1 . Microplastics, as the name implies, are tiny plastic particles found in the environment. Any plastic particle that has a diameter of less than 5 mm is considered to be microplastic. For a long time, a majority of people were unaware of the presence of microplastics and their effects on the environment. However, these particles have become a significant topic of debate in recent times after researchers noted their presence in almost every corner of the globe. from Mount Everest to the Mariana Trench.
There are two categories of microplastics: primary and secondary. Primary microplastics are tiny particles meant for external commercial use such as cosmetics, as well as microfibers to make other textiles, such as fishing nets. Secondary microplastics are particles that result from the breakdown of larger plastic items, such as water bottles.
There are various sources of microplastics. Wastewater treatment plants and sewage treatment plants are the major sources of primary microplastics, most of which are residues (残留物) of cosmetics, paint, household and industrial waste. Single-use plastics plastic items meant to be used just once and then discarded, such as a straw — are the main source of secondary plastics in the environment.
The problem with microplastics is that like plastic items of any size they do not readily break down into harmless molecules. Plastics can take hundreds or thousands of years to decompose (降解). That means once produced, we cannot get rid of them. Microplastics exist on beaches and deeper waters, and have been detected in marine organisms from plankton to whales, in commercial seafood, and even in drinking water. They are mistaken for food by marine animals and some plastics are so tiny that they end up in the animal tissues. They are passed across the food chain, and some find their way to humans.
Scientists are still unsure whether consumed microplastics are harmful to human or animal health and if so, what specific dangers they may pose. Even so, many countries are taking action to reduce microplastics in the environment. The best approaches to controlling microplastics include proper handling of plastics and thorough treatment of wastewater.
1. According to the first two paragraphs, microplastics are_________| A．common in our daily life |
| B．used to make glass bottles |
| C．found in all the uninhabited areas |
| D．tiny plastic particles with a diameter of 5mm |
| A．The use of straws should be forbidden. |
| B．Household waste contains microplastics. |
| C．Industrial waste is a source of secondary plastics |
| D．Wastewater and sewage treatment plants are useless. |
| A．Because they’re consumed as food. |
| B．Because they exist on the beaches. |
| C．Because they easily break down. |
| D．Because they’re left out in the food chain. |
| A．To analyze the sources of microplastics. |
| B．To warn people of the danger of microplastics. |
| C．To give an overall introduction to microplastics. |
| D．To persuade people to give up the use of microplastics. |
