1. Introduction
Both H2O and land resources are progressively going stressed through the action or inactivity of worlds ( Eletta, 2007 ) . Marine ecosystems are threatened by major anthropogenetic perturbations and, although debasement of the Marine environment could hold planetary effects, the significance remains ill understood ( Lohrer, Thrush, & A ; Gibbs, 2004 ) . Water pollution has become a serious concern. Foreign substances can change the physical and chemical parametric quantities of both the H2O column and deposit. While some substances can be considered a beginning of foods for micro-organisms, others are toxic to marine ecosystems ( Eletta, 2007 ) .
Marine deposits are normally used as a gage in environmental monitoring plans because they accumulate pollutants at concentrations above those in the H2O. This accretion can be enhanced in enclosed and semi-enclosed countries, where the exchange of H2O with unfastened sea is reduced ( Bakan & A ; Ozkog, 2007 ) . Cu is omnipresent in the environment, with 50 ppm in the Earth ‘s crust and 0.25 ppb in ocean H2O ( Chester, 1990 ) . Variations in concentrations of Cu occur due to both of course happening and anthropogenetic beginnings. Cu is an indispensable micronutrient to both workss and animate beings ( Bakan & A ; Ozkog, 2007 ) . As such, beings have mechanisms to cover with the specific Cu degrees in their environment. The sum of Cu required for normal metamorphosis is little, at both high and low concentrations can be damaging.
AAS and XRF, along with other mass analysis techniques such as ICP-MS, have been used extensively to find hint metal degrees in H2O and deposits samples ( Eletta, 2007 ; Atgina, El-Aghab, Zarars?zc, Kocatas, Parlakd, & A ; Tuncela, 2000 ) .
The purpose of this study is to look into fluctuation of Cu concentrations in deposits, between Portsmouth Hard and Langstone Harbour, every bit good at comparing the techniques used to find these concentrations. Additionally, foods in covering Waterss are compared for the two sites.
1.1. Study countries
Portsmouth Hard ( site A )
Portsmouth Hard is a tidal coastal mudflat in busy commercial seaport. The sample site ( fig.1 ) is located next to a concrete shipway, near to a railroad station, Gosport ferry and a landing country for little fishing boats. This site has a potentially a high hazard of taint from a assortment of beginnings, chiefly engine hydrocarbon waste and heavy metal taint ( Fones, 2010 ) .
Langstone Harbour ( siteB )
Langstone Harbour is a coastal mudflat in semi-enclosed seaport, which lies between Hayling Island and Portsmouth. The sample site ( fig. 1 ) is near a shipway and stopping point to big figure of recreational boats ( Fones, 2010 ) . The seaport is covered by a broad scope of appellations, including SSSI and Ramsar. In add-on to being an of import environmental site, Langstone continues to be active an seaport for both commercial and recreational vass, with 263 Marine sums vass go throughing through the seaport in 2009 ( Langstone Harbour Board, 2009 ) . This site has a possible hazard of hydrocarbons and hint metals from the recreational boats and aggregative ships.
2. Materials and Method
2.1 Sample aggregation
The samples were collected from Portsmouth Hard on the 11th March 2010 and from Langstone Harbour on the 12th March 2010. Sediment samples were collected at low tide from a 5m trying country that was chosen utilizing judgemental sampling. At each site six replicate deposit samples were collected from the upper 2cm of deposit, utilizing a fictile spatula, and transferred into plastic bags. The bags were labelled, placed into a coolbox and transferred back to the University where they were stored at 4°C. A 125mL plastic bottle was filled with distilled H2O to move as the analytical space sample ( Fones, 2010 ) .
2.2 Sediment analysis
Sediment samples were analysed utilizing a Perkin Elmer 1100B fire atomic soaking up spectrometer ( AAS ) , utilizing an air-acetylene fire, and a Philips PW1480 X-ray fluorescence spectrometer ( XRF ) . AAS standardization was carried out utilizing standard solutions.
For the samples analysed by AAS the deposit was homogenised in the plastic bag. Approximately 30mL of the sediment/water slurry was added to a 50mL extractor tubing. The tubing from each group were placed into a Fisher Scientific Accuspin 1 extractor, along with a tubing incorporating 30ml of distilled H2O to be used to look into for taint from the vass, and spun for 10 proceedingss at 3,500rpm. The supernatant was poured off go forthing the deposit. The centrifuged deposit was emptied into a PTFE beaker and dried in the oven for a hebdomad.
The dried samples were homogenised and 1.0g weighed out and placed into a 15mL extractor tubing. Approximately 0.5g of certified sediment mention stuff, HR-1, was besides placed into a 15mL extractor tubing. A concluding 15mL extractor tubing was labelled ARBlank. Acid digest was carried out by adding 2mL of Aqua Regia ( three parts concentrated hydrochloric acid and one portion of concentrated azotic acid ) to each tubing.
Acid digest samples were diluted to convey them within the standardization scope. Each samples had 8mL of Milli-Q H2O added, 1mL of this solution was put into a fresh tubing and a farther 9mL of Milli-Q H2O added. The diluted samples were analysed for Cu utilizing flame ASS.
Initial readyings for the XRF samples were carried out in a similar mode. The dried samples were homogenised and pressed into pulverization pellets, utilizing a imperativeness that exerts a force per unit area of 4000psi, before being analysed for Cu utilizing XRF. All values were clean corrected.
2.3 Alimentary analysis
The alimentary samples were analysed utilizing a QuAAtro Auto Analyser. The H2O samples for alimentary analysis were filtered, utilizing 0.7?m glass fiber filters, at the clip of aggregation. For each replicate 20mL of H2O was filtered into a plastic pot and 100?L of Mercury II chloride added to repair the sample.
2.4 Statistical analysis
Statistical analysis was carried out utilizing the PASW bundle. The samples were assessed for normalcy utilizing ocular analysis of histograms and the Kolmogorov-Smirnov trial, before undergoing statistical analysis.
3. Consequences and Discussion
3.1 Comparison of Cu concentrations between the two sites
Beginnings of Cu in the Marine environment are varied. Natural inputs include minerals in the stone that make up deposits, biological atoms and hydrothermal systems. Anthropogenic inputs can be straight into the H2O, or leached after deposition on land, every bit good as from dust from the ambiance. Historically Cu has been a cardinal biocide in antifouling marine pigments. Preservatives, such as Chromated Copper Arsenate ( CCA ) are used extensively on vass constructed of wood. Surveies have shown that after submergence the constituents of CCA, Cu, Cr and As, are lost from the wood ( Brown, Eaton, & A ; Thorp, 2001 ) . Both sites are capable to anthropogenetic perturbation, with the greater development at Portsmouth Hard proposing that it would be more likely to hold elevated degrees of heavy metals.
The information from both Portsmouth Hard and Langstone Harbour was found to be usually distributed, with Kolmogorov -Smirnova consequences of omega = 0.200 n = 11 and z = 0.200 N = 7 severally.
For XRF the average concentration of Cu was 36.00?g/g ±3.915 at Portsmouth Hard and 49.57?g/g ±3.387 at Langstone Harbour. The independent samples T-test disproved the void hypotheses, that there is no important difference in concentrations of Cu between Langstone Harbour and the Hard for XRF. The Levene ‘s trial showed that the significance of F ( 2.068 ) was greater than 0.05 ( P = 0.170 ) so confer withing the equal discrepancy estimation, T ( 16 ) = -2.412, P = 0.028. The two-tail significance indicates that the chance is less than 0.05 and hence the average difference of 13.571 is significantly different from nothing.
Relatively, the independent samples T-test for AAS information was non shown to be important. The average concentration of Cu was 31.80?g/g ±4.499 at Portsmouth Hard and 30.86?g/g ±2.955 at Langstone Harbour. The Levene ‘s trial showed that the significance of F ( 4.812 ) was less 0.05 ( P = 0.044 ) so confer withing the Equal discrepancies non assumed estimations, T ( 15 ) = 0.175, P = 0.863. The average difference of 0.943 is non significantly different from nothing. In this instance, the void hypotheses, that there is no statistically important difference in concentrations of Cu between Langstone Harbour and the Hard for AAS, was accepted.
The consequences from the two techniques do non let for a finding of which, if either, of the sites has the greater concentration of Cu. The possible grounds for the disagreement in consequences between the two techniques are discussed below.
3.2 Comparison of AAS and XRF trace metal techniques
A cardinal determination in experimental design is the pick of analytical technique. For sediment geochemistry factors impacting this pick including the scope of chemical elements to be determined, the acceptable degree of uncertainness and the cost ( Phedorin, et al. , 2000 ) .
Both techniques employed in this probe have associated strengths and failings. ISO 11466, extraction of hint elements soluble in aqua regia, suggests that greenish blue regia will non wholly fade out most dirts and similar stuffs. It goes to on to province that as such elements extractible in aqua regia can non be described as ‘totals ‘ . Additionally the standard suggests that these elements can non be regarded as the bio-available fraction, an of import factor when sing possible toxicity, as the extraction process is excessively vigorous to stand for biological procedure. The procedure used in this probe besides differs from that given in the criterion.
Key defects of XRF include matrix and particle-size effects. These consequence in fluctuations in the fluorescent strengths of the aroused elements due to both the chemical composing and granulation of the sample ( Stallard, Apitz, & A ; Dooley, 1995 ) . This can restrict the truth and preciseness of XRF analysis, a factor that was perchance non considered carefully plenty when the power pellets were formed.
To do a comparing between two analytical techniques it is of import to measure the comparative truth of the methods against the known certified values of a mention sample ( Pilotto, Goff, & A ; Weatherburn, 1998 ) . The information from both the XRF criterion, XRF HR-1, and the mention sample extracted in Aqua Regia, HR-1, was found to be usually distributed ( Kolmogorov -Smirnova z = 0.200 n = 17 and z = 0.200 N = 6 ) .
The mean for the concentration of Cu in the mention samples, XRF HR-1, was found to be 100.17?g/g ± 2.44, while the concentration of the known criterion is reported in the company literature as 79.9?g/g ±11.4 ( National Water Research Institute, 2006 ) . In this instance, the technique appears to hold over estimated the concentration of Cu, although the void hypotheses, that there is no important difference between the average concentration of Cu measured in the mention samples and the known concentration of the mention criterion, is upheld by the independent sample T-test, T ( 5 ) = 8.301, P & lt ; 0.05.
The mean for the concentration of Cu in the mention samples extracted in Aqua Regia, HR-1, is 53.82?g/g ± 3.23. In this instance the techniques appears to hold underestimated the concentration of Cu, although likewise the void hypotheses, that there is no important difference between the average concentration of Cu measured in the mention samples and the known concentration of the mention criterion extracted in aqua regia, is upheld by the independent sample T-test, T ( 16 ) = -8.064, P & lt ; 0.05. Means, plus the per centum mistake from the certified value can be found in table 1.
|
XRF |
Percentage Mistake from the Certified Value |
Associate in applied science |
Percentage Mistake from the Certified Value |
Certified Value |
|
|
Copper |
100.17?g/g ± 2.44 |
25.37 |
53.82?g/g ± 3.23 |
32.64 |
79.9?g/g ± 11.4 |
The mention stuff used in this probe was from a fresh water, non a marine beginning, although this does non look to keep a important bearing on the consequences and was employed by Stallard, Apitz, & A ; Dooley ( 1995 ) when look intoing the usage of XRF for analysis of metals in marine deposits. The degree of Cu in the mention sample, compared to that in the samples to be analysed, appears to be a more of import consideration. In this instance the lowest concentration of Cu found by XRF was 18?g/g, with the highest being 64?g/g, for AAS the lowest concentration was 11?g/g and with the highest being 54?g/g, all of which are notably lower than the Cu concentration given for the certified mention sample.
3.3 Comparison of the two hint metal techniques at each site
Having concluded that there is no meaning difference between the two hint metal techniques, when looking at the certified mention sample, the below computations investigate whether this decision is upheld within the field informations.
The average difference in Cu concentrations, measured by XRF and AAS, is 10.941. The mated samples T-test ( T ( 16 ) = 4.737, P & lt ; 0.05 ) shows that average difference is non significantly different from nothing. Therefore the nothing hypotheses, that the average difference in the entire Cu concentrations measured by XRF and AAS is non significantly different from zero, can be accepted.
The average difference in the entire Cu concentrations measured by XRF and AAS at Portsmouth Hard is 5.500. The mated samples T-test shows that average difference in Cu concentrations measured by XRF and AAS is non significantly different from nothing ( T ( 9 ) = 2.661, P & lt ; 0.05 ) . Therefore the nothing hypotheses, that the average difference in the entire Cu concentrations at Portsmouth Hard, measured by XRF and AAS, is non significantly different from zero, can be accepted. The average difference in the entire Cu concentrations measured by XRF and AAS at Langston Harbour is 18.714. The mated samples T-test for Langstone Harbour shows that average difference in wholly Cu concentrations measured by XRF and AAS is non significantly different from nothing ( T ( 6 ) = 6.507, P & lt ; 0.05 ) . Therefore the nothing hypotheses, that average difference in the entire Cu concentrations at Langstone Harbour, measured by XRF and AAS, is non significantly different from zero, can besides be accepted.
These consequences are consistent with the findings from the above subdivision and with other surveies that have found no statistical difference between the hint metal measurings made with the two techniques ( Atgina, El-Aghab, Zarars?zc, Kocatas, Parlakd, & A ; Tuncela, 2000 ; Radu & A ; Diamond, 2009 ) .
3.4 Comparison of alimentary concentrations between Langstone Harbour and the Hard for NO3, PO4 and Si
Not all alimentary informations ( table 2 ) for NO3, PO4 and Si was found to be usually distributed, with Kolmogorov-Smirnova consequences for Portsmouth Hard of n = 10 omega = 0.110, omega = 0.018 and 0.003 severally, and for Langstone Harbour of n= 9, omega = 0.004, z= 0.200 and z= 0.143 ( consequences greater than omega = 0.05 representin normal distribution ) . The remotion of outliers resulted in normal distribution for PO4 ( n = 9 omega = 0.200 ) and Si ( n= 9 omega = 0.200 ) at Portsmouth Hard. Both outliers are from replicate 6 and it is possible that this sample was contaminated, either during aggregation or sample readying. The NO3 information for Langstone Harbour is non usually distributed, this is perchance due to disagreements in trying, with some samples being collected from the harbour side of the sand tongue and some from the unfastened H2O side ( fig. 1 ) .
As the information for NO3 was non usually distributed a non-parametric Mann-Whitney U trial was carried out. The supported the nothing hypotheses, that, under these fortunes, there is no important difference in concentrations of NO3 between Langstone Harbour and the Hard, z = -3.674, P = & lt ; 0.05.
For PO4 an independent samples T-test was carried out and disproved the void hypotheses, that there is no important difference in concentrations of PO4 between Langstone Harbour and the Hard. The Levene ‘s trial for equal discrepancy showed that the significance of F ( 0.521 ) was greater than 0.05 ( P = 0.481 ) so confer withing the equal discrepancy estimations, T ( 16 ) = 2.878, P = 0.011, the two-tail significance indicates that the chance is less than 0.05 and hence the average difference of 0.207 is significantly different from nothing.
For Si the independent samples T-test besides disproved the void hypotheses, that there is no important difference in concentrations of Si between Langstone Harbour and the Hard. The Levene ‘s trial for equal discrepancy showed that the significance of F ( 2.782 ) was greater than 0.05 ( P = 0.115 ) so confer withing the equal discrepancy estimations, T ( 16 ) = -3.075, P = 0.008, the two-tail significance indicates that the chance is less than 0.05 and hence the average difference of 2.048 is significantly different from nothing.
No. |
Nutrient Data for Portsmouth Hard – µmol/L |
Nutrient Data Langstone Harbour – µmol/L |
||||
NO3 |
PO4 |
Silicon |
NO3 |
PO4 |
Silicon |
|
1 |
10.992 |
0.566 |
5.952 |
21.497 |
0.748 |
6.972 |
2 |
12.59 |
0.724 |
7.122 |
19.373 |
0.545 |
7.51 |
3 |
10.836 |
0.682 |
7.019 |
19.532 |
0.449 |
7.252 |
4 |
10.607 |
0.556 |
6.316 |
34.339 |
0.419 |
10.62 |
5 |
13.233 |
0.783 |
7.662 |
34.028 |
0.396 |
10.605 |
6 |
14.378 |
1.863* |
19.231* |
35.065 |
0.68 |
11.562 |
7 |
10.755 |
0.843 |
9.644 |
32.676 |
0.458 |
9.908 |
8 |
10.058 |
0.6 |
6.849 |
31.95 |
0.4 |
9.879 |
9 |
9.967 |
0.6 |
6.782 |
31.908 |
0.5 |
9.636 |
10 |
11.679 |
1.1 |
8.169 |
21.497 |
0.748 |
6.972 |
3.5 Extra beginnings of mistake
Short term variableness in coastal environments can greatly impact hint metal concentrations in surface deposits. For illustration, increased overflow can do higher concentrations of metals leached by enduring, while surface conditions affect the resuspension of particulate affair ( Laslett, 1995 ) .
Mistakes can be introduced during trying processing. An of import consideration for hint metal analysis is contact with metal equipment, which may potentially pollute the samples. Another beginning of mistake can ensue from alterations in composing due to temperature alterations. It has been suggested that warming samples, from the ocean underside to room temperature, may switch the ion exchange equilibrium and do a release of ions from the deposit into the pore H2O ( Bufflap & A ; Allen, 1995 ) .
Mistakes can besides be introduced during processing. For illustration, when samples are centrifuged some all right atoms can stay suspended in the H2O, particularly if the deposit is disturbed while pouring extracted H2O from the tubing. Ankley et.al. ( 1991 ) , as cited by Bufflap & A ; Allen ( 1995 ) , reported that pore H2O samples showed important losingss ( 35-63 % ) of hint metals when filtered. While some of this loss could be due to the formation of precipitates or sorption by the glass fiber filters, it is possible that some of this is due to sediment atoms staying suspended in the H2O.
Decision
Although it is non possible to state with any certainty which site has the greater concentration of Cu, all concentrations reported fell below the likely consequence degree ( PELs ) of 108?g/g for marine deposit ( Canadian Council of Ministers of the Environment, 1999 ) . While these figures are non officially recognised in the UK, they are widely used as baseline to measure the grade to which inauspicious biological effects are likely to happen ( Pilotto, Goff, & A ; Weatherburn, 1998 ; Bakan & A ; Ozkog, 2007 ) . The happening of inauspicious biological effects can non be predicted entirely from concentration informations. The likeliness of inauspicious effects happening in response to Cu exposure depends on the sensitiveness of single species, every bit good as a assortment of physicochemical, biological and geochemical factors, which combine to impact bioavailability ( Canadian Council of Ministers of the Environment, 1999 ) .
The grounds for the disagreement between comparings of Cu concentrations, at the two sites, for two techniques, is non clear at this clip. It is possible that mistakes introduced, either during sampling, processing or though analytical standardization, have affected the consequences. Further probe, with improved methods and quality control steps, could supply a clearer result.
Both acerb digest ( AAS ) and XRF techniques have been widely employed in the survey of hint metals in deposit ( Atgina, El-Aghab, Zarars?zc, Kocatas, Parlakd, & A ; Tuncela, 2000 ; Bakan & A ; Ozkog, 2007, Bilinski, Franciskovic-Bilinski, Necemer, Hanzel, Szalontai, & A ; Kovacs, 2010 ) , although the usage of portable XRF appears to be favoured in some instances as it has a comparatively fast throughput and is non-destructive ( Stallard, Apitz, & A ; Dooley, 1995 ; Radu & A ; Diamond, 2009 ) .
The most appropriate technique depends mostly on the purpose of the probe. For illustration, if the information required is the entire concentration of metal it possible that XRF would be the better technique, sing the inability of aqua regia to digest the whole deposit and XRF ‘s that reports merely the entire component available in the to the full oxidized province. Although, statistical, in this instance, the information does non favor one technique over the other.
Mentions
Atgina, R. S. , El-Aghab, O. , Zarars?zc, A. , Kocatas, A. , Parlakd, H. , & A ; Tuncela, G. ( 2000 ) . Probe of the sediment pollution in Izmir Bay: hint elements. Spectrochimica Acta, 55, 1151-1164.
Bakan, G. , & A ; Ozkog, H. B. ( 2007 ) . An ecological hazard appraisal of the impact of heavy metals in surface deposits on biology from the mid-Black Sea seashore of Turkey. International Journal of Environmental Studies, 64 ( 1 ) , 45-57.
Bilinski, H. , Franciskovic-Bilinski, S. , Necemer, N. , Hanzel, D. , Szalontai, G. , & A ; Kovacs, K. ( 2010 ) . A combined multi-instrumental attack for the physico-chemical word picture of watercourse deposits, as an assistance to environmental monitoring and pollution appraisal. Fresenius Environmental Bulletin, 19, 248-259.
Brown, C. J. , Eaton, R. A. , & A ; Thorp, C. H. ( 2001 ) . Effectss of Chromated Copper Arsenate ( CCA ) Wood Preservative on Early Fouling Community Formation. Marine Pollution Bulletin, 42 ( 11 ) , 1103-1113.
Bufflap, S. E. , & A ; Allen, H. E. ( 1995 ) . Sediment pore H2O aggregation methods for hint metal analysis: A reappraisal. Water Research, 29 ( 1 ) , 165-177.
Canadian Council of Ministers of the Environment. ( 1999 ) . Canadian sediment quality guidelines for the protection of aquatic life: Copper. In Canadian environmental quality guidelines, 1999. Winnipeg: Canadian Council of Ministers of the Environment.
Chester, R. ( 1990 ) . Marine Geochemistry. London: Unwin Hyman.
Eletta, O. A. ( 2007 ) . Determination of some hint metal degrees in Asa river utilizing AAS and XRF techniques. International Journal of Physical Sciences, 2, 056-060.
Fones, G. ( 2010 ) . Laboratory Practical Work Notes ( Week 34 ) . University of Portsmouth.
Google. ( 2009 ) . Google Maps UK. Retrieved January 9, 2010, from Google Maps Uk: hypertext transfer protocol: //maps.google.co.uk
Langstone Harbour Board. ( 2009 ) . Annual Report 2009.
Lohrer, A. M. , Thrush, S. F. , & A ; Gibbs, M. M. ( 2004 ) . Bioturbators enhance ecosystem map through complex biogeochemical interactions. Letterss to Nature, 431.
National Water Research Institute. ( 2006 ) . Certified Reference Materials & A ; Quality Assurance Services ( 5.7 ed. ) . Burlington, Canada: Environment Canada.
Phedorin, M. A. , Bobrov, V. A. , Chebykin, E. P. , Goldberg, E. L. , Melgunov, M. S. , Filippova, S. V. , et Al. ( 2000 ) . Comparison of Synchrotron Radiation X-RayFluorescence with Conventional Techniquesfor the Analysis of Sedimentary Samples. The Journal of Geostandards and Geoanalysis, 24, 205- 216.
Pilotto, P. J. , Goff, J. R. , & A ; Weatherburn, D. C. ( 1998 ) . A modern-day contaminationrecord of stormdrain and harboursediments, Wellington, NewZealand. Environmental Geology, 36, 159-166.
Radu, T. , & A ; Diamond, D. ( 2009 ) . Comparison of dirt pollution concentrations determined utilizing AAS and portable XRF techniques. Journal of Hazardous Materials, 171, 1168-1171.
Stallard, M. O. , Apitz, S. E. , & A ; Dooley, C. A. ( 1995 ) . X-ray fluorescence spectroscopy for field analysis of metals in marine deposits. Marine Pollution Bulletin, 31 ( 4-12 ) , 297-305.
