1 00:00:05,00 --> 00:00:08,00 So, biomonitoring gives scientists important information about the 2 00:00:08,00 --> 00:00:12,00 chemicals we’re exposed to and how they affect our bodies. 3 00:00:13,00 --> 00:00:15,00 That information helps our government and public health officials 4 00:00:15,00 --> 00:00:17,00 make more informed decisions. 5 00:00:18,00 --> 00:00:21,00 CDC conducts a survey every 2 years to assess the health 6 00:00:21,00 --> 00:00:24,00 and nutritional status of adults and children in the U.S. 7 00:00:24,00 --> 00:00:28,00 It’s called the National Health and Nutrition Examination Survey, 8 00:00:28,00 --> 00:00:30,00 or NHANES for short. 9 00:00:30,00 --> 00:00:34,00 Scientists at the Biomonitoring Program use the NHANES survey results 10 00:00:34,00 --> 00:00:37,00 to gather exposure data, or information about the 11 00:00:37,00 --> 00:00:41,00 levels of chemicals in people’s bodies. Here’s how that works. 12 00:00:41,00 --> 00:00:45,00 First, scientists choose a sample — a small group of people who 13 00:00:45,00 --> 00:00:48,00 participated in the NHANES survey — to analyze. 14 00:00:48,00 --> 00:00:51,00 To reflect our diverse population here in the United States, 15 00:00:51,00 --> 00:00:54,00 scientists make sure to include people of different age groups, 16 00:00:54,00 --> 00:00:56,00 genders, and ethnicities. 17 00:00:56,00 --> 00:00:59,00 Then, they study blood and urine samples from this group 18 00:00:59,00 --> 00:01:02,00 of people to find out what chemicals and how much of 19 00:01:02,00 --> 00:01:04,00 those chemicals are in their bodies. 20 00:01:04,00 --> 00:01:08,00 Finally, CDC publishes the results in a report called the 21 00:01:08,00 --> 00:01:13,00 National Report on Human Exposure to Environmental Chemicals and Updated Tables. 22 00:01:13,00 --> 00:01:16,00 This report is the most comprehensive assessment ever made 23 00:01:16,00 --> 00:01:19,00 of human exposure to environmental chemicals. 24 00:01:20,00 --> 00:01:23,00 The first version of the report, published in March 2001, 25 00:01:23,00 --> 00:01:26,00 included exposure data about 27 chemicals. 26 00:01:26,00 --> 00:01:34,00 Additional reports followed in 2003, 2005, and 2009, along with several report updates. 27 00:01:34,00 --> 00:01:38,00 Each report and update included exposure data on more chemicals. 28 00:01:39,00 --> 00:01:42,00 The latest version includes exposure data for more than 29 00:01:42,00 --> 00:01:47,00 300 chemicals and includes findings from 1999 to 2016. 30 00:01:47,00 --> 00:01:51,00 Here are a few of the chemicals included in the report. 31 00:01:56,00 --> 00:01:59,00 All that biomonitoring data has led to important policy changes 32 00:01:59,00 --> 00:02:01,00 that protect our nation’s health. 33 00:02:01,00 --> 00:02:05,00 For example, biomonitoring research played an important role in 34 00:02:05,00 --> 00:02:07,00 reducing lead use in the United States. 35 00:02:07,00 --> 00:02:11,00 People who are exposed to high levels of lead can get lead poisoning, 36 00:02:11,00 --> 00:02:14,00 which may cause learning disabilities and behavior problems. 37 00:02:15,00 --> 00:02:18,00 Very high levels of lead in the body can cause seizures, 38 00:02:18,00 --> 00:02:20,00 coma, or even death. 39 00:02:20,00 --> 00:02:26,00 In 1981, the U.S. Environmental Protection Agency, or EPA, was considering changing the 40 00:02:26,00 --> 00:02:29,00 law to allow more lead in gasoline. 41 00:02:29,00 --> 00:02:32,00 But thanks in large part to biomonitoring research, 42 00:02:32,00 --> 00:02:35,00 the EPA decided to restrict the use of leaded gasoline instead. 43 00:02:35,00 --> 00:02:38,00 Here’s how it happened: 44 00:02:39,00 --> 00:02:41,00 The EPA’s research predicted that leaded gasoline would have a 45 00:02:41,00 --> 00:02:45,00 limited impact on blood lead levels, or the amount of lead people 46 00:02:45,00 --> 00:02:47,00 have in their bodies. 47 00:02:47,00 --> 00:02:50,00 But a CDC survey showed that blood lead levels had 48 00:02:50,00 --> 00:02:54,00 dropped from 1976 to 1980 and that the drop tracked 49 00:02:54,00 --> 00:02:56,00 decreased use of lead in gasoline. 50 00:02:56,00 --> 00:02:59,00 Over that time period, decreased use of lead in 51 00:02:59,00 --> 00:03:01,00 gasoline resulted from the introduction of unleaded 52 00:03:01,00 --> 00:03:03,00 gasoline in the United States. 53 00:03:04,00 --> 00:03:07,00 More research showed similar relationships between lead in 54 00:03:07,00 --> 00:03:09,00 gasoline and blood lead levels in other countries. 55 00:03:10,00 --> 00:03:13,00 Based on this critical scientific evidence, the EPA decided to 56 00:03:13,00 --> 00:03:16,00 restrict the use of leaded gasoline. 57 00:03:16,00 --> 00:03:20,00 And as remaining lead was removed from gasoline, blood lead levels 58 00:03:20,00 --> 00:03:22,00 continued to decline. 59 00:03:22,00 --> 00:03:26,00 Removing lead from paint has also made a big impact on lead levels in the U.S. 60 00:03:26,00 --> 00:03:32,00 By 1999, blood lead levels in children ages 1 to 5 had fallen to historic lows. 61 00:03:33,00 --> 00:03:36,00 But we haven’t completely solved the lead problem. 62 00:03:36,00 --> 00:03:40,00 While lead-based paint was banned from use in housing in 1978, 63 00:03:40,00 --> 00:03:45,00 as many as 24 million older homes still have lead paint or lead-contaminated dust. 64 00:03:45,00 --> 00:03:48,00 And about 4 million of those are home to young children, 65 00:03:48,00 --> 00:03:51,00 who are most likely to be affected by lead poisoning. 66 00:03:52,00 --> 00:03:57,00 So, biomonitoring scientists continue to track lead levels in Americans, helping us assess 67 00:03:57,00 --> 00:04:00,00 how well national programs aimed at reducing or eliminating 68 00:04:00,00 --> 00:04:02,00 lead exposure are working. 69 00:04:02,00 --> 00:04:07,00 More information about blood lead levels is available in CDC’s National Report on 70 00:04:07,00 --> 00:04:10,00 Human Exposure to Environmental Chemicals and Updated Tables. 71 00:04:11,00 --> 00:04:15,00 Biomonitoring also helped us put policies in place to reduce people’s 72 00:04:15,00 --> 00:04:17,00 exposure to secondhand smoke. 73 00:04:18,00 --> 00:04:22,00 Nicotine is the addictive chemical used in tobacco products like cigarettes, 74 00:04:22,00 --> 00:04:24,00 vaping devices, and chewing tobacco. 75 00:04:25,00 --> 00:04:28,00 Even people who don’t smoke or use other tobacco products 76 00:04:28,00 --> 00:04:30,00 might be exposed to nicotine when they spend time in places 77 00:04:30,00 --> 00:04:32,00 where other people are smoking. 78 00:04:32,00 --> 00:04:36,00 This is called secondhand smoke, and it can be harmful to people’s health. 79 00:04:37,00 --> 00:04:40,00 Cotinine is a substance that forms in your body when you are 80 00:04:40,00 --> 00:04:41,00 exposed to nicotine. 81 00:04:42,00 --> 00:04:44,00 By measuring the levels of cotinine in a person’s body, 82 00:04:44,00 --> 00:04:48,00 scientists can tell how much nicotine they have been exposed to. 83 00:04:49,00 --> 00:04:53,00 CDC biomonitoring scientists developed a way to measure very low levels 84 00:04:53,00 --> 00:04:55,00 of cotinine in people’s bodies. 85 00:04:55,00 --> 00:04:58,00 They found that 88% of people who didn’t smoke were exposed 86 00:04:58,00 --> 00:05:00,00 to secondhand smoke. 87 00:05:00,00 --> 00:05:02,00 And people who worked around tobacco had even 88 00:05:02,00 --> 00:05:04,00 higher levels of cotinine in their bodies. 89 00:05:04,00 --> 00:05:08,00 This data inspired new laws to restrict smoking in public buildings. 90 00:05:09,00 --> 00:05:14,00 When CDC measured cotinine levels again in 1999 and 2000, 91 00:05:14,00 --> 00:05:16,00 they found that average cotinine levels among people 92 00:05:16,00 --> 00:05:20,00 ages 3 and older had decreased by more than 70%. 93 00:05:20,00 --> 00:05:23,00 That means people were exposed to a lot less secondhand smoke. 94 00:05:24,00 --> 00:05:28,00 The 2006 Surgeon General’s Report celebrated this dramatic reduction. 95 00:05:28,00 --> 00:05:31,00 However, there is still more work to be done. 96 00:05:31,00 --> 00:05:35,00 Children’s cotinine levels are still twice those of adults. 97 00:05:35,00 --> 00:05:38,00 And newer tobacco products like e-cigarettes and vape pens 98 00:05:38,00 --> 00:05:40,00 could also present serious health risks. 99 00:05:41,00 --> 00:05:45,00 Biomonitoring scientists continue to track cotinine levels to assess 100 00:05:45,00 --> 00:05:48,00 how well efforts to reduce secondhand smoke exposure are working. 101 00:05:48,00 --> 00:05:52,00 For more information on cotinine levels, see CDC’s National Report on 102 00:05:52,00 --> 00:05:56,00 Human Exposure to Environmental Chemicals and Updated Tables.