Fill in each blank with a proper word given in the box. Each word can be used only once. Note that there is one word that you do not need.

A. predictions       B. tricky       C. determine       D. consumed       E. significant F. sampled       G. address       H. concentrations       I. comparison       J. conventional       K. index

Using dragonflies as contamination(污染) detectors

Mercury(汞)pollution from power plants and mining operations can end up in our air and water.

But it’s 【小题1】 to predict just how much of that environmental mercury will make its way into our food—and our bodies.

“We were working on developing a bioindicator, a biosentinel, that could inform us of the levels of mercury contamination across the US.”

Ecologist Collin Eagles-Smith of the United States Geological Survey and his colleagues came up with a practical way to 【小题2】 the scope of mercury contamination in an ecosystem by measuring mercury levels in a single species. Their bioindicator: juvenile dragonflies, or larvae(幼虫). Dragonfly larvae stay underwater, don’t move much, are easy to collect and live long enough to accumulate 【小题3】 amounts of mercury.

“If you have enough locations 【小题4】 with dragonflies, you can develop an index of the relative amount of mercury in the biological community. ”

The team measured mercury 【小题5】 in thousands of dragonfly larvae collected from waterways in 100 national parks during a 10-year period. And to amass the large sample number, they recruited volunteers through the Dragonfly Mercury Project.

The volunteers used dip nets to collect dragonfly larvae from their aquatic abodes(住所). National park staff then sent the larvae to laboratories for processing. For 【小题6】 the researchers also measured mercury concentrations(浓度)in other aquatic organisms.

“Using the relationships between dragonfly concentrations and fish concentrations, we were able to develop what we call an impairment 【小题7】 . ”

That index allowed the researchers to make health risk【小题8】 at each sample site.

“About 12% of the locations posed what we consider to be high or severe risk of health impairments to fish, wildlife or humans if they【小题9】 organisms from those locations. You can begin to build models that are predictive of how much mercury might be in a system and then apply that model to locations where you haven’t sampled dragonflies.”

“And that can inform future management actions to 【小题10】 the factors that are promoting the mercury production or simply inform agencies that may want to evaluate whether or not fish consumption advisories(警告)are necessary. ”

The study is in the journal of Environmental Science & Technology.