The use of cokriging algorithm for arsenic mapping in groundwater systems

5th International Perspective on Water Resources & the Environment Conference (IPWE 2012), MoroccoAccurate mapping of the spatial distribution of arsenic in groundwater is an important but equally difficult task to complete due to a number of uncertainties. Classical univariate interpolation algorithms could sometimes be insufficient to capture high concentration and high gradient areas. Under these circumstances, the use of an auxiliary parameter could provide better estimates of arsenic distribution. Based on this premise, arsenic cokriging with a correlated parameter can improve the performance of interpolation and can enhance the quality of predictions. In order to test this hypothesis, a water quality dataset from an arsenic containing aquifer in Simav Plain, Turkey is used to develop arsenic distribution maps. Arsenic is cokriged with correlated parameters such as manganese, iron and dissolved oxygen; and the results are compared with univariate interpolation algorithms such as ordinary kriging and inverse distance weighing. The comparisons were performed with cross validation at sampling locations and assessed based on mean and root mean squared errors. The results revealed that maps developed using arsenic cokriging with iron have given the smallest error value and have shown closest fit to the extreme values in the dataset. Accordingly, arsenic cokriging with iron is believed to be a promising approach in mapping arsenic distributions in groundwater

Evidence for sea water intrusion in karstic aquifer of Karaburun Peninsula, NW Turkey

IWA 2nd Regional Symposium on water, wastewater and environment, 22-24 March 2017, Cesme, İzmirKarstic aquifers are considered to be significant sources of groundwater and are mostly under threat due to sea water intrusion in many parts of the world. Seawater intrusion is also a common problem on karstic aquifers of Karaburun Peninsula in north of Mediterranean Region. The hydrogeology of Karaburun Peninsula is fairly complex and is mostly characterized by highly permeable karstic formations with significant water storage in an otherwise water scarce area. The karstic aquifers of the region were recently found to be under severe salt water intrusion, which significantly altered the position of fresh water/sea water interface as a result of excessive pumping and fault zones controlling the karstic network.The Scientific and Technological Research Council of Turkey project number 113Y04

Investigation of sea water intrusion in coastal aquifers: A case study from Karaburun Peninsula, Turkey

36th IAHR World Congress, 28 June – 3 July, 2015, The Hague, the NetherlandsGroundwater is an important natural resource; as of today, more than 2 billion people depend on groundwater. Determination of the quantity of available water resources is crucial due to continuously increasing water demand and unequal spatial distribution of water in the world. Coastal areas are typically considered to be areas of limited supply and large demand and groundwater is mostly the resource that is used for water supply purposes for coastal communities. Thus, there exist numerous studies in literature that focus on the determination of the groundwater characteristics in coastal regions with particular emphasis on the geological, hydrogeological and hydrochemical properties of coastal groundwater. Coastal aquifers are considered to be significant water resources and are mostly under threat due to salt water intrusion. The reason for salt water intrusion is mostly anthropogenic such as over exploitation but occasionally natural causes like tectonic boundaries or fault lines could be influential. When coupled with low recharge rates that are common in semi-arid regions such as the Mediterranean, effective and sustainable supply of water with sufficient quality and quantity becomes a real challenge for coastal communities

Hydrology and hydrochemistry of marble aquifer with point recharge from two deep sinkholes, Menderes Massive, western Turkey

Menderes Massive is a NE–SW-trending metamorphic terrain in western Anatolia. The massive is composed of regionally metamorphosed rocks of mica-schist and marble. The Bozdag Mountain is the main horst system in Kucuk Menderes river basin. It is composed of several N-S oriented small horsts and grabens and contains important karst features, such as poljes and sinkholes. Ayvacik and Subatan Poljes are typical closed depressions draining into Ayvacik and Subatan sinkholes (ponors). Both are developed along the N-S directed fault system. The main objective of this study is to determine the karstification and hydrogeochemical features of water circulating in marble terrain and controlled by deep sinkholes in the Bozdag Mountain. Detailed speleological studies demonstrated that the degree of karstification of marble rock depends on the regional tectonic structure, the mineralogy of marble and the water recharge rate into the sinkholes. Tritium isotope and tracer tests indicate very fast flow and connection between Subatan surface water and a spring in lower elevations with high Ca and Mg ion concentration at the south of the study area. Hidrogeologija in hidrokemija marmornega vodonosnika s ponornim točkovnim napajanjem (Masiv Meredes, zahodna Turčija)Masiv Menderes je območje metamorfnih kamnin v zahodni Anatoliji, Turčija. Razteza se v smeri SV–JZ in je sestavljeno predvsem iz regionalno metamorfiziranih sljudnih skrilavcev in marmorjev. Goro Bozdag sestavlja sistem manjših grud in tektonskih jarkov, orientiranih v smeri sever-jug. Masiv je delno zakrasel, s tipičnimi kraškimi oblikami, med katere spadata tudi polji Ayvacik in Subatan, ki se drenirata skozi istoimenske ponore. Obe polji sta razviti v prelomni coni orientirani v smeri sever-jug. Glavni namen opisane raziskave je določiti stopnjo zakraselosti območja in hidrokemične lastnosti vode, ki teče skozi marmornati masiv. Podrobne speleološke raziskave so pokazale, da je zakraselost močno pogojena z regionalno geološko strukturo, mineraloško sestavo marmorja in velikostjo dotokov v ponore. Izotopske analize tritija in sledenje podzemnih voda kažejo na hiter tok in povezavo med poljem Subatan in visoko mineraliziranimi izviri na jugu obravnavanega območja. 

Sample collection into sterile vacuum tubes to preserve arsenic speciation in natural water samples

The accurate speciation analysis of arsenic is a serious concern for water quality monitoring programs. Because the preservation of sample integrity until analysis is one of the most important aspects of speciation, this study aims to compare the performance of four different sample preservation methods under diverse conditions of sample quality. Natural samples with different characteristics were collected into the following containers to study their effectiveness: (1) standard high-density polyethylene bottle with no preservative; (2) empty, sterile Vacuette tube with no preservative; (3) sterile tripotassium ethylenediaminetetraacetic acid (K3EDTA) Vacuette tube with K3EDTA additive; and (4) empty, sterile Vacuette tube with added hydrochloric acid (HCl). Known concentrations of arsenite [As(III)] were also added to each container to monitor the oxidation of As(III) to arsenate [As(V)]. The results revealed recovery ratios exceeding 95% in all containers with sterile vacuum conditions. In particular, the K3EDTA Vacuette tube yielded a recovery very close to 100% of the spiked As(III), which is known to rapidly oxidize to As(V). Overall, collecting the sample into a container under sterile vacuum conditions and using a universally accepted preserving agent such as EDTA or HCl significantly improved the preservation of the original species distribution in the water matrix studied, compared to sampling without the use of preservation methods. After validation by future research, these sterile vacuum tubes can possibly be utilized for collecting and storing samples for the routine speciation analysis of other elements such as selenium, chromium, and antimony.Scientific and Technological Research Council of Turkey (109Y029

Estimation of hydraulic conductivity from specific capacity data for alluvial aquifer: A case study from Alaşehir Plain (Manisa)

71.Türkiye Jeoloji Kurultayı, 23-27 Nisan 2018, AnkaraAkiferlerin hidrolik iletkenliği, transmissibilitesi ve depolama katsayısı gibi hidrolik parametrelerinin pompaj kuyuları ile belirlenmesi oldukça zor ve pahalı bir işlemdir. Hidrolik iletkenliğin belirlenmesinde, debi, statik seviye, dinamik seviye ve etki yarıçapına ihtiyaç duyulmaktadır. Gözlem kuyuları olmadığı takdirde etki yarıçapı global rakamlarla ifade edilmektedir. Buna karşılık, statik su seviyesi, dinamik su seviye ve kuyu debisi kolaylıkla kuyu başında ölçülebilmektedir. Bu veriler ile kuyunun özgül debisi rahatlıkla hesaplanabilmektedir. Ülkemizde, binlerce su kuyusu alüvyon akiferde açılmaktadır. Kuyuların hidrolik parametreleri ise pompaj testlerinin uygulanamaması nedeni ile bilinmemektedir. Bu çalışma kapsamında ise hidrolik iletkenliğin bölgede aynı akiferden elde edilen özgül debi değerleri ile tahmin edilebilmesine gidilmiştir. Bu çalışma Alaşehir Ovası’nın en önemli yeraltı suyu akiferi olan alüvyon akiferde uygulanmıştır. Büyük miktarda çekilen yeraltısuyu çalışma alanında içme ve sulama amaçlı kullanılmaktadır. İnceleme alanında 120-150 m derinliğinde açılmış olan su kuyularından 5-30 L/s debi ile yeraltı suyu çekilebilmektedir. Açılan bu kuyularda çok az kullanılabilecek hidrolik parametre bulunmaktadır. Bu nedenle, kuyuların hidrolik parametrelerinin belirlenmesinde bilinen parametrelerden yola çıkarak bilinmeyeni tahmin eden yaklaşımlara ihtiyaç duyulmaktadır. Bu verilerden yola çıkarak, çalışma alanında düzgün verisi olan ve alüvyonda açılmış kuyu özgül debi değerleri ile kuyunun hidrolik iletkenliğinin belirlenmesine çalışılmıştır

Asssessment of groundwater potantial using MODFLOW-2005 numerıcal modeling method: A case study in Alaşehir (Manisa)

71.Türkiye Jeoloji Kurultayı, 23-27 Nisan 2018Dünyada yaşanan iklim değişikliği, aşırı nüfus artışı ve Türkiye gibi gelişmekte olan ülkelerde endüstrinin artması ile birlikte su kaynaklarının sürdürülebilir kullanımı önem kazanmıştır. Yüzey sularında kirlilik ve miktar açısından yaşanan problemler nedeniyle, tüm alanlarda yeraltısularının tüketimi artmaktadır. Ancak yüzey suları kadar kendini hızlı yenilemeyen yeraltısuları sürdürülebilirlik açısından çok büyük tehdit altındadır. Özellikle Türkiye yaşanan yarı-kurak iklim nedeniyle bu sorunlardan çok fazla etkilenmektedir. Bu nedenle yeraltısularının kontrol altına alınması zorunlu hale gelmiştir. Yeraltısularının kontrol altına alınmasında yapılacak olan çalışmalarda en önemli konulardan biri olan yeraltısuyu beslenim mekanizmasının belirlenmesidir. Beslenim mekanizmasının ortaya konulması ile yeraltısuyu kullanımları kontrol altına alınarak, geleceğe yönelik çalışmalar daha doğru ve kapsamlı hale gelecektir. Bu çalışma kapsamında Gediz alt havzası olan Alaşehir Havzası çalışılmıştır. Havzadaki alüvyon akiferdeki yeraltısuyu potansiyeli MODFLOW-2005 nümerik modellemesi ile değerlendirilmiştir

THREE DIMENSIONAL INTERACTIVE HYDROGEOLOGICAL MODEL OF THE KEMALPASA PLAIN

Kemalpaşa Ovası, Türkiye'nin batısında İzmir ili sınırları içerisinde yer almaktadır. Her geçen gün artan su talebinin yüzeysel akiferden karşılanamaması üzerine birçok orta ve büyük ölçekli sanayi tesisi derin kuyular açtırarak derin akiferlerden su temini yoluna gitmektedir. Yapılan jeolojik etüdlerde ovada üç farklı kaya grubunun varlığı tespit edilmiştir. Çalışma alanının temelinde, Mesozoyik yaşlı Bornova Karmaşığı bulunmaktadır. Bornova Karmaşığı, allokton rekristalize kiraçtaşları, kumtaşı-şeyl, killi şistler ve fillitlerden oluşmaktadır. Konsolide olmuş Neojen tortullarını oluşturan kumtaşı, kiltaşı ve kireçtaşları uyumsuz olarak temel kayalarını örtmektedir. Kuvaterner yaşlı alüvyonel çökeller en üstte yer almaktadır. Ovada, bu üç formasyonda oluşmuş dört farklı akifer tespit edilmiştir. Bunlar, (i) Bornova karmaşığı içerisindeki Mesozoyik yaşlı allokton rekristalize kireçtaşları, (ii) Neojen birimler içerisindeki kumtaşları ve çakıltaşı tabakaları, (iii) Neojen kireçtaşları; ve, (iv) en üstte yer alan konsolide olmamış alüvyon sedimanlar olarak tanımlanabilir. Bu çalışma ile, Kemalpaşa ovasında yer alan farklı niteliklerdeki akiferlerin hidrojeolojik karakterizasyonları yapılmış ve akiferlerin üç boyutlu interaktif modeli hazırlanmıştır. The Kemalpasa Plain is located within the boundaries of the province of Izmir Province in western Turkey. The irrigational water demands of the farmers and the process water requirements of the industrial establishments are most supplied from groundwater resources of the plain. This ever-increasing demands for water could no longer be satisfied by the alluvial surfacial aquifer and, hence, numerous deep wells are being drilled in the lower aquifers to supply these high demands. Based on the geological surveys performed in the plain, three different rock formations are observed in the plain. The Mesozoic-aged Bornova Complex forms the foundation of the study area. The Bornova Complex is composed of allochthonous limestone, sandstone, clayey schist and phyllite. The consolidated Neogene sediment units overlay the basement rock by discordance. These sedimentary units are composed of sandstone, claystone and limestone. Finally, as the youngest units of the region, the Quaternary aged alluvial sediments overlay all other units. In accordance with this geological structure, four different aquifers are determined in the plain. These are classified as: (i) Mesozoic-aged allochthonous limestone in Bornova Complex, (ii) Neogene-aged sandstone and gravel, (iii) Neogene-aged limestone; and, (iv) Quaternary-aged unconsolidated alluvial sediments. In this study, hydrogeological characterization of Kemalpasa plain aquifers discussed above will be conducted and a three dimensional interactive model of these layers is prepared. Finally, a three dimensional hydrogeological model of Kemalpasa plain is prepared

The infldence of the discharge of geothermal fluid on surface water quality: Case study Simav Plain (Kütahya)

Son yıllarda jeotermal enerji, temiz ve yenilenebilir bir enerji kaynağı olarak gündemdedir. Ancak, yüksek çözünmüş madde miktarı ve ısıl içeriği nedeniyle uygun şartlar altında önlem alınmadığı durumlarda jeotermal akışkanın yüzeysel su kalitesine önemli etkileri olacağı açıktır. Ülkemizde gelişen jeotermal enerji uygulamalarına paralel olarak, pek çok sahada atık jeotermal akışkana ilişkin sorunlar yaşanmaktadır. Bu sahalardan biri olan Simav Jeotermal Sahası'nda yürütülen bu çalışma ile atık jeotermal akışkanın kontrolsüz olarak yüzeysel sulara deşaıjının neden olduğır sorunlar incelenmiştir. Bölgedeki üç adet jeotermal sahadan (Eynal, Çitgöl ve Naşa) çıkan atıkjeotermal akışkanın ciddi bir ısıl ve kimyasal kirlenmeye neden olduğır tespit edilmiştir. Özellikle arsenik, bor, lityum v.b. toksik elementlerce zengin olan akışkanın herhangi bir kontrol tedbiri alınadan yüzeysel su kaynaklarına deşarjı, bu kaynakların olası diğer kullanınılarını olumsuz yönde etkilemektedir.In recent years, geotlıermal energy is on the agenda as a clean and renewable energy resource. However, witlı its high dissolved constituents and tlıermal content, geothermal fluid is known to have significant impacts on surface water quality when disposed in an urıcontrolled manner. In parallel to devetoping geotlıermal energy applications in our courıtry, many sites experience problems associated witlı waste geotlıermal fluid disposaL Being one of tlıese sites, Simav Geothermal Area is studied in this paper and problems associated witlı tlıe discharge of vaste geotlıermal fluid on surface water resources are assessed. The waste geotlıermal fluid originating from three locations (Eynal, Çitgöl and Naşa) in tlıe study area is fourıd to cause significant tlıermal and chemical contamination. Particularly, tlıe urıcontrolled discharge of geotlıermal fluid tlıat is rich in arsenic, boran, lithium and otlıer toxic elements in to surface water resources of tlıe area influences otlıer potential us es of tlıese resources

An integrated assessment of water quality in an arsenic containing aquifer: Milestones from hydrogeology to public health

5th International Perspective on Water Resources & the Environment Conference (IPWE 2012), MoroccoA multi-disciplinary research is being conducted in Simav Plain, Turkey where an arsenic containing aquifer is at the center of attention. The study is not only aimed to understand the sources and mechanisms of the presence of high arsenic levels in groundwater but also to determine the associated consequences with regards to human health. The high arsenic levels in most groundwater (N=33, avg. 162 ppb), surface water (N=9, avg. 76.6 ppb) and geothermal water (N=3, avg. 406 ppb) samples are strongly related to high occurrences of arsenic in rocks and soils of the plain, which range between 7.1 and 833.9 ppm with an average of 49 ppm. These values correspond to several orders of magnitude higher than international standards and world averages in water and soil, respectively. With this motivation, this research also focuses on human health in the study area associated with exposure to these high arsenic levels via numerous pathways. Consequently, more than 1000 individuals were personally surveyed by public health specialists to determine an inventory of diseases in the area. Furthermore, a verbal autopsy study was also conducted with relatives of the deceased, which were further verified with hospital records, to understand the underlying death cause. As a result, certain cancer rates were found to exceed national averages and the results statistically demonstrated a potential link with high arsenic levels mainly through oral exposure