respectively eheavy metal contents in fish and shrimps did not reachpolluted levels Given the pollution of Pb Hg and As inseawater and sediments at some stations within Jiuzhen Baythe potential risks of Pb Hg and As in living organisms toboth the local ecology and human health deserve increasedattention To ensure the safety of aquaculture products inJiuzhen Bay the sources of heavy metal pollution should bestrictly controlled and the polluted areas should be treatedto restore their ecological functions

Data Availability

No data were used to support this study

Disclosure

Xia Sun and Bao-Shi Li are the co-first authors

Conflicts of Interest

e authors declare that they have no conflicts of interest

Authorsrsquo Contributions

Xia Sun and Bao-Shi Li contributed equally

Acknowledgments

is work was financially supported by the National NaturalScience Foundation of China (Grant no 41676074) theNational Key Research and Development Program of China(no 2018YFC140707600) and the Basic Scientific Fund forthe National Public Research Institutes of China (Grant no2016Q04)

References

[1] P Zhang C J Jin Z F Sun G H Huang and Z L SheldquoAssessment of acid enhancement schemes for electrokineticremediation of CdPb contaminated soilrdquoWater Air and SoilPollution vol 227 no 6 p 217 2016

[2] G Hu S P Bi G Xu Y Zhang X Mei and A C LildquoDistribution and assessment of heavy metals off theChangjiang River mouth and adjacent area during the pastcentury and the relationship of the heavy metals with an-thropogenic activityrdquoMarine Pollution Bulletin vol 96 no 1-2 pp 434ndash440 2015

[3] J Lu A Li and P Huang ldquoDistribution sources and con-tamination assessment of heavymetals in surface sediments ofthe South Yellow Sea and northern part of the East China SeardquoMarine Pollution Bulletin vol 124 no 1 pp 470ndash479 2017

[4] L Zhang Z Shi J Zhang Z Jiang F Wang and X HuangldquoSpatial and seasonal characteristics of dissolved heavy metalsin the east and west Guangdong coastal waters South ChinardquoMarine Pollution Bulletin vol 95 no 1 pp 419ndash426 2015

[5] S Yin Y Wu W Xu Y Li Z Shen and C Feng ldquoCon-tribution of the upper river the estuarine region and theadjacent sea to the heavy metal pollution in the YangtzeEstuaryrdquo Chemosphere vol 155 pp 564ndash572 2016

[6] Q Rao Z Sun L Tian J Li W Sun and W Sun ldquoAs-sessment of arsenic and heavy metal pollution and ecologicalrisk in inshore sediments of the Yellow River Estuary ChinardquoStochastic Environmental Research and Risk Assessmentvol 32 no 10 pp 2889ndash2902 2018

[7] Q Cao H Wang Y Li et al ldquoe national distributionpattern and factors affecting heavy metals in sediments ofwater systems in Chinardquo Soil and Sediment ContaminationAn International Journal vol 27 no 2 pp 79ndash97 2018

[8] Z Sun J Li T He et al ldquoSpatial variation and toxicity as-sessment for heavy metals in sediments of intertidal zone in atypical subtropical estuary (Min River) of Chinardquo Environ-mental Science and Pollution Research vol 24 no 29pp 23080ndash23095 2017

[9] J Liang J Liu G Xu and B Chen ldquoDistribution andtransport of heavy metals in surface sediments of the Zhejiangnearshore area East China Sea sedimentary environmentaleffectsrdquoMarine Pollution Bulletin vol 146 pp 542ndash551 2019

[10] C Wang X Zou Z Feng Z Hao and J Gao ldquoDistributionand transport of heavy metals in estuarine-inner shelf regionsof the East China Seardquo Science of the Total Environmentvol 644 pp 298ndash305 2018

[11] Y-M Chen J-b Gao Y-Q Yuan J Ma and S Yu ldquoRe-lationship between heavy metal contents and clay mineralproperties in surface sediments implications for metal pol-lution assessmentrdquo Continental Shelf Research vol 124pp 125ndash133 2016

[12] Y N Zhang Q He J M Chen C Lin and W D Ji ldquoHeavymetals process in water and pollution risk assessment insurface sediments of the ZhuJiang river estuaryrdquo Acta Oce-anologica Sinica vol 35 no 2 pp 178ndash186 2013 in Chinese

[13] M F Yang S H Zheng Y Y Xi and S L Zhong ldquoehorizontal distribution and affecting factors of dissolvedheavy metals in seawater of DongShan bay fujian Province ofChinardquo Journal of Marine Sciences vol 34 no 2 pp 75ndash822016

[14] M M Mazrouh and M H Mourad ldquoBiochemical compo-sition and bioaccumulation of heavy metals in some seafoodin the mediterranean coast of Egyptrdquo Egyptian Journal ofAquatic Biology and Fisheries vol 23 no 1 pp 381ndash390 2019


[15] M K Ahmed M A Baki M S Islam et al ldquoHuman healthrisk assessment of heavy metals in tropical fish and shellfishcollected from the river Buriganga Bangladeshrdquo Environ-mental Science and Pollution Research vol 22 no 20pp 15880ndash15890 2015

[16] S Satapathy and C R Panda ldquoToxic metal ion in seafoodmeta-analysis of human carcinogenic and non-carcinogenicthreat assessment a geomedical study fromDhamra and PuriOdishardquo Human and Ecological Risk Assessment An Inter-national Journal vol 23 no 4 pp 864ndash878 2017

[17] B Zhao X Wang H Jin et al ldquoSpatiotemporal variation andpotential risks of seven heavy metals in seawater sedimentand seafood in Xiangshan Bay China (2011-2016)rdquo Che-mosphere vol 212 pp 1163ndash1171 2018

[18] R Zhao S Yan M Liu et al ldquoSeafood consumption amongChinese coastal residents and health risk assessment of heavymetals in seafoodrdquo Environmental Science and PollutionResearch vol 23 no 16 pp 16834ndash16844 2016

[19] J L Cheng Y N Ma T T Liu and Q Zhuo ldquoAccumulationand health risks of heavy metals in the seafood from ChinardquoJournal of Hygiene Research vol 46 no 1 pp 148ndash154 2017

[20] F Chen Gulf Chronicles of China-Eighth Fascicle ChinaOcean Press Beijing China 1993

[21] L Hakanson ldquoAn ecological risk index for aquatic pollutioncontrola sedimentological approachrdquo Water Researchvol 14 no 8 pp 975ndash1001 1980

[22] W X Liu Z K Luan and H X Tang ldquoEnvironmental as-sessment on heavy metal pollution in the sediments of le anriver with potential ecological risk indexrdquo Acta EcologicaSinica vol 19 no 2 pp 206ndash211 1999

[23] N X Zhang C H Cao R Z Ren et al ldquoHeavy metals in thesurface sediment of the dumping ground outside Jiaozhou bayand their potential ecological riskrdquo Environmental Sciencevol 32 no 5 pp 1315ndash1320 2011

[24] W D Ji Monitoring and Evaluation Methods of Heavy MetalPollution Elements in Offshore pp 196-197 China OceanPress Beijing China 2015

[25] N Sun W X Huang and H B Yu ldquoAnalysis and assessmentof heavy metals accumulation feature of sediments and ma-rine organisms from Zhanjiang Harborrdquo Marine Environ-mental Science vol 34 no 5 pp 669ndash672 2015

[26] M Soto-Jimenez F Paez-Osuna and F Morales-HernandezldquoSelected trace metals in oysters (Crassostrea iridescens) andsediments from the discharge zone of the submarine sewageoutfall in Mazatlan Bay (southeast Gulf of California)chemical fractions and bioaccumulation factorsrdquo Environ-mental Pollution vol 114 no 3 pp 357ndash370 2001

[27] Y H Xu R Q Liao J Su and L B Gong ldquoe content andpollution evaluation of six heavy metals in surface water andplankton in the eastern area of Qinzhou bayrdquo Oceanologia etLimnologia Sinica vol 48 no 5 pp 960ndash969 2017

[28] S X LI S q Wei J L Lin and D B Wang ldquoPollutionevaluation of heavy metals in sea water and surface sedimentsin maowei seardquo Journal of Jianghan University (NaturalScience Edition) vol 43 no 5 pp 471ndash476 2015

[29] Z Zeng C L Chen S Ke Z K Zhao and Q Xie ldquoecharacteristic and evaluation of heavy metal pollution inseawater and organisms of the Bohe BayrdquoOcean DevelopmentAnd Management vol 8 pp 24ndash28 2019

[30] T T Li L Wei Y L Lv et al ldquoOn distribution and pollutionof heavy metals in water environment of Jiaozhou bay inYellow seardquo Journal of Southwest China Normal University(Natural Science Edition) vol 41 no 6 pp 60ndash66 2016

[31] X L Zhang H T Chen Q Z Yao and X X Zhang ldquoeseasonal changes and flux of trace elements in the lowerreaches of Yellow Riverrdquo Periodical of Ocean University ofChina vol 43 no 8 pp 69ndash75 2013

[32] Y Che Q He and W-Q Lin ldquoe distributions of partic-ulate heavy metals and its indication to the transfer of sed-iments in the Changjiang Estuary and Hangzhou Bay ChinardquoMarine Pollution Bulletin vol 46 no 1 pp 123ndash131 2003

[33] R P Gambrell J B Wiesepape W H Patrick Jr andM C Duff ldquoe effects of pH redox and salinity on metalrelease from a contaminated sedimentrdquo Water Air and SoilPollution vol 57-58 no 1 pp 359ndash367 1991

[34] L X Zhang S Ren and J Cai ldquoEnrichment of heavymetals inthe surface sediments from the three regions of randomdumping in east China sea and assessment of their potentialecological riskrdquo Marine Science Bulletin vol 24 no 2pp 92ndash96 2005

[35] F X Guo S H Lv D Q Teng T Jiang and Z P JiaoldquoDistribution patterns and evaluation on potential ecologicalrisk of heavy metals in surface sediments of the Yellow seardquoJournal of Anhui Agricultural Sciences vol 39 no 15pp 9212ndash9216 2011

[36] S T Chen W L Wang and Q S Li ldquoAssessment of en-vironmental quality in seawater and sediment of Futou bayfujiardquo Environment and Sustainable Development vol 3pp 156ndash158 2017

[37] J Wang S Y Ye E A Laws H M Yuan X G Ding andG M Zhao ldquoSurface sediment properties and heavy metalpollution assessment in the Shallow Sea Wetland of theLiaodong Bay Chinardquo Marine Pollution Bulletin vol 120no 1-2 pp 347ndash354 2017

[38] P Zhang G Huang C An et al ldquoAn integrated gravity-driven ecological bed for wastewater treatment in subtropicalregions Process design performance analysis and green-house gas emissions assessmentrdquo Journal of Cleaner Pro-duction vol 212 pp 1143ndash1153 2019

[39] P Bustamante F Caurant S W Fowler and P MiramandldquoCephalopods as a vector for the transfer of cadmium to topmarine predators in the north-east Atlantic oceanrdquo Science ofthe Total Environment vol 220 no 1 pp 71ndash80 1998

[40] M Cheggour A Chafik N S Fisher and S BenbrahimldquoMetal concentrations in sediments and clams in fourMoroccan estuariesrdquoMarine Environmental Research vol 59no 2 pp 119ndash137 2005

[41] X J Zhang S Zhao C H Feng and H R Wang ldquoDistri-bution and accumulation factors of heavy metals in organismsin southern Bohai Bayrdquo Journal of Dalian Ocean Universityvol 29 no 3 pp 267ndash271 2014

[42] W P Sun J M Pan X Y Liu Y X Huang andM H ZhengldquoStudy of the content of heavy metals in the mollusks from thenear-shore of Zhejiang Provincerdquo Journal of Marine Sciencesvol 28 no 4 pp 43ndash49 2010

[43] W P Sun X Y Liu J M Pan and H X Weng ldquoLevels ofheavy metals in commercial fish species from the near-shoreof Zhejiang Provincerdquo Journal of Zhejiang University (ScienceEdition) vol 39 no 3 pp 338ndash344 2012


closely related to sediment types [9] e spatial distri-butions of heavy metals are often consistent with those offine-grained sediments [10] Most heavy metals becomepart of the sediment through different biogeochemicalprocesses which trigger precipitation and deposition [11]Heavy metals do not behave conservatively and they arealso affected by changing physicochemical conditions suchas salinity pH and redox conditions [12] When sedi-mentary environments change the heavy metals in thesediment may be released back into the water body throughvarious processes of remobilization producing secondarypollution within the environment [13] erefore marinesediments are considered an important sink of heavymetals especially in coastal areas

Heavy metals in seawater and marine sediments can bedirectly absorbed by organisms and then accumulated andtransformed within their bodies Accumulation may bemagnified via the food chain thereby threatening the marineecosystem and human health [14ndash16] Zhao et al [17] re-ported that some seafood from Xiangshan Bay might posenoncarcinogenic risks to both adults and children Althoughconsumption of most common types of seafood fromXiamen markets does not pose a noncarcinogenic risk sometypes such as yellowfin bream (Sparus latus) oyster and theRed alga (nori Porphyra tenera) could form a carcinogenicrisk [18] e levels of five metals in marine fish and shellfishfrom China are generally low based on published dataHowever some findings suggest that there are health risksfrom exposure to Cd and As in some shellfish [19] Con-sidering the pollution of heavy metals in seawater andsediments in coastal areas the risk of heavy metal pollutionin seafood deserves greater attention

Jiuzhen Bay is located on the southern coast of Fujianbetween Gulei and Liursquoao Peninsulas It is a concavesemienclosed shallow bay forming an estuary Its coastline is4597 km in length with a total embayed area of 6964 km2e entire bay is occupied by an intertidal shoal except forits tidal channel e intertidal area accounts for about 80of the bay area e tidal inlet runs from the bayrsquos mouth tothe Luxi River outlet [20] Jiuzhen Bay has rich marinebiological resources and is an important marine aquaculturebase in Fujian e main aquaculture species are shellfishAlong the coast of Jiuzhen Bay there are multiple industriessuch as wind power generation shipbuilding placer miningseafood processing and shipping In addition the nearbyGulei Port Economic Development Zone is one of the sevenpetrochemical bases in Chinae pollutant discharges fromthese various industrial enterprises may be causing seriousenvironmental impacts on Jiuzhen Bay

Given the environmental and sedimentation charac-teristics of Jiuzhen Bay most of the heavy metals enteringJiuzhen Bay accumulate within the bay To date there hasbeen no research on the distribution and ecological risk ofheavy metals in seawater sediments or seafood of JiuzhenBay e purpose of this study was to (1) determine thecontents and distributions of various heavy metals in sea-water sediments and living organisms within the bay (2)analyze the sources of these heavy metals and (3) evaluatethe degree of heavy metal pollution using the single-factor

pollution index comprehensive index evaluation and po-tential ecological risk index

e data provided here will assist the local governmentto monitor the change in the heavy metal pollution status ofthis area and implement targeted control measures

2 Materials and Methods

21 Sample Collection A total of nine stations were inves-tigated during the survey of May 2006 as shown in Figure 1A GO-FLO water sampler (General Oceanics Inc MiamiFL USA) was used for sample collection Water only withinthe surface layer was collected at stations where waterdepths were less than 5m (A1 B1 and B2) while watersamples from surface (Sur) and bottom (Bot) layers werecollected at stations with water depths of 5ndash20m (B3 C1 C2and E1ndashE3)Water samples were preserved at minus 20degC for lateranalysis Sediment samples were collected using a grabbucket-type bottom sampler sediments from the 0ndash2 cmsurface layer were placed in a polyethylene sealing bag andpreserved at minus 20degC for later analysis

Biological samples were collected by trawling and strictcriteria were used to select adults of local representativebiological species for the study Specimens were preserved atminus 20degC for later analysis

22 Laboratory Analysis Six heavy metalsmdashCu Pb Zn CdHg and Asmdashin seawater sediments and living organismswere analyzed in this study

All water samples were filtered using a hybrid celluloseester Millipore filter which was dipped before filtering inacid e filtrate was acidified to pHlt 2 with HNO3 andstored in a Teflon bottle

Before analysis of the sediment samples they werefreeze-dried All large debris was removed followed bygrinding and sieving Dry sediment samples were dissolvedin an equimolar mixture of HF HNO3 and HClO4 having avolumetric ratio of 3 1 05 and then evaporated to drynesse samples were redissolved with aqua regia and threeparts of this metal solution were diluted with HNO3

Edible parts of living organisms were removed usingbiomedical stainless-steel implements smashed using astamping machine blended and dried in an oven allowingmoisture content to be calculated Dried biological sampleswere digested like sediments

Cu Pb Zn and Cd were analyzed using an Agilent 7500ainductively coupled plasma source mass spectrometer(Agilent Technologies Inc Santa Clara CA USA) while Hgand As were analyzed using an atomic fluorescent pho-tometer AFS200T (Skyray Instrument Inc Stoughton MAUSA)

Total nitrogen (TN) total phosphorus (TP) dissolvedinorganic nitrogen (DIN) dissolved inorganic silicon (DSi)and PO4 were measured using a spectrophotometricmethod while total organic carbon (TOC) redox potential(Eh) and pH were analyzed using K2Cr2O7 oxidation-re-duction volumetric method and potentiometer and acidmeter method respectively DIN is the sum of NO3

minus NO2minus







Pi Ci times Sij (1)




Eir T

ir times C

ir T

ir times

Ci

Cin

RI 1113944n

i1E

ir

(2)








Pij

maxPi( 11138572

+ avePi( 11138572

2

1113971

(3)





11765 11770 11775 117802390

2395

2400

2405

2410

A1B1

B2 B3

C1C2E1

E2E3

degE

degN

GuleiEconomic

DevelopmentZone

Port

Gulei P

enins

ula

Luxi

Wujiang

Jiuzhen Bay

Liursquoao

Penin

sula



BCF Cx

Csw

BSAF Cx

Cs

(4)















Degree ofpotential

ecological risk


ecological risk


Moderatepotential

ecological risk




ecological risk


ecological risk

















11765 11770 11775 117802390

2395

2400

2405

2410

45

55

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

48

56

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

14

14

1822

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

5 45

45

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

23

26

29

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

27

29

(f )

Figure 2 Continued




11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References



















































Pi Ci times Sij (1)




Eir T

ir times C

ir T

ir times

Ci

Cin

RI 1113944n

i1E

ir

(2)








Pij

maxPi( 11138572

+ avePi( 11138572

2

1113971

(3)





11765 11770 11775 117802390

2395

2400

2405

2410

A1B1

B2 B3

C1C2E1

E2E3

degE

degN

GuleiEconomic

DevelopmentZone

Port

Gulei P

enins

ula

Luxi

Wujiang

Jiuzhen Bay

Liursquoao

Penin

sula



BCF Cx

Csw

BSAF Cx

Cs

(4)















Degree ofpotential

ecological risk


ecological risk


Moderatepotential

ecological risk




ecological risk


ecological risk

















11765 11770 11775 117802390

2395

2400

2405

2410

45

55

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

48

56

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

14

14

1822

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

5 45

45

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

23

26

29

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

27

29

(f )

Figure 2 Continued




11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References














































BCF Cx

Csw

BSAF Cx

Cs

(4)















Degree ofpotential

ecological risk


ecological risk


Moderatepotential

ecological risk




ecological risk


ecological risk

















11765 11770 11775 117802390

2395

2400

2405

2410

45

55

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

48

56

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

14

14

1822

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

5 45

45

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

23

26

29

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

27

29

(f )

Figure 2 Continued




11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References



























































11765 11770 11775 117802390

2395

2400

2405

2410

45

55

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

48

56

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

14

14

1822

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

5 45

45

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

23

26

29

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

27

29

(f )

Figure 2 Continued




11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References














































11765 11770 11775 117802390

2395

2400

2405

2410

45

55

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

48

56

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

14

14

1822

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

5 45

45

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

23

26

29

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

27

29

(f )

Figure 2 Continued




11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References
















































11765 11770 11775 117802390

2395

2400

2405

2410

034

03

03

(g)

11765 11770 11775 117802390

2395

2400

2405

2410

035

033031

(h)

11765 11770 11775 117802390

2395

2400

2405

2410

0406

(i)

11765 11770 11775 117802390

2395

2400

2405

2410

0506

05

(j)

11765 11770 11775 117802390

2395

2400

2405

2410

040

032

(k)

11765 11770 11775 117802390

2395

2400

2405

2410

03 05

0504

(l)












Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References























































Heavy metaltype



Cu 86 (11ndash21) 98









11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References














































11765 11770 11775 117802390

2395

2400

2405

2410

9

17

1

9

(a)

11765 11770 11775 117802390

2395

2400

2405

2410

95

3565

6535

(b)

11765 11770 11775 117802390

2395

2400

2405

2410

01

002

006

(c)

11765 11770 11775 117802390

2395

2400

2405

2410

005

002

001 004

(d)

11765 11770 11775 117802390

2395

2400

2405

2410

50

450

250

50

(e)

11765 11770 11775 117802390

2395

2400

2405

2410

7

65

(f )
























BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References



































































BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References























































BCF

Oyster 15185 10636 116 2200 54 976Clam 309 490 89 91 17 511Fish 48 249 89 3 93 262

Shrimp 1589 1164 43 15 33 170

BSAF

Oyster 847 408 050 12 090

lt001Clam 017 019 038 050 029Fish 003 010 038 002 154

Shrimp 089 045 018 008 054





within Jiuzhen Bay




4 Conclusions


Data Availability


Disclosure






Acknowledgments


References















































4 Conclusions


Data Availability


Disclosure






Acknowledgments


References












































































Documents

SpatialVariationsandPotentialRisksofHeavyMetalsin Seawater