Sediment Pollution - Science topic

Hola que tal, el primero definitivamente no es Petruca es Leptuca, el segundo tampoco es Petruca, creo que también puede ser Leptuca, pero falta ver otros detalles por que es un ejemplar interesante, saludos desde Guayaquil.

That's odd. My guess is that those studies aimed for that size for a specific reason. Do you mind mentioning those studies? But you are right, MPs are by definition <5 mm. For water and sediment samples I'd suggest sieving samples through 5 and 1 mm sieves prior to extraction by density separation means. Plastic particles in the range of 1-5 mm are, indeed, microplastics (the "larger" microplastics), plus it is easier to report the abundance in size ranges.

Cheers

Dear Abdul Rahman Mahmud

A paper is attached. It can be useful for your question.

Well,

Sample is individually soaked in deionized water for five minutes, then gently agitated in water through a large macroaggregate sieve (>2000 micro meters), a small macroaggregate sieve (250-2000mm), and a microaggregate sieve (53-250mm). At each sieving stage, deposit what the sieve collected into aluminum pans by rinsing the sieves out with deionized water, and then placed the filled pans in an oven to dry out. The smallest soil remnants (<53mm), or the silt and clay particles, that passed through the microaggregate sieve were also deposited with water into aluminum pans. Once the pans were dried, they were weighed and compared against the whole sample’s fresh weight to calculate the percentages of different-sized aggregates within each sample. or shaking sample together with flowing water as seen in the attached figure

Sincerely

Interesting..

Use of a single factor for converting soil organic carbon to soil organic matter is challenged. The basis for this challenge arises from four sources: the original papers published in the nineteenth century, empirical studies published throughout the twentieth century, theoretical considerations of organic matter composition, and a consideration of what led to the popularity and general acceptance of the conventional factor. The conventional factor of 1.724, based on the assumption that soil organic matter contains 58% carbon, appliesonly to some soils or only to particular components of soil organic matter. Studies published since the end of the nineteenth century have consistently shown that the factor of 1.724 is too low for most soils. In a review of previously published data, the median value for the conversion factor was found to be 1.9 from empirical studies and 2 from more theoretical considerations. A factor of 2, based on the assumption that organic matter is 50% carbon, would in almost all cases be more accurate than the conventional factor of 1.724. A consideration of the possible variation in organic matter composition predicts a range of factor values between 1.4 and 2.5, a range that is narrower than empirical results at least in part because of the interaction between the methods used to estimate organic matter and soil composition. Convenience, authority, and tradition rather than strength of evidence are in large part responsible for the widespread acceptance of the conventional factor. Source ; Geoderma 156 (2010) 75–83..PDF enclosed, some more related PDFs are enclosed..

SQGs are normalised using TOC for some organic compounds. These guidelines should be adjusted using site specific TOC levels in sediments. Some guidance can be found in these links:

soxhlet extraction  but I prefer US extraction will not take less time 

as mentioned by Dr. Polesello  Solvent are ( Hexane and DCM)

kind regards

this is not an easy question. As a basic approach the comparison with the Earth Crust Abundance values is quite correct.  I also would recommend comparing with average shale values; the values are, by good reasons, generally in the range of the upper crust. You may find tabulated values in the internet,  e.g. at Yuan-Hui Li (author); A Compendium of Geochemistry: From Solar Nebula to the Human Brain; Table VI-5a.

The main problem is the question of sample grain size you are using and the digestion method. A common recommendation to find background values is the use of fine grain sediments, meaning < 2 mm grain size. However, this range of grain size may contain a lot of sand fraction, which in river sediments generally consists of quartz. Due to transport mechanisms there is a general shift to quartz enrichment in river sediments. The more quartz grains in the sample the less will be the metal concentration, and you cannot compare with average values from literature. So, for sampling you should prefer backwater situations in Feni River or sections with slow moving water where you will find fine grained sediment (< 63 µm); or you have to sieve the material. You also should keep in mind that literature values rely on total digestion. So, with only few exceptions, you also have to do total digestion prior to analysis (e.g. digestion by HF, which is a really awkward job).  Some metals will be easily extracted nearly to total by aqua regia digestion, like Pb, Zn, Cd. These element concentrations can be compared to literature. An additional question is whether a comparison to literature values is really helpful when looking for enrichment of metals. A better proposal is comparison to local background values. For this you have to find out stream sediments from uncontaminated sections in your region, possibly rivers with a high catchment area. With some effort uncontaminated sediments can also be found in the lower part of sediment cores from bayous.

Possibly a look to our sediment surveys on Chilika Lake (India) or Elbe bayou sediments (Germany), both in Research Gate, will give you additional ideas, e.g. on the question of availability of heavy metals.

Good luck and kind regards

D. Zachmann

Dear Michal,

in Germany have been done several investigations regarding the setting of EQS values, including for sediment. The most recent study you can find here (prepared for the National Environmental Agency), but it is in German:

You find the EQS (the German abbreviation is UQN) proposals for the sediment in table 2. Further, regarding your question in terms of practical application of the EQS, I can inform you that we made several studies in relation with lower environmental quality objectives for regions where the natural background of metals in rivers in elevated. For the moment we have only one publication of our recent work which is in German, dealing with the metal concentration in the West Harz region, where the EQS for some metals are not met and lower environmental objectives are required. There your can find data for water and sediment, which are real measured data of the West Harz region.The respective publication you find here:

Another publication on this subject is submitted and will be hopefully published soon, there we investigated the same subject for the whole county Saxony-Anhalt in Germany. Further, at the IMWA conference in July we will present data for the whole Harz mountains, covering West Harz in Lower Saxony and East Harz in Saxony-Anhalt. Just for your information, we did this kind of study also for Northrhine-Westfalia and Thuringia, but these data are not yet published. Interesting in our studies is that we can use a data pool of usually a whole county as we work with the authorities and we have available the whole monitoring data set. Usually the data set for sediment or suspended matter is much smaller, but there are data. What we can conclude from our investigations, which had the focus on metals, is that there are regions which can not meet the EQS due to natural conditions and they will have exemptions in terms of the WFD targets as well as lower environmental objectives. In the frame of the work on the metals we developed also an approach for the determination of the natural background, which is subject of the abovementioned publication and which was recently adopted for the implementation of the Surface Water Direction in Germany (this is the German implementation Directive for the WFD).

Best regards,

Petra

·        Geoaccumulation Index (Igeo) = Log2 (Cn) / 1.5 (Bn)

Cn is the concentration of metals examined in soil samples and Bn is the geochemical background concentration of metal (n)  (Bn : 2.1 ppm for arsenic). Factor 1.5 is the background matrix correction factor due to lithospheric effects. The geoaccumulation index consists of seven grades or classes [20]. Class 0 (practically uncontaminated):Igeo ≤0; Class 1 (uncontaminated to moderately contaminated): 0<Igeo <1; Class 2 (moderately contaminated): 0<Igeo <2; Class 3 (moderately to heavily contaminated): 2<Igeo <3; Class 4 (heavily contaminated): 3<Igeo <4; Class 5 (heavily to extremely contami- nated): 4<Igeo <5; Class 6 (extremely contaminated): 5<Igeo. Class 6 is an open class and comprises all values of the index higher than Class 5.

Kind Regards,

Beste ARSLAN

This is not a direct answer to your question., but, it may help.  Dr. Edward Long, Washington State Department of Ecology, Olympia, USA has published several research articles on sediment quality assessments.  You may search his name on Research Gate to access some of his publications.  All the best!!!

You may refer to the following articles that may partially answer to your question.  "Temporal trends of selected chlorinated hydrocarbon pollutants in sediments of Kentucky Lake" By B.B. Sadi and B.G. Loganathan.  In. Global Contamination Trends of Persistent Organic Chemicals.  CRC Press. 2012. ISBN. 978-1-43983830-3., and "Persistent organic pollutants and stress protein levels in freshwater mussels from Kentucky Lake".  Organohalogen Compounds 2007, 69, 1384-1387. You may download full articles from my page on Research Gate.  All the best!!! Loganathan.

You may get more information through Canadian Environmental Quality Guidelines - Canadian Sediment Quality Guideline

Respected Sir,

I can provide you with a paper which may help you to sort out the soil tests necessary to detect pollution levels in soil near solid waste landfill/ dumping yard. I have used it in my research.

You can use  Sodium fluorosilicate (Na2SiF6) as a primary standard to create a standard curve with your spectrophotometer. See below. Given the accuracy of this method this is adequate. If you have material you have run in the past when you used a CRM run it as an in-house standard if you have enough of it and it is reproducible. If you only have a small amount of material purchase some diatomite and calibrate against something you know and then you will have a larger stock on in-house standard. Not perfect, but at least from batch to batch you know if you are going astray. 

Primary silica standard: dissolve 0.5642 g in a Nalgene 1 liter volumetric flask fill to 1 liter with Nanopure/Milli-Q water. Dissolution is slow, so allow at least 30 minutes. This cannot be rushed. The concentration of this standard is 3000 µmoles Si/liter. Store in a 1000 ml Nalgene bottle. Standard is stable indefinitely. The below concentrations should cover your range.

a. Dilution from primary standard: when making a dilution, use Nanopure/Milli-Q water and store in Nalgene bottles. Using a 50 ml Nalgene volumetric flask, add the following amounts of primary silica standard and then bring the volume to 50 ml total.

30 µM Si - 0.5 ml of primary Si std.

60 µM Si - 1.0 ml of primary Si std.

120 µM Si - 2.0 ml of primary Si std.

240 µM Si - 4.0 ml of primary Si std.

360 µM Si - 6.0 ml of primary Si std.

480 µM Si - 8.0 ml of primary Si std.

600 µM Si - 10.0 ml of primary Si std.

900 µM Si - 15.0 ml of primary Si std.

1200 µM Si - 20.0 ml of primary Si std.

 Tnak Sergei I will read your paper 

Dear friend, 

I think that Tessier method is good and standard procedure but for further information, I suggest to read this article :

Review Article

Heavy Metal and Trace Metal Analysis in Soil by Sequential Extraction: A Review of Procedures

Regards 

Along with the above references, you can also check the followings for further reading. The book "Principles of Lake Sedimentology" by Hakanson and Jannsson, could be another good option for you.

Please check the attached files. These articles might be helpful for you.

Yeah - nice recent paper by Reis et al.

Your question - as always there are advantages and disadvanteges for both ways. The advantages of using OES device is for example the possibility to look at other analytes during the thermodesorption (i.e. sulfur) to identify thermal digestion of HgS,  secondly the whole experiment for a single samples takes you 5-10 minutes (using AMA - I guess it will be several mutiple experiments each at 3-5minutes).

But the disadvantage of OES is the non-oxidating (argon) atmosphere analysis of organic rich samples becomes a problem due to memory effects and production of tar like substances during sample heating.

So we just simply went the way of OES... but definitely the other way using oxygen atmosphere combustion has its perspectives.

Sediments have a great capacity to accumulate pollutants in aquatic systems, even when these compounds present low concentrations in the waters, and therefore are regarded as one of the most representative environmental indicators of contamination and can be used to map, trace and monitor anthropogenic sources of contamination and/or anomalies caused by geochemical natural processes. Many scientists have studied mercury contamination in surface sediments of sheltered environments, like estuaries, lagoons and bays. In their studies mercury contamination due to anthropogenic activities was observed. Two of these identified sources were: chloro-alkali factories, in which mercury cathodes were used for chlorine production and factories which processed imported ore containing traces of mercury.

It is known that the concentration of a contaminant in sediment tends to increase when particle sizes decrease because of enlargement of the surface area per unit. Therefore, an estimation of contaminant immobilization requires information about the grain size distribution and relationship between particle size, mineralogical differences and concentration of the contaminant in the sediment. Normalization is a common approach to compensate for anomalous metal concentrations in sediments and soils caused by grain size and mineralogical differences. In aquatic ecosystems, inorganic mercury enters a complex cycle in which it can be methylated in water and/or in sediments producing methylmercury, the most toxic form of Hg. Methylmercury level in sediments is controlled by competing and simultaneous methylation and demethylation reactions.

In order to achieve comparable measurements in the determination of phosphate forms in freshwater sediments, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission has launched a project the first step of which was to select and evaluate collaboratively existing extraction procedures. After evaluation of four sequential extraction schemes, a modified version of the Williams protocol was selected as the most promising method for achieving comparability and was named SMT extraction scheme. (Please refer the paper by Ruban et al., 1999. J. Environ. Monit., 1, 51–56).

A sequential extraction method (SEDEX) developed by Kathleen C. Ruttenberg is a good method to consider in marine sediments. (Please refer Ruttenberg, 1992. Limnol. Oceanogr., 37(7), 1460-1482)

What you asking to do is not going to be easy. First keep samples moist and air tight after collection so you don't loose an gaseous forms of N. Use a TKN method something like this: 

for total N. Orthophosphate is easier. You need to opperationally define how you want to describe the P. I would say do a basic exchange / extraction with a soil extractant on an air dried sample like Mehlich 1 extraction:

Add some activated carbon to collect up troubling organics and Phosphonates. Repeat in a duplicate sample and run extract (without Carbon added) into an ICP or do wet oxidation to convert all P into P2O4

Last step is a full microwave digestion in hydrofluric acid. This will dissolve everything. Then you neutralize the HF and run basic colormetric analysis for P

This will give you Wet total N

Total extractable Ortho P, Total extractable P and Total P

I am in midst of a dissertation on sequentially extracted organic P fractions....

Good Luck

We use a sediment core sampler from AMS. It has a valve at the tip of the core that does not let sediment or water out. It comes with disposable clear plastic (polycarbonate?) liners and PVC end caps. We cap the cores and freeze them in the same orientation as collection in a -20 fridge, and then transfer them to -80 deg-C for horizontal, longer-term storage to decelerate biological activity. As Mr. Rona suggested, we are interested in both the biology and the chemistry of the cores. The cores can also be cut into sections and stored.

My personal view is that it's almost impossible to get an SRM/CRM for every matrix in existence, especially one that's certified for the substance for which you're monitoring. The comparability of the physicochemical properties of the two matrices will determine whether the results are comparable. To Neus's point, numerous soil-based matrices exist, and depending on the analysis and extraction method, and the nature of the chemical you're analyzing, the results between two can be considered comparable.

However, there appear to be a couple of SRM's and CRM's for both inorganic and organic components in marine sediment (NIST SRM's 1941b, 1944, 2702, NIES CRM 12, etc). While it would probably be best to use matrices that are closest to your matrix, you could possibly make an argument for the urban dust depending on what you're measuring. Which compound are you looking at?

I have simulate sediment and flow interaction using Moving Particle Semi Implicit method which is a particle method same as SPH. As you may know, MPS and SPH are the most similar methods among other Lagrangian methods. Please, feel free to ask your question on the issue.

I wrote paper on heavy metal mobility in sediments: Migration and Forms of Metals in Bottom Sediments of Czerniakowskie Lake, Bull Environ Contam Toxicol. Feb 2013; 90(2): 165–169.

A good choice could be Non-Metric MultiDimensional Scalling (NMDS). But I suggest reading Legendre & Legendre (2012) for an introduction to different types of analyses. Which would perform best depends on type of data, range of gradients…

Legendre, P., and L. Legendre. 2012. Numerical ecology, 3rd English edition. Developments in Environmental Modelling, Vol. 24. Elsevier Science BV, Amsterdam. xiv + 990 pp

If it's suspended sediment flux that you are more interested in, several methods of estimating suspended sediment transport have been evaluated rigorously in classic work by Professors Des Walling and Bruce Webb (1981; 1985 etc.). They also tested the accuracy and precision of several estimation methods against actual field data obtained from intensive field sampling in the field using Automatic Water Samplers and turbidity meters. Further examinations of the statistical methodologies involved have been published by Ferguson (1987) and Clarke (1990). Phillips et al (1999) evaluated 22 suspended sediment load estimation equations for northern England catchments.

Moe recently, Art Horowitz (2003) worked on sediment rating curves for US and European rivers and he recommends that sampling is done on a hydrological, rather than a calendar, basis to minimise errors. See also the Crowder et al (2007) study of suspended sediment load–discharge relationships for US Midwest basins, and the work of Brown et al (2010) who used multiple load estimation approaches for basins in the UK, Germany and The Netherlands.

See also the detailed work over the last 15 years on such problems by the Atlanta, Georgia, USA group led by Art Horowitz, e.g.:

Arthur J. Horowitz, Kent A. Elrick and James J. Smith. 2001. ‘Estimating suspended sediment and trace element fluxes in large river basins: methodological considerations as applied to the NASQAN programme.’ Hydrological Processes, 15, pp.1107–1132. DOI: 10.1002/hyp.206.

Incidentally, Moatar and Meybeck (2005, p. 430) argue that some of the uncertainty issues also apply to nutrient load estimation: ‘concentration data are still commonly the limiting factor on the quality of river flux estimates’.

Much of the uncertainty in estimating sediment transport arises from a failure to account for suspended sediment concentration variations during storm events, when suspended sediment concentrations can vary by 2-3 orders of magnitude or more. I’ve attached here one of own papers on this issue, and hysteresis problems in particular, as an illustration in urban rivers.

I’ll try and send the full references for some of these studies later.

Through environmental control has it been totally possible to totally eliminate organometallic compounds, PAH, MTBE and trace metals from the industrial effluents?

This is a very interesting question, but I am afraid it's quite impossible to answer. The real problem is this one: if you work on natural samples (soils or sediments), you cannot change the refractive index used from one sample to another one. If you do that, you will never be sure that you could compare each sample. Furthermore, if you find a refractive index which seems well adapted for small particles, what would happen for a mixed sample containing higher particles. We had this problem for example when working on riverine suspended particulate matter. Both sizes and mineralogy could change between high and low flow, but we had to kept the same methods for the analyses on Malvern. In my memory, we decided to keep the usual refractive index proposed by the company.

Nevertheless, personally I do not support the use of TEQ in sediments. Dominant compounds in this compartment may not be taken up evenly by organisms. Moreover, CCME guidelines are based on toxicity to sediment dwelling organisms, while dioxins toxicity is much more of concern for vertebrates, in particular mammals.