视频文本

Next, we'll take a look at the most recent reports published by local water works
下面我们来看地方供水系统发布的最新的报告
and see what level of nitrates exist in your drinking water.
来分析一下日常饮用水中含有多少硝酸盐
These two charts sum up the most recent data for nitrate levels in drinking water in De Moines and Aimes.
这两个表格总结了关于De Moines和Aimes的饮用水中硝酸盐的含量的最新情况，
The number highlighted in yellow
黄色标记的数字是两个城市的
is the amount of nitrate detected as reported by each city's public works department.
公共工作部门检测到的硝酸盐的含量
De Moines Water Works or DMWW obtains water from the Raccoon River and ground water under the influence of it.
De Moines自来水，简称为DMWW，它的水源来自于河水和地下水，其中地下水又受河水影响据水利部门，
A challenge according to the Water Works is that
水利部门的一项挑战就是
the Raccoon River has the highest average nitrate concentration of any of the 42 largest tributaries in the Mississippi River Basin.
这条河的河水中硝酸盐的含量是密西西比河湾处42条支流中最高的
De Moines Water Works removes nitrates from the water by operating its nitrate removal facility,
水利部门通过硝酸盐处理装置将水中的硝酸盐析出
the largest of its kind in the world.
这个装置是世界上同类装置中规模最大的
This keeps nitrate, nitrogen levels below 10 milligrams per liter, the EPA limit for safe water.
这就使硝酸盐和氮减少到每升10毫克一下，从而符合环保局的安全标准
Aimes water comes from 22 ground water wells drawing from the Aimes Aquifer.
Aimes的饮用水来自于地下蓄水层打出的22眼地表水井，
Aquifers are pockets of water deep underground that
地下蓄水层
have the benefit of different types of filtration before the water is extracted.
存储着深层地下水，在被打上来之前需要进行一系列的过滤处理
The benefits of such a system are demonstrable
这样一个系统的优势显而易见
considering the differences in measured nitrate levels in De Moines at 5 to 9 milligrams per liter
在De Moines水中的硝酸盐含量为每升5-9毫克，
and at Aimes at less than 0.10 milligrams per liter.
而在Aimes这一数值小于每升0.10毫克
Measurements can also indicate levels of microbial contamination
这些措施还能表明微生物的污染水平，
which leads to our next discussion of microbial safety of organic foods versus conventional foods.
这就会引出我们要讨论的下一个话题，那就是有机食品和传统食品中微生物污染哪个更高，
In summary, nitrite and nitrates can be hazardous to very young children by forming methmoglobin,
总而言之，硝酸盐和亚硝酸盐能够通过产生有害物质从而威胁儿童的生长，
which prevents the blood from carrying sufficient oxygen
因为这种物质能够减少血液中的含氧量，
but are not known to have negative health effects to adults
但是它对成人的身体健康却不会产生负面影响
until extreme levels of 10 milligrams per liter are reached
除非含量达到每升10毫克，
since the acidic environment of the adult stomach stops the break down of nitrate to nitrite at levels below the maximum.
因为成人胃中的酸性环境能够有效阻止硝酸盐变为亚硝酸盐
Nitrites and nitrates are monitored and controlled by current USDA practices for both conventional and organic food.
传统食品和有机食品中的亚硝酸盐和硝酸盐含量都由农业部进行监控
E-coli is a naturally occurring bacteria found in the intestinal tract of warm-blooded organisms.
大肠杆菌是生长在温血动物大肠中的常见细菌
Kept within the confines of an animal or human's intestinal tract, E-coli is harmless.
在肠道中的大肠杆菌对人和动物都是无害的，
However, if E-coli reaches uncooked or un-cleaned food through bad food safety practices or fecal contamination,
但是如果大肠杆菌通过不正规的处理方式或者粪便到达了生的，或者没有洗净的食物上
it can cause severe food poisoning and even death to humans.
那么就会造成严重的食物中毒甚至导致死亡，
In 2002, 2003, and 2004, researchers from the University of Minnesota undertook an extensive study
从2002-2004年明尼苏达大学的研究人员展开了深入研究，
to compare rates of E-coli contamination from use of animal manure in crop preparation on farms in Minnesota and Wisconsin.
对比明尼苏达州和威斯康辛州由于使用粪肥使植物沾染大肠杆菌的情况
The researchers asked farmers to complete a questionnaire that
研究人员让当地农民填写调查问卷，
covered farm practices with a focus on application standards of animal manure based on composting time greater or less than six months.
问卷中包括了一些与耕作习惯有关的问题，重点关注粪肥的使用是否符合标准，即堆肥的制作过程是否超过六个月
Participating farmers were visited two to three times during the test period.
在测试期间，研究人员会到参与调查的农民家中拜访两至三次，
Samples of fruits and vegetables were collected directly from the farm fields
水果和蔬菜样本都是直接从农场中采摘的，
and without any washing or rubbing off of soil particles were transferred into sterile,
没有对表面的土壤和灰尘进行任何处理，直接装入密封的专用袋中，
Zip-lock bags Gloves and knives used were sanitized with alcohol swabs between collections to prevent cross-contamination.
采摘过程中用到的刀子和手套等每次都要经过酒精消毒以防交叉感染

视频及简介

视频简介：

本课程的目标是，向公众提供最新的有关营养方面的信息和话题，内容涵盖饮食因素对于癌症的影响作用，健康的饮食习惯，学校能提供的营养有哪些，咖啡因与癌症的联系，水果蔬菜与癌症预防等。通过本课程的学习，人们可以学习到健康的生活饮食习惯，在每天的饮食中防癌症于未然