Heavy metals in seafood: maximum allowable limits

Heavy metals in seafood: maximum allowable limits

Seafood, in particular fish are a good source of protein and omega 3 fatty acids. As well these beneficial nutrients, seafood can contain trace amounts of different metals. Heavy metals present in water both naturally and introduced to the water system are absorbed by animals living in that environment. While trace elements are found in most seafood, much higher levels are found in predatory sea animals, due to the cumulative effect of their consumption. Analysis of trace metals is important to remain compliant with different countries food laws.

Trace elements in Spinach: regulations

Green leafy vegetables are good for you. They are an easy go to for a range of vitamins and minerals, including vitamin A, E and K, folate, calcium, magnesium, and potassium. While once a less desirable vegetable that needed cartoon sailors to promote it, spinach has gained popularity due to its versatility as an ingredient and nutrient density, even among other green leafy vegetables.

Trace Mineral Analysis of Hair

The analysis of hair may seem more like something you would see on dramatic police forensics TV show, but it’s become an accessible form of mineral analysis. If you or your doctor have concerns it can be a pain free first step to diagnosing potential issues.

What is it?

Hair analysis takes a sample of hair, usually from the back of the neck, and measures the levels of various minerals present in the hair and therefore the body. The analysis use Mass Spectrometry to compare the minerals in the hair to reference samples which can then provide a quantity of the mineral found in the sample. 

Why Would I need analysis?

If you or a health professional have concerns about your health, that you think have may be due to toxicities or deficiencies, you could have your hair analysed to confirm this. The advantage of hair analysis is that it’s an opportunity to quantify minerals in your body without the need for any invasive procedures like blood tests at the beginning. If the hair testing yields concerning results, further testing can be pursued.

Toxic elements

It’s important to understand what toxicity is and not to panic at results that may show that you have toxic minerals in your body. Many substances can be toxic when they are at certain levels in the body. Vitamin A and D are important substances that the body needs to function, however at high enough levels they can be toxic. Hair analysis can identify minerals that can be toxic and provide analysis of what levels are in the body. These are usually heavy metals like arsenic or lead that can have negative impacts on the body at toxic levels. Lead toxicity can produce symptoms such as fatigue, nausea or joint pain. Hair mineral analysis can be a first step in diagnosis of potential toxic minerals.   

Nutritional minerals

In the human body minerals play a number of roles. If a person doesn’t have the required amount they are considered deficient in that mineral. Minerals can play a part in some metabolic pathways in the body, the transport of other nutrients or elements throughout the body, or the growth of bone and muscle. A person with mineral deficiencies can display a range of symptoms. For example, Magnesium deficiency can lead to mild symptoms such as muscle cramps or lethargy or have long term effects such as high blood pressure and diabetes. Hair mineral testing can isolate and quantify levels of these important minerals. Hair analysis can also provide the ratios of different minerals to each other, which also plays an important role in nutrition.    

Importance of reference samples (reference material)

To determine the amount of a given mineral in the hair sample, testing laboratories need to use reference samples. A reference sample is a known concentration of a specified mineral. When this is measured it can then be used as a comparison to the mineral in your hair and assess the quality of the analysis. If a reference sample isn’t used, then it is difficult to perform quality control of the analysis. Most reputable laboratories conform to an accredited method for hair analysis and will include the level of the reference sample in their reports.    

Importance of interpretation

As with any analysis, the results need to be interpreted. Most testing laboratories will provide results only. Analysis provides a list of the minerals identified and the levels that they are present at (hopefully compared to reference levels). To the average person these results won’t mean a lot. This is why it is important to have a qualified health professional interpret the results and suggest a course of action. In the case of nutritional mineral deficiencies, a nutritionist or dietician may be able to interpret results and recommend any dietary changes that you may need. A doctor, however is the best person to consult with regarding your results. Once a doctor has seen the mineral levels, they can propose additional analysis (such as blood tests), possible therapies, or investigation as to the source of toxic minerals or nutritional deficiencies. It is not advisable to attempt to remedy deficiencies or toxic levels by yourself. Always seek professional advice.    

Hair mineral testing is an easy, non-invasive option for mineral testing in the body, that may offer some explanation of symptoms you may be displaying. It is, however, important to remember that this test is usually just a first step in any diagnosis of possible toxic or nutritional issues. 

Analysis of heavy metals in hair

Analysis of heavy metals in hair

Modern research studies these days focus a lot on analysis of balance of trace metals in humans. Investigations have shown that many trace elements can influence human health. For example, the excess of some toxic metals or deficiency of some essential metals can be the significant factor in many physical or psychological conditions such autism.

Rapid test methods for plant analysis

Rapid test methods for plant analysis

Plant analysis provides important information about the nutritional value, quality, and current condition of plants. Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) are two of the most used laboratory techniques. But these techniques require tedious sample preparation, more expenses, and more time. This led to the development of rapid techniques which can help in on-site decision making.

Soil test kits

Soil test kits

In any agricultural activity, the first step is soil testing. This gives information about the soil’s fertility and its physical and chemical properties. To obtain such information, analysts use soil test kits for on-site testing. Analysts can then determine if the soil is viable for planting. They can also determine what should be added to the soil to improve its fertility.

Analysing for Staphylococcus aureus

Analysing for Staphylococcus aureus

Staphylococcus aureus is facultative anaerobic, gram-positive cocci. It was named as such because of its grape-like (Greek: staphyl) forming clusters of cells and golden (aureus) colour of colonies. S. aureus can cause diseases through direct infection or indirectly by the production of toxins. This bacterium is known as a leading cause of bloodstream infections with consequences such as infective endocarditis, septic arthritis, and osteomyelitis.

EPA Regulation for Diesel Particulate Emissions in Cars and Light-duty Trucks

Diesel Exhaust Particles (DEP) are released into the air when diesel fuel is burned by engines and pose a serious threat to the environment as well as to human life. Diesel exhaust is a complex mixture of gases, vapours, liquid aerosols and particulate substances that are the products of combustion. 

Slurry sampling by ICP-MS for heavy metal analysis

Most of the analytical techniques used for the determination of heavy metals in solid samples require sample digestion. This way, the sample in the liquid state can be introduced into an analytical instrument. However, sample digestion can lead to loss of volatile compounds. This also leads to having partly soluble compounds present in the analysed material.

On the other hand, methods such as X-ray fluorescence that directly work with solid samples have limits of detection that are unsatisfactory. That’s why scientists have developed an analytical technique that doesn not require sample digestion while still producing satisfactory detection limits. This method is based on inductively coupled plasma – mass spectrometry (ICP-MS).

In the ICP-MS method, the sample is introduced undigested into an analytical instrument. It starts with pumping sample (mostly liquid) into nebulizer where it is turned into a fine aerosol with argon gas. From there it goes to spray chamber, after which fine particles are injected to the plasma torch. In plasma torch, ionisation of the sample occurs. The ions are then directed to mass analyser and detector.

For slurry sampling by ICP-MS, the sample should be ground and dispersed in a suitable chemical. Studies showed that sample particle size of 8 µm would act the same as liquid droplets in the nebulizer. They will undergo the same ionisation process in the plasma torch.

Slurry nebulisation ICP-MS is useful for multi-element analysis in many types of rock samples. It can also be used for sediment and soil testing. It is also an alternative technique for the determination of volatile elements such as arsenic, antimony, and tin. For the determination of low levels of uranium, thorium, niobium, and tantalum, slurry nebulisation ICP-MS is also useful. The limits of detection using this technique are less than 1 ng/g for many elements such as chromium, selenium, silver, cadmium, tin, and antimony.

Acetaldehyde testing in wine

Acetaldehyde is often present in wine in low levels. It is present as a metabolite of yeasts, particularly if fermentation conditions aren’t ideal, as a by-product of acetobacter and from the oxidation of ethanol. In wine, it is considered a fault with a sensory threshold of 100-125mg/L. It imparts a cut apple or straw flavour to the wine. In some sherries, however, that same flavour is a known organoleptic characteristic of the beverage, and its production is targeted. Samples can be tested to determine if acetaldehyde is present above sensory threshold levels and suitable for release.  

An enzyme assay and spectrophotometry can be used to quantify acetaldehyde in a sample. Acetaldehyde will oxidise in the presence of NAD+ and water to produce acetic acid, NADH + H+. This reaction is catalysed by aldehyde dehydrogenase. To measure the acetaldehyde concentration, the sample is mixed with a known quantity of NAD+ and aldehyde dehydrogenase. A spectrophotometer, which measures the absorbance of light at a particular wavelength is then used. The absorbance of the sample is then measured at 340 nm to determine NADH concentration. The acetaldehyde can then be quantified by determining its stoichiometric ratio to NADH. The test only takes a few minutes to complete analysis.

"Acetaldehyde — Waterhouse Lab". Waterhouse.ucdavis.edu. N.p., 2016. Web. 23 Aug. 2016.

Rotariu, L., Arvinte, A., Litescu, S.-C., & Bala, C. (n.d.). Fast Enzymatic Method For Acetaldehyde Determination In Wine Quality Control, 105–110.