In this study, a comprehensive analysis of groundwater was performed to assess contamination and phenol content in Batman, Turkey, particularly in residential areas near agriculture, livestock and oil industry facilities. From these areas, where potentially contaminated groundwater used for drinking and irrigation threatens public health, 30 groundwater samples were collected and analyzed for heavy metal concentrations (Al, As, B, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, NO3, P, Pb, phenol, S, Sb, Se, SO4, Sr, U, and Zn). Compared with the standards of the Environmental Protection Agency, Al, Fe, and Mn concentrations in groundwater exceeded secondary drinking water regulations, NO3 concentrations were high for maximum contaminant levels, and As, Pb, and U concentrations exceeded maximum contaminant level goals in all samples. Ni, Sb, and Se concentrations also exceeded limits set by the Turkish Standards Institution. Nearly all samples revealed concentrations of Se, Sb, Hg, and phenol due to nearby petroleum refineries, oil storage plants, and agricultural and livestock areas. The results obtained from this study indicate that the groundwater in Batman contains elements in concentrations that approach or exceed limits and thus threatens public health with increased blood cholesterol, decreased blood sugar, and circulatory problems.

INTRODUCTION

Located in Southeastern Anatolia, Turkey, the city of Batman has developed rapidly with the growth of the local agriculture and livestock sectors, until the discovery of oil in the area promoted the growth of the oil industry (Figure 1). Accounting for approximately 80% of all oil extraction in Turkey, Batman has become an attractive labor destination and currently supports a population of more than 400,000 people. The city also hosts agricultural, livestock, and oil industry activities, including oil drilling and storage by the Turkish Petroleum Corporation (TPAO), oil transfer by the Petroleum Pipeline Corporation (BOTAS), and oil refinery by the Turkish Petroleum Refinery Corporation (TUPRAS). In fact, the city produces approximately 26,000 barrels of oil per day, all refined in local facilities of TUPRAS. Both crude and refined oil are then transferred to other cities and harbors by pipelines and trucks. Leakage from petroleum storage and from pipelines constitutes a threat in terms of groundwater contamination in the research area. Furthermore, agricultural activities including the use of fertilizer, pesticides, and manure piles from livestock have important effects on groundwater contamination.
Figure 1

Location map, contaminants, and sampling wells of the study area.

Figure 1

Location map, contaminants, and sampling wells of the study area.

The globally pervasive development of industry has prompted researchers worldwide to scrutinize the phenomenon of groundwater contamination (Sponza & Karaoglu 2002; Gowd & Govil 2008; Krishna & Mohan 2014), in which use of water for drinking is critically at risk and thereby threatens public health (Yildiz et al. 2008). Although some of these researchers have shown that industrial zones indeed cause water contamination (Aremu et al. 2002; Sponza & Karaoglu 2002; Nalbantcilar & Guzel 2006; Gowd & Govil 2008; Shankar et al. 2008; Krishna et al. 2009; Ullah et al. 2009; Azizullah et al. 2011; Dasaram et al. 2011; Afzal et al. 2014; Krishna & Mohan 2014), even in Batman (e.g., Pinarkara et al. 2013; Nalbantcilar et al. 2015), no information is currently available regarding the degree of contamination in the area's groundwater. As well, all drinking and domestic water needs of the research area are met from groundwater. In response, to determine the extent to which Batman's groundwater threatens public health due to contamination, groundwater samples for chemical analysis were collected from predetermined wells in the area, and the results were compared with the standards of the Environmental Protection Agency (EPA 2012) and Turkish Standards Institution (TSE 2005).

HYDROGEOLOGY

As Figure 2 shows, Batman is surrounded by the Miocene–Pliocene Selmo Formation to the north, Quaternary (old) alluvial deposits to the west, and actual alluvial deposits to the northeast (Eren et al. 2012; Pinarkara 2014). The Selmo Formation consists of brown, gray, and mottled altered claystone, sandstone, gravel, mudstone, and conglomerate, along with white gypsum layers at greater depths. Heterogeneous Quaternary gravel, sand, and silt mixtures up to 15-m thick appear in the Batman River beds, where the upper part of the Selmo Formation and both the old and recent alluvium deposits forming the aquifer layers are located (DSI 1979; MTA 2007). On both banks of the Batman River, the groundwater level in the recent (old) alluvium is 3–4 m (5–20 m), whereas beneath the surface of the Selmo Formation, it is 20 m. Otherwise, impervious layers of beddings of claystone and siltstone conveniently collect groundwater in the base in a way that produces an aquifer that supplies all of Batman's drinking water. This water is drawn from boreholes in old alluvial deposits drilled at 20–100 m depth at a flow rate of 10–40 L/s.
Figure 2

Hydrogeological map (Pinarkara 2014) and cross sections of the study area.

Figure 2

Hydrogeological map (Pinarkara 2014) and cross sections of the study area.

Figure 2 demonstrates that the directions of groundwater flow are from northeast to southwest and from south to north. According to the General Directorate of State Hydraulic Works (DSI 1979) report, transmissivity values range from 10 to 500 m2/d for old alluvium and from 5 to 100 m2/d for recent alluvium.

SAMPLING AND ANALYTICAL PROCEDURES

To investigate groundwater contamination in Batman, 30 water samples from 20 to 100 m deep wells were collected in December 2012. Samples 11, 27, 28, 29, 30, 34, 35, 36, 38, 41, 42, 44, 48, 49, and 54 were collected from wells in the Selmo Formation, and all others were taken from wells in the old alluvium (Figure 2). Regardless of the source, each sample was collected after pumping the water from the sampling well for approximately 1 h, and then it was filled into sterilized containers to which 10% hydrochloric acid was added to attain pH levels of <2. After being preserved in a portable fridge at +4 °C, laboratory analyses were performed on the 30 samples according to the standard methods of the American Public Health Association (APHA 1992). Analyses of NO3 and phenol quantities were performed in the laboratory of the Diyarbakir Metropolitan Municipality. To detect all major and heavy metal content, the samples were chemically analyzed with the 2C Full Suite (ACME Analytical Laboratories, Vancouver, Canada) using inductively coupled plasma mass spectrometry (ACME 2005).

HYDROCHEMICAL PROPERTIES OF THE GROUNDWATER

Table 1 shows the analyses of the groundwater samples. The distributions of Al, As, Cd, Cr, Cu, Fe, Hg, Li, Mg, Ni, NO3, Pb, phenol, Sb, U, and Zn in the groundwater (Figures 3 and 4) were interpreted in terms of the possible contamination zones in the area.
Table 1

The results of groundwater sample analyses

Sample no. Al As Ba Ca* Cd Cl* Co Cr Cu Fe HCO3Hg K* Li Mg* Mn Mo Na* Ni NO3Pb Phenol S* Sb Se SO4Sr Zn 
30 0.7 56 48.2 3.4 0.9 0.5 130 1.6 1.2 8.8 0.4 0.9 8.6 5.7 17 20.5 0.3 0.6 
521 66 37.5 3.7 0.5 1.5 2.4 305 150 1.8 1.5 9.3 25.4 2.3 1.9 84 1 20 17.6 0.3 0.7 14 
11 23 0.7 241 67.6 7.2 1.7 5.5 299 4.9 27.7 0.3 27.5 12.3 12 0.4 11 0.8 21.2 3.9 10 
13 34 1.0 104 54.3 5.9 2.6 2.3 229 1.3 3.1 20.5 0.4 15.9 13.1 0.4 28 0.8 16.7 0.7 2.5 26 
15 24 0.8 109 56.1 7.5 3.2 37 236 1.4 3.3 21.7 0.2 0.9 17.6 16.3 10 0.1 23 10 1.2 20.8 0.7 2.7 
16 30 1 260 84.5 29.3 5.7 8.9 308 1.3 6.6 35.3 0.9 0.6 26.2 40.6 13 0.5 21 13 2.1 27.2 1.4 6 23 
17 45 0.7 76 51.9 2.2 3.3 24 186 1.8 3.1 14.3 1.8 0.7 11 0.3 13 10 0.6 18 11 0.8 21.1 0.5 1.2 
22 116 1 104 92.3 37.5 0.2 5.3 2.9 1,539 280 1.7 2.9 19.3 18.8 0.3 34.7 44.6 67 0.5 13 3.8 43.4 0.7 2 53 
27 51 0.9 158 72.5 30.5 0.3 16.4 5.2 237 4.4 33.7 2.3 0.9 19.4 6.8 40 0.9 32 26 4.3 15.4 51.8 1.2 6.6 12 
28 21 0.9 387 75.0 8.3 1.5 1.8 309 0.6 29.5 0.3 0.7 24.1 22.4 0.2 14 4.7 1.2 29.9 1.2 6.2 33 
29 174 0.9 0.1 460 83.7 25.4 0.1 3.5 32 347 10.9 36.7 10.1 0.7 29 34.1 22 1.7 18 12 3.7 1.2 28.2 1.3 6.5 
30 21 0.7 195 47.5 3.1 252 1.5 4.5 22.5 1.4 0.4 20.8 10.6 0.4 28 0.9 5.3 0.8 4.3 77 
34 24 1.1 0.1 438 85.1 27.5 4.3 1.7 323 0.8 12 35.1 0.8 0.6 42.5 46.7 1 24 14 32.2 1.5 4.3 
35 55 0.9 0.1 280 77.2 18.3 0.1 6.1 1.6 241 1.4 7.9 19.7 1.8 0.7 23.9 46.6 24 1.4 21 10 5.1 2.2 16.7 0.8 3 26 
36 18 0.8 205 71.3 33.1 3.7 3.1 240 1.3 5.5 32.0 2.2 0.4 18.8 30.8 10 0.2 18 4.8 1.1 16.0 1.3 9 49 
37 43 0.7 0.1 202 74.4 0.1 18.4 1.5 1.9 302 1.1 9.9 31.3 2.8 0.8 34 35.6 56 2.4 11 4.9 1.1 24.0 1.1 3.9 1,719 
38 22 1.3 0.1 366 117 36.7 2.8 412 1.5 10.9 45.1 1.3 0.8 44 26.1 60 0.2 24 26 4.7 1.7 57.0 1.4 4.3 
39 28 1 0.1 222 99.2 73 0.1 2.0 3.7 293 0.1 0.5 13 41.3 10.6 1.2 49.8 14.6 36 2.8 32 4.3 1.2 69.0 1.3 4.4 12 
40 4,456 1.4 0.1 241 85.0 0.6 27 14.1 8.5 4.1 461 293 0.2 0.6 14 39.5 1,080 0.1 42.5 26.8 15.7 1,189 5.1 76 33 0.5 4.1 64.5 1.2 3.8 373 
41 89 1.1 143 104 25.4 0.1 4.2 3.5 48 331 0.2 1.3 6.3 41.5 4.6 0.5 31.6 50.4 65 2.9 23 26 4.7 6.1 61.1 1.3 4.1 
42 114 0.7 146 41.6 7.8 0.1 7.7 2.4 70 220 0.1 1.1 2.5 24.5 4.1 0.8 12.1 0.4 10.5 47 0.8 13 4.7 2.9 0.8 3 
43 33 0.9 0.1 299 91.2 21.4 0.3 0.7 2.8 354 0.1 0.5 11.2 35.1 21.7 1.2 43.9 2.9 7.7 47 0.6 34 17 0.9 56.5 1.1 4.3 
44 62 1.5 0.1 797 59.9 11 6.5 9.5 301 9.2 35.5 3.1 0.7 36.5 5.2 23 43 0.5 155 3.2 2.1 18.6 1.5 5.7 24 
45 159 1.0 0.1 190 93.6 23.9 0.3 2.3 69 317 0.3 1.4 9.2 36.1 6.8 4.2 40 0.6 25.4 57 0.3 22 28 3.3 4.2 58.2 1.2 4.5 13 
46 260 1.8 0.1 141 79.4 27.9 0.5 2.8 2.5 169 284 0.1 7.3 32.6 23.2 0.7 35.2 0.6 34 206 1.2 17 19 4.4 2.1 39.4 1.1 3.4 
48 41 0.8 249 90.8 42 0.1 5.4 0.6 264 2.3 8.2 43.2 1.6 0.4 20.6 2.5 77 39 2 36 14 4.5 2.2 22.4 1.4 3.6 
49 157 1.3 622 63.1 0.1 16.7 3.3 4.8 25 248 0.9 4.6 29.6 2.4 0.7 21.6 0.2 38.9 46 2 27 4.3 0.5 10.9 1.4 5.9 461 
50 129 1 242 59.4 13.6 10.2 1.7 293 0.3 4.3 31.1 0.9 1.5 37.5 35 57 0.3 14 3.8 0.8 15.5 1.3 6.5 90 
51 174 1.3 0.1 395 87.9 33.8 0.2 2.9 3.4 57 265 1.3 8.3 34.2 12.9 0.6 26.7 46.7 69 0.8 29 22 2.9 48.4 1.3 3.1 
54 145 1.4 334 53.4 0.1 15.1 0.1 9.9 1.4 61 227 0.9 7.9 23.4 6.3 2.6 18.3 0.3 14.4 54 3.1 19 1.2 12.1 0.9 4.3 10 
EPA 200 010  2,0002,000  55 250  100100 1,3001,300 300  22    50    10–10  0–15 2,000+  66 5050 250  030 5,000 
TSE 200 10   250  50 2,000 200     50  200 20 50  10   10 250    
Sample no. Al As Ba Ca* Cd Cl* Co Cr Cu Fe HCO3Hg K* Li Mg* Mn Mo Na* Ni NO3Pb Phenol S* Sb Se SO4Sr Zn 
30 0.7 56 48.2 3.4 0.9 0.5 130 1.6 1.2 8.8 0.4 0.9 8.6 5.7 17 20.5 0.3 0.6 
521 66 37.5 3.7 0.5 1.5 2.4 305 150 1.8 1.5 9.3 25.4 2.3 1.9 84 1 20 17.6 0.3 0.7 14 
11 23 0.7 241 67.6 7.2 1.7 5.5 299 4.9 27.7 0.3 27.5 12.3 12 0.4 11 0.8 21.2 3.9 10 
13 34 1.0 104 54.3 5.9 2.6 2.3 229 1.3 3.1 20.5 0.4 15.9 13.1 0.4 28 0.8 16.7 0.7 2.5 26 
15 24 0.8 109 56.1 7.5 3.2 37 236 1.4 3.3 21.7 0.2 0.9 17.6 16.3 10 0.1 23 10 1.2 20.8 0.7 2.7 
16 30 1 260 84.5 29.3 5.7 8.9 308 1.3 6.6 35.3 0.9 0.6 26.2 40.6 13 0.5 21 13 2.1 27.2 1.4 6 23 
17 45 0.7 76 51.9 2.2 3.3 24 186 1.8 3.1 14.3 1.8 0.7 11 0.3 13 10 0.6 18 11 0.8 21.1 0.5 1.2 
22 116 1 104 92.3 37.5 0.2 5.3 2.9 1,539 280 1.7 2.9 19.3 18.8 0.3 34.7 44.6 67 0.5 13 3.8 43.4 0.7 2 53 
27 51 0.9 158 72.5 30.5 0.3 16.4 5.2 237 4.4 33.7 2.3 0.9 19.4 6.8 40 0.9 32 26 4.3 15.4 51.8 1.2 6.6 12 
28 21 0.9 387 75.0 8.3 1.5 1.8 309 0.6 29.5 0.3 0.7 24.1 22.4 0.2 14 4.7 1.2 29.9 1.2 6.2 33 
29 174 0.9 0.1 460 83.7 25.4 0.1 3.5 32 347 10.9 36.7 10.1 0.7 29 34.1 22 1.7 18 12 3.7 1.2 28.2 1.3 6.5 
30 21 0.7 195 47.5 3.1 252 1.5 4.5 22.5 1.4 0.4 20.8 10.6 0.4 28 0.9 5.3 0.8 4.3 77 
34 24 1.1 0.1 438 85.1 27.5 4.3 1.7 323 0.8 12 35.1 0.8 0.6 42.5 46.7 1 24 14 32.2 1.5 4.3 
35 55 0.9 0.1 280 77.2 18.3 0.1 6.1 1.6 241 1.4 7.9 19.7 1.8 0.7 23.9 46.6 24 1.4 21 10 5.1 2.2 16.7 0.8 3 26 
36 18 0.8 205 71.3 33.1 3.7 3.1 240 1.3 5.5 32.0 2.2 0.4 18.8 30.8 10 0.2 18 4.8 1.1 16.0 1.3 9 49 
37 43 0.7 0.1 202 74.4 0.1 18.4 1.5 1.9 302 1.1 9.9 31.3 2.8 0.8 34 35.6 56 2.4 11 4.9 1.1 24.0 1.1 3.9 1,719 
38 22 1.3 0.1 366 117 36.7 2.8 412 1.5 10.9 45.1 1.3 0.8 44 26.1 60 0.2 24 26 4.7 1.7 57.0 1.4 4.3 
39 28 1 0.1 222 99.2 73 0.1 2.0 3.7 293 0.1 0.5 13 41.3 10.6 1.2 49.8 14.6 36 2.8 32 4.3 1.2 69.0 1.3 4.4 12 
40 4,456 1.4 0.1 241 85.0 0.6 27 14.1 8.5 4.1 461 293 0.2 0.6 14 39.5 1,080 0.1 42.5 26.8 15.7 1,189 5.1 76 33 0.5 4.1 64.5 1.2 3.8 373 
41 89 1.1 143 104 25.4 0.1 4.2 3.5 48 331 0.2 1.3 6.3 41.5 4.6 0.5 31.6 50.4 65 2.9 23 26 4.7 6.1 61.1 1.3 4.1 
42 114 0.7 146 41.6 7.8 0.1 7.7 2.4 70 220 0.1 1.1 2.5 24.5 4.1 0.8 12.1 0.4 10.5 47 0.8 13 4.7 2.9 0.8 3 
43 33 0.9 0.1 299 91.2 21.4 0.3 0.7 2.8 354 0.1 0.5 11.2 35.1 21.7 1.2 43.9 2.9 7.7 47 0.6 34 17 0.9 56.5 1.1 4.3 
44 62 1.5 0.1 797 59.9 11 6.5 9.5 301 9.2 35.5 3.1 0.7 36.5 5.2 23 43 0.5 155 3.2 2.1 18.6 1.5 5.7 24 
45 159 1.0 0.1 190 93.6 23.9 0.3 2.3 69 317 0.3 1.4 9.2 36.1 6.8 4.2 40 0.6 25.4 57 0.3 22 28 3.3 4.2 58.2 1.2 4.5 13 
46 260 1.8 0.1 141 79.4 27.9 0.5 2.8 2.5 169 284 0.1 7.3 32.6 23.2 0.7 35.2 0.6 34 206 1.2 17 19 4.4 2.1 39.4 1.1 3.4 
48 41 0.8 249 90.8 42 0.1 5.4 0.6 264 2.3 8.2 43.2 1.6 0.4 20.6 2.5 77 39 2 36 14 4.5 2.2 22.4 1.4 3.6 
49 157 1.3 622 63.1 0.1 16.7 3.3 4.8 25 248 0.9 4.6 29.6 2.4 0.7 21.6 0.2 38.9 46 2 27 4.3 0.5 10.9 1.4 5.9 461 
50 129 1 242 59.4 13.6 10.2 1.7 293 0.3 4.3 31.1 0.9 1.5 37.5 35 57 0.3 14 3.8 0.8 15.5 1.3 6.5 90 
51 174 1.3 0.1 395 87.9 33.8 0.2 2.9 3.4 57 265 1.3 8.3 34.2 12.9 0.6 26.7 46.7 69 0.8 29 22 2.9 48.4 1.3 3.1 
54 145 1.4 334 53.4 0.1 15.1 0.1 9.9 1.4 61 227 0.9 7.9 23.4 6.3 2.6 18.3 0.3 14.4 54 3.1 19 1.2 12.1 0.9 4.3 10 
EPA 200 010  2,0002,000  55 250  100100 1,3001,300 300  22    50    10–10  0–15 2,000+  66 5050 250  030 5,000 
TSE 200 10   250  50 2,000 200     50  200 20 50  10   10 250    

(* in ppm; the others in ppb) compared to EPA (2012) drinking water standards; [(+) Health Advisories; italicized values exceed MCLG; bold values exceed MCL; underlined values exceed SDWR]; and TSE (2005) standards [(=) only exceeds TSE standards].

Figure 3

Al, As, Cd, Cr, Cu, Fe, Hg, and Li iso-concentration maps of the groundwater.

Figure 3

Al, As, Cd, Cr, Cu, Fe, Hg, and Li iso-concentration maps of the groundwater.

Figure 4

Mg, Ni, NO3, Pb, phenol, Sb, U, and Zn iso-concentration maps of the groundwater.

Figure 4

Mg, Ni, NO3, Pb, phenol, Sb, U, and Zn iso-concentration maps of the groundwater.

Al displayed concentrations of 18–4.456 ppb, and Cd was detected in only four samples in concentrations of 0.1–0.6 ppb. Mg was found in all samples at concentrations of 8.8–45.1, whereas Ni in some samples ranged from 0.2 to 26.8 ppb. Al, Cd, and Ni distributions were centrally concentrated and peaked in sample 40 (Figures 3 and 4).

Ranging from 0.7 to 1.8 ppb, As was detected in all samples except sample 6. Notably, 1.5 ppb was in sample 44 and, most densely, 1.8 ppb was in sample 46 (Table 1) (Figure 3). Except in sample 4, Pb also exhibited high concentrations throughout the groundwater in the study area, with the highest concentration in sample 40 at 5.1 ppb (Table 1) (Figure 4).

As Figure 4 shows, uranium was distributed throughout the area investigated, and occurred in all samples at concentrations of 0.6–6.6 ppb, with the highest concentrations detected in samples 29, 50, and 27 at 6.5 ppb, 6.5 ppb, and 6.6 ppb, respectively (Table 1). Cr, Cu, and Li concentrations were high in the center of the study area, whereas Zn was highest to the south (Figures 3 and 4). Furthermore, although Cr, Cu, Li, Mg, S, and Zn emerged in all samples, Co and P were detected only in a few samples. Fe concentrations in the groundwater were greater in western Batman (Figure 3).

The Hg content found in eight samples of groundwater decreased and nearly disappeared towards the residential suburbs within the study area, yet high concentrations were found in the center of the area with a value of 0.3 ppb (Figure 3). The phenol concentration increased in the city center, although it did not appear at all in samples 4, 11, 22, and 39 (Figure 4). In samples 40 and 44, phenol was detected at 76 ppb and 155 ppb, respectively.

NO3 found in groundwater samples throughout the study area ranged in concentration from 1.9 to 50.4 ppm. The concentrations intensified towards the countryside of the settled area. Similarly distributed throughout the area, Sb was found in most water samples in the range of 0.5–5.1 ppb, and was most concentrated in the center (Table 1) (Figure 4).

Lastly, Se was detected to varying degrees in all samples except samples 4, 6, and 42, with the highest concentrations found in samples 41 and 27 at 6.1 and 15.0 ppb (Table 1). Se was mostly concentrated in the southern part of the study area, close to the industrial area.

CLUSTER ANALYSIS OF THE GROUNDWATER

In the groundwater samples, the element pairs Cd–Al, Co–Mn, Li–Na, Cd–Co, Co–Ni, Cd–Ni, Ni–Al, Mn–Al, Al–Co, Mn–Ni, and Mg–Sr exhibited exceptionally strong correlation coefficients (Cc >0.90), Li–Ca exhibited strong positive correlation coefficients (0.90 > Cc > 0.70), and both U–Fe and NO3–Mo exhibited weak negative correlation coefficients (Cc < −0.3), as shown in Table 2. Due to the negative correlation in the study area, U and Mo values frequently decreased in samples in which Fe and NO3 values increased. In contrast, in samples in which the concentration of each element of the element pairs displaying an exceptionally strong correlation was high, the other element was similarly high (Table 2) (Figures 3 and 4).

Table 2

Correlation coefficients between the element pairs of the groundwater samples (the full color version of this figure is available in the online version of this paper, at http://dx.doi.org/10.2166/wh.2016.290)

 
 

The analyses results and correlation coefficients demonstrate that element pairs such as Ni–Al, Cd–Al, and Mn–Al, which possess strong correlation coefficients in the same sample (e.g., sample 40), were derived from the same source. In addition, correlation analyses were run to determine the relations of elements to each other. This association suggests that strong relationships within element pairs result from industrial activities.

In order to understand the relationship between elements of groundwater samples, cluster analysis was run by using correlation coefficients. According to the cluster analysis dendrogram of the samples, five significant groups appeared broadly (Figure 5). Named the main component group, the first group represents (Co–Mn–Al–P–Cd–Ni)–Pb, NO3–Sb, and the (Ba–U)–Fe subgroup. The elements exceeding standard values are mostly clustered in this group in terms of groundwater contamination. The second group, namely the heavy metal group, includes (Cl–Br)–(Mg–Sr), [(Ca–S)–(Li–Na)]–B, and As. In this group, elements which mostly stem from erosion of natural deposits and geological properties, and which will not create a contamination problem in groundwater, are clustered together. The third group, the Hg group, represents only the Hg–Mo element pair, whereas the fourth group consists of (Cu–phenol) and K. It is called the phenol group due to phenol, the only element of petroleum origin, being in the group. Lastly, the fifth group, the Se group, encompasses (Cr–Se) and Zn. This group is termed the Se group due to the fact that Se has a high concentration compared to TSE standards in terms of contamination. This cluster shows the discrimination between the elements.
Figure 5

Cluster analysis of the groundwater.

Figure 5

Cluster analysis of the groundwater.

DISCUSSION

Investigations and water analyses conducted in this study reveal that agricultural, livestock, and oil industry facilities clearly affect groundwater quality. Consequently, drinking groundwater from the study area is generally risky in terms of public health. To explain the extent of this risk, the above-mentioned results were compared with Standard 266 of the TSE's (2005) report regarding the quality of water intended for human consumption and the EPA's (2012) maximum contaminant level goals (MCLG), maximum contaminant levels (MCL), and secondary drinking water regulations (SDWR) in its Drinking Water Standards and Health Advisories report.

Figures 1 and 2 illustrate that groundwater infiltration derives from the industrial, agricultural, and livestock areas in the central part of Batman where settlements are concentrated. These areas are therefore major factors of groundwater pollution in the area. The Mn concentration of 1,080 ppb in sample 40 exceeds SDWR limits. Detected in all samples, Al peaked at 4,456 ppb in samples 6, 40, and 46, which exceeded MCLG and TSE limits (Table 1). As in groundwater can increase the population's risk of cancer because As ranged between 0.7 and 1.8 ppb, which also does not meet MCLG.

Pb concentrations ranged from 0.1 to 5.1 ppb and therefore exceeded MCLG in all samples except sample 4 (Table 1). As Figure 4 shows, Pb in groundwater increases towards industrial areas, as expected; this finding suggests that industrial activities contribute to increased Pb concentrations, and that the erosion of natural materials can therefore be a source of this increase. Pb concentrations meet public health goals, for drinking water can cause delays in physical and mental development in infants and children, and kidney problems and high blood pressure in adults (EPA 2009).

Uranium concentrations exceeded MCLG in samples, the greatest degree of which was found in sample 27 at 6.6 ppb (Table 1). Uranium exhibited high concentrations in most samples, mostly as a result of the erosion of natural materials (Figure 4). As a health risk, excessive U increases the possibility of cancer and kidney toxicity (EPA 2009). Likewise, Fe is reported in excess of both SDWR and TSE limits at values of 300 and 200 ppb in samples 6, 22, and 40.

Samples 40 and 41 contained Hg at concentrations of 0.2 ppb, whereas samples 45 and 50 contained Hg at 0.3 ppb. Although water with Hg concentrations in excess of 2.0 ppb can cause kidney damage when consumed, the results of this study indicate no concerning health issues due to the Hg concentration in this groundwater (EPA 2009). Hg originates from the erosion of natural materials and oil refinement wastes; regardless of formation boundaries in the study area, increased concentrations in the area surrounded by industrial facilities indicates that the source of contamination is related to industrial activities.

The most important contamination sources within the investigation area are activities dependent on oil, which create phenol contamination. Phenol concentrations in groundwater samples obtained from areas close to these activities reach 115 ppb and are far denser than those of other regions (Figure 4). However, it is seen that oil-based compounds in groundwater can reach very high concentrations from time to time. According to the Chamber of Turkish Geological Engineers report (JMO 2004), an explosion occurred in the basement of a building in the northwest of Batman's industrial area on 3 May 2004; as a result, three people died. It was determined that petroleum contamination in groundwater caused this accident. The EPA (2012) has reported that lifetime exposure to phenol at 2,000 ppb in drinking water should not be expected to cause any adverse effects; this is based on phenol exposure of a 70-kg adult who consumes 2 L of water per day. Although phenol concentrations are less than the lifetime limits and thus currently pose no risk to public health, they should nevertheless be monitored. However, the Food and Drug Administration (FDA) has reported that the phenol concentration in bottled drinking water should not exceed 1 ppb (FDA 2014). According to this limit, the phenol concentration in the samples poses a risk; when applied to the skin or ingested in large quantities, phenol can cause cardiac arrhythmia and induce tremors and seizures (ATSDR 2008). Phenol's properties, such as water solubility and colorlessness, can dangerously increase its risk without warning. In Batman, the general presence of phenol in groundwater is attributable to oil industry facilities downtown and oil transfer lines.

NO3 concentrations exceed MCL in groundwater samples collected from areas where agriculture and livestock activities are common (Table 1) (Figure 1), as shown in the element distribution map in Figure 4. Its concentrations reach values of 44.6 ppm, 46.6 ppm, 46.7 ppm, 46.7 ppm, 50.4 ppm, and 77 ppm in samples 22, 35, 34, 51, 41, and 48, respectively. The high concentrations of NO3 have an anthropogenic origin in the groundwater in the city center (Figure 4). Samples 41 and 48 in particular also exceed TSE limits (Table 1). Infants aged less than 6 months who drink water containing nitrate in excess of the MCL can become seriously ill and, if untreated, may die (EPA 2009). The EPA (2012) has reported that 1-day NO3 exposure to a 10-kg child is 100 ppm and that the reference dose, which is daily exposure to human population (including sensitive subgroups) and is likely to be without an appreciable risk of deleterious effects during a lifetime, is 1.6 mg/kg/day.

Common in groundwater samples from the industrial areas, Sb peaked in concentration at 5.1 ppb in sample 35 and exceeded TSE limits (Table 1) (Figures 1 and 4). Its proximity to the upper MCL limit indicates that the source of this contamination most likely is related to industrial activities (EPA 2009). The EPA (2012) has reported that 1-day Sb exposure to a 10 kg child is 10 ppb, lifetime exposure to adults is 6 ppb, and the reference dose, which is daily exposure to human population and is likely to be without an appreciable risk of deleterious effects during a lifetime, is 0.0004 mg/kg/day. Sb can increase blood cholesterol and decrease blood sugar, and puts people's health at risk in concentrations close to the limit.

Se, which was detected in all samples, exhibited different concentrations (Table 1). The greatest concentrations were found in samples 27 and 41, both from industrial areas, thereby suggesting that the source of contamination is attributable to industrial activities and discharges from petroleum refineries in these areas (Figure 1). Sample 27 also exceeded the TSE limit (Table 1). The EPA (2012) has reported lifetime exposure to Se at 50 ppb, and the reference dose is 0.005 mg/kg/day in drinking water. When Se concentration exceeds the MCL, it can cause hair or fingernail loss, numbness in fingers or toes, and circulatory problems (EPA 2009). It should thus be observed in terms of risk to public health.

Al, As, Cd, Fe, Hg, Li, Mg, Mn, Ni, Pb, phenol, Sb, Se, and Zn concentrations in the groundwater samples collected from areas where oil refinery, storage, and delivery facilities are located indicate that the groundwater is polluted due to nearby industrial activities. The effect of anthropogenic origin agricultural and livestock activities on the groundwater in Batman's settlement area can, moreover, be seen by the presence of NO3 and S.

CONCLUSIONS AND RECOMMENDATIONS

This study provides significant data regarding the status of water contamination and possible risks threatening public health in Batman, Turkey. Analyses of 30 samples of groundwater in the study area reveal average concentrations of Al (237 ppb), As (1 ppb), Pb (1 ppb), Fe (97 ppb), Mn (42 ppb), NO3 (28 ppm), phenol (25 ppb), Sb (3 ppb), Se (2 ppb), and U (4 ppb), of which even the values of Al, As, Pb NO3, and U have densities at levels that threaten public health. In addition, in the study area, the groundwater is at risk of contamination from anthropogenic, geological, industrial, and oil related elements.

As, Pb, and U concentrations detected in the groundwater exceed MCLG, whereas Al, Fe, and Mn concentrations exceed SDWR and TSE limits. Together, it suggests that Batman's groundwater is contaminated by these elements. The most probable sources of As, Pb, and U in the groundwater, all of which pose significant health risks, are the erosion of natural materials and industrial activities. Especially in industrial areas with agricultural and livestock related activities, where the use of fertilizer and pesticides is widespread, NO3 exceeds MCL and TSE limits and is a most significant source of groundwater pollution, which can cause terminal illnesses in infants up to 6 months old.

Despite the low presence of Hg and phenol, which may pose a significant threat to public health and most often originate from oil refinery waste, and although Sb and Se exceed TSE standards, their presence needs to be carefully considered. The fact that U does exceed the MCLG in all samples, and thus poses the risk of cancer, makes it a critical threat to public health. Resulting from industrial activities, Sb and Ni also pose a health risk, as Sb concentrations in some samples approach MCL limits. In only one sample did Ni exceed TSE limits.

Although concentrations of the above-mentioned elements, including As, Pb, Mn, Ni, Sb, Se, and U, might not fail to exceed drinking water standards, this does not suggest that these elements do not pose risks to public health. Values in terms of drinking water standards in groundwater are due to problems stemming from years of accidents in the study area and from oil production, transfer, and storage. In addition, the study area receives 510 mm precipitation annually, 97% of which occurs during winter and spring. Since the region receives significant rainfall and because the aquifers supplying Batman are pervious and unconfined, contaminants are continuously washed out and eventually cause groundwater contamination. It is therefore necessary to pay attention to elements with concentrations approaching the upper limits of EPA and TSE standards that may threaten public health due to increased blood cholesterol, decreased blood sugar, and circulatory problems.

Overall, the present investigation first suggests that because all samples, except samples 4 and 6, contain NO3, water from Batman should not be used for drinking or domestic purposes because the amount of NO3 threatens public health. Second, the water from improperly drilled wells affected by the agriculture, livestock, and oil industries should also not be used for drinking or domestic purposes. Third, it is necessary to take precautions to prevent groundwater contamination caused by pollutants reported in the city center, and if necessary, the activities of the contamination source should be limited. Fourth, because groundwater in the study area is likely to experience contamination by As, Hg, phenol, Pb, Sb, Se, and U in the near future, the quality and extent of contamination of groundwater should be continually screened. Lastly, given the contaminants and aquifers in the region, water for drinking and domestic purposes should be provided from more reliable and cleaner sources.

ACKNOWLEDGEMENTS

This work was supported by the Research Fund of the Batman University, Project Number: 2010-MF-3.

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