Introduction

Afghanistan is a landlocked mountainous country with a total area of 652,000 km2 and a population of around 32 million, located within south and central Asia between the latitudes of 29° 21′ S to 38° 30′ N and longitudes of 60° 31′ W to 75° 00′ E (Fig. 1). Approximately, 10–12% of country’s land is arable that is about 6.5–7.8 million ha. The country’s climate is arid to semi-arid where the weather is cold in winter and hot and dry in summer with temperature that ranges from −20 °C in winter to 50 °C in summer. The annual precipitation in Afghanistan varies according to region, ranging from 75 mm in the southwest up to 1270 mm in the northeast with an average annual precipitation of 300 mm (JICA, 2011). A considerable drought occurred between 1999 and 2003 and in the last three decades while the number of karez wells decreased from 6781 to 686 in this period (Habib, 2014). A karez well is an ancient irrigation system consisting of a tunnel dug at a very slight upward gradient into rising ground so that water from deep within the earth runs out to the surface. The length of the karez wells varies with the geographical environment. Karez is like qanats that were used in Persia and the Middle East, which is an old system of water supply from a deep well with a series of vertical access shafts. According to the Ministry of Energy and Water (MEW, 2016) of Afghanistan, long-term total annual precipitation in Afghanistan is 164 billion m3, evaporation is 87 billion m3 (53% of the total annual precipitation), groundwater recharge is 16 billion m3 (10% of the total annual precipitation), surface water runoff is 61 billion m3 (37% of the total annual precipitation), and the total annual available water resources are 77 billion m3 (Table 1).

Fig. 1
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Location map of Afghanistan

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Table 1 Annual precipitation data by basin in Afghanistan (MEW, 2016)
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For a sustainable and stable development, water is a critical factor in Afghanistan as it is the most important resource and the main source of energy production. The importance of water is well recognized where agriculture accounts for more than 50% of the country’s GDP and without water, agriculture would not exist. Ahmad and Wasiq (2004) indicated that more than 93% of water is used for irrigation in the country, but Ansari (2014) even reports it as 99% of the total water used annually. The water being used with a huge amount for agriculture is substantially wasted due to weak and traditional irrigation practices. The Afghanistan National Development Strategy (ANDS, 2008) indicates that more than 50% of the irrigation water is used in surplus and unfortunately wasted. Additionally, more than 15% of the agricultural land is being irrigated by groundwater in karez wells fed by springs and shallow wells. The total cultivated land is approximately 3.9 million ha, of which, 2.6 million ha is irrigated and 1.3 million ha is rainfed (Qureshi, 2002). About 85% of the labor force is employed in the agriculture sector (Ahmad and Wasiq, 2004). The annual use of water for irrigation is estimated to be 26.8 billion m3 (MEW, 2016). According to JICA (2011), one million ha of the land was cultivated in 2003 with irrigation facilities, while Mahmoodi (2008) argues that Afghanistan’s irrigated land has decreased from 3.3 million ha in 1980 to 1.8 million ha in 2008, which has had a direct effect on the economy of the country.

Access to safe drinking water is still a problem in the country, which has caused different health issues and even child mortality especially in rural areas. According to Qureshi (2002), only 24% of the total population have access to safe drinking water, while Saffi and Kohistani (2013) claim that on a national level, only 27% of the population has access to safe drinking water. Considering that 27% of the country’s population has access to safe drinking water, this percentage is still very low and the drinking water quality has to be improved. Although Afghanistan has enough available water resources at the present, there will be still some issues in the future due to the population increase and climate changes. Moreover, in addition to the improvement of the quality of drinking water, it has to be used systematically within a managed framework. Therefore, it is essential for the government to adopt water resources management strategies and apply them right away. Vining and Vecchia (2007) anticipate a 10% reduction in the total annual precipitation during the next 50 years in Afghanistan. Also, snowmelts will occur earlier during the year because of the surface temperature increment in mountainous regions (Mack et al., 2010a).

Some studies about the quality of groundwater have been conducted by the Danish Committee for Aid to Afghan Refugees (DACAAR) and the United States Geological Survey (USGS) in Afghanistan. DACAAR has worked for more than two decades in Afghanistan providing drinking water through bore wells equipped with hand pumps for the rural population of the country. The Afghan Ministry of Rural Rehabilitation and Development (MRRD) is also a major actor providing drinking water to the rural population through the National Solidarity Program (NSP) but DACAAR has undertaken investigations into groundwater quality, which is our topic of interest here. It should be noted that groundwater is the main source of drinking water throughout the country. Little knowledge is available about the quality of groundwater countrywide. Therefore, the aim of this study is to extensively review the existing literature, evaluate groundwater resources and their quality, reanalyze some existing raw data from the literature and available reports, categorize and address the major factors that deteriorate groundwater in the country, and finally recommend some future investigations and remedial actions for groundwater quality in the country.

Geological characteristics of Afghanistan

The geology and tectonics of Afghanistan are significantly complicated (Fig. 2). The country is located within the range of the great tectonic upheaval that has produced the world’s highest mountain ranges such as the Hindu Kush, Pamir, Karakoram, and Himalaya (Broshears et al., 2005). Afghanistan’s geology includes Proterozoic metamorphic rocks, Paleozoic metamorphic and sedimentary rocks, basic igneous rocks, acidic igneous rocks, volcanic rocks, Paleocene sedimentary rocks, Cretaceous-Paleocene sedimentary rocks, Triassic sedimentary rocks, Cretaceous sedimentary rocks, Neogene sedimentary rocks, Jurassic sedimentary rocks, Permian-Triassic sedimentary rocks, and Quaternary sediments. Tünnermeier and Houben (2005) determined that the Kabul Basin formed by plate movements occurring during the Late Paleocene with metamorphic rocks surrounding the basin. Based on the tectonic origin, the Helmand basin is a structurally closed and large basin that started to form during the middle Tertiary because of the collision of numerous former Gondwanaland fragments (Whitney, 2006). Karstic and jointed aquifers are observed in different parts of the region where geological and tectonic factors have affected groundwater aquifers in the country.

Fig. 2
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Geological map of Afghanistan (USGS, 2007)

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Water resources of Afghanistan

Surface water

Afghanistan has different types of rivers; some of them are perennial, in which their main source is the snowmelt. However, some others just flow during rainy seasons and are dry in summer. All the rivers that flow during the year originate from the central mountains such as the Amu Dary, Helmand River, Farah Rud, Kabul River, Arghandab River, Harirud and Murghab River, Kunar River, Panjshir River, Kunduz River, Abi Panj River, and Koccha River. Based on the hydrologic setting, Afghanistan has five river basins shown in Fig. 3: (1) the Amu Darya river basin, (2) the Helmand river basin, (3) the Kabul (Indus) river basin, (4) the Harirud–Morghab river basin, and (5) the Northern river basin (Blind river system). The annual water resources are estimated as 75 billion m3, from which 57 billion m3 are surface and 18 billion m3 are from the groundwater with a total annual water withdrawal of about 20.3 billion m3 in the country (Ahmad and Wasiq, 2004; JICA, 2011; Mahmoodi, 2008; Habib, 2014). However, recent estimates by the Ministry of Energy and Water (MEW, 2016) indicate that the country’s annual potential water resources are 77 billion m3, which is a 2 billion m3 difference from the amount reported by the literature.

Fig. 3
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River basins of Afghanistan (Mack et al. 2014a)

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According to MEW, the available water resources in the basins are as follows: Kabul, 15.183 billion m3, Helmand, 17.136 billion m3, Amu, 18.763 billion m3, Northern, 9.825 billion m3, and Harirud, 16.053 billion m3. The Water Sector Strategy of Afghanistan (2008) reports the surface water availability by basin, where Kabul has 20.76 billion m3, Helmand 9.3 billion m3, Amu 22 billion m3, Northern 1.88 billion m3, and Harirud 3.06 billion m3 of surface water. Itis also important to mention that most of Afghanistan’s water is delivered from snowmelt in the Hindu Kush Mountains. There are three major river systems flowing out of the Hindu Kush Mountains in Afghanistan, which are the Kabul river system, the Amu Darya system, and the Helmand-Arghandab river system.

There are at least 62 dams in Afghanistan of which, about 20 are large dams (Shroder and Ahmadzai, 2016). Favre and Kamal (2004) mapped a total of 24 dams including existing and proposed ones. Some famous dams in Afghanistan are as follows: Kajaki Dam (Helmand Province), Salma Dam (Heart Province), Dahla Dam (Kandahar Province), Darunta Dam (Nangarhar Province), Mahipar Dam (Kabul Province), Naghlu Dam (Kabul Province), and Sarobi Dam (Kabul Province). These dams have been used for irrigation and hydropower production purposes.

Groundwater

The natural system of groundwater in Afghanistan involves five hydrogeological units of the upper Cretaceous-Paleocene fracture-karstic aquifers, crystalline rocks, quaternary aquifers, Triassic–lower Cretaceous pressure thermal water, and Neogene aquifer-aquitard (Saffi and Kohistani, 2013). The principal aquifer systems include the following: (a) Quaternary deposits in the major river valleys particularly in the Kabul river basin, the river systems in the Helmand river basin to the east (Ghazni, Tarnak, Arghistan, and Arghandab), the Harirud river and certain river systems within Northern flowing rivers and Amu Darya basin; (b) semi-consolidated Neogene age deposits in the Kabul river and other river basins; (c) carbonate rock aquifer systems on the northern flank of the Hindu Kush mountain range and along portions of the Helmand river in Oruzgan Province; and (d) carbonate rock systems at other locations (Uhl, 2003). However, geological properties of the region are very complex while from 1956 to 1963, geological and hydrogeological surveys were conducted in the country and 90% of the aquifers found were from the Quaternary age. The Kabul Basin aquifers consist of gravel and sand that has a slight cemented property in deeper areas where they can be classified as permeable to very permeable. The largest aquifer is the Logar aquifer which is around 30 km2 with 50 m average thickness (Tünnermeier and Houben, 2005). According to Mack et al. (2010a), the primary aquifer of the Kabul Basin is highly permeable consisting of sand and gravel with a thickness of less than 80 m in the valleys. They also found that the upper aquifer is underlain by another aquifer comprised of compacted gravel, sand, and clay which is less permeable and around 1000 m thick. The annual groundwater recharge estimate in the Kabul river basin for the unconsolidated aquifer systems is 520.00 million m3/year, 2970.00 million m3/year for Amu Darya basin, 1140.00 million m3/year for Harirud-Murghab river basin, 2480.00 million m3/year for Helmand river basin, and 2140.00 million m3/year for the Northern river basin (Uhl, 2003).

Groundwater is the first and most important resource for drinking water where access to safe drinking water is still limited especially in rural areas of the country as mentioned in the “Introduction” section. Campbell (2015) asserts that 70.9% of the urban, and 39.4% of the rural population in Afghanistan has access to safe drinking water, which means that about 46% of the total population has access to safe drinking water. If we even consider this report as the highest one in terms of access to safe drinking water, there is still a great concern about the quality of water causing different kinds of diseases risking the human health as far as very little is known about its quality because of very limited studies. The Kabul City shallow groundwater is a good example that is unsafe for human health. According to Houben et al. (2009b), insufficient water hygiene can be connected to the high infant mortality rate to some degree. Thus, studies are required to be conducted to investigate groundwater contamination sources in order to prevent further problems that may rise due to groundwater.

Groundwater is also used for irrigation purposes, especially in the areas where there is no access to surface water. Water pumps and turbines are commonly used to withdraw the groundwater for both drinking and irrigation in rural areas; some karez wells (qanats) and springs are also sources for drinking and irrigation water in some areas as it is already mentioned that more than 15% of the irrigated land receives groundwater. Uhl (2006) claims that even most of the urban areas rely on groundwater for drinking, though more than 95% of the groundwater usage in the country is still accounted for by irrigation. Due to the drought that occurred between 1999 and 2003, most of the karez wells and springs dried up. A comprehensive study was carried out by Taher et al. (2014) to observe the static and dynamic groundwater levels in 71 wells in the Kabul Basin from 2004 to 2013.

Talking about the groundwater flow, in the Kabul Basin, water basically flows through saturated alluvium and other basin-fill sediments, water might also flow below the alluvium through fractures in the bedrock but that amount is assumed to be less than the flow through the alluvium (Broshears et al., 2005).

Groundwater quality in Afghanistan

There are few studies carried out in Afghanistan in the last three decades in order to determine groundwater quality of the entire country in detail. The Danish Committee for Aid to Afghan Refugees (DACAAR) is one of the organizations working since 1992 in Afghanistan to supply drinking water to Afghans. DACAAR has undertaken some comprehensive groundwater quality studies and their recent publication by Saffi and Kohistani (2013) is a reliable study about groundwater quality of Afghanistan. The US Geological Survey is another organization that has been working since 2004 to train and support the Afghanistan Geological Survey teams in the Ministry of Mines and Petroleum, as well as scientists in the Ministries of Energy and Water, Agriculture, Irrigation and Livestock, and some other non-governmental organizations in the country to facilitate groundwater investigations (Mack et al., 2014a). Some other studies investigating groundwater quality just concentrate on Kabul Province or Kabul Basin are those by Tünnermeier and Houben (2005), Broshears et al. (2005), Mack et al. (2010a), Sundem (2014), Frahmand (2011), and Mack et al. (2014b). For other provinces, Ansari (2014) assessed physico-chemical characteristics and groundwater quality index in Lashkar Gah City in the Helmand Province, Saffi and Eqrar (2016) investigated groundwater contamination due to arsenic in Maidan Wardak and Ghazni provinces, and Sundem (2014) examined groundwater quality in both Kabul and Maimanah provinces. Still, some other studies have been undertaken by the Government of Afghanistan, UNDP, UNICEF, World Bank, DACAAR, FAO, and the Norwegian Church Aid as cited by Uhl (2003). The Federal Institute for Geosciences and Natural Resources (BGR) is another organization working on groundwater investigations in Afghanistan since 2003 where BGR’s groundwater project is funded by the German Federal Republic.

Effects of natural factors on groundwater quality

Contamination results from several pollutants such as arsenic, boron, fluoride, and sulfate in several areas of Afghanistan. The water quality mapping for Afghanistan, of which about 50% is completed, shows that groundwater is plagued by high levels of fluoride and arsenic in some areas. Water quality mapping in the other half of the country cannot be completed due to security concerns currently (UNICEF, 2014). According to Saffi and Kohistani (2013), the provinces of Ghazni, Farah, Panjshir, Laghman, Faryab, Logar, and Ghazni have arsenic contamination in groundwater that exceeds the World Health Organization (WHO) guideline of 10 μg/L of As. Recent research by Saffi and Eqrar (2016) studied 764 drinking water points including hand pump tube wells and dug wells to identify arsenic contamination in groundwater of Ghazni and Maidan Wardak provinces. They found that 61% of the water samples exceeded the WHO guideline of 10 μg/L of As, and 38% of the analyzed water samples exceeded the National Drinking Water Quality Standard of Afghanistan (NDWQS) of 50 μg/L of As. Also, out of 42 countries affected by arsenic, Afghanistan is ranked as 22nd with groundwater naturally deteriorated by arsenic; the province of Ghazni had the highest concentration of arsenic in groundwater exceeding the WHO limit (Mukherjee et al., 2006). Moreover, Amini et al. (2008) believe that there is a high probability that Northern Afghanistan’s groundwater is contaminated by arsenic though that area is not tested yet and there is no statistical data. However, in the Kabul Basin, two drinking water samples out of 108 exceeded the US Environmental Protection Agency (USEPA) drinking water standard with a highest value of 22.7 μg/L (Broshears et al., 2005), which means that arsenic concentration is not of great concern in some provinces. Still, no complete data exists that can cover the entire country on groundwater contamination due to arsenic. Some significant cases of arsenic concentration in groundwater can be seen in Table 2. The areas where considerable contents of arsenic in the samples from groundwater exist include Ghazni, Laghman, Logar, Herat, and Balkh provinces. Geogenic arsenic occurs in these regions from arsenic minerals embedded in dense clay matrices that promote the mobilization of arsenic into the groundwater. All arsenic-containing minerals, especially sulfides, which are associated frequently with gold ores, copper and iron, are sources of arsenic.

Table 2 Arsenic concentration in groundwater of Afghanistan (mg/L)
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According to the study by Saffi and Kohistani (2013), which was carried out in 19 provinces of Afghanistan for drinking water quality analysis, they found significant fluoride concentrations in north, northeastern, west, and northwestern parts of the country that exceeded the WHO limit of 1.5 mg/L for drinking water. Around 15.9% of the 1758 analyzed water samples exceeded the WHO’s drinking water limit. The highest cases of fluoride concentration observed in groundwater from some provinces are presented in Table 3. The high concentrations of fluoride in groundwater are often found in areas with granite rocks.

Table 3 Fluoride concentration in groundwater of Afghanistan (mg/L)
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In 31 out of 108 samples from groundwater in the Kabul Basin had boron concentration above 1000 μg/L, which can be problematic for sensitive plants such as apples and grapes (Broshears et al. 2005). In another study of water samples taken from 19 provinces, 1758 (42%) water samples from the drinking water points including springs, hand pumped wells, rivers and groundwater monitoring wells had significant Boron concentration that exceeded the WHO limit of 0.5 mg/L (Saffi and Kohistani, 2013). These cases are summarized in Table 4. The element boron usually occurs in groundwater in the form of the anions borate (BO2) in this region. B is present in their acid form (boric acid H3BO3), this acid is not readily dissociate; it remains stable until pH > 9 (Hem, 1985).

Table 4 Boron concentration in groundwater of Afghanistan (mg/L)
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Suspension of anhydrite and gypsum minerals during their long period of habitation is the cause of high sulfate concentration in the groundwater of north, northeastern, and northwestern Afghanistan, where the range of sulfate concentration varies from 12 mg/L in Tanfeer Village in Dih Yak District of Ghazni Province to 9000 mg/L in Ali Abad village in Nahri Shahi District of Balkh Province (Saffi and Kohistani, 2013). The concentration of sulfate in 17% of the samples analyzed from groundwater in the Kabul Basin is above the WHO’s 250 mg/L limit for drinking water (Tünnermeier and Houben 2005). Table 5 indicates the sulfate concentration in the groundwater resources of Afghanistan. Also, location of high concentration of sulfate, As, B, and F in groundwater resources of Afghanistan is presented in Fig. 4. The results show high concentration of arsenic, boron, fluoride, and sulfate in some provinces that exceed the WHO limit and the National Drinking Water Quality Standard of Afghanistan (NDWQS).

Table 5 Sulfate concentration in groundwater of Afghanistan (mg/L)
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Fig. 4
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Groundwater contamination map of Afghanistan due to natural factors

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Effects of anthropogenic factors on groundwater quality

Agricultural activities, septic tanks system and domestic-municipal wastes are the most important problems among anthropogenic factors that affect the quality of groundwater in Afghanistan.

Agricultural activities

Agriculture plays an important role in the economic growth of Afghanistan where 50% of the country’s GDP relies on it. Additionally, more than 80% of the country’s population lives in rural areas where the main source of income is based on agriculture and livestock. While it is a vital source of income for Afghans and it is hoped that the country’s economy will improve due to the expansion of agriculture, it has some adverse impacts on contamination and pollution of groundwater on the other hand. There is significant amount of excess nitrates that can easily contaminate groundwater from the overuse of chemical fertilizers on farmland. In agricultural areas, nitrates and pesticides in shallow alluvial aquifers are the most usual non-point source pollutions noticed due to the widespread application of fertilizers (Bartzas et al. 2015; Böhlke 2002; and Kim et al. 2009; Zhou 2015). Animal waste that contains nitrate is also a considerable factor for groundwater contamination in areas with livestock. Frequently nitrate concentrations in agricultural areas are linked with microbial and pesticide contaminations (Mahvi et al. 2005). Still, nitrate contamination in groundwater is a common problem in many parts of the world due to many causes, e.g., intensive agriculture, untreated sanitation in densely populated areas, or from non-point sources such as irrigation of land by sewage effluents. Nevertheless, the heavy use of nitrogenous fertilizers in crop systems is the largest contributor to anthropogenic nitrogen in groundwater worldwide (Suthar et al., 2009). Some of the major concerns about nitrate (NO3 −) contamination/loading in both groundwater and surface water systems include health risks to humans through drinking water (i.e., methemoglobinemia and potential carcinogenic effects) and degradation of the local ecosystems (i.e., excessive plant and algal growth) (Murgulet and Tick, 2009). Numerous studies report that the use of rural land, especially agricultural practices, can cause nitrate contamination of underlying groundwater (Bouwer, 1978; Driscoll, 1986; and Vowinkel and Tapper 1995). Thus, agricultural activities are one of the noticeable anthropogenic factors contaminating groundwater in the country. Poor quality of water is not just harmful for human health, but it will affect the productivity and quality of agricultural crops as well. Azizullah et al. (2011) confirm that use of poor quality water for irrigation will lower productivity of crops. Since more than 50% of the irrigation water is wasted due to the traditional and weak irrigation practices in Afghanistan, the risk of groundwater contamination due to runoff of extra water contaminated with nitrates and pesticides is high. Still, there is no a specific strategy or guidance in the country to be followed in order to prevent this type of groundwater contamination. The nitrate concentration in the groundwater is studied by Saffi and Kohistani (2013) with some remarkable figures in several provinces as shown in Table 6. In another study, Zhou (2015) observed considerable nitrate concentration in about 700 well points data with majority in Asia, especially in Afghanistan where nitrate was measured from year 1990 to 2013. The results of this study showed that concentration of nitrate exceeded 100 mg/L in groundwater in Afghanistan. Locations of high concentrations of nitrate, Escherichia coli, and fecal coliforms in some provinces are presented in Fig. 5.

Table 6 Nitrate concentration in groundwater of Afghanistan (mg/L)
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Fig. 5
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Groundwater contamination map of Afghanistan due to anthropogenic factors

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Septic tanks system

In Afghanistan, most of the cities and towns do not have central sewer line systems; there are just individual septic tanks installed for each house. These tanks are not constructed in a proper way to prevent infiltration of wastewater into the groundwater. In Kabul City, one third of the wastewater infiltrates into groundwater due to the absence of a wastewater disposal network (Houben et al. 2009a). Subsurface sewage disposal systems are the largest sources of groundwater contamination (Miller, 1980). The wastewater and human excreta obviously carries bacteria, viruses, E. coli, and nitrates that are dangerous to health, especially for children. Nitrate is a very important factor for drinking water hygiene because above 50 mg/L concentration of nitrate from the WHO limit can adversely affect human health especially children health. Ansari (2014) found nitrate concentration of 132.4 mg/L in a shallow well groundwater sample in Lashkar Gah City in the Helmand Province where the main cause of groundwater contamination was wastewater infiltration from the nearby septic tanks that were constructed improperly or without engineering. The 132.4 mg/L nitrate concentration exceeds the 50 mg/L guideline value of the WHO. With the expansion of cities and construction of new houses, the number of these inappropriate septic tanks is increasing day by day, which will cause a serious problem for groundwater quality in the country in the future. Ansari (2014) further claims that sanitation in Lashkar Gah City is at a very low level with no facilities for wastewater or solid waste treatment. Broshears et al. (2005) measured the nitrate concentration in 108 wells in the urban area of Kabul river basin, groundwater in 14 wells exceeded the USEPA drinking water standard of 10 mg/L N. In this research, E. coli was noted in 24 samples out of 108, which is a clear indication of fecal contamination. In a study carried out by Houben et al. (2009b) on Kabul City groundwater quality, they found that in water samples from 290 shallow and deep wells, 42% of the samples exceeded the WHO limit. In another study conducted by the Afghanistan Geological Survey (AGS), they collected water samples from 92 groundwater, karez, spring, and 8 surface water sites for quality determinations, while bacterial contamination such as E. coli and total coliform were detected in both groundwater and surface water that exceeded the standards for international drinking water (Mack et al., 2010b). Hence, there are different kinds of waterborne diseases in the country such as diarrhea, cholera, and dysentery (Ansari, 2014; Saffi and Kohistani, 2013; and Habib, 2014) because of the poor septic tanks system that causes the drinking groundwater quality contaminated. Tables 7 and 8 indicate particular significant contamination of groundwater due to fecal coliforms and E. coli in some provinces of Afghanistan.

Table 7 Fecal coliforms concentration in groundwater of Afghanistan (Col/100 ml)
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Table 8 E. coli concentration in groundwater of Afghanistan (Col/100 ml)
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Domestic and municipal wastes

Landfills for waste are one of the foremost threats to groundwater resources (Fatta et al., 1999) not only in Afghanistan but throughout the world (US EPA, 1984). The solid waste placed in landfills or open dumps is subject to either groundwater underflow or infiltration from precipitation or any other possible infiltration of water (Nagarajan et al., 2012). Domestic wastes are also one of the significant anthropogenic factors in the groundwater contamination process in Afghanistan. As per Houben et al. (2009b), because of weak waste disposal and sewage treatment systems, shallow groundwater in the Kabul City is extremely polluted. Lashkaripour and Hussaini (2008) report that groundwater in the Kabul Basin is substantially affected by sewage in the neighborhood of urban areas. Mack et al. (2010a) also confirm that the contamination of groundwater by human activities in central Kabul sub-basin is due to the absence of waste and wastewater treatment facilities and contains concentrations of boron, nitrate, and chloride. Uhl (2006) insisted that the weak drainage and wastewater disposal practices have caused water quality deterioration in urban areas of Afghanistan. Ansari (2014) also claims that the absence of solid waste treatment systems in Afghanistan have caused a potential for groundwater contamination. He further argues that the dumping of solid wastes from Lashkar Gah City in Helmand Province in rivers or sites outside the city is an important anthropogenic factor that may cause groundwater pollution. These examples show that the Environmental Protection Agency of Afghanistan is still not able to overcome these problems and may not be able to do it in the near future.

Groundwater quality concerns in the country

Quality of groundwater is a concern for both human health and the environment in Afghanistan. For example, the population exposed to elevated arsenic in drinking water in the Ghazni and Logar areas is estimated at 500,000.00 (Murcott, 2012). One study was conducted where in three mining regions, and the villagers located in the mountainous areas were seriously exposed to arsenic in the drinking water around Ghazni region (Ravenscroft et al., 2009). The source of arsenic was presumed to be oxidation of arsenopyrite associated with copper mineralization.

A majority of the Afghan population suffers the problem of adequate and safe supplies of water because of contamination from a wide variety of sources such as lack of water resource management regulations and lack of the river basin infrastructure, compounded by a recent 5-year drought and seasonal flooding (Williams-Sether, 2008). Estimates show that 191 out of 1000 children die before their 5th birthday, of which 44 die because of unsafe water and poor sanitation as cited by Saffi and Kohistani (2013). Some major concerns were reported by Saffi and Kohistani (2013) regarding groundwater quality and quantity with quantitative groundwater concerns of (1) continuing water logging, (2) imbalance in streams/river and aquifer interaction, (3) continuing lowering of the groundwater table, (4) drying of most of the karez, large diameter wells and springs, (5) excessive discharge trends and deteriorating water quality, and (6) depletion of groundwater natural storage. Qualitative groundwater concerns are (1) arsenic contamination, (2) boron contamination, (3) salinity contamination, (4) fecal coliform bacteria, (5) nitrate contamination, (6) fluoride contamination, (7) chromium contamination, (8) hardness, and (9) sodium and chloride contamination. The study covers 19 out of 34 provinces in Afghanistan and can be counted as countrywide study as there is no other data that can cover the entire country. In the Kabul river basin, water samples were taken from 108 wells during July and November 2004, which showed that 13 wells exceeded the USEPA drinking water standards for nitrate, with 44 wells with excessive boron, 22 wells with excessive bromide, 54 wells with excessive dissolved solids, 14 wells with excessive sulfate, 11 wells with excessive chloride, and 73 wells with excessive fecal coliform bacteria contamination (Thomas and Eqrar, 2011). Moreover, Shroder and Ahmadzai (2016) claim that Afghanistan is one of the worst countries in South and Central Asia in terms of access to improved and healthy water supplies. Thus, these concerns should be taken into account to ensure a countrywide investigation on groundwater quality data collection, analysis, and results in order to establish some preventive regulations linked to anthropogenic contamination of groundwater. Even though the Environmental and Water Laws of Afghanistan emphasize the protection of water resources, these laws are not fully enforced in the country due to the weak law enforcement in the country at the moment. Article number 38 of the Environmental Law “Preventing and Remedying Effects of Pollution of Water Resources” says that an owner of land, a person in control of land or a person who occupies or uses the land on which any activity or process is performed or undertaken which causes or is likely to cause significant pollution of a water resource, must take the following measures to prevent any such pollution from occurring:

  • Cease, modify, or control any action or process causing the pollution

  • Comply with any prescribed waste standard or pollution management practice

  • Contain or prevent the movement of pollutants

  • Eliminate any source of the pollution

  • Remedy the effects of the pollution

  • Remedy the effects of any disturbance to the bed and banks of a watercourse

Furthermore, the Water Law Article number 30 “Non-Contamination of Water Resources” states that

  • Real and legal persons cannot contaminate water resources by using or discharging garbage, wastewater, industrial waste, chemicals, and toxics beyond the limit

  • A violator, based on this law, is required to compensate for losses and shall be punished depending on the circumstances

However, none of these rules are enforced and applied practically in the field yet. In addition, most people are not aware of such laws or do not understand and cannot even read these laws in rural areas, which accounts for 80% of the Afghan population because of the illiteracy. Thus, much effort is required to ensure Afghan society can fully understand the importance of such a precious resource, which is under risk of deterioration.

In June 2015, a National Groundwater Conference was held with cooperation of related Afghan ministries and non-governmental organizations (NGOs) involved and supporting groundwater investigation projects in Afghanistan. This was the first conference on a national level that addressed concerns about groundwater problems in Afghanistan and offered solutions for the comprehensive study of groundwater of the entire country. This conference announced their final declaration emphasizing groundwater coordination between the responsible ministries, establishment of an information management system for effective communication and sharing of data among the stakeholders for any development associated with groundwater, mapping of groundwater resources for the whole country, determination of support and funding needed from donors working in Afghanistan, enforcement of law, and preparation of an action plan for the next 5 years. The key ministries attending the conference were the Ministry of Energy and Water (MEW), Ministry of Mines and Petroleum (MMP), Ministry of Agriculture, Irrigation and Livestock (MAIL), Ministry of Urban Development of Afghanistan (MUDA), and Ministry of Rural Rehabilitation and Development (MRRD). Therefore, there is hope that some detailed information about Afghanistan’s groundwater will be available in the future based on the decisions that were made at this conference. Yet, there are many challenges ahead for these countrywide studies where security is the first and the main challenge.

Conclusions and recommendations

Groundwater is the main source of drinking water in Afghanistan where no detailed countrywide studies are available about quality yet. Usually, groundwater is deteriorated naturally or via human activities. Natural significant factors that affect the quality of groundwater in Afghanistan are arsenic, boron, fluoride, and sulfate based on the existing literature, which are concerns for human health and even agriculture. Among the anthropogenic factors that can affect groundwater quality adversely are agricultural activities, septic tanks system, and domestic and municipal wastes. Still, little or no information is available for the groundwater quality of the whole country. Also, the government has not enforced the regulations in place to prevent further groundwater contamination, particularly due to anthropogenic factors. Since very little attention has been paid toward groundwater deterioration in the country, there will be a serious risk to groundwater quality in the next 10–20 years due to the population increase, huge mining activities (just begun), increased industrial activities, and with the expansion of agriculture. Therefore, government and involved institutions should take necessary actions to prevent further groundwater contaminations that may reduce problems associated with groundwater especially considering health issues.

The major factors threatening the groundwater resources are domestic and industrial wastes, septic tanks that are rapidly increasing in the cities, and agricultural activities that need to be managed. The wastewater from latrines and septic tanks infiltrating into groundwater which contaminates the water in the cities and may cause a large health problem for drinking water in the future. Therefore, it is very important to monitor groundwater resources continuously. Study of water resources, especially groundwater resources is one of the fields that require very good and effective knowledge in both theory and practice. In addition to expertise, investigation of groundwater will need sufficient funding, equipment, time, and obviously security, which is the biggest challenge at the moment. Finally, taking all concerns into account, further studies should show much bigger picture of the case so that to understand the problem in details.