密歇根新闻广播 五大湖河流出现杀虫剂

Insecticides widely used on farms, lawns and gardens — known as neonicotinoids — are showing up in rivers across the Great Lakes region.

Michelle Hladik, a research chemist with the U.S. Geological Survey and the lead author of the new study in the journal Environmental Pollution, says they found the highest concentrations of neonicotinoids in the rivers they tested during the spring and summer months.

"This was expected," she says. "These higher concentrations happened after planting of mostly corn and soybeans and then [in] summer you can get other types of broadcast applications."

She says they found neonicotinoids in Great Lakes rivers throughout the year, typically at low levels. But she says there are concerns about aquatic¹ creatures being continually exposed to these insecticides.

"If you want to compare them to acute and chronic² toxicity³ levels, rarely were we ever above an acute toxicity level," she says. "But for one of the compounds, imidacloprid, we did exceed the chronic toxicity level multiple times."

Hladik says researchers are finding aquatic invertebrates⁴ such as water fleas⁵ appear to be the most sensitive to the insecticides.

"These small invertebrates are the basis for food for a lot of other species in an aquatic environment," she says. "So there is concern that if these lower level organisms are being affected⁶, that can then affect the food source that other species need."

Hladik says they also found a correlation⁷ between land use and neonicotinoids in the rivers. For instance, rivers with a significant amount of agriculture or urban activity or both around them had more frequent detections and higher concentrations of neonicotinoids.

1 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

2 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

3 toxicity   

n.毒性，毒力

参考例句：

• The hoarse grunt or squeal is characteristic of toxicity.嘶哑的哼声和叫声是中毒的特征。
• Dieldrin is related to aldrin,and its toxicity to earthworms is similar.狄氏剂与艾氏剂有关，对蚯蚓的毒性是相似的。

4 invertebrates   

n.无脊椎动物( invertebrate的名词复数 )

参考例句：

• Insects and worms are all invertebrates. 昆虫和蠕虫都是无脊椎动物。 来自辞典例句
• In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和许多其它无脊椎动物中，这些排泄结构称为肾管。 来自辞典例句

5 fleas   

n.跳蚤( flea的名词复数 )；爱财如命；没好气地（拒绝某人的要求）

参考例句：

• The dog has fleas. 这条狗有跳蚤。
• Nothing must be done hastily but killing of fleas. 除非要捉跳蚤，做事不可匆忙。 来自《简明英汉词典》

6 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

7 correlation   

n.相互关系，相关，关连

参考例句：

• The second group of measurements had a high correlation with the first.第二组测量数据与第一组高度相关。
• A high correlation exists in America between education and economic position.教育和经济地位在美国有极密切的关系。