Shallow ground-water systems are commonly used for drinking water sources and they make up a large part of the baseflow in rivers and lakes.However, shallow ground-water supplies are generally young (recently recharged) and, because there has been a wide variety of man-made pollutants produced in the 20th century, are more susceptible to contamination than deeper ground water. They are produced in meteorites and other extraterrestrial materials by intense cosmic radiation with target materials, in the Earth's atmosphere by cosmic ray spallation of target elements (Garden variety), and on the solid surface of the earth by cosmic ray spallation, thermal neutron and muon captures, and other nuclear reactions with principal target atoms.
In the atmosphere, these substances have mixed and spread worldwide.
These atmospheric substances, such as tritium (H) in water vapor from detonation of nuclear bombs in the 1950s and early 1960s,and chlorofluorocarbons (CFCs) from refrigeration and other uses from the 1950s through the 1980s, dissolve in precipitation, become incorporated in the Earths hydrologic cycle, and can be found in ground water that has been recharged within the past 50 years.
It's time to talk about the different types of relationships and love and to prepare to set rules for dating.
Talking about relationships in regular, everyday conversations lets you and your child talk about your family values when it comes to friendship, dating, and love.
Even though they can make many decisions on their own, teens still need boundaries from you.