Brad Paisley - Water 1bg4 source=lnms&tbm=isch&sa=X&ei=DlkzU52oDYTk2QWNlIG4AQ&sqi=2&ved=0CAcQ_AUoAg&biw=1067&bi h=493#imgdii =_

57. When freshwater resources become saline, they can no longer be used for irrigation or drinking. Saline water is toxic to plants, and high sodium levels cause dry soils to become hard and compact and reduce their ability to absorb water. Salinity is not dangerous to humans, but water becomes nonpotable for human consumption at about 250 mg/l.

58. What can increase salt concentrations in water and soils in several ways? Groundwater extraction and irrigation can increase salt concentrations in water and soils. First, irrigation increases the salinity of soil water when evaporation removes water but leaves salt behind. Irrigation has caused high salinity levels in what areas in the United States? the lower reaches of the Colorado River, and California's Central Valley Aerial view of central California fields suffering from severe salinization. Source: � United States Department of Agriculture, Agricultural Research Service

59.Irrigation can also cause salinization by what (2) ways? by raising the water table and lifting saline groundwater near the surface into the root zone Irrigation, Kufra Growing, Sahara, Africa Wallpapers-diq.com

60. A third type of salinization occurs in coastal areas, where excessive groundwater pumping draws seawater into aquifers and contaminates wells. In coastal aquifers freshwater floats on top of denser seawater. When this lens of freshwater is diminished by withdrawals, seawater rises up from below. If you poured some ocean water into a lake, the ocean water would sink to the bottom. (Temperature dependent) /

61.The Institute of Ecosystem Studies found that salinity levels have also increased significantly in urban and suburban areas in the northeastern United States. The authors attributed this rise to two main factors? use of salts for de-icing roads in winter and increased levels of street paving Salt (sodium chloride) in solid form and in a liquid, 23% solution called brine