Worried about PFAS?

Well, it is a bit complicated as we are talking about PFAS as the collective name for a huge group of chemicals that according to some counts include over 12,000 synthetic per-and polyfluoroalkyl substances that have unique chemical uses including as lubricants, sealants and for waterproofing and heat resistance. The real problem is that they are highly resistant to degradation both in the environment and in human bodies and have thus been dubbed forever chemicals.

Although they have been around since the 1950s, concerns about their presence and toxicity have been gradually increasing. The reason being that the physical and chemical properties that make PFAS persistent and mobile in the environment also make them particularly challenging to analyse. Analytical methods sensitive enough to detect environmentally relevant concentrations didn’t become widely available until the early 2010s.

Now PFAS contamination has been found to be global. PFAS have been detected in regions with little human activity, including the atmosphere of remote locations, the Arctic and Antarctic seas and remote soils of every continent.

But let’s start from the beginning

PFAS have existed for over 90 years with the first form, polychlorotrifluoroethylene (PCTFE), discovered in 1934 in Germany. Bought by 3M in 1957, it was commercialised under the name Neoflon for use in semiconductors, chemicals and electronic components.

In parallel and almost by accident, DuPont had in 1938 found that a frozen, compressed sample of the fluorocarbon tetrafluoroethylene had spontaneously formed a white, waxy solid that would be dubbed PTFE (polytetrafluoroethylene) and later trademarked as Teflon. It was initially used in the Manhattan Project in gaskets and valves to hold toxic uranium hexafluoride in pipes when building the first nuclear bomb. Over the next several years, the company expanded the chemical’s use into cookware, stain repellents in fabrics and textiles and industrial coatings.

Not to be beaten, 3M scientists continued their development of PFAS chemicals resulting in perfluorooctanoic acid (PFOA) in 1947 and perfluorooctane sulfonic acid (PFOS) in 1953. They were both resistant to heat, oil, stains, grease and water. In 1951, 3M provided PFOA to DuPont to be used as an aid when coating products with Teflon. Both PFOS and PFOA would go on to be used as a component in a wide variety of products for years, including Scotchgard, stain resistant carpets and later firefighting foam. The 3M company kept expanding the range of PFAS by introducing perfluorohexane sulfonic acid (PFHxS) in 1958, again to be used in stain-resistant fabrics, fire-fighting foams, food packaging, and as a surfactant in industrial processes.

Within 20 years of its initial discovery in 1934, PFAS in its many forms had gone from a laboratory accident, to an atomic bomb project component, to an ingredient in everyday household products.

The dangers of PFAS

You would have thought that when synthesising indestructible compounds they would be extensively tested for potential toxicity before being released. Very conveniently according to publicly released information PFAS were long presumed to be biologically inert. However, legal disclosures and investigative reporting later uncovered evidence that companies that manufactured PFAS knew of their toxic effects on human health and the environment by 1970, forty years before it was generally known in the public health community.

Their human toxicity and ecosystem impacts have since received extensive public, scientific and regulatory attention. Testing of human blood in the USA, starting in 1999, found PFOA, PFOS, and PFHxS, the worst of the worst, in 99% of the sampled population. By 2006, PFAS had been found in ground and surface water, in soil and sediments, and in wildlife. The toxic properties and their inability to break down in the environment and to build up in human blood had become more evident.

Mounting evidence of the adverse health effects of PFAS showed that exposure to certain levels of the forever chemicals increased cancer risk such as liver, kidney, and testicular cancers, lowered birth weight in babies, produced higher levels of cholesterol, reduced kidney function, caused thyroid disease, altered sex hormone levels, and damaged the immune system resulting in a reduced vaccine response.

In 2007 a concerned European Commission asked the European Food Safety Authority (EFSA) to review health aspects of some PFAS as there was a clear need to assess the potential risks associated with human exposure to this class of substances. EFSA, in its opinion published in 2008, concluded that it was unlikely that adverse health effects from dietary exposure to PFOS or PFOA were occurring in the general population but stressed that this opinion was based on very limited data.

However, the more we look, the more alarming the health threat appears to be. Emerging research found PFAS in consumer products such as cosmetics, packaging, waterproofing, inks, pesticides, medical articles, polishes and paints, metal plating, pipes and cables, mechanical components, electronics, solar cells, textiles and carpets. As a result two of the highest-profile compounds, PFOS and PFOA, were added to the Stockholm Convention for the protection of human health and the environment from persistent organic pollutants (POPs) in 2009 and 2019, respectively, limiting their use and production. PFHxS was added to the list in 2022. In 2023, the International Agency for Research on Cancer (IARC) declared PFOA a category one human carcinogen.

What about exposure from food and water?

Potential human exposure pathways for PFAS include inhalation, incidental soil and dust ingestion, dermal contact, diet and drinking water. Diet and drinking water are considered the main sources of human exposure to PFAS in the general population. Two main processes are thought to lead to PFAS contamination of food, namely bioaccumulation in aquatic and terrestrial food chains, and transfer from contact materials used in food processing and packaging. Local water supply is a special case with high levels of PFAS detected close to industrial sites, military institutions and fire training facilities. Apart from water, foods like fish, fruit and eggs and egg products have been shown to contribute the most to human exposure.

In 2018, EFSA changed their tune based on new information for dietary exposure and toxicity. In establishing a tolerable intake of 13 ng/kg body weight per week (TWI) for PFOS and 6 ng/kg body weight per week for PFOA, they now concluded that exposure of a considerable proportion of the population exceeded the proposed limits for both compounds.

This was further strengthened in the EFSA opinion from 2020 evaluating the combined exposure to the sum of the four most potentially dangerous compounds: PFOA, PFNA, PFHxS and PFOS. Effects on the immune system with reduced antibody response to vaccination were considered the most sensitive and thus the most critical for the risk assessment. Since accumulation over time is important, the tolerable intake was lowered to a combined 4.4 ng/kg body weight per week for the four PFAS, considered protective also to other potential adverse effects observed in humans. Unfortunately parts of the European population exceed this TWI, which EFSA concluded was a concern.

International focus on PFAS

Worldwide, regulatory PFAS guidance has been rapidly evolving, with the inclusion of a wider range of PFAS covered in advisories and a continued decrease in what is deemed safe PFAS concentrations. In the USA a recent extensive review was published in 2022 by the National Academies of Sciences, Engineering, and Medicine titled Guidance on PFAS Exposure, Testing, and Clinical Follow-Up. The review found that an estimated 2,854 U.S. locations (in all 50 states and two territories) have some level of PFAS contamination and almost 100 percent of the U.S. population is exposed to at least one PFAS. They concluded that although not all of the contamination exceed health advisories, the pervasiveness of the contamination is alarming.

In a 2023 response to the PFAS challenge, the Government of Canada published a Draft State of Per- and polyfluoroalkyl substances (PFAS) Report. The report provides a qualitative assessment of the fate, sources, occurrence, and potential impacts of PFAS on the environment and human health in Canada. With the application of precautionary assumptions that are protective of human health and the environment when addressing gaps in information, the report provides the basis for a class-based approach to inform decision-making on PFAS in Canada. The report also conclude that PFAS as a class are harmful to human health and the environment.

Japan is no stranger to chemical contamination. But despite the history, combined with Japan having one of the world’s largest chemical industries and many Japanese companies producing or using PFAS chemicals, the attention paid to these chemicals has been far less than in the USA and Europe, at least in the public domain. Some researchers have recently warned of adverse effects on humans after high concentration levels of PFAS were detected in various parts of the country, which fuelled concern among residents. A report from Japan’s Food Safety Commission proposes the first-ever daily intake limits for PFOS and PFOA linked to health risks, emphasising safety in food consumption. It suggests a tolerable daily limit of 20 ng/kg body weight for each compound.

Based on advice from EFSA, the European Commission in 2022 established maximum levels for PFOS, PFOA, PFNA, and PFHxS in eggs, fish and bivalve molluscs and meat and offal. The varying maximum levels are laid out in Regulation (EC) 2022/2388.

Regulators worldwide have proposed or regulated varying concentrations for some PFAS in drinking water. Suggested maximum levels vary from 4 ng/L in the USA to 560 ng/L in Australia. However, it is impossible to compare the suggested maximum levels between countries as they are based on coverage of different numbers of PFAS. Some limits only cover PFOS and PFOA while others include all measurable PFAS.

The future is still uncertain

To eliminate the threat posed by PFAS will not be easy as they are still used in many applications where the use is considered proprietary with information not readily available or public. Gaining a complete picture of the threat is also a challenge because of the chemical and toxicological differences among individual PFAS and uncertainty about the exposure level at which their adverse effects may occur. In addition, many of the chronic diseases associated with PFAS exposure have also myriad other causes.

Unfortunately for all of us, it is difficult to reduce exposure to PFAS through personal behaviour modifications. There are so many routes of potential dietary exposure to PFAS from non-stick cookware, grease-resistant paper, fast food wrappers, microwave popcorn bags, and retail and convenience packaging. Add to that the use of PFAS in our clothes, our furniture, cosmetics, sunscreens, shampoos, carpets, menstrual products, dental products and even in artificial turf.

The best we can do is to keep up the pressure on regulatory authorities to lower the PFAS limits in the water supply and look at banning their use in most consumer products and food packaging.

And finally let’s learn from the mistake of releasing chemicals before they have been tested for harmful effects to humans and the total environment.

Toxic arsenic in rice

We have written about the toxicity of arsenic in food twice before. The first time was in 2012 covering a 2009 opinion from the European Food Safety Authority (EFSA) and a 2012 report from the US Food and Drug Administration. The second time was in 2020 based on research from the University of Washington covering the impact of climate change on further accumulation of arsenic in rice due to a warmer climate.

Previous problems in determining the chemical form of arsenic (arsenic speciation)

Arsenic exists in several different forms in nature bound to a number of other compounds resulting in varying toxicity. It is the inorganic arsenic (compounds that do not contain carbon) commonly found in water and rice that is particularly toxic. Soluble inorganic arsenic is rapidly and nearly completely absorbed after ingestion and widely distributed to almost all organs. Organic arsenic commonly found in fish and other seafood is far less toxic.

And here we have a real problem in that arsenic analysis at speciation level has been very difficult. Unfortunately, the EFSA risk assessment in 2009 had to make assumptions about the proportion of inorganic arsenic in different food commodities based on the total arsenic levels reported to allow calculation of specific exposure to the toxic species. With an improved focus on arsenic speciation, the European Commission asked EFSA to first update the exposure assessment based only on inorganic arsenic results and secondly to update its risk assessment of inorganic arsenic to consider new studies on its toxic effects.

The new exposure results

In 2021, EFSA published an updated exposure assessment. It was based on a total of 13,608 analytical results on inorganic arsenic of which 7,623 covered drinking water and 5,985 covered different types of food, in particular rice and rice-based products. Samples were collected across Europe between 2013 and 2018. Consumption data from 23 different European countries and a total of 44 different dietary surveys (87,945 subjects) were used to better estimate the chronic dietary exposure of inorganic arsenic.

The highest dietary exposure to inorganic arsenic was seen in the young population (infant, toddlers and other children) with mean values in the different surveys ranging between 0.07-0.61 μg/kg bodyweight per day, and high exposure consumers (the 95th percentile estimates) between 0.17-1.20 μg/kg bodyweight per day. In the adult population (adults, elderly and very elderly), mean dietary exposure estimates ranged between 0.03-0.15 μg/kg bodyweight per day, and between 0.06-0.33 μg/kg bodyweight for high intake consumers (the 95th percentile estimates).

These dietary exposure estimates of inorganic arsenic were noticeably lower than previously reported, with the new estimates being around 1.5–3 times lower across the different age classes. This difference can be explained by the use of measured rather than previously calculated inorganic arsenic and more accurate consumption data. The higher dietary exposure seen in the young population is to a large extent due to consumption of rice-based foods for infants as well as biscuits, rusks and cookies for children.

And the new risk assessment results

In 2024, EFSA published a new risk assessment of inorganic arsenic in food based on the new exposure assessment and updated toxicity results. The latter used findings from existing human epidemiological studies not normally available, and not animal studies as proxies for human effects. The epidemiological studies showed that chronic intake of inorganic arsenic via diet and/or drinking water was associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung.

For its risk assessment, EFSA considered the increased incidence of skin cancers associated with inorganic arsenic exposure as the most relevant harmful effect. The experts concluded that ensuring protection against skin cancer would also be protective against other potentially harmful effects.

When assessing genotoxic and carcinogenic substances that are unintentionally present in the food chain, EFSA calculates a margin of exposure (MOE) for consumers. The MOE is a ratio of two factors: the dose at which a small but measurable adverse effect is observed called the reference point, and the level of exposure to a substance for a given population.

In its 2009 opinion, EFSA calculated the reference point as a range of values between 0.3 and 8 µg/kg bodyweight per day of inorganic arsenic associated with cancers of the lung, skin and bladder, as well as skin lesions. In the new opinion of 2024, the reference point was lowered to a single value of 0.06 μg/kg bodyweight per day using a case–control study of skin cancer (squamous cell carcinoma) carried out in the US. This is in the range of the new mean dietary exposure estimates for inorganic arsenic in adults (0.03–0.15 μg/kg bodyweight per day), and below any of the high exposure estimates in adults ( 0.07–0.33 μg/kg bodyweight per day). In adults, the calculated MOEs ranged between 2 and 0.4 for mean consumers and between 0.9 and 0.2 for high consumers, respectively. An MOE calculated from human data of 1 or less would correspond to an exposure level to inorganic arsenic that might be associated with an increased risk of skin cancer and thus raises a health concern.

The same conclusion applies to the younger age groups despite their higher exposure to inorganic arsenic as the harmful effect seen in adults are due to chronic exposure and the epidemiological studies would have captured their dietary exposure during early life.

So what can be done to limit the risk?

As has been indicated above, rice is a major contributor to inorganic arsenic exposure as it is a dietary staple for millions of people around the world. So what can be done to limit the risk?

Authorities could introduce maximum levels for arsenic in rice, consumers could look at rice types and try to buy rice from regions with less natural levels of arsenic, rice preparation in kitchens could be changed or rice consumption could be reduced if there are alternatives available.

Regulating inorganic arsenic levels

Unfortunately, regulating a naturally occurring element in such a widely eaten food as rice is no easy task. Arsenic levels can vary widely in rice from different countries and states, and among different rice cultivars. This raises difficult questions about how a regulated standard could be monitored and enforced.

Codex Alimentarius has adopted a recommended limit for inorganic arsenic of 200 μg/kg for polished rice, and 350 μg/kg for husked rice. In the European Union maximum levels for inorganic arsenic in rice was introduced in 2016 varying from 100-300 μg/kg depending on the specific product. The Australian guidelines are for total arsenic (organic and inorganic) in rice and set a maximum level of 1000 μg/kg.

However, looking at the reported inorganic arsenic levels in rice reported to EFSA only 15 samples exceeded European Union maximum levels and still a health concern was identified.

Buying rice with proven lower levels

The amount of arsenic in rice depends on the variety of rice and where it was grown. Brown rice has more arsenic than white rice since arsenic is accumulated in the outer layers of the grain, while basmati rice regularly has the lowest levels. Globally, inorganic arsenic in polished rice varied from < 2 to 399 μg/kg in a recent study. The lowest levels were found in East Africa followed by Indonesia and California, while West African rice had an order of magnitude higher inorganic arsenic followed by South America and Southern American states like Texas and Luisiana.

Although it can be quite difficult to know where the rice is grown, it is clear that basmati rice is a preferred choice and brown rice should be avoided despite its better nutritious profile.

Changing rice preparation

Rinsing rice before cooking has a minimal effect on the arsenic content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. However, cooking rice in excess water efficiently reduces the amount of arsenic in the cooked grain by 40% to 60%. It is recommended to use six cups of water to one cup of rice. After boiling the rice, pour off the remaining water, then rinse the cooked rice again.

Unfortunately, this cooking method common in Asia will also reduce some of the nutrients but is recommended on balance to minimise arsenic toxicity.

Limit rice consumption

It is not necessary to eliminate rice completely from your diet, but If you eat a lot of rice eat it less often substituting rice with other whole grains, such as quinoa, barley, ferro, amaranth, bulgur and millet. They’ll be just as nutritious and don’t have arsenic in them because they don’t take up arsenic from the ground as they grow.

Arsenic in rice is a real concern. Be more choosey with the type and origin of your rice, always cook it with excess water, and be aware of how much you’re consuming. Try looking at other whole grain alternatives to keep your arsenic consumption to a minimum.

Tainted spinach

Spinach (Spinacia oleracea) is a leafy green vegetable that originated in Persia. It belongs to the amaranth family and is related to beets and quinoa.

Popeye, a pugnacious, wisecracking cartoon sailor popularised the beneficial effects of spinach by showing superhuman strength after ingesting an always-handy can of spinach.

And it’s true, spinach is considered very healthy, as it’s loaded with nutrients and antioxidants and is also high in insoluble fibre. Eating spinach, as part of a generally healthy diet, may benefit eye health, reduce oxidative stress, help prevent cancer, and reduce blood pressure levels.

There is a small caveat about the fairly high levels of nitrate in spinach. But nothing to worry too much about as we have previously explained.

So all good?

Well, that is until December 2022 when about 200 Australians were reported as being poisoned with symptoms typically occurring within one hour after eating fresh baby spinach leaves. They were reported to show quite serious symptoms including nausea, blurred vision, delirium, confusion, hallucinations, rapid heartbeat, flushed face and dried mouth and skin. Quite a list!

While there were several hospitalisations, most people affected were experiencing symptoms for a short time and recovered fairly quickly. After some considerable detective work the baby spinach was found to be contaminated with the leaves of the noxious weed thornapple, a poisonous invasive species that is found across Australia and in several other countries. 

Thornapple, also known as Jimson weed, devil’s snare and devil’s trumpet, with the scientific name Datura stramonium, belongs to the Solanaceae family of plants. This family includes both healthy kitchen staples like tomatoes and potatoes but also highly poisonous plants such as thornapple, mandrake (Mandragora officinarum) and belladonna (Atropa belladonna) that all contain a group of toxins called tropane alkaloids. This group comprises more than 200 different compounds with limited data on their occurrence in food and feed and their toxicity.

As usual it is the dose that makes the poison. As a matter of fact, small amounts of plant extracts containing tropane alkaloids have been used for centuries in human medicine and are still used, like atropine, hyoscyamine and scopolamine. These uses include for example the treatment of wounds, gout and sleeplessness, and pre-anaesthesia. Extracts from belladonna were used to dilate pupils for cosmetic reasons and to facilitate ophthalmological examination. In India, the root and leaves of thornapple were burned and the smoke inhaled to treat asthma. Some of these poisonous plants have also been used as recreational drugs, although under such less controlled circumstances ingestion could be deadly.

The thornapple culprit!

Thornapple is cultivated worldwide for its chemical and ornamental properties. The plant is one of the 50 fundamental herbs used in traditional Chinese medicine, where it is called yáng jīn huā. It prefers warm-temperate and sub-tropical regions, and as an invasive weed is often found on river flats, roadsides and agricultural lands where it competes with summer crops. It spreads by seed, with each plant producing up to 30,000 seeds and living for up to 40 years in the soil.

The active constituents in thornapple include scopolamine, atropine and other tropane alkaloids acting on the nervous system. Combined they cause stimulation of the nervous system in low doses and depression of the system at higher doses. Ingestion of plant parts may lead to generalised confusion, delirium and powerful hallucinations that often leave the person in a state of panic and severe anxiety.

All parts of the plant contain the highly poisonous tropane alkaloids. They are toxic also in tiny quantities with symptoms like flushed skin, headaches, hallucinations, and possibly convulsions or even coma. Eating a single leaf can lead to severe side effects as was noted in the Australian outbreak.

How did it get into spinach?

The baby spinach producer confirmed that when checking they found thornapple leaves in its baby spinach fields. It is likely that the high amount of rainfall during 2022 in Australia had contributed to the spread of the weed. A few young leaves that would have been looking like baby spinach leaves at that stage of growing were picked up during spinach harvest.

This is not a unique occurrence as seeds of tropane alkaloid-producing plants have been found as impurities in other important agricultural crops such as linseed, soybean, millet, sunflower and buckwheat. The consumption of a few berries from henbane (Hyoscyamus niger) or from belladonna has previously caused severe intoxication, including deaths in young children.

What can we learn?

From this incident we can learn that vigilance is important to avoid contamination of toxic weeds in agricultural crops.

It is also important to have an efficient reporting and tracing system of food related toxic events to capture outbreaks early.

However, fortunately it’s all clear for the baby spinach itself.

Consuming micro- and nanoplastics

We seem quite good at inventing ‘things’ and we rush them to market before giving enough thought to potential negative consequences. The question is will we ever learn? Ulrich Beck, a past sociology professor at the University of Munich, pointed to inherent long-term risks with new products that are often disregarded by an enthusiastic subordination of nature by science and technology. (Image by storyset on Freepik)

There are many examples of how this can backfire.

DDT was hailed as a wonder chemical that would revolutionise agriculture until Rachel Carson published her book ‘Silent Spring’ in 1962. It is now known that DDT caused direct mortality of some birds by poisoning their nervous system, caused bird eggs to have thin shells and reduced levels of a hormone necessary for female birds to lay eggs. It could indeed lead to a silent spring.

PFAS are a large, complex group of manufactured chemicals that are ingredients in various everyday products. They are used to keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective. Now we know of numerous human health effects including altered metabolism and fertility, increased risk of being overweight or obese, and reduced ability of the immune system to fight infections. Something we have to live with as PFAS are persistent chemicals spread everywhere in nature.

Neonicotinoids are insecticides that have been repeatedly called ‘perfect’ for use in crop protection. Since their introduction in the early 1990s, neonicotinoids have become the most widely used insecticides in the world on a variety of crops. However, in a 2013 report by the European Food Safety Authority it was stated that neonicotinoids pose an unacceptably high risk to honey bees, and that the industry-sponsored science upon which regulatory agencies’ claims of safety have relied may be flawed and contain data gaps not previously considered. As bees, consisting of around 20,000 species worldwide, are one of the primary pollinators of both native plants and agricultural crops the impact of neonicotinoids could spell disaster for worldwide food production. Bumblebees are also economically important pollinators and appear to be particularly sensitive to neonicotinoid pesticides, which affect both bumblebee colony growth and foraging efficiency. It is clear that we overuse pesticides at our own peril because human and natural environments are unquestionably linked. And still many countries have no restrictions on neonicotinoid use.

Do you want some plastics with that?

And so we come to plastics, such a useful innovation for many aspects of life. Attempts to produce plastic materials started already in the middle of the 19th century. However, the world’s first fully synthetic plastic was Bakelite, invented in New York in 1907. Many chemists have since contributed to the science of developing a variety of plastic materials. Over 9 billion tonnes of plastics are estimated to have been made over the last 70 years.

The success of plastics has caused widespread environmental problems due to their slow decomposition rate in natural ecosystems. At the macro level, plastic pollution can be found all over the world creating garbage patches in the world’s oceans and contaminating terrestrial ecosystems.

Of all the plastics discarded so far, OECD calculated that only 19% had been incinerated and 9% recycled. However, the real problem can be found at the micro (or even the smallest nano) level.

Microplastics can either come from a primary source like microfibers from clothing, microbeads in cosmetics, and plastic pellets. Or there are secondary microplastics arising from the degradation of larger plastic products through natural weathering processes after entering the environment. Microplastics can now be found wherever we look and will find their way into the food we eat.

Studies have found microplastics in foods including tea, salt, seaweed, milk, seafood, honey, sugar, beer, vegetables, fruit and soft drinks. It has been estimated that 5 g of plastic particles on average enter the human gastrointestinal tract per person per week. A recent Australian survey of microplastics in rice found that consumption of a single serve of rice may contribute 3-4 mg of microplastics, equivalent to an intake of around 1 g per person annually. Even tap water contains microplastics while bottled water contains even more.

So what’s the problem?

The actual plastic polymers are not the problem although residues of the monomers used in the manufacture of the complex polymers may be toxic. What is more of a problem is the variety of additives used to change the properties of the plastic, some of which can be quite toxic. These include plasticisers, flame retardants, heat stabilisers and fillers among many others.

According to current knowledge, microplastics at 0.001 to 5 millimetres in size are considered to pose a comparatively low risk to human health as they are considered to be too ‘bulky’ to be absorbed by human cells and are largely excreted again. However, experimental studies indicate that such particles passing through the gastrointestinal tract can lead to changes in the composition of the gut microbiome and in turn the development of metabolic diseases such as diabetes, obesity or chronic liver disease.

The situation is different with smaller particles, submicro- and nanoplastics. These particles are less than 0.001 millimetre in size. A laboratory study by the German Federal Institute for Risk Assessment found that the smaller the particles, the more they were absorbed. While microplastics only “seeped” into the cell to a small extent, particles in the submicrometre range could be measured in larger quantities in intestinal and liver cells.

Whether ingested micro- and nanoplastics pose a health risk is being investigated in numerous studies but is largely unknown to date. Using specific analyses there are indications that they could activate mechanisms involved in local inflammatory and immune responses and could crucially be involved in carcinogenesis.

What to do?

Not easy to say at this stage. We could of course try to reduce the use of plastics to diminish future contamination, but this is easier said than done with the ubiquitous use of plastics for all kinds of applications.  Some reduction can be achieved by washing fruit and vegetables before consumption. Washing rice before cooking reduced the microplastic content by around 25%.

American researchers pointed out that without a well-designed and tailor-made management strategy for end-of-life plastics, humans are conducting a singular uncontrolled experiment on a global scale, in which billions of metric tons of plastic material will accumulate across all major terrestrial and aquatic ecosystems on the planet.

We can do better!

Marine biotoxins and climate change

I worry about food safety and so it seems do 60% of respondents in a global survey involving 150,000 people in 142 countries. However, while they are mostly concerned about the safety of the current food supply, I worry about the impact of climate change in worsening the food safety situation. We have already covered the impact of climate change on the accumulation of heavy metals and growth of moulds producing mycotoxins.

But of course there is more.

In this last blog in the series covering the food safety impact of climate change we will look at increases in the presence of marine biotoxins produced by blooms of harmful algae.

Toxins produced by some algal species

During recent decades, there has been an apparent increase in the occurrence of harmful algal blooms in many marine and coastal regions. Changes in climate may be creating a marine environment particularly suited to the growth of harmful species of algae. Two major functional groups of marine algae, or phytoplankton, are involved in causing toxic blooms – diatoms and dinoflagellates. There are also toxic cyanobacteria, sometimes called blue-green algae, that are not strictly speaking algae but very similar in action.

Certain toxins produced by these organisms are particularly dangerous to humans. A number of illnesses are caused by ingesting seafood contaminated by the toxins.

The most important harmful algae and their poisoning syndromes include diatoms from the genus Pseudo-nitzschia (amnesic shellfish poisoning), and species of dinoflagellates from the genera Alexandrium, Pyrodinium, and Gymnodinium (paralytic shellfish poisoning), Karenia (neurotoxic shellfish poisoning), Dinophysis and Prorocentrum (diarrhetic shellfish poisoning), and Gambierdiscus (ciguatera fish poisoning). There are also cyanobacteria that produce a range of toxins that can affect humans drinking or swimming in contaminated water causing a similar range of symptoms. Their toxins include microcystin, nodularin, cylindrospermopsin, anatoxin-a, anatoin-a(s), lyngbyatoxin and saxitoxins.

As the names of the syndromes imply the toxins can cause memory loss, digestive problems, seizures, lesions and skin irritations, and finally paralysis that may include the respiratory system. Indeed an impressive list.

Some of these toxins can be acutely lethal and are among the most powerful natural substances known. They affect fish, birds and mammals including humans. Because these toxins are tasteless, odourless, and heat and acid stable, normal screening and food preparation procedures will not prevent intoxication.

Increase in the growth of harmful algae

Dinoflagellate abundances have increased to the detriment of diatom populations in some marine ecosystems linked to increases in sea surface temperatures. This can have serious consequences.

As an example a calculation was performed of the impact of climate change on the length of the period of toxic blooms in Puget Sound, an important area of shellfish farming. Results suggested that by year 2100 the period of optimal growth of the toxic dinoflagellate Alexandrium catenella may potentially expand from 68 days to up to 259 days due to warmer water temperatures. This would have severe implications for regional food safety as A. catenella produces paralytic shellfish poisoning. It would totally close the area for shellfish harvesting for most of the year devastating the local economy.

Another example of a dinoflagellate known to generally favour warmer conditions is Gambierdiscus toxicus, one of the species producing ciguatoxin. Increases in ciguatera fish poisoning has been observed with elevated sea surface temperatures. Clinical signs in humans eating fish containing the toxin include gastrointestinal, neurologic, and cardiovascular signs. Gastrointestinal signs include vomiting, diarrhea, abdominal pain and cramps. Neurologic signs include itching, pain, visual blurring, weakness, depression and headache. Cardiovascular signs include arrhythmia, bradycardia, hypotension, and cardiac block.

Cyanobacteria can reproduce quickly in favourable conditions, where there is abundant sunlight, still or slow-flowing water and sufficient levels of nutrients, especially nitrogen and phosphorus. In still conditions, surface water may form a separate warm top layer in which cyanobacteria is able to access sunlight and nutrients. If these combined factors are present for several days, cyanobacteria multiply and form large blooms. The problem seems to be getting worse. Polluted farm runoff continues largely unabated, and the climate crisis is producing warmer weather and water temperatures, along with more rainfall – all conditions that feed the blooms. News reports of blooms in the USA have increased every year since 2010, when there were a total of 71 stories about outbreaks. In 2018 there were 452 reports about harmful outbreaks.

Incomplete understanding

As already mentioned above harmful algal blooms usually increase during the warm summer months. As daily temperatures continue to rise, the number of days ideal for harmful algal growth increases. As the planet’s oceans warm, coastal regions are seeing more and more algal blooms, often worsened by fertilizer and manure that runs off from farms. With toxic algal blooms becoming more potent and lasting longer, scientists are taking a closer look at their links to a changing climate. What was once considered a summertime matter is now being considered a year-round issue.

However, the extent to which regional climate change will influence harmful algal bloom dynamics is uncertain as separating the effects of climate change from natural variability remains a key scientific challenge. Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. Nonetheless there is only basic information to speculate upon in which regions or habitats harmful algae may be the most resilient or susceptible. 

We can continue to test for the presence of toxins in seafood as is currently the practice in many countries. But the potential escalation of outbreaks could easily overwhelm the system. Should we risk it? I for one worry about the future given the current trajectory of global warming.

Mycotoxins in a Changing Climate

Global climate change is an issue we should take very seriously now or it will threaten our future food supply. However, I am writing this in June 2020 in the middle of the coronavirus pandemic that is attracting all the attention. There are so far more than 6 million people affected worldwide and soon more than 400,000 deaths.

Most countries, but not all, have reacted with urgency to the acute situation with people movements severely restricted and huge amounts of money spent to support economies. More than one hundred attempts to develop vaccines agains the COVID-19 disease are under way to prevent future outbreaks.

Willingness to limit climate change lacking

We already have the “vaccines” or knowhow to prevent further escalation of the changing climate. Although climate change in the longer term will threaten food security, that is global access to food, and negatively impact food safety with the potential to cause much more pain and suffering, hunger and deaths, it is not getting the same attention as a novel acute disease.

There are many pathways through which climate related factors may impact food safety including: changes in temperature and precipitation patterns, increased frequency and intensity of extreme weather events, ocean warming, and changes in the transport pathways of complex contaminants.

Food security might be the more serious challenge as sufficient access to nutritious food is already an issue in many parts of the world, but long-term quality of life is also threatened by food contamination. We have already covered accumulation of arsenic as an example of heavy metal increases in food caused by climate change. Here we will cover aflatoxin as an example of an increased threat from a range of mycotoxins as fungal growth is influenced by climate change.

Mycotoxin threat will increase

Mycotoxins are compounds naturally produced by a large variety of fungi (moulds) that can cause acute effects, including death, along with chronic illnesses from long-term exposure, including various forms of cancer. It has been estimated that 25% of the world’s yearly crop production is already contaminated with mycotoxins. Mycotoxins are known to occur more frequently in areas with a hot and humid climate.

Aflatoxins, which have the highest acute and chronic toxicity of all mycotoxins, assume particular importance. Aflatoxin produced by Aspergillus flavus and A. parasiticus is a genotoxic carcinogen, but is also a potent acute toxin, and is widely distributed associated especially with maize, groundnuts, tree nuts, figs, dates and certain oil seeds such as cottonseed.

Aflatoxins are a group of approximately 20 related fungal metabolites. They are heat stable and difficult to destroy during processing. Thus exposure, both acute and chronic, can have significant impacts on vulnerable groups, especially babies and children. Four aflatoxins – B1, B2, G1 and G2 – are particularly dangerous to humans and animals.

Health effects of aflatoxin exposure

Outbreaks of acute aflatoxicosis were reported in Kenya in 2004 with 125 deaths resulting from consumption of aflatoxin contaminated maize with repeated events in 2005 and 2006. Most recently several deaths attributed to aflatoxins were reported during the summer of 2016 in the United Republic of Tanzania.

However, chronic effects are much more common. Hepatocellular carcinoma, or liver cancer, is the third leading cause of cancer deaths worldwide, with prevalence 16-32 times higher in developing countries than in developed countries. Of the 550,000-600,000 new cases worldwide each year, about 25,000-155,000 may be attributable to aflatoxin exposure. Most cases occur in sub-Saharan Africa, Southeast Asia, and China with largely uncontrolled aflatoxin exposure in food.

The geographical areas subject to aflatoxin growth in maize and wheat are expected to change with temperature increases – it is predicted that aflatoxin contamination and the associated food safety issues will become prevalent in Europe with a temperature increase of +2°C.

Changes in contamination patterns

Aflatoxin contamination causes significant loss for farmers, businesses, and consumers of varied susceptible crops. Climate change alters the complex communities of aflatoxin-producing fungi. This includes changes in space, time and in the quantity of aflatoxin-producers. Generally, if the temperature increases in cool or temperate climates, the respective countries may become more susceptible to aflatoxins. However, tropical countries may become too inhospitable for conventional fungal growth and mycotoxin production.

Although some regions can afford to control the environment of storage facilities to minimize post-harvest problems, this happens at high additional cost.

Many industries frequently affected by aflatoxin contamination know from experience and anecdote that fluctuations in climate impact the extent of contamination. Climate influences contamination, in part, by direct effects on the causative fungi. As climate shifts, so do the complex communities of aflatoxin-producing fungi. This includes changes in the quantity of aflatoxin-producers in the environment and alterations to fungal community structure.

Fluctuations in climate also influence predisposition of hosts to contamination by altering crop development and by affecting insects that create wounds on which aflatoxin-producers proliferate. Aflatoxin contamination is prevalent both in warm humid climates and in irrigated hot deserts. In temperate regions, contamination may be severe during drought.

Public health threat

As usual prevention is much better than late action to repair already existing damage. This is especially important in at risk regions such as parts of Africa and Asia where the risks of exposure to mycotoxins may increase under predicted climate change conditions.

The combination of future food scarcity and contamination of a larger part of the food supply has the potential of creating an explosive public health threat.

Global warming and arsenic in rice

In a series of posts we are going to look at the impact of global warming on food production and the potential for an increase in toxic compounds in our normal diet. First off is rice and higher levels of arsenic found in the rice grain when exposed to higher temperatures during cultivation.

Rice is the world’s most important foodstuff providing nutrients and energy to more than one half of the world’s population. Unfortunately, rice can also contain arsenic, which can cause multiple health conditions and diet-related cancers. In an earlier post we described possible chronic health effects of natural levels of arsenic in food and water.

Here we will cover two issues – the influence of higher global temperatures on arsenic levels in rice and types of arsenic compounds formed in soil under different environmental conditions.

Temperature dependence of arsenic accumulation

Arsenic occurs naturally in soil at different levels across the world. When farmers grow crops like rice under flooded conditions, arsenic is drawn out of the soil and into the water. As rice plants extract water through their roots to its leaves, arsenic follows as it mimics other molecules that rice plants preferentially draw out of the soil.

Now researchers at the University of Washington have found that warmer temperatures, at levels expected under most climate change projections, can lead to higher concentrations of arsenic in rice grains at ranges where they begin to have further health concerns. Arsenic concentrations in the grain more than tripled between the low- and high-temperature treatments.

However, the researchers didn’t have the means to check the type of arsenic compounds found.

Some forms of arsenic are more toxic than others.

It is important to know that not all arsenic is the same as arsenic exists in several different forms. Fish and seafood usually contain high levels of arsenic, but most of this is arsenobetaine, an organic form with little toxicity. It is the inorganic arsenic that can be found in water and rice and a range of other food commodities that has been of particular concern.

However, arsenic speciation is not easy to perform, which has created some confusion. Inorganic and methylated oxyarsenic species have been a focus of research, but thioarsenates, in which sulfur takes the place of oxygen, have largely been ignored.

Now University of Bayreuth researchers, together with scientists from Italy and China, have for the first time systematically investigated under which conditions, and to what extent, sulphur-containing arsenic compounds are formed in rice-growing soils. It turns out that the amounts of thioarsenates formed are linked to the pH-values of the soils and other environmental parameters.

Formation of thioarsenates in soil, their uptake in rice plants and their potential risks to human health urgently require further research as at least one organic sulphur-containing arsenic compound discovered in rice fields is already known to be carcinogenic.

A bad situation potentially made even worse

Arsenic is one of WHO’s 10 chemicals of major public health concern and in particular for the millions of people who rely on rice as their staple food. Young children are also at risk if rice-based products make up a large part of their diet.

Global warming has the potential to make a bad situation even worse. With an increase in global temperatures higher levels of arsenic in rice will follow and the composition of the arsenic compounds may change, for better or worse.

So please be careful in contributing to global warming.

Food fraud – milk

Food fraud is nothing new, but the intensity and frequency have been on the rise. From counterfeit extra-virgin olive oil to intentional adulteration of spices and the manufacturing of fake honey, food fraud has been estimated to be a $US40 billion a year industry. In a series of posts we will cover a range of recent issues.

Milk is the third in our series on fraudulent food

Next to prostitution, historians consider counterfeiting the world’s second oldest profession. Similar to fraudulent honey and olive oil, which we covered in previous posts, food fraud involving milk has been around for centuries and is actually to my surprise number one on the list of food tampering issues worldwide, due in particular to current cheating in the developing world.

But the Western world has had its problems too. It was common in the old German Empire to dilute milk by 50 per cent and to restore the original consistency by adding a range of substances like sugar, flour, chalk or gypsum. Spoiled or otherwise contaminated milk was sold without hesitation.

In the mid-19th century, New York’s dairy farmers increased their profits by feeding their cows with cheap waste from distilleries. This resulted in watery and blue-tinted milk that farmers mixed with starch, plaster, chalk and eggs to improve texture and colour, then diluted further with water.

Milk fraud has now spread to the developing world due to an increased demand for milk.

Increased milk consumption

Milk in its natural form has a high food value, since it is comprised of a wide variety of nutrients which are essential for proper growth and maintenance of the human body. In recent decades, there has been an upsurge in milk consumption worldwide, especially in developing countries, and it is now forming a significant part of the diet for a high proportion of the global population.

As a result of the increased demand, some unscrupulous producers are indulging in milk fraud. This malpractice has become a common problem in the developing countries, which might lack strict vigilance by food safety authorities.

One of the oldest and simplest forms of milk fraud is through the addition of variable volumes of water to artificially increase its volume for greater profit. This can substantially decrease the nutritional value of milk, and if the added water is contaminated there is a risk to human health because of potential waterborne diseases. For infants and children this may be a serious concern as they are more vulnerable, at a critical stage of growth and development and are dependent on milk products for supplies of vital nutrients. Babies fed fraudulent milk are at risk of malnutrition and even death.

Adulterants added to milk

Although the vast majority of food fraud incidents do not pose a public health risk, there have been fraud cases that have caused extensive illness. Perhaps the most widely cited, high-profile case involved the addition of melamine to milk-based products to artificially inflate protein values. In 2008, it was reported that melamine-contaminated baby formula had sickened an estimated 300,000 Chinese children with symptoms of irritability, dysuria, urination difficulties, renal colic, hematuria, or kidney stone passage. Hypertension, edema, or oliguria also occurred in more severe cases, killing a reported 6 infants. 

A range of other inferior cheaper materials may be added to diluted milk to increase the thickness and viscosity of the milk, to maintain the composition of fat, carbohydrate, and/or protein and to increase shelf-life. They include reconstituted milk powder, urea, rice flour, salt, starch, glucose, vegetable oil, animal fat, and whey powder, or even more hazardous chemicals including formalin, hydrogen peroxide, caustic soda, and detergents.

Some of these additions have the potential to cause serious health-related problems.

Toxic effects caused by some milk adulterants

The presence of urea in milk may cause severe human health problems such as impaired vision, diarrhea, and malfunctioning of the kidneys. It may also lead to swollen limbs, irregular heartbeat, muscle cramps, chills and shivering fever, and cancers, though these are less likely with the concentrations present in the adulterated milk.

Formalin is highly toxic to humans in small amounts and is classified as a carcinogen. Its ingestion is known to cause irritation, often leading to dry skin, dermatitis, headaches, dizziness, tearing eyes, sneezing and coughing, and even the development of allergic asthma.

Hydrogen peroxide damages the gastrointestinal cells which can lead to gastritis, inflammation of the intestine, and bloody diarrhea.

Detergents have been shown to cause food poisoning and gastrointestinal complications. Some detergents also contain the toxic ingredient dioxane, which is carcinogenic in nature.

Difficult to quantify food fraud

It is not known how widespread milk fraud is as those who commit fraud want to avoid detection and do not necessarily intend to cause physical harm. Thus, most incidents go undetected since they usually do not result in a food safety risk and consumers often do not notice a quality problem.

The full scale of food fraud is not known, as the number of documented incidents may be a small fraction of the true number of incidents. However, some researchers contend that food adulteration is not necessarily more common now, but reputational repercussions are certainly more far-reaching with today’s worldwide media coverage.

Detecting food fraud relies on testing. As new tests are developed we get better at detecting frauds, but the fraudsters will always be looking for new ways to cheat those tests. 

Newer technology will help fight food fraud in the future. These include tracers and edible inks that can be used to tag foods, biomarkers, and DNA fingerprinting. 

While it might seem alarming to hear reports of fake and adulterated foods, this might actually be a good thing, because it means testing and surveillance is working.

Toothpaste danger?

Toothpaste has been around for a very long time with historic references as far back as 377 BC. Modern toothpastes are very different though and contain a myriad of ingredients to improve their mechanical properties, appearance, or smell in order to appeal to consumers. Should we be worried?

Two caveats are needed upfront.

First one, please note the question mark in the title. I am not saying that toothpaste is dangerous, just asking the question after some recent experiences.

Second one, although toothpaste is not food, and this blog is about food, you will at least inadvertently swallow some, and some ingredients will easily be absorbed through the lining of the mouth with a 90% efficiency.

So here we go.

The best toothpaste ever

Some years back our brand of toothpaste exclaimed it was clean and fresh. We were quite happy with that, what more could you ask for? But the marketing gurus obviously thought you needed more so changed it to extra clean and fresh. That’s fine too we thought. We don’t mind having extra clean teeth.

Never satisfied the marketing gurus wanted something more so changed to extra clean and lasting fresh. Well, come on now, didn’t the freshness last before? But there’s more, now the toothpaste exclaims it is extremely clean and lasting fresh. This must be the best toothpaste ever. And this is how they describe the effects:

• This toothpaste doesn’t just freshen your breath, it invigorates it.
• Thanks to its micro-active foam that leaves you with a pure breath sensation that last and a feeling of clean like no other.

So what is different?

Several warnings

Curious, for once we decided to read the small print on the tube. Upfront there are several warnings:

• “Do not swallow, be sure to spit out”
• “Not for use by children 6 years of age and under”
• “Do not brush more than three times a day”
• “If irritation occurs discontinue use”

Quite a list of warnings and as it happened one of us had an “irritation” and had to stop using it. The label claimed it could possibly be an allergy to one of the ingredients.

Checking the ingredients

So what is in this toothpaste? Quite a lot as it happens, but at least no sugar it claims upfront. That’s a relief.

First on the list of ingredients is water and not much to say about that.

Second is the sugar substitute sorbitol followed much further down the list by the artificial sweetener sodium saccharin. Of course, even if there is no sugar, a sweet taste is important for palatability. Saccharin has been shown to cause bladder cancer in rats, but through a mechanism that is not available in humans. No harmful effects are expected from those two ingredients although artificial sweeteners like saccharin might influence the gut flora. This is still to be clarified.

Hydrated silica is an odourless, tasteless, white, gelatinous substance, which is chemically inert. As a fine gel it is abrasive and helps to remove plaque. It is generally considered to be safe, although it might wear down the enamel exposing the dentin underneath.

Glycerin is a colourless, odourless, viscous liquid that is sweet-tasting and non-toxic, so no problem there.

Pentasodium triphosphate is produced on a large scale as a component of many domestic and industrial products, particularly detergents. It has very low human toxicity but in volume can have negative environmental effects by supporting algal growth.

PEG-6 (polyethylene glycol) belongs to a group of petroleum-based compounds that are widely used in cosmetics as thickeners, solvents, softeners, and moisture-carriers. In itself not considered toxic although it can inadvertently be contaminated by other toxic compounds depending on the manufacturing process. A minority of people are allergic to PEG compounds.

Alumina or aluminium oxide is primarily used as an abrasive and thickening agent, but also functions as an anti-caking agent and absorbent. It is safe to use for cosmetic purposes. However, it must be noted that aluminum is a neurotoxin.

Sodium lauryl sulfate is a surfactant responsible for the foaming action of the toothpaste but it also interferes with the functioning of taste buds by breaking up phospholipids on the tongue. As it is further down the ingredient list the amount in the toothpaste should be fairly low but it should be noted that it has been linked to skin irritation and painful canker sores, with research suggesting that the compound should not be used in people with recurring sores. Sodium lauryl sulfate could potentially be contaminated with 1,4 dioxane, a carcinogenic byproduct.

Flavour is not further specified but might be mint as it is common in toothpaste.

Xanthan gum is a common food additive. It is an effective thickening agent and stabiliser to prevent ingredients from separating. It can cause some side effects such as flatulence and bloating in high doses, but the low amount in toothpaste should not be a problem.

Cocamidopropyl betaine is a mixture of closely related organic compounds derived from coconut oil and dimethylaminopropylamine. It is used as a surfactant and foam booster. It can be an irritant particularly if impurities like amidoamine and dimethylaminopropylamine are not tightly controlled.

Sodium citrate possesses a saline, mildly tart flavour. It is commonly used for flavour or as a preservative. The chemical has been verified to be of low concern.

Titanium dioxide is often used as a pigment, brightener, and opacifier, which is an ingredient that makes a formulation more opaque. Although not relevant for toothpaste, if in powder form and inhaled it can possibly cause cancer. However, titanium dioxide in toothpaste may become dangerous when it is nanoparticle size, an issue still to be resolved.

Carrageenan is an extract from a red seaweed commonly known as Irish Moss. It is a native to the British Isles, where it’s been used in traditional cooking for hundreds of years. Some scientists claim that it can cause a range of health effects while others claim it is perfectly safe. Although the jury is still out, amounts in toothpaste is supposedly too low to cause any health effects.

Sodium fluoride is another controversial compound. It can be toxic in high doses but the low doses ingested through toothpaste and fluoridated water can in a worst case situation cause some slight discolouration of children’s teeth. There have only ever been three reported cases of fluoride toxicity associated with the ingestion of fluoride-containing toothpaste. One involved a 45 year old woman with unusual swelling and pain in her fingers. As it happened the woman admitted to the regular ingestion of large amounts of toothpaste, consuming a tube of it every two days because she “liked the taste”. When asked to switch to a non-fluoride form of toothpaste, her  condition subsided.

Zinc chloride polishes the teeth and reduces oral odour by destroying or inhibiting the growth of microorganisms. We need zinc for healthy development, but in high doses it  might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage in some people. Levels in toothpaste are generally considered as safe.

Sodium hydroxide is a good example of a compound that can cause harm in high doses but is completely harmless in a diluted form.

Limonene is a chemical found in the peels of citrus fruits and in other plants. It is used to make medicine and as a flavouring. Limonene is safe in food amounts. It also appears to be safe for most people in medicinal amounts when taken by mouth for up to one year.

CI 74160 Phthalocyanine blue BN is a bright, crystalline, synthetic blue pigment. The compound is non-biodegradable, but not toxic to fish or plants. No specific dangers have been associated with this compound.

CI 74260 Phthalocyanine green G is a synthetic green pigment available in the form of a soft powder. Classified as not expected to be potentially toxic or harmful although one or more animal studies have shown toxic effects at moderate doses.

So what to do

Well I am happily continuing to use the toothpaste but with some reflections each time. I wouldn’t mind if they removed the blue and green colourings. Sure it looks nice with blue and green stripes among the white but is it really necessary. And to the whiter than white from titanium dioxide, do we need the nanoparticles?

I am happy that they have resisted putting triclosan in their toothpaste to stop bacterial growth as the zinc chloride might to the job as efficiently. But I can only hope that they have full control of their chemistry to avoid toxic byproducts being formed.

Regulators in different countries provide some controls for toothpastes but I would be surprised if there were any extensive testing of the product on the market.

On the other hand we only use about 0.3g of toothpaste per brush so exposure to any of the chemicals in the toothpaste is minimal.

Good to know!

Groundbreaking opinion on dioxin toxicity

 

Curtesy the European Commission

We have previously covered the group of 29 nasty chemicals collectively called dioxins and dioxin-like PCBs because of their similar mode of action.

In brief, they are toxic chemicals that persist in the environment for years and accumulate at low levels in the food chain, usually in the fatty tissues of animals.

However, different interpretations among scientific organisations of their absolute toxicity have led to some confusion.

Harmonisation needed

In an attempt to develop a better understanding of the risks to human and animal health conferred by dioxins and dioxin-like compounds, the European Food Safety Authority initiated a groundbreaking review of the available scientific literature and exposure information. In an exhaustive opinion published in November 2018, EFSA’s Panel on Contaminants in the Food Chain concluded that such environmental pollutants, although only present at low levels in food and feed, pose a considerable health concern.

Accordingly, the Panel set a new tolerable weekly intake (TWI) for dioxins and dioxin-like PCBs in food of 2 picograms per kilogram of body weight, an incredibly low limit reflecting their severe toxicity.

The new TWI is seven-times lower than the previous EU tolerable intake set by the European Commission’s former Scientific Committee on Food in 2001. The change is based on the availability of new epidemiological human and experimental animal data on the toxicity of these substances and more refined modelling techniques for predicting levels in the human body over time.

Current protection not sufficient

The new TWI is protective against effects on semen quality, the most sensitive adverse health effect, as well as a lower sex ratio of sons to daughters, higher levels of thyroid-stimulating hormone in new-borns and developmental enamel defects on teeth.

Worryingly, data from European countries indicate an exceedance of the new tolerable intake level with the main contributors being fatty fish, cheese and livestock meat.

Average and high exposures were, respectively, up to five and 15 times the new TWI in all age groups.

Should you take action?

As there are little or no acute health effects from consuming single foods containing dioxins and dioxin-like PCBs, it’s more a matter of cumulative chronic effects outside the direct control of individual consumers.

Although the presence of these compounds in food and feed has declined in the last 30 years thanks to the efforts of public authorities and industry, a further concerted effort is needed to bring current exposure to safe levels.

Thus, continued vigilance is important, particularly in light of the new proposed TWI. As this is not always the case and testing of food is expensive, some pressure from consumer groups could be beneficial.