More flooding is likely this week after Storm Bert brought torrential rain over the weekend, the environment secretary has said.

Steve Reed said the impact “should be less severe” than it was on Sunday and Monday morning, as communities in England and Wales start a massive clean-up after the widespread flooding.

A former chair of the Environment Agency, Emma Howard Boyd, has said not enough money was spent on maintenance of existing flood defences and recommended a focus on tackling “surface water” flooding.

A severe flood warning is still in place for the River Nene at Billing Aquadrome and nearby business parks in Northamptonshire, while 132 flood warnings remain in place across England and six in Wales.

The Met Office weather forecast shows an area of low pressure moving into southern parts of the UK on Tuesday night into Wednesday, bringing heavy rain for some.

Mike Silverstone, the deputy chief meteorologist at the Met Office, said: “On Tuesday night we’ll see outbreaks of rain spreading north-eastwards, which could be heavy at times.

“We’re expected this to be heaviest across the south [and] south-east of England, although subtle changes over the next 24 hours will have an impact on how this develops. There could also be strong winds for a time, and it’s possible this will require a weather warning.”

Hundreds of homes were flooded, roads were turned into rivers and winds of more than 80mph were recorded across parts of the UK.

People in some affected areas have said they do not believe the chaos will be cleared by Christmas.

Extreme rainfall is more common and more intense because of human-caused climate breakdown across most of the world, particularly in Europe. This is because warmer air can hold more water vapour. Flooding has most likely become more frequent and severe as a result.

Howard ​Boyd​ told Radio 4 that during her time at the Environment Agency “one of the areas that we struggled with getting more money to … was on the maintenance of our flood defences”.

“The ongoing maintenance is so important to making sure that the existing infrastructure that we’ve got is fit for purpose,” she said. “Another area that we really need to be aware of … with warmer, wetter winters, we need to be ready for surface water flooding, and this is roughly accountable for 60% of our flooding, and needs a very different response to the flood defences that we see up and down the country.”

Reed told the House of Commons on Monday evening that an estimated 107 properties have flooded across England.

He added: “Further flooding is sadly likely over the next few days as water levels rise in slower flowing rivers such as the Severn and the Ouse.

“The Environment Agency anticipates that any impacts should be less severe than we have seen in recent days.”

A man in his 80s died after his car entered water at a ford in Colne, Lancashire, on Saturday, while a body was found in the search for Brian Perry, 75, who went missing while walking his dog near the Afon Conwy River in north Wales on the same day.

This summer was the first time 31-year-old Daisie Morrison had been on a cruise when she set sail on a two-week holiday with two friends, also in their early 30s.

“One of my friends suggested it,” she says. “She had seen different influencers on Instagram going on cruises. You go to so many places that we wanted to visit, so we were all quite keen.”

The previous summer, Morrison says, she had been on a group holiday around Italy, which in contrast had involved “spending a lot of time, money and stress” getting around. With the cruise, “you just wake up in a new place every day”.

Far from being unusual, Morrison is part of a generation of holidaymakers who are at the heart of the expansion of an industry once seen as the preserve of rich retired couples. The number of passengers taking ocean cruises has more than doubled from 13 million in 2004 to nearly 32 million – and that is despite the devastation to the industry during the Covid pandemic.

The Cruise Lines International Association (Clia), which represents the industry, expects this number to approach 40 million in 2027, and says the key to such growth will be attracting millions of new-to-cruise travellers. Millennials, according to its latest report, are “the most enthusiastic cruise travellers of the future”.

It is not surprising that the industry needs a new target market, when many cruise ships “can start to feel a bit like care homes at sea”, says Xavier Font, a professor at the University of Surrey, who has studied the cruise ship industry. “So the cruise companies need an entirely new brand of ship. They are then turning these into either the party cruise ship, say, or the family cruise ship.”

As the industry has expanded and ships have become much more numerous and visible, this has increased concerns about the environmental impact of this type of holiday. But Font believes this is having little impact on the popularity of cruises.

“[The thought process is:] ‘I’m now going to have a break, just back off,’” he says. “The slogan ‘What happens in Vegas, stays in Vegas’ was brilliant, right? Because this idea that I can be a good person all the time but that one week I’m just going to be bracketing it, it seems to me that applies to everywhere in the world, not just Vegas.”

Emma Otter, a cruise expert who sells trips through the holiday company Travel Counsellors, provides further evidence of this sentiment. She says the company recently surveyed 2,000 travellers and found that 45% of them said the climate crisis was something they factored in when choosing a holiday. This, she says, increased to 65% of those aged between 25 and 34. But do any of her clients ask her about sustainability when looking at cruise holidays? “It rarely comes up,” she says.

Morrison, for her part, says she was aware that cruising is the least sustainable way to travel, “so I did feel quite guilty about it”.

Going on a cruise was not the immediately obvious holiday choice for Tom and Abby, a married couple in their early 30s. “It was the first time for both of us,” says Tom. In fact, he previously considered cruises to cater chiefly to “retirees and elderly people”.

When they decided to go on a weeklong tour of the Norwegian fjords in May, rather than embarking on a road trip or flying abroad, it was partly for practical reasons: they had a six-month-old baby.

“When you have a baby, your perspective shifts a bit … You value things by convenience a lot more than adventure,” says Tom, a construction consultant who lives in Manchester, who preferred that we use his first name only. “A cruise seemed to offer the best of both.”

Each day allowed them to explore a new location, including historic villages and natural sites such as waterfalls, says Tom. “You’d draw back the curtains and there would be a different view out of the window each morning.”

Tom looked at the carbon footprint of his trip on his return and was surprised. “You’re told flying is bad for the environment and that getting on a boat isn’t nearly as bad,” he says. “But cruise ships’ carbon footprints are [much higher], which makes sense, since you’re taking the hotel with you.”

Otter, who has been “banging the drum about cruises not just being for old people” for the past 30 years, says social media has played a big part in driving up the numbers of younger people taking cruise holidays. “Cruising is right in your face now. It’s in your front rooms, it’s on your phones, it’s on TikTok … Daily, you know you can see that somebody will be on a cruise.”

Cruise companies have also become very good at providing something for everyone onboard, she says, and providing it at a price Otter thinks can compare favourably with land-based holidays.

“You’ve got places that are very Instagrammable, such as Santorini. The cost of going there for somebody on a family holiday can be significant, whereas if they visit it on a cruise, they can say: ‘Yes, we’ve seen that.’ And the teenagers are happy as they have done their Instagram reels where there’s a picture of them with the Santorini sunset – box ticked.”

Targeted at some of the industry’s newer, younger cohort is a bold new generation of ships, sometimes referred to as “cruisezillas”, with the biggest having doubled in size over the last quarter of a century. The biggest, Icon of the Seas, was launched earlier this year with 20 decks and capacity for more than 7,000 passengers. Royal Caribbean, the vessel’s parent company, has two even bigger ships commissioned to sail in the next two years.

One of the company’s aims is to attract a cross-generational audience, so the ships come with areas that have activities specifically targeting teenagers or toddlers. Icon’s Thrill Island, for example, includes the Flow Rider, a 12-metre-long (39ft) surf simulator, that has been built to face away from the sea “so your selfies will be better and your friends will see you against the actual ocean”, says Tim Klauda, a vice-president at Royal Caribbean International in a promotional video for the ship.

At the same time, brands such as Virgin Voyages, which launched its first ship in 2021, are unashamedly targeting customers in their 20s and 30s like Daisie Morrison and her friends. Virgin ships are all adults-only and, unusually for cruise itineraries, offer overnight stops at islands such as Ibiza.

While the cruise ship industry is celebrating the growing number and diversity of its travellers, this rapid growth is already proving to be a turnoff for some. When Nick Webb, a 32-year-old design engineer based in Monmouthshire, embarked on an 11-day tour of Venice, Dubrovnik and a handful of Greek islands a few summers ago, he had hoped for a stress-free way to take in the sights. But as cruise ships like his own swelled the numbers of tourists at each port, he quickly found this mode of travel came with its own stresses.

“You know those videos online of people running out to get sun loungers at 6am? It was exactly like that,” he recalls. His travel agent sold the voyage as targeted towards adults, but there were still lots of children onboard, he says. “They were all in the main pool, which wasn’t very big … It wasn’t relaxing if you did manage to get a space on the top deck.”

Webb wouldn’t entirely rule out going on another cruise, he says, but would only do so at an off-peak time. While he appreciated the ease of rolling out of bed at a different location each morning, he was a bit shocked by what he saw. “Looking down from Santorini, there were four or five cruise ships, all spewing smog into the air. It was so busy – it was horrible.”

Otter has been going on cruise holidays with her two children, aged nine and 11, for the past six years. “This year my daughter did say: ‘Mum, do you know, I think I would get bored on a land holiday,’” she says. It is children like her daughter who are helping to “future proof” the industry, she adds. “When she’s 15, when she’s 20, when she’s 30, she’ll go on holidays with her friends, and she’ll say to them: ‘Let’s go on a cruise.’”

“We’re all living through the enshittocene, a great enshittening, in which the services that matter to us, that we rely on, are turning into giant piles of shit,” author Cory Doctorow wrote earlier this year.

In 2023, Doctorow coined the word “enshittification”, which has just been crowned Macquarie Dictionary’s word of the year. The dictionary defined the word as follows.

“The gradual deterioration of a service or product brought about by a reduction in the quality of service provided, especially of an online platform, and as a consequence of profit-seeking.”

Social media users, if they don’t know the word, will viscerally understand the concept, the way trolls and extremists and bullshitters and the criminally vacuous have overtaken the platforms.

Think Twitter, a once useful and often fun microblogging site twisted by a tech bro into X, a post-truth swamp.

Or Facebook, where you’re now more likely to be presented with crocheted arseless chaps from Shein than a humblebrag from a dear friend.

Or Instagram, where cute dog videos once reigned. Now, yet another unfathomable algorithm serves up a diet of tradwives, gym bros and uwu girls.

The dictionary’s committee described enshittification as “a very basic Anglo-Saxon term wrapped in affixes which elevate it to being almost formal; almost respectable”.

Without those affixes – if one were to say, for example, merely that X has got a bit shit – the deliberate degradation of the platform is erased.

With those affixes, the impression is conveyed of the platform owners tampering with their own product until the bad stuff, like guano on a rock, eclipses the original form.

Doctorow wrote that this decay was a three-stage process.

“First, platforms are good to their users; then they abuse their users to make things better for their business customers; finally, they abuse those business customers to claw back all the value for themselves,” he wrote.

“It’s frustrating. It’s demoralizing. It’s even terrifying.”

The Macquarie Dictionary committee’s honourable mentions went to “right to disconnect”, and “rawdogging”.

But enshittification not only won their vote, it took out the people’s choice award.

“This word captures what many of us feel is happening to the world and to so many aspects of our lives at the moment,” the committee said.

Doctorow himself is surprisingly optimistic about where this could all end up.

Action on competition to prevent market dominance, regulation on things such as digital privacy, more power for users to decide how they use platforms, and tackling the exploitation of workers could reverse the process, he wrote, because “everyone has a stake in disenshittification”.

Big tech can’t be fixed, he argues, but maybe it can be destroyed.

He adds a fourth stage to the tech platforms’ scatological journey from being good to users, to abusing them in favour of their customers, to abusing their customers to serve themselves.

“Then they die,” he wrote.

Ryan Kobayashi, who flew to Los Angeles from Hawaii in search of his missing daughter, has been found dead near the Los Angeles international airport. Ryan Kobayashi had been searching for his 31-year-old daughter, Hannah Kobayashi, who was last seen at the airport on 8 November en route to New York City.

“After tirelessly searching throughout Los Angeles for 13 days, Hannah’s father, Ryan Kobayashi, tragically took his own life,” the family wrote in a statement shared by the Rad Movement, a missing persons non-profit. “This loss has compounded the family’s suffering immeasurably.”

According to the Los Angeles county medical examiner, Ryan Kobayashi’s body was discovered in a parking lot on Sunday. Los Angeles police responded to reports of an apparent suicide there at 4am. He was 58.

The Kobayashi family has urged the public to “maintain focus” on the search for Hannah.

“Hannah IS still actively missing and is believed to be in imminent danger. It is crucial for everyone to remain vigilant in their efforts to locate Hannah,” the family’s statement read.

Hannah Kobayashi boarded a flight from Maui on 8 November, intending to visit her aunt in upstate New York. She landed in Los Angeles that day, but left the airport and missed her connecting flight.

In Los Angeles, Hannah Kobayashi visited the Grove shopping mall, where she spent time at Taschen bookstore and attended the LeBron XXII Trial Experience, an event held at the Nike store, on 10 November. The next day, Hannah Kobayashi’s mother texted to see if she’d made it to New York. Hannah Kobayashi responded no. The same day, she messaged a friend saying that someone was trying to steal her identity.

“Deep Hackers wiped my identity, stole all of my funds, & have had me on a mind f**k since Friday,” she wrote to a friend. “I got tricked pretty much into giving away all my funds” for “someone I thought I loved”.

The text messages appeared suspicious to Hannah Kobayashi’s family. “It just didn’t seem right because it’s not how she normally texts,” Sydni Kobayashi, Hannah’s sister, told the Los Angeles Times.

That was the last day that anyone heard from Hannah Kobayashi – and the same day Ryan Kobayashi decided to fly to Los Angles in search of her. The following day her family filed a missing persons report.

On 15 November, the Los Angeles police department released a missing persons poster of Hannah Kobayashi. In a statement released that day, the family said it had obtained surveillance video showing Hannah Kobayashi in downtown Los Angeles near Crypto.com Arena. In the footage, the family wrote: “It is evident that Hannah does not appear to be in good condition and she is not alone.”

Two days later, Syndi Kobayashi wrote on Facebook: “LAPD has not been of much help and are not taking this as seriously as we would hope because my sister is considered an adult who can make her own choices.” On 21 November, her family held a vigil for Hannah at the Crypto Arena where she was last seen, where her aunt, Laire Pidgeon, told NBC News that the family was trying to make the police “take us seriously because it’s been 11 days”.

A frontrunner to be deputy national security adviser in Donald Trump’s administration reportedly withdrew from the running after learning that he would have to work with Sebastian Gorka, the president-elect’s choice as counter-terrorism adviser.

Michael Anton, a conservative speech writer and national security official in Trump’s first presidency, removed his name from contention over Gorka’s appointment against a backdrop of acrimonious past relations between the pair, the Washington Post reported.

His withdrawal graphically signifies the unease provoked by the prospective return to the White House of Gorka, a controversial figure who was forced out of Trump’s first administration, where he worked closely with Steve Bannon, within its first seven months.

His departure is believed to have been engineered by John Kelly, who became White House chief of staff in July 2017 with the task of bringing order to the chaos that characterised Trump’s first months. Kelly, who later resigned, has since turned against Trump, saying he met “the general definition of a fascist” in interviews given shortly before this month’s presidential election.

Gorka, who has worked at the National Defense University, has drawn multiple accusations of Islamophobia.

Being considered anathema by Anton – who was believed to be under consideration to become deputy to the prospective national security adviser, Mike Waltz – is all the more striking given Anton’s own hardline views on Islam, which he has called “a militant faith”. He argued that “only an insane society” would accept Muslim immigrants following the 9/11 terrorist attacks.

But his opinions have paled in comparison to those of Gorka, who has depicted the religion as a threat to western civilisation and has peddled fears about America falling under sharia law.

He was a vocal supporter of the Muslim travel ban enacted against citizens of seven majority Muslim countries during Trump’s first administration. When he departed, he wrote a resignation letter lamenting the president’s failure to use the term “radical Islamic terrorism” in a speech on Afghanistan.

The Washington Post cited a source in Trump’s national security transition team as saying there was widespread dismay at the prospect of Gorka’s return, which does not need to be confirmed by Senate hearings.

“Almost universally, the entire team considers Gorka a clown,” the source said. “They are dreading working with him.”

Anton has previously written about the animosity between Gorka and himself. He recounted how Gorka called him a “coward” and scolded him in a Fox News green room.

Gorka, who first came to attention as a firebrand pundit working at the rightwing Breitbart News, declined comment, telling the Post: “I don’t comment to the fake failing news.”

Anton’s reported withdrawal follows scathing comments on Gorka’s qualifications by John Bolton, who was national security in Trump’s first term before being fired.

Speaking to CNN, he called Gorka “a conman” and said the FBI should investigate his credentials.

“I wouldn’t have him in any US government,” Bolton told the network’s Kaitlan Collins. “I don’t think it will bode well for counter-terrorism efforts.”

Gorka, a US-British citizen and the son of Hungarian immigrants to the UK, drew criticism when he appeared at Trump’s first inauguration ball wearing an honorary medal from the Hungarian nationalist organisation, Vitézi Rend. The World Jewish Congress has said some members of the outfit were complicit in the deaths of hundreds of thousands of Hungarian Jews in the Holocaust.

His views on Islam have been distinguished by a rejection of interpretations attributing the root causes of Islamist terrorism to poverty, repression or US foreign policy mistakes.

“This is what I completely jettison,” he told the Washington Post in 2017. “Anybody who downplays the role of religious ideology … they are deleting reality to fit their own world.”

In a video filmed after Hamas’s murderous 7 October attack on Israel last year, he said he had watched unedited footage of the episode and offered advice to Israeli leaders on how to deal with the Palestinian militant group.

“Kill every single one of them,” he said. “God bless Israel. God bless Judeo-Christian civilisation.”

There isn’t a galaxy far, far away enough where women can escape sexist online trolls.

Emily Calandrelli became the 100th woman to go to space when she joined a group of six space tourists in a launch led by Blue Origin, the aerospace company owned by the billionaire Jeff Bezos.

“We got to weightlessness, I immediately turned upside down and looked at the planet and then there was so much blackness. There was so much space,” Calandrelli said in a video posted to social media that showed her reacting with awe to seeing Earth from space.

She added: “I didn’t expect to see so much space, and I kept saying that’s our planet! That’s our planet! It was the same feeling I got when my kids were born, and I was like, ‘That’s my baby!’”

But it was not long before the comments beneath the video were flooded with hateful, objectifying remarks.

The astronaut and MIT engineer said some sexualized her reaction to viewing the planet from space. The incident led to Blue Origin taking down the original video from its social media accounts.

Calandrelli, who also hosts a television show on Netflix called Emily’s Wonder Lab, where she’s known as “Space Gal”, said the reactions made her sad and angry, but she doubled down on her joy. In an Instagram post, she wrote she refuses “to give much time to the small men on the internet.

“I feel experiences in my soul. It’s a trait I got from my father,” she said. “We feel every emotion deeply and what a beautiful way that is to experience life. This joy is tattooed on my heart.

“I will not apologize or feel weird about my reaction. It’s wholly mine and I love it.”

Calandrelli said in an interview with CNN that the beauty of sending more women into space is that they “get to describe it in a way that moms can understand, that women can understand”.

Blue Origin did not respond to a request for comment.

Forecasters, environment officials and politicians have been strongly criticised over the warnings issued before Storm Bert and the fitness of flood defences to cope with increasingly common extreme weather.

A huge clear-up is under way across swathes of Wales and England, with hundreds of properties flooded and a former Welsh mining town hit by a landslip from a coal tip, leaving buildings deep in sludge and mud.

By Monday evening there will still be more than 100 flood warnings active in Wales and England. A major incident was declared at Billing Aquadrome in Northamptonshire where people were rescued from flooded homes and stranded vehicles.

There was also huge disruption on the rail network in parts of southern England and Wales with lines blocked by flood water, fallen trees and debris. Fire crews rescued 57 children from a school bus after it became stuck in flood water in Worcestershire.

The Met Office was criticised for issuing only a yellow warning as Storm Bert swept in across western and southern Britain over the weekend rather than amber or red.

A Met Office spokesperson said a “full assessment” of its warnings would take place but insisted: “Storm Bert was well forecast, 48 hours in advance, with a number of warnings in place ahead of the system reaching the UK.

“We work closely with partners to assess the potential risks of extreme weather, and the warnings covering Wales highlighted the potential for homes and businesses to flood with fast-flowing or deep flood water possible, causing a danger to life.”

In one of the worst-hit areas, Rhondda Cynon Taf in south Wales, where up to 300 properties were flooded, Natural Resources Wales (NRW) was criticised for not issuing warnings in time. A spokesperson conceded that some people appeared to have received warnings only minutes before homes were flooded.

NRW, which previously warned that the amount of investment in flood defences needed to be tripled, said there was “no silver bullet” for managing the flood risk in the area.

Sally Davies, a duty tactical manager at NRW, said a “very intense, localised area of rain” up to 160mm fell in the area on Sunday, and that the River Taff rose 300mm every 15 minutes at the height of the rainfall.

“But there is no silver bullet,” she said. “As a steep and fast-responding catchment, with much of the floodplain already built upon, reducing the flood risk is not at all straightforward.”

John Morgan, the manager of the Rheola pub in Porth, close to Pontypridd, blamed NRW for not doing more. He said: “This is the third time in four years that we have been flooded. Years ago, this river used to be dredged every year. Now it’s not dredged at all, it all builds up under the bridge. What good are warnings at three o’clock in the morning? What needs to be done is the defences, dredge the rivers, build walls.”

Dozens of people in Cwmtillery, south Wales, were forced from their homes as mud and water came up to their windows. Blaenau Gwent borough council confirmed the landslip was a “washout of a former coal tip in the area”.

One resident, Rob Scholes, said: “My neighbour phoned and said: ‘Don’t open your front door,’ so I didn’t and we just watched it come up. I really don’t think we’re going to get this cleared up by Christmas.”

The only severe flood warning in England and Wales remained in place at Billing Aquadrome, where a major incident was declared. People waded through water to escape the flooding, holding carrier bags containing belongings.

Huw Irranca-Davies, the Welsh deputy first minister, said there had been record spending on measures to counter flooding but it was simply not possible to protect every single home.

Heledd Fychan, the Plaid Cymru Senedd member for South Wales Central, said not enough had been done since the devastating storms of 2020.

She said: “This weekend’s events demonstrate that lessons have not been learned, leaving communities at the mercy of the weather without adequate mitigating measures.”

Andrew RT Davies, the leader of the Welsh Conservatives, said: “We must ask why only a yellow flood warning was issued when the forecast was so dire. And given that these areas, such as Pontypridd, were so badly impacted in 2020, we have to ask why lessons have not been learned.”

The UK environment secretary, Steve Reed, said: “This government inherited from the previous government flood defences that are in the worst condition on record. We’ve allocated in the budget £2.4bn to upgrade our flood defences, better maintain those we already have, build new flood defences to keep people safe.”

Germany is drawing up a list of bunkers that could provide emergency shelter for civilians, the interior ministry has said, at a time of rising tensions with Russia.

The list would include underground train stations and car parks as well as state buildings and private properties, a ministry spokesperson said.

A digital directory of bunkers and emergency shelters will be drawn up so people can find them quickly using a planned phone app. People would also be encouraged to create protective shelters in their homes by converting basements and garages, the spokesperson told a press briefing.

He declined to give a timetable, saying it was a big project that would take some time, involving the Office of Civil Protection and Disaster Assistance and other authorities.

The country of 84 million people has 579 bunkers, mostly from the second world war and the cold war era, which can provide shelter for 480,000 people, down from about 2,000 bunkers previously.

The spokesperson said the key points of the plan were agreed at a conference of senior officials in June and a special group was looking into it.

Since Russia’s full-scale invasion of Ukraine in 2022, concerns have been growing about Moscow’s potential to target other Nato members. In October, German intelligence chiefs warned that Russia would probably be capable of launching an attack on the military alliance by 2030.

German officials say the country is already experiencing a sharp rise in Russian spying and sabotage activities. Last week the Russian president, Vladimir Putin, said the conflict in Ukraine had characteristics of a “global” war and he did not rule out strikes on western countries.

Few manmade substances are as individually ubiquitous and dangerous as PFAS and microplastics and when they join forces there is a synergistic effect that makes them even more toxic and pernicious, new research suggests.

The study’s authors exposed water fleas to mixtures of the toxic substances and found they suffered more severe health effects, including lower birth rates, and developmental problems, such as delayed sexual maturity and stunted growth.

The enhanced toxic effects raise alarm because PFAS and microplastics are researched and regulated in isolation from one one another, but humans are virtually always exposed to both. The research also showed those fleas previously exposed to chemical pollution were less able to withstand the new exposures.

The findings “underscore the critical need to understand the impacts of chemical mixtures on wildlife and human health”, wrote the study’s authors, who are with the University of Birmingham in the United Kingdom.

PFAS are a class of about 15,000 compounds typically used to make products that resist water, stains and heat. They are called “forever chemicals” because they do not naturally break down and accumulate, and are linked to cancer, kidney disease, liver problems, immune disorders, birth defects and other serious health problems.

Microplastics are tiny bits of plastic that are either intentionally added to products or are shed by plastic goods as they deteriorate. They have been found throughout human bodies, and can cross the blood-brain barrier. Research has linked them to developmental harms, hormone disruption cardiovascular disease and other health issues.

Plastic is often treated with PFAS, so microplastics can contain the chemical.

Researchers compared a group of water fleas that had never been exposed to pollution with another group that had been exposed to pollution in the past. Water fleas have high sensitivity to chemicals so they are frequently used to study ecological toxicity.

Both groups were exposed to bits of PET, a common microplastic, as well as PFOA and PFOS, two of the most common and dangerous PFAS compounds. The mixture reflected conditions common in lakes around the world.

The study’s authors found the mixture to be more toxic than PFAS and microplastics in isolation. They attributed about 40% of the increased toxicity to a synergy among the substances that makes them even more dangerous. The authors theorized the synergy has to do with the interplay in the charges of microplastics and PFAS compounds.

The remainder of the increased toxicity was attributed to simple addition of their toxic effects.

Fleas exposed to the mixture showed a “markedly reduced number of offspring”, the authors said. They were also smaller at maturation and showed delayed sexual growth.

The effects they observed “significantly advance” the understanding of exposure to multiple chemicals and substances, the authors wrote.

“It is imperative to continue investigating the toxicological impacts of these substances on wildlife to inform regulatory and conservation efforts,” they said.