Below the water table, in the phreatic zone, permeable units that yield groundwater are called aquifers. The ability of the aquifer to store groundwater is dependent on the primary and secondary porosity and permeability of the rock or soil.onsequently, the water table is lower during the summer. This disparity between the level of the winter and summer water table is known as the zone of intermittent saturation, wherein the water table will fluctuate in response to climatic conditions.
The CDC says about 310,000 American kids (1 to 5 years old) have blood-lead levels over 10 micrograms/dL. A U.S. child's main risk of lead poisoning comes from the lead-based house paints in near-universal use before 1950. The paints were banned for housing use in 1978.
Lead is a metal found in the earth, and it is a poison. For years, lead was used in paint, gasoline, plumbing and many other items. Lead can still be found in some products sold today. As these things are used or get worn out, the lead they contain can spread.Lead paint was banned from home use in 1978. If you live in a home built before 1978, or near a busy road, there could be lead in your house dust and soil.ften, lead poisoning is caused by lead you can't even see. Dust from lead paint is still the number one source of childhood lead poisoning. Lead poisoning can cause problems with a child's growth, behavior, and ability to learn. Lead can also harm babies before they're born.