**Redox Reactions in Groundwater with Health Implications Implications**

**Redox Reactions in Groundwater with Health** 

DOI: 10.5772/intechopen.68751

#### Gunnar Jacks Gunnar Jacks Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.68751

#### **Abstract**

Mobilisation into groundwater of many trace elements are redox dependant and of health concern. A short list includes arsenic, manganese, chromium, selenium, nitrogen as nitrate and uranium. Arsenic is mobile in groundwater essentially under two conditions, under reducing conditions mobilising ferrous iron and arsenite and at high pH when the fer‐ ric oxyhydroxides lose their positive charge. Manganese is mobilised under moderately reducing conditions as Mn2+ and might affect the mental capacity at chronic exposure from drinking water. Chromium is mobile as carcinogenic chromate under oxidising con‐ ditions. Manganese oxides may oxidise Cr(III) solids. Chromium may come from natural as well as anthropogenic sources. Selenium, an essential element, rarely exceeds permis‐ sible limits but irrigation with groundwater with elevated selenium could cause toxic selenium intake via food. Selenium is mobile in groundwater under oxidising conditions. Nitrate from excess use of fertilisers may be a problem for bottle-fed children below the age of 1 year, forming methaemoglobinemia. Uranium is mobile under oxidising condi‐ tions as U(VI). Mobility and toxicity depends on numerous factors. The threat from ura‐ nium is its effect on the readsorption in the kidney of water and salts from the primary urine. Oxidation state and speciation govern uranium mobility.

**Keywords:** redox, groundwater, trace elements, mobility, health
