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 poisoning. Lead poisoning is a type of metal poisoning caused by lead in the body. The brain is the most sensitive. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, inability to have children, and tingling in the hands and feet. It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent. In severe cases anemia, seizures, coma, or death may occur. Exposure to lead can occur by contaminated air, water, dust, food, or consumer products. Children are at greater risk as they are more likely to put objects in their mouth such as those that contain lead paint and absorb a greater proportion of the lead that they eat.