Spatiotemporal variation of groundwater quality using integrated multivariate statistical and geostatistical approaches in Amol–Babol Plain, Iran Tahoora Sheikhy Narany & Mohammad Firuz Ramli & Ahmad Zaharin Aris & Wan Nor Azmin Sulaiman & Kazem Fakharian Received: 5 August 2013 /Accepted: 9 May 2014 /Published online: 4 June 2014 # Springer International Publishing Switzerland 2014 Abstract In recent years, groundwater quality has be- come a global concern due to its effect on human life and natural ecosystems. To assess the groundwater qual- ity in the Amol–Babol Plain, a total of 308 water sam- ples were collected during wet and dry seasons in 2009. The samples were analysed for their physico-chemical and biological constituents. Multivariate statistical anal- ysis and geostatistical techniques were applied to assess the spatial and temporal variabilities of groundwater quality and to identify the main factors and sources of contamination. Principal component analysis (PCA) re- vealed that seven factors explained around 75 % of the total variance, which highlighted salinity, hardness and biological pollution as the dominant factors affecting the groundwater quality in the Plain. Two-way analysis of variance (ANOVA) was conducted on the dataset to evaluate the spatio-temporal variation. The results showed that there were no significant temporal varia- tions between the two seasons, which explained the similarity between six component factors in dry and wet seasons based on the PCA results. There are also significant spatial differences ( p >0.05) of the parameters under study, including salinity, potassium, sulphate and dissolved oxygen in the plain. The least significant difference (LSD) test revealed that ground- water salinity in the eastern region is significantly dif- ferent to the central and western side of the study area. Finally, multivariate analysis and geostatistical tech- niques were combined as an effective method for dem- onstrating the spatial structure of multivariate spatial data. It was concluded that multiple natural processes and anthropogenic activities were the main sources of groundwater salinization, hardness and microbiological contamination of the study area. Keywords Groundwater quality . Statistical analysis . Two-way ANOVA . Geostatistical technique . Amol– Babol . Iran Introduction Groundwater is a primary resource for drinking, as well as industrial and agricultural use in the arid and semi- arid regions of the world such as Iran (Shahbazi and Esmaeli-Sar 2009; Subyani and Al Ahmadi 2010). Nearly 95 % of freshwater in Iran is utilized for agricul- ture, out of which 80 % is supplied from groundwater (Ahmadi and Sedghamiz 2007). In areas around the southern coast of the Caspian Sea, such as Amol–Babol Plain, in Mazandaran Province, groundwater is the main source of water supply for potable and irrigation activ- ities. Currently, many deep and shallow wells had been constructed by farmers for agriculture and domestic Environ Monit Assess (2014) 186:5797–5815 DOI 10.1007/s10661-014-3820-8 T. Sheikhy Narany (*) : M. F. Ramli : A. Z. Aris : W. N. A. Sulaiman Faculty of Environmental Studies, Universiti Putra Malaysia, UPM, Serdang, Selangor, Malaysia e-mail: Tahoora_sh@yahoo.com K. Fakharian Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran