3 . 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 . In the first test of its kind in Europe, and only the second in the world, Belgian researchers tested 39 brands of straws (吸管) for the group of synthetic (合成的) chemicals known as poly-and perfluoroalkyl substances (PFAS). The straws are made from five materials — paper, bamboo, glass, stainless steel and plastic. PFAS were found in the majority of the straws tested and were most common in those made from paper and bamboo. They were not found only in steel straws tested.

PFAS are used to make everyday products, from outdoor clothing to non-stick pans, resistant (抵抗to water, heat and stains. They are, however, potentially harmful to people, wildlife and the environment. They have been related to a number of health problems, including lower response to vaccines (疫苗), lower birth weight, thyroid disease, liver damage, kidney cancer and testicular cancer. They break down very slowly over time and can last thousands of years in the environment, a property that has led to them being known as “forever chemicals”.

A growing number of countries, including the UK and Belgium, have sopped the sale of single-use plastic products, including drinking straws, and plant-based versions have become popular. The PFAS concentrations (浓缩物) were low in them and, bear in mind that most people tend to only use straws occasionally, bringing a limited risk to human health. However, PFAS can remain in the body for many years and concentrations can build up over time.

It isn’t known whether the PFAS were added to the straws by the producer for waterproofing or the PFAS were the result of contamination. Potential sources of contamination include the soil the plant-based materials were grown in and the water used in the production process. However, the presence of the chemicals in almost every brand of paper straws means it is likely that it was, in some cases, being used as a water-resistant coating, say the researchers.