Sources Of Polycylic Aromatic Hydrocarbons In Mangrove Sediments Biology Essay
In this survey, the distributions of PAHs in surface deposits of 15 Stationss from a little Rhizophora mangle island located within the estuary of Kemaman River were determined. Sediments were soxhlet extracted utilizing a 1:1 mixture of dicholoromethane and hexane as dissolver. Desulphurization was done utilizing quicksilver intervention while fractional process was done utilizing silica-alumina column chromatography technique. The hydrocarbons were detected utilizing Gas Chromatography-Mass Spectrometer ( GCMS ) .
Consequences showed entire identified PAHs ( TIP ) ranged between 0.12 – 1.42 i?g g-1.
Regardless of site, the most common compounds detected were those of higher molecular weight mostly known to be associated with burning of fuel stuffs. A strong correlativity exists between benzo [ ghi ] perylene and TIP suggested that burning of fuel stuffs ( vehicular emanations ) could be a major subscriber of PAHs to these deposits. Based on the strategic location of the island within the Kemaman estuary, it is postulated that the most likely beginnings of the PAHs compounds are overflows and atmospheric deposition from assorted related activities from Chukai Township and from nautical beginnings such as discharges from ships and fishing boats.Keywords: South China Sea, river estuary, PAHs, fuel burning, vehicular emanationIntroductionHappening of hydrocarbons in the Marine environment comes from many different beginnings and can by and large be classified into two major beginnings viz.
biogenic and anthropogenetic beginnings. Hydrocarbons of biogenic beginning of course occur at low concentrations in different substrates, such as H2O and deposits, and are portion of the natural hydrocarbon baseline of an ecosystem. These hydrocarbons originate from tellurian works waxes, biogenesis by marine beings and diagenesis transmutation of non-hydrocarbon biosynthetic natural merchandises such as steroid alcohols and hopanols.
Hydrocarbons of anthropogenetic beginning, on the other manus, are introduced into the environment as a consequence of activities related to oil geographic expedition, nautical conveyance ( operational discharges and oiler accidents ) , harbour activities and domestic and industrial wastewaters. Due to their hydrophobic nature, hydrocarbons particularly polycyclic aromatic hydrocarbons ( PAHs ) in aquatic environment quickly be given to be adsorbed onto particulate stuffs and so deposited in deposit as a concluding sink. Therefore, it non surprising that deposit is by and large recognized as the most of import reservoir of these contaminations [ 1, 2 ] . Background values for PAHs in deposits reported to be in the scope of 0.01 to about 1 mgkg-1 dry weight. However there is a high chance of happening them higher in the river oral cavity, estuaries and bays, every bit good as in countries associated with ship traffic, oil production and transit [ 1 ] .
It is by and large accepted that the Malayan Marine environment is progressively being threatened by oil pollution, viz. oil and lubricating oil pollutants [ 3-5 ] .Consequently, mangrove woods, an of import baby’s rooms and engendering evidences for a assortment of life resources, being a coastal ecosystem are hence highly vulnerable to the menaces of oil pollution. Few surveies have been carried out to measure the distribution and accretion of PAHs in Rhizophora mangle woods and estuaries in certain parts. Tam et Al. [ 6 ] have reviewed the degrees of PAHs observed in Rhizophora mangle and marine deposits of Hong Kong, China and other countries in the tropical part ; by and large the values ( Table 1 ) showed important fluctuation with locations and these differences could be related to fluctuations in and the extent of activities in the countries of survey.Table1: Concentration of entire polycyclic aromatic hydrocarbons ( PAH ; ngg-1 d.
w. ) in Rhizophora mangle deposits and marine deposits in Hong Kong and other metropoliss in China.SitesMeanS.E.ScopeSample StationsMentionMangrove deposits in Puerto Rico18202349500-600014Klekowski et Al.
( 1994 )Mangrove deposits in Carribean Island502554103-165713Bernard et Al. ( 1996 )Mai Po mudflat in Hong Kong547142400-8313Zheng ( unpublished )Marine coastal deposits in Hong Kong5532537-442020Zheng and Richardson ( 1999 )Marine underside deposits in Hong KongConnell et Al. ( 1998 )Background40-6066Eastern buffer949340-2304Deep bay998947-2314Tolo Harbour42439-504Victoria seaport66-1166Typhoon shelter42-11599Marine deposits in Pearl River Estuary21963087408-10 81110Mai et Al. ( 2000 )Marine deposits in South China Sea14625-27516Yang et Al.
( 2000 )Marine deposits in Xiamen Harbour36787247-4809Zhou et Al. ( 2000 )Beginning: Tam et Al. 2001 [ 6 ] ;Malaysia is estimated to hold about 612,580 hour angle of Rhizophora mangle woods, the majority of which are located in Sabah and Sarawak. Peninsular Malaysia has an estimated 103,203.11 hour angle of Rhizophora mangle woods, out of which merely ca. 1987 hour angle. are found in Terengganu [ 7 ] .
Kemaman estuary is alone in that non merely it has the largest extent of Rhizophora mangle wood in Terengganu, it is besides in the locality of Kemaman supply base, the chief supply port that service the oil and gas operation in the South China Sea. The estuary is besides merely ca. 20 km South of the Kerteh petroleum oil terminus, which receives oil from the South China Sea oil Wellss. Studies [ 4, 8, 9 ] on the hydrocarbon distributions in this part suggested some indicants of oil and lubricating oil taint when compared to other countries in the east seashore of the Peninsular [ 10, 11 ] . Kemaman estuary is good studied with regard to physical procedures ( e.g. sediment conveyance phenomenon ) in the estuary [ 12 ] and besides the extent of Rhizophora mangle woods [ 7 ] but surveies on chemical conveyance and/or distribution of pollutants, peculiarly on hydrocarbons, are still limited. Yet, the definition of a baseline degree of hydrocarbons is indispensable when trying to find chemical alterations introduced by anthropogenetic effects.
Consequently, this survey is initiated to supply the relevant and much needed information on current degrees of polycyclic aromatic hydrocarbons every bit good as fingerprinting beginnings of these compounds in the country.STUDY METHODOLOGYSampling and sample pre-treatmentKSBJettyLKIMJettyPulau Cik Wan DagangFisherCukaiSg. LimbongJettyLegend: KSB – Kemaman Supply BaseLKIM – Jetty ( Lembaga Kemajuan Ikan Malaysia )Figure 1: Location of Pulau Cik Wan Dagang and possible beginnings of hydrocarbon inputsFigure 1 shows the location of Pulau Cik Wan Dagang which is located in the Kemanan estuary.
The island is non populated and is really a Rhizophora mangle island which is subjected to tidal influence. Besides included in the diagram are possible beginnings of hydrocarbon input into the estuary ; Sg. Limbong is really a little river which is now turned into a concrete channel and domestic sewage system ( sistem peparitan ) of Chukai town really drains into this channel conveying possible wastes into the estuary ; breakwaters and KSB are possible beginnings as fishing boats and supply ships uses these installations, severally. A sum of 15 Stationss were selected for the aggregation of surface deposits on the island ( Figure 2 ) . Sediments were collected utilizing a Ekman grab sampling station, wrapped in pre-cleaned aluminium foil and transported to the research lab in an ice thorax packed with ice. Once in the research lab, samples were frozen until farther analysis. These samples were subsequently lyophilized followed by screening utilizing a 500µm screen.
Merely the fraction & A ; lt ; 500µm were used in the analysis.Figure 2: Map demoing the location of trying Stationss.Analytic methodological analysisThe analytical process adopted for the extraction of hydrocarbon compounds was based on standard method proposed by UNEP [ 13 ] . Briefly, deposits were soxhlet extracted utilizing DCM: hexane ( 1:1 ) mixture for eight hours. Prior to the extraction, an internal alternate criterion ( 9,10 – Dihydroanthracene ) was spiked into the deposit for recovery appraisal ; this process typically yields recoveries of PAHs in the part of 55 – 80 % . PAHs concentration was recovery-corrected utilizing the spiked alternates. Removal of sulfur from the infusion was done by utilizing quicksilver intervention.
The sulphur free infusions were so concentrated to about 1 milliliters utilizing a combination of rotary evaporator ( & A ; lt ; 35 & A ; deg ; C ) and nitrogen blow-down followed by fractional process on partly deactivated ( 5 % ) silica-alumina column. The PAHs fraction was eluted utilizing a combination of 30 milliliters 10 % DCM and 20 milliliters 50 % DCM in hexane, and the infusions collected in one fraction. Procedural spaces were run throughout the survey to guarantee there was small or no noticeable taint of the samples.
Designation and quantification of PAH ‘s fraction were carried out utilizing GC-MS by comparing the keeping times compared to that of external PAHs criterions. Confirmation of extremums was besides carried out utilizing the MS library. Sixteen USEPA precedence PAHs compounds were analysed in this survey ; these compounds were as follows: naphthalene ( NAP ) , acenaphtylene ( ACY ) , acenaphtene ( ACE ) , fluorene ( FLU ) , phenanthrene ( PHEN ) , anthracene ( ANT ) , fluoranthene ( FTH ) , pyrene ( PYR ) , benzo ( a ) anthracene ( BaA ) , chrysene ( CHR ) , benzo ( B ) fluoranthene ( BbF ) , benzo ( K ) fluoranthene ( BkF ) , benzo ( a ) pyrene ( BaP ) , dibenz ( a, H ) anthracene ( DA ) , benzo ( g, H, I ) perylene ( BgP ) and indeno ( 1,2,3, cadmium ) pyrene ( IP ) . Sums of these 16 compounds were jointly known as entire identified PAHs ( TIP ) .
In the GC-MS analysis, the GC runing status was as follows: HP-5 fused silica column ( 30 m x 0.25 mm i.d ; 0.
25 i?m filmed thickness ) ; injection temperature was set at 290 & A ; deg ; C utilizing a splitless manner ; column temperature was programmed in the undermentioned mode: clasp at 50 & A ; deg ; C for 1 min, first temperature incline of 50 – 140 & A ; deg ; C at 5 & A ; deg ; C min-1 followed by the 2nd temperature incline of 140 – 290 & A ; deg ; C at 4 & A ; deg ; C min-1 and so maintained at 290 & A ; deg ; C for 13 min ensuing in a entire tally clip of 82 mins ; He was used as the bearer gas with a flow rate at 1.2ml min-1. The GCMS interface was set at 300 & A ; deg ; C.
RESULTS AND DISCUSSIONPolycyclic aromatic hydrocarbon distributionTable 2 shows the distribution of TIP and selected fingerprinting parametric quantities in surface deposits of Pulau Cik Wan Dagang. TIP found in these deposits ranged from 0.12 to 1.42 µg/g dry wt with mean of 0.60 + 0.45 µg/g dry wt.
Regardless of trying sites, it is interesting to observe that most common PAHs detected were those of higher molecular weight mostly known to be associated with burning of fuel stuffs viz. DA, BgP and IP. CHR was another compound rather normally detected in the samples. The burning of fuels generates a compositionally characteristic series of chiefly non-alkylated PAHs, irrespective of the fuel type burned [ 14 ] .
The undermentioned nine compounds are frequently the most dominant members of this series viz. FTH, PYR, BaA, CHR, BbF, BkF, BaP, DA, BgP and IP. This chiefly burning derived PAHs are referred quantitatively in the undermentioned subdivision as a composite term ?Comb ( Table 2 ) , defined as the amount of the concentrations of these nine compounds in each sample. The consequences ( Table 2 ) show that ?Comb represent about 41 to 93 % of the entire PAHs identified in the samples bespeaking the of import part of this beginning of input into the country under survey.
Another interesting characteristic is that for some Stationss ( e.g. Stationss 1,4 and 5 ) , despite the comparatively low TIP, ?Comb represent highly high proportions ( & A ; gt ; 80 % ) of the TIP.An association of BgP with vehicular emanation beginning has long been established [ 15 ] ; in this survey, about all Stationss showed the presence of BgP in their deposits. A strong correlativity between BgP compound with the TIP ( Figure 3 ) ( r=0.91 ) indicates that vehicular emanation could be a major beginning of PAHs found in these deposits. Exhaust emanations from route conveyances could be deposited onto dirts and enter the estuary through run-offs from nearby Chukai township via Sg Limbong or through direct atmospheric deposition into the estuarine and Marine environment.
A major route runs across Chukai and Kemaman rivers ; emanations from vehicles providing the path could potential contribute to the PAHs content through atmospheric deposition into these river systems. Equally of import, emanations from nautical activities such as from ships and fishing boats utilizing the breakwaters located along the estuary and supply vass grounding and /or utilizing the Kemaman Supply Base ( KSB ) installations in the country could besides deposited the PAHs into the marine environment.Table 2: Distribution of entire identified PAHs and selected fingerprinting parametric quantitiesin surface deposits of Pulau Cik Wan Dagang, Kemaman EstuarySampling stationTIP ( µg/g )?Comb ( µg/g )% CombBgP ( µg/g )10.2410.21589.
51549.40.355Tip: entire identified PAHs ; ? Comb: amount of entire burning derived PAHs ;neodymiums: non detectedFigure 3. Correlation between benzo ( g, H, I ) perylene and entire identified PAHsReappraisal of the distribution form of the single PAHs compounds found in this survey showed the depletion of low molecular weight PAHs compounds such as ACE, ACY, PHEN, ANT, PYR from bulk of the deposit samples. It is unsure at present whether these absences are really built-in to these samples or because of a possible proficient job happening in the analysis of PAHs compounds. Therefore, it is conceded that farther survey is needed to verify these findings. However, present consequences clearly show that PAHs compounds were present in these samples and based on the present observation, they were of anthropogenetic beginning likely ensuing from burning of fuel stuffs.True, it is hard to accurately place PAHs beginnings based on the fact that these analytes could be emitted by figure of possible beginnings or undergo assorted procedures before being deposited into the deposits.
Nonetheless, old research workers [ e.g. 1, 10-11, 16-17 ] have evaluated possible beginnings of PAHs found in deposits by using single ratios of selected PAHs compounds molecular markers in their beginning allotment ( Table 3 ) . The copiousness ratio of two and three pealing to four to six pealing PAHs ( LMW/HMW ) can be used to measure the petrogenic and pyrolytic beginnings. Ratio between benzo ( ghi ) perylene and indeno ( 1,2,3, cadmium ) pyrene proposing burning input beginnings either from gasolene or Diesel exhaust while ratio between Benzo [ a ] anthracene and the amount of Benzo [ a ] anthracene and chrysene can potentially distinguish between general burning procedure with grass, wood and coal burning beginnings. However a grade of cautiousness is needed when utilizing the latter ratio, a value of & A ; gt ; 0.5 by and large favours grass, wood and coal burning beginnings but Yunker et Al. ( 2002 ) as cited by Mille et Al.
( 2006 ) [ 17 ] , has reported that burning residues from airdrome and car traffics and maritime activities sometimes yield values in surplus of this ratio therefore can non be wholly be excluded. In add-on to ratios listed in Table 3, methyl phenanthrene to phenanthrene ( MP/P ) ratio of & A ; lt ; 1 is besides taken as an indicant of burning beginnings while a value of & A ; gt ; 1 is declarative of petrogenic beginning ( Zakaria et. Al, 2002 ) .Table 3: Suggested PAHs beginnings based on the ratios of some PAH cmpoundsRatio PAHs beginningLMW/HMWBgP/ InPBaA/?228Pyrolytic& A ; lt ; 1aPetrogenic& A ; gt ; 1aGasoline fumes3.5aDiesel fumes1.1aCombustion& A ; gt ; 0.35bGrass/ wood/ coal burning& A ; gt ; 0.
5bLMW/HMW: ratio between the amount of two and three pealing PAHs and the amount of four to six pealing PAHs. BgP/InP: ratio between benzo ( g, H, I ) perylene and indeno ( 1,2,3, cadmium ) pyrene. BaA/?228: ratio between benz [ a ] anthracene and the amount of benz [ a ] anthracene and chrysene.aZhang et Al. ( 2004 ) [ 16 ] ; bMille et Al. ( 2006 ) [ 17 ]Table 4 shows the ratios of selected PAHs compound in mangrove deposit of Pulau Cik Siti Wan Dagang.
All the values of LMW/HMW were lower than 1, bespeaking important PAHs input from pyrolytic beginnings which is a common cause of taint, such as atmospheric deposition that might hold introduced PAHs into H2O organic structures. The ratios of BgP/IP for Stationss 3, 13, 14 and 15 were about 3.5, proposing burning input of gasolene, while Stationss 2, 10, 11 and 12 were about 1.1, demoing that these PAHs were derived from Diesel burning ( Figure 4 ) . BaA/?228 ratios of Stationss 7 and 11 were over 0.
35, proposing that they were from burning beginnings. The ratios in surplus of 0.5 as exhibited by Stationss 9, 13 and 14 are declarative of burning of grass, wood or coal.The concentration of PAHs analysed in this survey were compared with the effects-based guideline values such as the effects range low ( ERL ) and effects range-median ( ERM ) values provided by the US National Oceanic and Atmospheric Administration ( Long et al. , 1995 as cited by Zhang et Al. 2004 [ 16 ) .
This comparing shows that PAHs degree from these Stationss ( 0.124-1.396 ?g g-1 ) does non transcend the degree of the ERL value ( 4.022 ?g g-1 ) , proposing the PAHs found in the survey country are non likely to do any biological consequence.
However, it must be noted that the degrees of PAHs in mangrove deposits of some Stationss on Pulau Cik Wan Dagang have exceeded the background degree of PAHs found in uncontaminated deposits ( 0.01-1 ?g g-1 ) indicating that some parts on the island are demoing mark of taint.Table 4: Ratios of some PAH compounds in the Rhizophora mangle depositsStationLMW/HMWBgP/InPBaA/?22810.
710.6150.023.46sodiumssodiums: non availableGasoline fumesDiesel fumes31415131110122Figure 4: Plot of BgP/IP versus ?PAHs for the deposits collected from Pulau Cik WanDagang Mangrove forest.CONCLUSION AND FURTHER RESEARCHDatas obtained from the PAHs analyses revealed the presence of PAHs compounds by and large associated with the burning of fuels stuffs i.e.
pyrolytic beginnings. Analysis of diagnostic molecular markers suggest that the most likely beginnings of these compounds were of assorted beginning, viz. overflows and atmospheric deposition from Chukai Township and besides nautical beginnings such as discharges from ships and fishing boats. From the toxicity point of position, present degrees of PAHs in these deposits are non likely to do any serious biological effects. However, it must be conceded that a follow up survey is seasonably and really needed since the consequences discussed in the present article is based on trying carried out in twelvemonth 2001.
In future, organic C analysis should be conducted for the deposits. Standardization of PAHs to organic C is necessary since it is an of import commanding factor of sorption of PAHs on deposit [ 18 ] .RecognitionThe writers would wish to admit the support of the Department of Chemical Sciences, Universiti Malaysia Terengganu for the grant to concluding twelvemonth undergraduate pupil ( HM ) and Malayan Nuclear Agency-Reactor Interest Group ( MNA-RIG ) for partial support of this undertaking. Technical support from the analytical research lab of FST and assist in trying from the Mangrove Research Unit ( MARU ) of Institute of Oceanography ( INOS ) UMT are besides acknowledged.