Arsenic-contaminated groundwater is currently estimated to affect 150 million people worldwide. However, the full extent of the problem remains elusive. Arsenic can strongly affect groundwater quality through natural geogenic leaching processes from host rocks and sediments. Arsenic concentrations may also increase due to a low hydrologic gradient, resulting in slow groundwater flow and a highly arid environment leading to evaporative concentration. Arsenic-contaminated water represents one of the most serious global health threats, with approximately 150 million people currently dependent on arsenic-contaminated groundwater. To determine where to best apply limited resources for groundwater testing, geostatistical modeling can identify areas that may be affected by arsenic contamination by finding statistically significant relationships between measured arsenic concentrations and environmental predictors. This also has the advantage of being able to use spatially continuous predictive datasets to identify areas of high arsenic risk, where groundwater quality data is lacking. While this method can efficiently predict the occurrence of large-scale contamination, it is generally ineffective at the scale of individual wells due to small-scale aquifer heterogeneities that are not detectable at the surface. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay The effects of arsenic are rare in Pakistan. Elevated levels of arsenic in blood and hair samples from people living in predominantly rural areas with high exposure to arsenic in groundwater. Food crops in the provinces of Sindh and Punjab also indicate a potentially serious health threat due to uptake of arsenic by plants through irrigation water extracted from shallow Holocene aquifers. However, a lack of resources in the country has prevented a comprehensive assessment of arsenic in groundwater. Pakistan is characterized by the flat Indus Plain in the east; the Himalaya, Karakoram and Hindu Kush mountain ranges in the north; hilly regions of the north-west; and the Baluchistan plateau to the west. Due to the extremely arid climate in the Indus plain, extensive irrigation uses aquifer resources and a widespread canal system that distributes water from the Indus River and its major tributaries across the adjacent plains. A chemically reducing environment generally dominates in the aquifers along these rivers, which is generally due to the abundance of organic material together with a limited oxygen supply, and causes the desorption of arsenic from iron oxy(hydr)oxides. The study focuses on determining risk based on our new groundwater quality dataset and has produced the first statistically based arsenic hazard model and health risk map for Pakistan. Through the findings we came to know that high concentrations of arsenic exist mainly along the Indus River and its tributaries. Very high arsenic concentrations (>200 mg/liter) have been measured primarily in the southern half of the Indus Plain. Overall iron concentrations are low and do not exceed 1.9 mg/litre. The highest iron concentration measured in a water sample with arsenic greater than 10 mg/liter is only 0.86 mg/liter. Additionally, low nitrate levels (mean, 2.7 mg/liter; median, 1.3 mg/liter) in wells with arsenic >10.