VOA慢速英語(yǔ)：警告牌提示人們游泳遠(yuǎn)離污染水源

The dry conditions in California are good for people wholike to swim in the Pacific Ocean. Because of the drought, there is less waterrunoff from cities into the ocean. As a result, the ocean water is cleaner. Butpollution remains a problem in other areas, including popular beaches.

Angelo Bellomo works for the Los Angeles County Department of PublicHealth.

“When we have runoff from the urban environment, it could be carrying with itcontamination due to animal waste (and) sewage overflows; and if thoseenter the beaches through the normal pipes that terminate in the ocean, youwant to avoid contact with water during those periods.”

He adds that people could become infected with a number of diseases fromswimming in polluted ocean water.

Public health officials are looking for a fast way to identify water quality levelsalong the California coast. Currently, they use laboratory tests. If the testsshow the quality is poor, warning signs are placed along the coastline. Butbecause lab workers need more than a day to test the water, the informationon the sign can be outdated.

Leslie Griffin works for an environmental group called “Heal the Bay.” Shesays the current warning system is not very helpful.

“Right now it takes 18 to 24 hours to get those water quality results, but wethink that that is a little ridiculous because we want people to know the day ofwhen they are going in the water whether or not they can be getting sick.”

Until lab tests can be completed faster, researchers in California are usingwhat they call a “predictive modeling system.” The system makes aneducated guess about water quality. Heal the Bay says the system can makea prediction about water quality in as little as 15 minutes.

Researchers use computers to gather information about the environment. Thedata includes wind speed and direction, information about ocean waves andrecent bacterial contamination. Because each beach is different, computermodels are created for each one. The researchers then use the data topredict the possible quality of the water that day. The process is called“Nowcasting.”

Angelo Bellomo says the predictive modeling system looks promising.

“We think that the modeling that we have seen so far is generally moreaccurate than the testing that we are doing, and the reason for that is thateven though it is a model and its predicting water quality, it is more timely.”

Hong Kong and the American state of Ohio have similar methods of predictingwater quality.

I’m Marsha James.

Elizabeth Lee reported on this story from Los Angeles. Christopher Jones-Cruise adapted it for Learning English. George Grow was the editor.

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Words in This Story

runoff– n. water from rain or snow that flows over the surface of the groundinto streams; water from cities that flows into the ocean

contamination – n. the state of being dangerous, dirty or impure becausesomething harmful or undesirable has been added

sewage– n. waste material that is carried away from homes and otherbuildings in pipes

terminate – v. to end in a given way or at a particular place

outdated– adj. no longer useful or acceptable

ridiculous – adj. extremely silly or unreasonable