2 . Plastic is everywhere, from the Arctic ice to vital organs in the human body. In fact, previous estimates suggest that the average person swallows a credit card-worth of microscopic plastic particles(颗粒) every week. But new research shows that this could actually be an understatement.

Microplastics are plastics smaller than 5 millimeters, found in industrial waste, beauty products, and formed during the degradation of larger plastic pieces. Over time, they break down into even smaller nanoplastics. These tiny particles can pass through our intestines and lungs into our bloodstreams, reaching vital organs like the heart and brain.

While the idea of eating plastic is unsettling in itself, the major concern here is that these plastic particles contain chemicals that can interrupt our body’s natural release of hormones, potentially increasing our risk of reproductive disorders and certain cancers. They can also carry toxins(毒素) on their surface like heavy metals.

In the past, researchers have shown bottled water can contain tens of thousands of identifiable plastic fragments in a single container. However, until recently, only the larger microplastics were detectable with available measuring tools, leaving the area of nanoplastics largely a mystery.

Using Raman microscopy (显微镜学), capable of detecting particles down to the size of a flu virus, the team measured an average of 240, 000 particles of plastic per liter of bottled water, 90 percent of which were nanoplastics, a revelation 10 to 100 times larger than previous estimates.

These plastics likely originate from the bottle material, filters used to “purify” the water, and the source water itself. “It is not totally unexpected to find so much of this stuff, ” the study’s lead author, Columbia graduate student Naixin Qian, said in a statement. His team hopes to expand their research into tap water and other water sources to better inform our exposure to these potentially dangerous particles. “The idea is that the smaller things get, the more of them I reveal, ” he added.

4 . As plastic waste increases rapidly around the world, an essential question remains unanswered: What harm, if any, does it cause to human health?

A few years ago, as microplastics began turning up in the organs of fish and shellfish, the concern was focused on the safety of seafood. Shellfish were a particular worry, because in their case, unlike fish, we eat the entire animal — stomach, microplastics and all. In 2017, Belgian scientists announced that seafood lovers could consume up to 11,000 plastic particles (粒子) a year by eating mussels (贻贝), a favorite dish in that country.

By then, however, scientists already understood that plastics continuously fragment small pieces in the environment, tearing over time into fibers even smaller than a strand of human hair — particles are so small that they easily fly in the air. A team at the U.K.’s University of Plymouth decided to compare the threat from eating polluted wild mussels in Scotland to that of breathing air in a typical home. Their conclusion: People will take in more plastic by breathing in or taking tiny, invisible plastic fibers floating in the air around them—fibers from their own clothes, carpets, and soft covering on furniture — than they will by eating the mussels.

So, it wasn’t much of a surprise when, in 2022, scientists from the Netherlands and the U.K, announced they had found tiny plastic particles in living humans, in two places where they hadn’t been seen before: deep inside the lungs of surgical patients, and in the blood of unknown donors. Neither of the two studies answered the question of possible harm. But together they signaled a shift in the focus of concern about plastics toward the cloud of dust particles in the air, some of them are so small that they can get into deep inside the body and even inside cells, in ways that larger microplastics can’t.

Dick Vethaak, a professor of ecotoxicology (生态毒理学), doesn’t consider the results alarming, exactly—“but, yes, we should be concerned. Plastics should not be in your blood.” “We live in a multi-particle world,” he adds, referring to the dust, pollen (花粉), and smog that humans also breathe in every day. “The trick is to figure out how much plastics contribute to that particle burden and what does that mean.”

Forests give us shade, quiet and one of the harder challenges in the fight against climate change. Even as we humans count on forests to soak up a good share of the carbon dioxide we produce, we    1     (threaten) their ability to do so. The climate change we are hastening could one day leave us with forests that emit more carbon than    2    absorb.

Thankfully, there is a way out of this trap—but it involves striking a subtle balance. Helping forests flourish as valuable “carbon sinks” long into the future    3       require reducing their capacity to absorb carbon now. California is leading the way, as it does on so many climate efforts, in figuring out the details.

The state's proposed Forest Carbon Plan aims to double efforts    4    (thin) out young trees and clear brush in parts of the forest. This temporarily lowers carbon-carrying capacity. But the remaining trees draw a greater share of the available moisture, so they grow and thrive,     5    (restore) the forest's capacity to pull carbon from the air. Healthy trees are also better able to fend off (抵挡) insects. The landscape is considered less easily burnable. Even in the event of a fire, fewer trees    6     (consume).

The need    7    such planning is increasingly urgent. Already, since 20l0, drought and insects have killed over 100 million trees in California, most of them in 2016 alone，and wildfires have burned hundreds of thousands of acres.

California plans to treat 35,000 acres of forest a year by 2020, and 60,000 by 2030—financed from the proceeds of the state's emissions-permit auctions. That's only    8     small share of the total acreage that could benefit, about half a million acres in all, so it will be vital to prioritize areas at greatest risk of fire or drought.

State governments are well accustomed to managing forests,     9     traditionally they've focused on wildlife, watersheds and opportunities for recreation. Only recently have they come to see the vital part forests will have to play in storing carbon. Califomia's plan,     10     is expected to be finalized by the governor next year, should serve as a model.

All Change in Curitiba!

Like many other major world cities, Curitiba in southern Brazil has had to deal with issues such as pollution, poverty, and limited public funding. However, the architect and three-times mayor of the city, Jaime Lerner, has introduced some     1     solutions.

As part of his ‘Master Plan’, Lerner hoped to make the city more environmentally friendly. He initiated a recycling scheme. In return for delivering recyclable rubbish to specified     2     points, residents receive a bag of vegetables or bus tickets. As a result, Curitiba now has one of the highest recycling rates in the world. Lerner also ordered the     3     of 26 urban parks. As well as preventing pollution, these control flooding.

Lerner did not win over all the city’s residents immediately, however. When his plans to     4     part of the centre were passed, local businesses were up in arms, fearing a reduction in profits. Realising he needed to act quickly, Lerner had the     5     of six blocks completed within three days. When a group of motorists attempted to drive through the new pedestrian area, Lerner arranged for local primary schools to hold a painting workshop on the streets. The drivers were forced to turn back. Luckily for Lerner, this rebellion was     6    . The increase in profit rapidly persuaded shop owners to change their minds.

Lerner’s determination helped     7     the Curitiba of today. The average income per capita has risen from a level that was below the Brazilian average in the 1970s to 66% above the average, and surveys indicate high levels of resident satisfaction.

So, is it all just one big success story? In some respects, Curitiba may have been too successful for its own    8    . People and businesses have come to the city, which now has more than 1.8 million residents. This has put the city under enormous stress. Forty years ago, buses transported 54,000 passengers a day. Now the number is 2.3 million. According to some experts, the transport system has reached its     9     efficiency capacity. Following a rise in complaints about the noisy and     10     buses, the service is in decline.

9 . The Man Who Ate his Boots is a fascinating account of expeditions that went wrong. The book examines the 19th century search for a route to Asia by way of the Northwest Passage through the Arctic Ocean. Author Anthony Brandt describes the many attempts by both land and sea that ended in failure and tragedy, including the 1845 expedition led by Sir John Franklin. Brandt shows how these brave, yet sometimes foolish, explorers could have avoided starvation, frostbite, and even death if they had copied the survival techniques of the local Inuit people. Some of the more surprising details the book reveals include:

IGLOOS The explorers, despite repeatedly watching the Inuit build igloos, insisted on using canvas tents. Tents freeze in sub-zero temperatures and give little protection to anyone inside them. If they had learned to build igloos, the explorers would have been warm even in the worst Arctic weather.

SEALSKIN If the explorers had worn sealskin and furs like the Inuit, they wouldn’t have suffered from the frostbite that was common among them, but rare among the Inuit.

DOG TEAMS Why didn’t the British use dog teams to pull their sleds? Pulling sleds themselves was a tradition among many explorers right into the early 20th century. It cost Scott and his men their lives on their return from the South Pole in 1912.

The British did get something right, however, when Captain Edward Parry grew salad vegetables in boxes on board his ship. It was known that fresh vegetables and fresh meat prevented scurvy (坏血病)，although at that time the reason for this (vitamin C) had not been discovered. Parry’s men wouldn’t have been as healthy if they hadn’t eaten the salads.

Why Are Trees Tree-shaped?