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Verrrrly Intellestink (how to test fish for mercury)

Discussion in 'Northeast Ohio Fishing Reports' started by Elamenohpee, Dec 13, 2004.

  1. Elamenohpee

    Elamenohpee Banned

    EPA > Region 10 > Lab Page > > Fish Grinding

    Fish Grinding
    This document is intended to be used as a guideline for the grinding and homogenization of fish tissue for mercury analysis. Prepared at the USEPA R10 laboratory on 8/20/2003 by Xin Li (ECO intern) and Kathy Parker USEPA Chemist.

    Small Fish, Whole Body
    Medium and Large Fish, Whole Body
    Using Dry Ice
    Small Tools

    Prior to the start of grinding, freeze the fish solid. All fish parts should be at least partially frozen during grinding. This will allow easier handling and a finer grind.

    Small Fish (smaller than 4 inches), Whole body:
    Fish that are similar in size to smelt can be homogenized in a small Cuisinart Food Processor -
    For best result, the fish should be ground frozen.
    If not frozen, use dry ice or liquid nitrogen in the grinding process.
    Example of small fish - smelt:
    Cuisinart Food Processor -

    Medium (5-8 inches) and Large (larger than 9 inches) Fish, Whole body:
    The fish should be cut up into bite-size chunks using a cleaver and rubber headed hammer prior to grinding.
    Use scissors to remove the fins and tail.
    Grind a few chunks in a large Cuisinart Food Processor with a small handful of dry ice (if the fish is not frozen).
    After all the portions are ground, mix the portions together by hand or with a spoon and then regrind.
    Repeat the grinding and mixing until the tissue looks homogenized.
    Example of medium fish - snapper:
    Example of large fish - salmon:
    Large Cuisinart:

    Skin should be frozen.
    Cut it into small pieces, about the size of a dime.
    Place portions of the skin into the bowl of a Bamix Hand Blender.
    Then place dry ice on top of the skin in the Bamix bowl.
    Start grinding. Stop frequently to loosen the lid during the grinding process so it doesn't freeze to the bowl.
    Mix the skin portions together and grind again to mix.
    Bamix Hand Blender and Bowl:

    The head should be frozen.
    Cut the head into small chunks to fit through a Hobart Meat Grinder. The smaller the chunks, the faster the grinding.
    Mix the first grinding by hand and then grind again. Repeat the mixing and grinding twice.
    Dry ice is not needed with the Hobart.
    Hobart Meat Grinder:
    King Salmon Head:

    Place fat in the bowl of a small Cuisinart Food Processor.
    Grind until it is homogenized.
    Fat does not take very long and does not need dry ice.

    Using Dry Ice for Fish or Skin:
    Place the sample in a Cuisinart Food Processor or whatever machine is being used.
    Cut up small chunks of dry ice and place on the sample.
    The amount of dry ice depends on the size and the species of fish. Smaller fish need less dry ice while larger fish need more dry ice.
    The machine may freeze the lid to the bowl during the grinding process. To prevent this, move the lid once or twice during the grinding.

    Tools used:

    • Cleaver with Rubber head hammer for chopping up fish
    • Large knife for cutting up small fish or tissue
    • Small knifes used for scaling
    • Cutting board
    • Scissors were used to remove fin and tail
    • Metal mesh glove for cutting fish into chunks and filleting
    • Small and large cuisinarts used to grind small and large fish, respectively
    • Bamix Handle Blender used to grind for the skin
    • Hobart Meat Grinder used to grind large heads
    • Spoons and bowls used for mixing.



    Unit: OEA
    Point of contact: Katherine Parker
    Phone Number: (360) 871-8716
    Last Updated: 06/15/2004 02:02:40 PM


    In conclusion...I'd recomend against fixing your fish in theis manner.

    What a freakin' joke....and they issue warnings on this kind of quack science :eek: :eek:
  2. Have you ever done that before? Do you understand the science behind getting heavy metal concentrations from fish tissues? Do you know why they do certain things like whole fish and skin on and skin off and filets only, the science behind it, the reason it is done for some species and not others. Do you konw that the fundamentals of cellular biology, preparing cell cultures and extracting cells from a large mixed substance were based on something as simple as the hand held food processor and this is where it originates from. No one says you have to follow these guidelines. They are the cautionary suggestions put in place for your own health, it is not law in most cases. But until you have done it, have a background in it, or understand the methodology better than this outline I suggest you not be so critical and borderline rude towards the people that do. I don't see any basis for this being called a joke. It is a proven, discrete list of scientific methods to test for concentrations of heavy metals in fish/animal tissues.

    There is a reason its called fish tissue analysis, not fish cheek, or caudal fin, or or nicely cut filet analysis. And the simple steps you copied and pasted in are the exact reason why. It takes an unbiased look at a substances concentration throughout ALL of the tissue of the sample, or where it is found due to the biology of the fish.

    Would it be any different if instead of blender or grinder it said "scientific tissue homoganizer". Because thats all its doing, so why not use something with the same function that costs 20 dollars than something that costs several hundred. Just becuase it uses something as simple as a filet knife, cutting boards, and blenders does not make it any less of a sound practice. The tissue is still sampled for the same chemicals which is the end result desired, there just happens to be a fairly easy way to get to that point.

  3. And...
    that is for region 10
    Ohio is not in region 10 of the USEPA jurisdiction
    State environmental agencies carry precident on many matters over the USEPA, and in this case the Ohio warnings are base off of data gathered from Ohio agencies in this case the OEPA, ODNR, and Department of Health.

    Secondly you even show that this was put on a web page by an intern as a lab practice. Knowing that you should know that this is most likely an abbreviated step by step outline of the process involved without the technical jargon. Most USEPA and OEPA guideline manuals for procedures involving water quality are several inches thick.
  4. Elamenohpee

    Elamenohpee Banned

    Well doc, I aint no rockit sientist, but I do's no that if'n you don't want to eat no poo poo...then don't put it in yer milkshake or smere it on yer stake
  5. Elamenohpee, why do you call that procedure "quack science"? How would you go about preparing tissue for analysis in your lab?


    By humorous coincidence, the add at the top of this page was an add for Cuisinart :p
  6. Elamenohpee

    Elamenohpee Banned

    Start Here
    There isn't one state in the union without some sort of warning pertaining to fish consumption. Test the parts people eat!!!!! Seems pretty simple to me.
  7. That is a NATIONWIDE MERCURY ADVISORY. That is the only one that covers freshwater fish over every state. Secondly, yes many states do have advisories about fish consumption over a varying number of chemicals and that is for the sheer fact they are there. The Ohio EPA test for over 30 things as it is now. I suggest you really start here because that is the one that matters, and that is the one that is all inclusive. The history of it, where is tested, what is tested, and what the results are.

    What does "test the part people eat have to do with it". They are by doing it as anall inclusive method, but it changes and is dependant upon the fish, the size of the fish, the size of the watershed, etx. But what good would testing just the perfect filet of fish serve? Do you honestly think that every person that consumes fish in this state, let alone this club does that. The answer is NO, fish are often processed and sold as such. It is a FISH TISSUE test not a FISH FILET test. What do you think imitation crab meat is, it is a processed multispecies colored blob of fish. Testing JUST the portion people eat in no way shows the contamination level within the FISH. The fact of the matter is, differnet chemicals go to different portions of the tissue due to their nature. If you test ONLY for mercury in a fish and cut your sample fish into perfect white meat only filets, do you know what you will get. A decievingly low result of mercury concentration in fish tissue. Because that is NOT where mercury goes in a tissue cell. So there you have it. Your method essentially prodcues a false result, a lie. If you test one specific area of the fish you are being inherintly biased and that is NOT science. That is one sided policy making. This is not policy, its not law, it is information for your own benefit which you can make your own choice about.
  8. Ruminator

    Ruminator TeamOGF

    Ashton, are you saying that other portions of fish other than the filets are used in making other fish products?
    I easily caught what LMNOP is saying and the reasoning, but it obviously isn't comprehensive enough if other fish parts are used in other products. (if you eat these products)
    If all you ever eat is fresh caught fish filets with the belly meat trimmed how would you fare? Maybe this is what he is getting at and didn't state it?
    Interesting to say the least, I'm really glad that we have you(Ashton) and your professional knowledge to draw from.
  9. Elamenohpee

    Elamenohpee Banned

    Why don't you then, ashtonmj, provide us with what would be a safer method of fish consumption. Give us some information that directly affects us. Seems like a very simple matter, but then that might just eliminate some liberal based positions.

    What are the levels of contaminants in a perfect white meat only filet compared to a whole fish?
  10. Yes other portions of fish than filets are used in making SOME fish products. I am not specifically naming things you or I may eat, but people do eat cheek meat, people do use fish bodies to creat fish stock. Are they necessarily things we buy, no not really, but there are things that contained processed fish products. I suggest you check out the Audobon society, they have a nice little color coded scale about what fish you should and shouldnt eat determined by the health of the fish and the health of the fishery itself. Also just take into account your own personal health, where you fish and what you fish for. This is a simple fact of being informed and knowing what to do with the information.

    PLAIN AND SIMPLE this is a comprehensive measure of a variety of contaminents in the fish tissue. To sample ALL the fish tissue, you need to use ALL the fish. Ruminator what you stated is exactly what the state and every other agency recommends to trim your fish to avoid the ingestion of contaminents. Advisories are general too they have to encompass everyone. A mother of child bearing age obviously has a different body than someone that is elderly, or a young mail, so all process these differently.

    The best scientific methods showing pure unbiased scientific results are already in use to determine fish consumptions. Would it be better if things were tested more localy, moer frequently, yes, but frankly there isnt the time nor money more importantly. I did give you information that directly effects you, the OEPA division of surface water website. You can see every body of water tested in the state, for what species, for what contaminent. How much more detailed do you want? Would you like primary source medical journals of the effects of PCB contamination on a fetus, or mecury degradation on DNA that is then further passed down into your offsprings DNA. If you would read the information I provided on the OEPA website or the Ohio department of health about merucry contamination and how it works you would have seen that because its nature as a heavy element, and being heavier that water, and insoluble in water, it finds its way into fatty cells and tissues. Hence not being in the white filet meat of fish. It finds its way to darker meats, fatty parts of the fish, etc. So that goes right back to your final question about numbers in white meat versus the whole fish. You are asking a poposterous question. There are too many variables in that. Secondly one fish does not make the sample statistically and scientifically viable. The age of the fish can change that, where you catch that fish changes that, the species of fish changes that. Again I suggest you go to the OEPA link I gave you and back track to the division of surface waters home page and read the 10 year back log of Fish Tissue analysis they have available for the public to read. There you can see your hard numbers on the actual numbers of fish for what contaminents.

    Eliminate liberal based opinions?! you are joking me right?! Sir, I am a biologist first and foremost, and as a biologist I have ethics to report unbiased scientific findinds above all, especially before political affiliations. I have represented some crook companies that did some bad things before to our nations waterways and believe me I have wanted to screw them over badly, and I professionaly represented them and gave them the best, accurate, unbiased data. That is my job, that is my belief, that streches well beyond some catch phrase, bad word, of the year. This is SCIENCE, science has nothing to do with politics, it is a methodology, it is a study.
  11. Ruminator

    Ruminator TeamOGF

    Why is it that you feel the desire/need to be confrontational and derisive? You could accomplish the same and MORE without such.
  12. DaleM

    DaleM Original OGF Staff Member

    LMNOP, let just settle down on your comments. I think we've heard about enough of your remarks. Read what ashtonmj has posted. If you can't take what someone with his knowledge is trying to share, then don't post your negitive remarks. WE really don't need that here.
  13. joe01

    joe01 Functional Fisherman

    Mmmmmm Mercury& PCB's the best tasting fish I'll ever eat!lol
  14. Lewzer

    Lewzer Powderfinger

    We had a long discussion on the testing methodologies of the OEPA/DOW in the past. I mentioned the fish grinding and someone else, ashtonmj, MA???, posted about preparation of the test samples FILLETS for the consumption advisories.
    It was a good thread, one where factual info was posted and one where I learned alot...
    Last edited by a moderator: Apr 30, 2015
  15. Edited at the request of those in charge.

    Sorry folks.
  16. Folks, asntonmj knows what he is talking about. Nuff said.
  17. Elamenohpee

    Elamenohpee Banned

    Wow!!!!! This really must have touched a nerve with some of you guy's....WOW!!!!!, what an over-reaction!!!!!

    Obviously in your haste to read what you wanted to, you've missed the point! (seems like a lot of that goes on around here)

    I have much more to say, but I think I'll just let you guys settle down...afterall it's the Christmas season
  18. rockbass

    rockbass Banned

    Man I was thinking the same thing Elamenohpee! It has happened to me too!