Another concern is that long-term pollution,at even low levels,can affect whole ecosystems,with resultant impacts on biodiversity that bring about additional changes in how ecosystems operate.

• 另一个涉及的问题是长期污染，即使在一个很低的水平它也能影响整个自然界，影响到生物的多样性，其结果使生态系统在如何发挥作用方面发生意想不到的变化。