Posts by Nanogirl

Using Science for Good not Evil.

The importance of celebrity scientists

Last week, I was honoured to have been able to join Dr Neil deGrasse Tyson on stage during his New Zealand cosmic perspective tour.

As the only American to have been awarded the Stephen Hawking medal for science communication, Dr Tyson has been called the American face of science.

I was astounded and inspired at the ability of a scientist to fill stadiums and arenas as thousands of members of the public came to learn more about astrophysics.


It made me think about how, after leaving formal education the public rely on the media, social media and search engines as their science information source.  Science communicators like Dr Tyson are crucial for helping to empower people to connect with the ever-changing world of science.

Yet, traditionally scientists strive towards a conventional pathway to earning scientific and public attention which goes something like this:

  1. Gain recognition from published research that is validated by peers.
  2. Grow research, which grows scientific reputation, which grows scientists status in science.
  3. Earn ultimate accolade of Nobel Prize, the one public symbol of scientific excellence for those deemed to have produced the world’s best science.

However, if I were to ask you to name one Nobel Prize winner and state their discovery I doubt you would be able to do so.

That is the challenge that scientists and engineers like myself have managing both public and research profiles. There is a constant battle between working on engagement and communication programs tied to public issues while also trying to dive deep into research projects while managing labs and writing peer reviewed papers for our scientific career paths.


The media celebrity culture that we live in has huge influence, and the need for evidence based science communicators is crucial to help battle an endless stream of non-scientist celebrities that are paid to endorse products and opinions about scientific concepts.

Celebrity scientists have taken a pathway that bypasses the traditional closed door meetings between government and policymakers and instead go directly to the public making sure that science is firmly on the public agenda.

Dr Tyson and other celebrity science communicators like Professor Brian Cox and Bill Nye are changing the landscape of how science is accessed and asking the public to join them on their journey through supporting their endeavors.

Importantly, as the gender and ethnicity of these celebrity scientists diversifies, the stereotypes around what scientists and engineers can look like are broken and the doors into these fields feel more open to all.

Our world is filled with information and creating new pathways for scientists to gain celebrity status while still being recognised in their field is a challenging task, yet one that will have an influential role in shaping how our citizens encounter and make sense of the science around them.


‘Potentially toxic’ nanoparticles in baby formula – why the sensationalist headlines do nothing but scare parents


Wow, now that is a new headline that would scare the bejeebers out of you if you were currently using baby formula.

The Sydney Morninig Herald goes on to say:

A world-leading team in nanotechnology at Arizona State University tested seven off-the-shelf baby formula products and found two – Nestle’s NAN HA 1 Gold and Nature’s Way Kids Smart 1 – contained needle-shaped hydroxyapatite nanoparticles.

Hydroxyapatite nanoparticles – those sound scary right?


Hydroxyapatite – the main mineral found in bone (source)

Well, lets start with the long word – hydroxyapatite. This is a naturally forming mineral made from calcium and phosphates.  It is the main material that your bones and teeth are made from and exists in a colloidal form in milk.

When you dry milk to make baby formula, the water is removed and the milk is concentrated down into small particles also known as a powder.

Now let’s move on to the word – nanoparticles.  These are tiny particles with at least one dimension less than 100 nanometres or around 1000 times thinner than the width of your hair.
Your silver jewelry will be giving off silver nanoparticles right now, and your sunscreen will be using them to protect you from UV rays.  They are in our food, our electronics, even our stained glass windows!

So the headline really should read:


However that sort of title is not going to sell newspapers.

Still worried? Lets dig deeper into the research.

The study was commissioned and published by Friends of the Earth which is an environmental advocacy group.  In it they analysed six off-the-shelf baby formulas bought in America, five of which were powders and one was a liquid concentrate.

They dissolved the baby formula in water, spun it around to pull out the particles and put them into a Transmission Electron Microscope to see what the tiny particles looked like.


TEM image of nanoparticles found in baby formula (source)

What they found were all sorts of shapes and sizes of particles which contained calcium, phosphorous and oxygen.  These are also the same elements that make up bones and teeth.

When it comes to particles, the shape and size can make a difference between safe and unsafe, as some particles if small enough could move into our bloodstream through the wall of our gut after we eat them.

This doesn’t necessarily mean that they are harmful, every single day we are all inhaling, and eating nanoparticles that are just around us in our environment.

toast-1077984_1920For example; if you had a piece of toast for breakfast, you would likely have eaten carbon nanoparticles, which to the human eye look like the burned bits on the top. I don’t see any headlines scaring people about nano dangers in toast so where did the “potentially toxic” part of this headline come from?

Well, in 2016 the European Commission published a consumer safety study that looked at nano hydroxyapatite.

Their summary was that “nano-hydroxyapatite in needle shaped form is of concern in relation to potential toxicity in cosmetic products”.

They based this on research which they admitted was not in line with the SCCS Memorandum on Relevance, Adequacy and Quality of Data in Safety Dossiers on Nanomaterials.  None of the studies they looked at actually exposed any people to the substance.  The few studies that were carried out used rats, and the study that caused the most concern injected 50 mg/kg body-weight of needle shaped nano-hydroxyapatite into the tail veins of 6 male Sprague Dawley rats.  Just for context the lethal dose of nano-hydroxyapatite is 200 mg/kg body-weight, so their bloodstreams were filled with some pretty high doses of nano needles.  After 48 hours, they analysed the livers of the rats and found some inflammatory cell infiltration and increased white blood cell levels in the rats.  This study, where rats are injected with medium to high doses of nano hydroxyapatite directly into their bloodstream and is how the particles became labelled “potentially toxic”.  The report clearly shows the other studies where rats that were rubbed with or injected with needle shaped nano hydroxyapatite particles showed little to no reaction.

It’s important to remember when reading this that its not just how much of a material we’re exposed to that is important, but also the pathway to exposure can make a difference.

So what happens to these needle shaped nano hydroxyapatite crystals when your baby ingests them?

Well the friends of the earth study exposed them to different gastric fluid solutions and found that they rapidly and almost instantaneously dissolved.

Basically this scientific test implies that when your baby drinks the formula, the nanoparticles dissolve in their stomach ready for the calcium and phosphate be absorbed by the body.

The skeptics among you may still be concerned that hydroxyapatite nanoparticles are in baby food, but let me just note that research has shown that we form calcium phosphate nanoparticles naturally in our stomachs to help increase the our intestinal immune system.

For those nano-phobes still among us, it might be worth sharing this image:


Image showing natural breast milk contains nano particles (source)

which shows that normal human breast milk is naturally composed of nano particles of milk fat casein-protein globules – see not all nanoparticles are scary or dangerous.

So in conclusion, scientific jargon has been used to scare parents using evidence from a scientific paper which has findings of no special significance.

Based on current research, the hydroxyapatite nanoparticles found in baby formula are most likely safe, are in small doses, in a form that your baby can easily digest and could even be beneficial for your baby in the long run.

UPDATE 3rd July 2017

Since writing this blog, Friends of the Earth have contacted me on twitter to offer me a copy of the report that they are making their Australian baby formula claims from.

Firstly the report is not peer reviewed and so can not be treated with the same scientific rigour that the article I refer to in this article can.

Secondly, the report shows that the samples which were bought in Australia, were opened in Australia (I’m assuming not in a clean room) and then transferred to a ziploc bag and mailed to the labs for testing in the US.


Example page from the Friends of the Earth report showing how samples had been opened prior to testing and placed in a non-sterilised ziploc bag for transport.

Proper scientific methods include removing all possible sources of contamination when using high resolution equipment such as TEM and XRD and thus the photo from this report shows evidence that all of the samples tested by Friends of the Earth could potentially have been contaminated through poor sample handling and packaging.

Friends of the Earth also felt it appropriate to tag my employer in a twitter post I can assume with the only purpose of trying to get me in trouble and jepordise my career.


In order to clear this up, my blog has always stated in the “about me” section that my writings here are purely my opinion and not the views held by my employer.  However, I do feel that I should include that my research for the last 15 years has been in nanoparticles and nanotechnology and my whole career started in nano hydroxyapatite systems and I spent 6 years using hydroxyapatite in a nanostructured form to try and help remineralise teeth for cavity repair and protection. I also have several years of hands on experience with the techniques mentioned in the report including SEM, TEM, XPS and XRD and have taught undergraduate and postgraduate courses explaining the principles of these techniques.

I will admit that I have very little experience with baby formula other than making it up for to help friends of mine who are parents.

An open letter on fluoride, science and kindness

Dear Lorraine,

I noticed that last week you chose to send this message to Green Party MP Julie Anne Genter:


Having read the original message I’ve decided not to identify you other than by your first name (Lorraine), however I do want to say that I was really shocked at the insensitivity of your message – let alone the bad science (I’ll come to that).  I decided to create a flowchart for you to follow for the next time that you decide to interact with another human being, especially when communicating with people that you don’t know.  I’ve called it “Lorraine’s Flow Chart” as it was written with you in mind, but feel free to share it with others.


Lorriane’s Flow Chart For Future Communications With Other Humans

Now, as promised, I would like to clarify some of the science behind your comments.

You wrote:

“People don’t realise how toxic fluoride is, even at low levels”

As you don’t offer any form of reference to your statement, firstly I don’t know who you mean by ‘people’, or what you are classing as a ‘low’ level of fluoride.

Let me offer some scientific evidence:

In a recent paper in the American Journal of Public Health titled “Community Water Fluoridation and Intelligence: Prospective Study in New Zealand” the researchers are very clear in their findings.  They conducted a study on a sample of the general population from people born in Dunedin, New Zealand, between April 1, 1972 and March 30, 1973 and followed them for 38 years.  They found “No clear differences in IQ because of fluoride exposure even after adjusting for potential confounding variables, including sex, socioeconomic status, breastfeeding, and birth weight (as well as educational attainment for adult IQ outcomes).

Their peer reviewed conclusion specifically states that:

These findings do not support the assertion that fluoride in the context of community water fluoridation programs is neurotoxic.

I used this example because it is an amazing, peer reviewed, long-term study of the effects of fluoride in a New Zealand context, which is where you, Julie Anne and I live.

Next point.  In your message you state that “People don’t know how toxic fluoride is”, and you might be right.  So I thought I’d do some calculations, because it is toxic if you consume too much of it.  So of course is vitamin D, calcium and even water…does this mean we need to start warning people about the dangers of drinking water too?

The amount of fluoride in our water supply is adjusted to keep our water supply level to between 0.7 ppm and 1.0 ppm. This is the optimal amount that provides protection against tooth decay, and is monitored to make sure that the levels stay within that range.

So how much fluoridated water would you have to drink before you die from toxicity?

To help out, I decided to make some calculations for you.  I’ve based my calculations Ln taking a look at your LinkedIn profile and estimating that you are an adult female weighing around 68kg. (If I am incorrect on your weight, please feel free to correct me and I will re-calculate for you).

Based on this assumption I made you a personal “Fluoride in New Zealand Tap Water Toxicity” chart:


Table showing that it would take 1220 glasses of fluoridated tap water to possibly be toxic to Lorraine when considering fluoride toxicity risks

So perhaps your next email about the toxicity of fluoride should be more clear and state that “even at levels of fluoride that are in New Zealand tap water, you would need to drink 1220 glasses of water in a day for it to be possibly toxic”.

I think you are missing a very important point.  Perhaps your messages should be less concerned about the levels of fluoride in the water, and more concerned about the dangers of water itself!

I looked up the MSDS (materials safety data sheet) for water which states that:

Toxicity to Animals:LD50: [Rat] – Route: oral; Dose: > 90 ml/kg LC50
MSDS sheets are documents that contain information on the potential hazards of chemical products, and are documents that scientists like myself must use when completing our health and safety programs for any substance that we use.


From this I calculated your personal water toxicity risk:


Table showing that it would take 24 glasses of fluoridated tap water to possibly be toxic to Lorraine when considering hyperhydration

This means that the water itself is far more toxic than the fluoride  in it.  If you want to give medical and scientific advice to people that you don’t know then you should probably focus on the much higher chance that somebody dies from hyperhydration by drinking 24 glasses of water, than the…highly achievable…7000 glasses of water needed for death by fluoride toxicity.

Your next statement says that you think:

“dentists will be extremely embarrassed if it is found that they are wrong”

The thing is, science doesn’t work that way.  We scientists don’t become embarrassed if we are found wrong – we love it.


Let me explain scientific method to you.

Although anybody can do science, professional scientific researchers follow a scientific method which allows them to explain occurrences using a logical, consistent, systematic method of investigation.

This involves collecting large amounts of data from well thought-out experiments and analysing that data to arrive at a well-tested, well documented theory that is supported by the evidence.  The theory is then subjected to critique by other experts in the field and only if approved by them is it allowed to be published in a peer reviewed journal for others to read and learn from.  We can be wrong for sure, but it’s very difficult to publish wrong data without it being picked up.  It’s almost impossible for hundreds of scientists to publish the same wrong data – it’s actually our job as peer reviewers of other people’s science to pick holes in research, trying to prove that it is wrong before allowing it to be published.  So there is no embarrassment in science, just a rigorous method.

You say that:

More and more research is being conducted into fluoride

You are right, and ‘s the great thing about science: we continue to research to find out things that we don’t know.  I spent 7 years of my life researching fluoride, and even back then there had already been a lot of research carried out.  For instance, we knew then what we know now – that the levels of fluoride in the tap water in New Zealand are not toxic, and in fact have been shown to have positive outcomes for our population, including:

  • In children and adolescents, a 40 per cent lower lifetime incidence of dental decay (on average) for those living in areas with water fluoridation.
  • For adults, a 21 per cent reduction in dental decay for those aged 18 to 44 years and a30 per cent reduction for those aged 45+ (as measured by tooth surfaces affected).
  • A 48 per cent reduction in hospital admissions for treatment of tooth decay, for children up the age of four years.

Finally, I took a look at the link that you included, which was notably to a blog site rather than to a peer reviewed scientific article. Carol S. Kopf, the author of the blog,  is also the media director for the Fluoride Action network, an international coalition to end water fluoridation.  As you might expect, her views are heavily biased against fluoride.  

The blog post refers to research from Dr A.K. Susheela of India who states that she talked about the results of her studies on women ingesting fluoride at the 27th Conference of the International Society for Fluoride Research, Beijing, China, Oct. 2007. Her study was called: Fluoride Ingestion and Health Hazards with Focus on Anaemia in Pregnancy and low birth weight babies: Guidelines for rectification: Susheela A.K, Mondal NK, Rashmi G, Ganesh Kamala, Bhasin Shammi, Gupta Gunjan.

So I looked everywhere for a peer reviewed conference paper that Dr Susheela would have written up, which is how science that is presented at conferences is assessed to be accurate with good scientific method.  I couldn’t find any.

I did however manage to find one research paper written by Dr Susheela which seems to be connected to this blog statement in her paper “Effective interventional approach to control anaemia in pregnant women“, published in the journal Current Science, a science journal from India.

Science journals are ranked using an impact factor which is used to compare different journals within a certain field.  For example the highly regarded The New England journal of medicine has an impact factor of 59.558 and the medical journal The Lancet has an impact factor of 44.002. By way of comparison Current Science has an impact factor of 0.83.

The study that the link you provided could be loosely connected to involved only women in India who were already pregnant, medically anemic and showed high levels of fluoride in their blood.

Just to be clear, India is one of several countries known to have dangerously high levels of fluoride in their drinking water, with villages like Sogival having groundwater fluoride levels of 4.84 ppm.  Not only is their water naturally high in fluoride, but the women in this study were also eating black rock salt, a type of salt with high levels (157 ppm) of fluoride commonly found in Indian street food and Indian snacks and spices.


The link that you refer to is not a study that links fluoride to miscarriages and stillbirths as you claim. If you actually read the research you would see that its a study on pregnant women in a “developing country” who are already anaemic, ingesting high levels of fluoride and suffering from other risk factors including dietary deficiencies, parasitic infestations, urinary tract infections and malaria.

The paper itself is clear in it’s conclusion and states:

“The first factor (application of intervention) throws up a bit of a confusing result to which we do not have a concrete answer at the moment”

They find no concrete evidence that the very high levels of fluoride are directly correlated to the low birth weight of some of the babies, but – as you can see when you read the paper – the women in this study are already unwell when judged by western medicine standards.

Back to your original, offensive advice for Julie-Anne. In New Zealand miscarriage affects 1 in every 4 women. Having a miscarriage can be traumatic and many women experience huge grief over their loss.  It is a very sensitive subject and very personal to those involved.  If you haven’t had to experience the grief of a miscarriage or the challenges around infertility then please understand that it can involve pain, a sense of loss, and a daily struggle to try and remain positive while sometimes feeling like a failure.

In closing, I’d like to leave you with a quote that a colleague of mine has on her office wall that I love and hope you might too:

“We’re all smart. Distinguish yourself by being kind

How your daughters future doors may already be closed by the time she is six

Imagine you are reading a story to a child; the story goes something like this:

  “There is one person at work who is really, really smart. They can figure out how to do things quickly, they come up with answers much faster and better than anyone else. 

Now imagine telling this story:

“There is one person at work who is really, really nice. They like to help others with their problems, they are friendly to everyone.”

At the end of the story, you show pictures of adult males and females to the child and ask them which person they think was being described.


What gender do you think they would pick for each story?

This exact experiment was carried out alongside a series of others as part of a recent study published in the journal Science.

The scientists found that a child’s perception of brilliance goes through dramatic changes between ages 5 and 7.

After the story, the five year olds associated brilliance with their own gender at roughly equal levels.

Just one year later, the 6 year old girls were significantly less likely than the boys to associate brilliance with their own gender.

By the age of 7, when given a choice of toys to play with, the majority of the girls chose not to play with games labelled for ‘really, really smart children’.

This is serious! Our girls are making choices by the age of 7 that they are not smart enough, even though at this age they are outperforming the boys academically at school!

What’s sad is that these results agreed with many previous studies that also show the emergence of gender stereotypes starts at the age of 6.


Why don’t our girls believe in themselves?

With children growing up under a myriad of social influences including the stereotyped toys, media and language it’s hard to pinpoint one thing that caused this perception change. Evidence shows that some teachers treat and reward behaviour in their students differently, unintentionally praising the boys more for academic achievement and the girls for being neat and tidy.

Have you ever told a male child that he was really smart and a female child that she was really pretty? Subtle changes in language such as not only encouraging girls to look a certain way, but to act a certain way can help create positive change.

Interestingly, one 2014 study took anonymous, aggregate data from Google searches and found that parents in the US were two and a half times more likely to ask “is my son gifted?” than “is my daughter gifted?”. They also discovered that parents were twice as likely to google “is my daughter overweight?” than “is my son overweight?”. For the record the data shows that boys are 9 percent more likely to be overweight than girls.

Although the exact causes are not clear, a long term lack of belief in their ability to achieve subjects associated with intelligence and brilliance has the potential to steer many young women away from careers requiring these skills.

As an Engineering lecturer at the University of Auckland I can attest to us graduating more students. Data from the Ministry of education shows that out of all of the school leavers who met the university entrance requirement, only 10 percent of females achieved the calculus and physics subject requirements needed to enter the engineering degree compared to 33 percent males. Just like the girls who didn’t play with games labelled for really, really smart children, it seems our female teenagers don’t study the perceived really, really smart subjects.

Diversity is so important; McKinsey research shows that companies in the top quartile for gender diversity are 15 percent more likely to have financial returns above their national industry medians. Having more females in our tech sector is directly tied to the success of our future economy.

Our fight not about academic differences in gender, it’s around the perceived intelligence that our young people have about themselves. 

Next time you tell a story to a five year old, help your future technology economy by making it a stereotype breaking one.


Why Detox Diets Don’t Work – the science behind how your body removes toxins

The health store shelves are filled with optimistic claims of weight loss products. It’s tempting after what may have been weeks of “I’ll start the diet tomorrow” to think about cleansing out your system to kick start your new body.

Quick fix detox teas, juices and supplements are heavily marketed, enticing you to drink a magical natural potion which will rid you of your over-eating and partying sins so you can start afresh.

Combinations of cayenne pepper, lemon juice and honey taste so disgusting, you might be convinced that they must be good for you, but the truth is in the scientific evidence for which there is none.

In fact a 2015 review of clinical evidence about detox diets published in the Journal of Human Nutrition and Dietetics concluded that there is no compelling evidence to support the use of detox diets for weight management or toxin elimination. They found that many clinical studies are hampered by flawed methodologies and small sample sizes and that no randomized controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans.


Detoxing is marketed based on the idea that some combination of alcohol, preservatives and fast food burgers can cause a build-up of toxins in the body. I’m yet to find one detox kit that actually describes and names which toxins that they remove and how they manage to do this.

The reality is that our bodies are constantly being exposed to a huge number of chemicals. Not all chemicals are bad, and the presence of chemicals in the body doesn’t mean that they are doing harm or building up. Some natural chemicals can be much more harmful than some synthetic ones and we have been exposing ourselves to harmful substances since the beginning of man. To survive, our bodies have evolved to defend against and remove unwanted substances. Our skin, lymphatic system, kidneys and liver combine to form an incredible intrinsic detoxification system.

Detox marketing describes how our liver and kidneys act like filters, but need to be cleaned out to remove the toxins that are trapped there, akin to periodically rinsing a dirty sponge. In reality, our liver’s main role is to detox by taking in blood from the digestive system and filtering out toxins like alcohol and medication by-products. It does this by converting the toxins through a series of chemical reactions into substances that can be eliminated in bile.

Our kidneys also detox by excreting waste products into our urine using over two million filtering units called nephrons which remove waste and send useful minerals back to the bloodstream.


The liver is a self-cleansing organ, it doesn’t store toxins unless you have been diagnosed with serious liver disease and no amount of lemon juice concoction can rinse it out in any other way than it is already capable of.

Detox dieters often make claims that they feel better and have more energy on their cleansing diet. The chances are it’s not the juice causing this but the fact that the juice is replacing a diet full of processed fats, sugar, alcohol, soda, and snack foods. By eliminating these, your liver and kidneys are not overburdened with filtering a bad diet and can carry out their normal detoxification duties. What detoxers are likely experiencing is the feeling of a healthy well balanced body functioning normally. The only thing a detox diet is proven to clean out is your wallet, so instead of looking for a quick fix, give your liver a break and consider making evidence based long term healthy lifestyle choices instead.

How Microbeads in your bodywash could be helping chemicals enter the foodchain

In 1976 chemical engineer John Ugelstad invented a technique on earth that other scientists believed could only be carried out in the weightless conditions of space. His discovery enabled the mass production of monodisperse spheres, tiny microscopic spherical plastic beads. The beads were typically 0.5 to 500 micrometres in diameter, about the width of 1 to 5 strands of human hair.

These little beads enabled new advances to be made in cancer treatments and helped create alternative methods for HIV, bacteriology and DNA research. Tiny latex beads still form the basis for some home pregnancy tests today and thanks to Uglestad’s discovery the medical use of microbeads has helped move drug treatments forward.

More recently, microbeads have moved from medical additives to exfoliators found in face washes, toothpaste, body scrubs, and other everyday beauty products. The non-biodegradable solid plastic beads are commonly made from polyethylene, polypropylene, and polyethyleneterephthalate, the same plastics used for single-use shopping bags and plastic bottles.

After washing off your skin, the microbeads go down the plughole and into the waste-water treatment plant where some of them become trapped in the filtering sludge, but due to their small size some microbeads pass through into our waterways and oceans.

Because their size and shape is similar to many plankton species, microbeads are eaten by marine creatures such as shrimp and fish caught for human consumption. Plastic particles from microbeads and other plastic items in the ocean have been found in the stomachs of fish, shellfish, turtles and birds and have caused harm to these creatures.

Plastic microbeads have been found to act like magnets around organic pollutants with reports indicating a single immersed plastic particle can absorb up to 1,000,000 times more of these chemicals than the water around it. The common pollutants including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides, and perfluorinated surfactants (PFCs) have been found to stick to the beads due to their large surface area and the chemistry of the plastics used.

This absorption transforms the microbeads into chemical carrying dots and new research published in the journal environmental science and technology found that when feeding on similar sized food in the water, fish also ate PBDE exposed microbeads from a commercial facial scrub. After just 21 days, 12.5 per cent of PBDE chemicals were found to have leached from the ingested microbeads into the tissues of the fish causing concern that persistent organic pollutants accumulate in the tissue of fish exposed to microbeads and other plastic debris in their environment. Research is now underway to determine the implications of this chemical exposure pathway for public health by calculating how much pollution could be entering this human food chain.

Although many large cosmetics companies have made voluntary commitments to phase out microbeads by 2020, they are easy to spot as plastic spheres visible in the liquid if consumers wanted to avoid them. Alternatives include sea salt, apricot kernels and ground seeds which can be used as biodegradable skin exfoliates.

Microbeads, are just one source of our oceans plastic pollution problem, and many other plastics grind down over time into small plastic pieces causing similar issues.

This year, Canada became the first country in the world to list microbeads as a toxic substance under the environmental protection act, allowing it to ban them in personal care products. The US has also moved to ban the production of personal care products and cosmetics containing microbeads from July 2017. It’s pleasing to see these other nations leading the way with their legislation, looking at the recent science research let’s hope that New Zealand will follow suit.


This post was originally posted in the New Zealand Herald


The science behind Rio’s green Olympic pool

How an accidental 160 litres of dechlorinating agent enabled green algae to thrive:

The green swimming pool has been one of the big mysteries of this year’s Rio Olympics. Why would one pool turn murky and green when the adjacent pool was still clear and blue?


Olympic pools at Rio this year, with one looking murky and green instead of clear and blue (image source)

The first official line from Olympic officials was that after extensive tests, they had finally pinpointed the reason to be a chemical imbalance caused by too many people using the water.

Mario Andrada, a Rio 2016 spokesman, said last Wednesday morning that “mid-afternoon, there was a sudden decrease in the alkalinity in the diving pool, and that’s the main reason the color changed,”

His interview with the NY Times stated that “He noted that a lot of people had been in the pools in the past week at the Maria Lenk Aquatic Center, and that their presence had touched off changes in the water’s chemical balance.”

The optimum pH for chlorinated pool water is 7.4, since this is the same as the pH in human eyes and mucous membranes and also gives good chlorine disinfection.

So could too many people in a pool make it more acidic?

Well the natural pH of skin is lower than chlorine at around 4.7 so his theory is plausible – too many people in a pool could have made it too acidic.

However, although I’m not a pool owner, I did spend my teens as a competitive swimmer in pools all over the world.  No matter how busy they were, I’ve yet to see one turn green.

Also, you would think that seeing the Olympics is an invite only event, they would have had a heads up around how many people were coming and adjusted for that!

Perhaps it wasn’t just the presence of people in the pool, but what they did in there.

We all know from our childhood paint lessons that blue and yellow = green, so what if all of the Olympic swimmers not only swam but also peed in the pool?


We all know from our childhood paint lessons that blue and yellow = green, so what if all of the Olympic swimmers not only swam but also peed in the pool?

Well, with at least 3.73 million litres of water in the pool,and an average person peeing only 800 to 2,000 millilitres per day you would need at least 1 million people to pee their daily amount in the pool in one day to make any significant impact on the colour  overnight. As there are only 11,000 Olympic athletes in total at the event, I also don’t think pool peeing was cause of the green hue.

Leaking bodily fluids into the pool does cause other issues due to an ammonia derivative called chloramine which forms from the interaction between the urine and chlorine mix. Chloramine however doesn’t usually have a habit of turning the water green, it just irritates the swimmers eyes on contact.

During a press conference today, Rio officials stated that on August 5th, someone accidentally added 160 litres of hydrogen peroxide to the pool.
Accidentally? 160 litres?  How on earth does somebody not notice that?

This is a man standing next to a 200 litre drum.  80 % of liquid from a drum this big seems like quite a lot of liquid to have been poured into the pool without noticing. (Image source)

Hydrogen peroxide is a de-chlorinating agent, with an equation showing that 0.48 mg of hydrogen peroxide removes 1 mg of free chlorine.
Chlorine is added to a pool to kill bacterial and keep it clear.  It breaks down into hypochlorous acid and hypochlorite ions which kill bacteria and microorganisms.  Although the exact mechanism for how chlorine does this is still unclear for some bacteria, it is thought to oxidise them by attacking the lipids in cell walls, destroying enzymes within the cell.
The accidental addition of hydrogen peroxide would have reduced the ability of the chlorine to oxidize matter and kill microorganisms giving them to chance to colonise the pool.
blog-algae-green-pool-algaeAlgae spores and bacteria are constantly entering the pool, being brought in by wind or rain or on the skin or swimsuits of people in the pool.
As living aquatic creatures, algae multiply rapidly and with the addition of sunlight can bloom overnight, thriving in warm water making it look cloudy and green.

So there you go, it looks like the acidic hydrogen peroxide altered the pool water pH while chemically undoing the job of the chlorine by acting as a dechlorinating agent resulting in a pool with perfect conditions for green algae to settle in to.