PTE AcademicReading
Reading & Writing: Fill in the Blanks
Below is a text with blanks. Click on each blank, a list of choices will appear. Select the appropriate answer choice for each blank.
0 / 6 空欄記入済み
Tracking Pollution Through Urban Rivers
environmental scienceUrban rivers provide a useful window into environmental change because they collect water from streets, parks, and industrial zones. After heavy rain, can carry oil, metals, and plastic fragments into waterways, which may in sudden drops in water quality. Scientists therefore monitor rivers over time, rather than relying on a single sample, to identify patterns and make informed decisions about management.
A common approach is to measure nutrients such as nitrogen and phosphorus, since high concentrations often on fertiliser use and leaking sewage systems. When these nutrients , they can trigger algal blooms that reduce oxygen levels and harm fish. Researchers also compare results across seasons, because temperature and river flow affect how quickly pollutants break down. In addition, microscopic pollutants are increasingly detected in sediment, where they can persist for years.
However, collecting reliable data requires careful planning. Field teams must take responsibility for consistent methods, including the location of sampling sites and the timing of collection. If instruments are not properly , the final dataset may be misleading, even when the analysis is sophisticated.
Policy responses are most effective when they combine regulation with public participation. For example, improving waste treatment can be costly, but it is often more than repeated clean-up campaigns. By investing in prevention and educating residents about everyday choices, cities can reduce pollution at its source and protect ecosystems in the long term.