A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
How are harmful elements and compounds in plants, soils, rocks, and sediments regulated?
Regulatory limits for safe levels of elements in water and foodstuffs are established by the U.S. Environmental Protection Agency (EPA) and the U.S. Food and Drug Administration (FDA). However, there are generally no regulatory limits that scientists can refer to when dealing with plants, soils, rocks, and sediments. Therefore, to determine whether a plant, soil, rock, or sediment contains a 'high or unusual' quantity of a specific element, it is necessary to determine what quantity is 'normal or usual.' These levels are referred to as background or baseline measurements, but they may be somewhat different.
A background measurement represents natural concentrations of an element in natural materials that exclude human influence. This measurement represents an idealized situation and is typically more difficult to measure than a baseline.
A baseline measurement represents concentrations measured at some point in time and is not generally a true background. Baseline concentrations are typically expressed as a range, not a single value.
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Does the Earth's magnetic field affect human health?
The Earth's magnetic field does not directly affect human health. Humans evolved to live on this planet. High altitude pilots and astronauts can experience higher levels of radiation during magnetic storms, but the hazard is due to the radiation, not the magnetic field itself. Geomagnetism can also impact the electrically based technology that we rely on, but it does not impact people themselves...
Does the USGS have reports on the background levels of elements in soils and other surficial materials?
The following USGS products will be helpful in determining the background levels of various elements in soils and other surficial materials: Geochemical and Mineralogical Data for Soils of the Conterminous United States (2013) Data for samples collected at three intervals (0-5 cm surficial soils, A-Horizon soils, and C-Horizon soils) across the entire conterminous U.S. These data provide the best...
How frequently are volatile organic compounds (VOCs) detected in groundwater?
Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including refrigerants, plastics, adhesives, paints, and petroleum products, have been detected in about one-third of the wells sampled by the National Water-Quality Assessment (NAWQA) Program of the USGS. Chloroform and other trihalomethanes, the most commonly detected compounds, were found in about 9...
Testing Coal-Tar Sealcoats for Toxic PAH Emissions
A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
Slimy Summer Swimming: Harmful Algal Blooms in Lakes, Rivers and Streams
You may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. USGS scientists Dr. Barry Rosen, Dr. Jennifer Graham and Dr.
You may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. USGS scientists Dr. Barry Rosen, Dr. Jennifer Graham and Dr.
What elements are harmful to living organisms and how do they get into our environment?
Listen to hear the answer.
rare earth oxides
These rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Image Number D1115-1. Photo by Peggy Greb, USDA-ARS.
These rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Image Number D1115-1. Photo by Peggy Greb, USDA-ARS.
Related Content
- FAQ
Does the Earth's magnetic field affect human health?
The Earth's magnetic field does not directly affect human health. Humans evolved to live on this planet. High altitude pilots and astronauts can experience higher levels of radiation during magnetic storms, but the hazard is due to the radiation, not the magnetic field itself. Geomagnetism can also impact the electrically based technology that we rely on, but it does not impact people themselves...
Does the USGS have reports on the background levels of elements in soils and other surficial materials?
The following USGS products will be helpful in determining the background levels of various elements in soils and other surficial materials: Geochemical and Mineralogical Data for Soils of the Conterminous United States (2013) Data for samples collected at three intervals (0-5 cm surficial soils, A-Horizon soils, and C-Horizon soils) across the entire conterminous U.S. These data provide the best...
How frequently are volatile organic compounds (VOCs) detected in groundwater?
Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including refrigerants, plastics, adhesives, paints, and petroleum products, have been detected in about one-third of the wells sampled by the National Water-Quality Assessment (NAWQA) Program of the USGS. Chloroform and other trihalomethanes, the most commonly detected compounds, were found in about 9...
- Multimedia
Testing Coal-Tar Sealcoats for Toxic PAH Emissions
A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
A USGS scientist adjusts an air pump used to measure emission of polycyclic aromatic carbons (PAHs) into the air.
Slimy Summer Swimming: Harmful Algal Blooms in Lakes, Rivers and StreamsYou may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. USGS scientists Dr. Barry Rosen, Dr. Jennifer Graham and Dr.
You may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. USGS scientists Dr. Barry Rosen, Dr. Jennifer Graham and Dr.
What elements are harmful to living organisms and how do they get into our environment?Listen to hear the answer.
rare earth oxidesThese rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Image Number D1115-1. Photo by Peggy Greb, USDA-ARS.
These rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Image Number D1115-1. Photo by Peggy Greb, USDA-ARS.
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