In a new study, researchers have discovered bottled water sold in stores can contain 10 to 100 times more bits of plastic than previously estimated—nanoplastics (纳米塑料) so tiny that they cannot be seen under a microscope.

At one-thousandth the average width of a human hair, nanoplastics are so small that they can migrate through the tissues of the digestive tract or lungs into the bloodstream, distributing potentially noxious synthetic (人造的) chemicals throughout the body and into cells. One liter of water contains an average of 240,000 plastic particles from seven types of plastics, of which 90% are identified as nanoplastics and the rest are microplastics, according to the new study.

According to Sherri Mason, a researcher, the new finding strengthens long-held expert advice to drink tap water from glass or stainless steel containers to reduce exposure. That advice extends to other foods and drinks packaged in plastic.

Nanoplastics are the most worrying type of plastic pollution for human health. “The chemicals can be carried to your liver, kidney, and brain and even make their way across the placental boundary and end up in an unborn child,” said Mason.

“Based on other studies, we expected most of the microplastics in bottled water would come from leakage of the plastic bottle itself, which is typically made of PET (聚对苯二甲酸乙二醇酯) plastic,”said Qian, a doctoral student at Columbia University. Studies have found that particles of this plastic can be broken off by repeatedly opening and closing the cap of the bottle, crushing the bottle or subjecting it to heat, such as in a car.

“We can avoid consuming foods and beverages (饮料) in plastic containers. We can wear clothing made from natural fabric s and buy consumer products made from natural materials,”said Jane Houlihan, an expert in environmental health.“We can estimate the plastic in our daily lives and find alternatives whenever possible.” Several studies have also reported lower microplastic levels in tap water.

Starbucks will stop using plastic straws from its stores globally by 2020, in a nod to the growing push for businesses to be more environmentally friendly. The Seattle-based company said on Monday it will instead use straws made from other materials, and lids designed not to need straws. McDonald's also recently said it would switch to paper straws in the UK and Ireland by next year, and test alternatives to plastic straws in some US locations. In February, Dunkin' Donuts said that it would refuse polystyrene foam (塑料泡沫) cups from its stores by 2020.

Environmental activists have been pressuring businesses to ditch plastic straws because they can end up in the ocean and hurt marine life. The push gained great support after a video in 2015 showed rescuers removing a straw from a sea turtle's nose in great detail. Local governments have also been looking at the issue. Last week, Seattle’s ban on single-use plastic straws and utensils in food service outlets took effect, and Starbucks says it already offers alternative straws there. Similar proposals are being considered elsewhere, including New York and San Francisco.

While straws have become a highly-concerned issue, they make up only about 4% of the plastic trash by number of pieces, and far less by weight. Straws add up to only about 2,000 tons of the nearly 9m tons of plastic waste that hits waters each year.

Life today is much easier than it was hundreds of years ago, but has brought new problems. One of the biggest is pollution. Pollution come in many ways. We see it, smell it, drink it and even hear it.

Men have been polluting the earth. Many years ago, the pollution was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, men moved to another place.

Air pollution is now the most serious. Air makes people sick. And lots of people now are trying to use something to clear the air. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us become angry more easily.

Many countries are making rules to fight air pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.

Pollution by SO² is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is true that if there are fewer people driving, there will be less air pollution.

Although most of the pollution is caused by us, we are the ones who can change the situation. The earth is our home. We must take care of it. And we must pay more attention to the information in pollution at the same time.