Assessment of ammonium, nitrate, phosphate, and heavy metal pollution in groundwater from Amik Plain, southern Turkey.

Abstract

Amik Plain is one of the most important agricultural areas of Turkey. Because the groundwater resources have been used not only for irrigation but also for drinking purpose, groundwater resources play a vital role in this area. However, there exist no or a very limited number of studies on groundwater quality and its physicochemical and heavy metal composition for Amik Plain. This study aimed to assess groundwater of Amik Plain in terms of human health and suitability for irrigation based on physicochemical variables, heavy metals, and their spatial distribution. A total of 92 groundwater samples were collected from wells and were analyzed for temperature (T), salt content (SC), dissolved oxygen (DO), ammonium (NH4(+)), nitrate (NO3(-)), and phosphorus (P) and such heavy metals as cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn). The temperature, SC, DO, NH4(+), and NO3(-) parameters were measured in situ immediately with YSI Professional plus instrument (Pro Plus). Water depth was taken from owner of the wells. Heavy metal analyses were carried out in triplicate using inductively coupled atomic emission spectrometer (ICP-AES). The ICP-AES was calibrated for all the metals by running different concentrations of standard solutions. Descriptive statistical analyses were calculated to characterize distribution of physicochemical properties and heavy metal contents of groundwater. Correlation analysis was used to assess the possible relationships among heavy metals and physicochemical properties of the groundwater. Spatial variability in groundwater parameters were determined by geostatistical methods. Result shows that the highest and lowest coefficient of variation occurred for NO3(-) and T, respectively. Mean water table depth was 92.1 m, and only 12 of all the samples exceeded the desirable limit of 50 mg/L for NO3(-) content. The metal concentrations showed a dominance in the order of Fe > Mn > Ni > Cr > Cu > Zn > Co > Cd > Pb. All the samples had much higher Cd concentration than the guideline value for drinking water while Cu and Fe concentrations were below the guideline limit recommended by WHO.