Istanbul Water Research Articles

Water in Istanbul and beyond: past, present, future

Water in Istanbul and beyond: past, present, future

Determination of PCDD/F and DL-PCB pollution levels, source appointment and risk assessment of surface sediments in dam lakes in Istanbul, Türkiye.

The current situation of the water resources of Istanbul, which is one of the important metropolises of Europe, should be known and constantly monitored by the reasons of the rapid increase in the city population, the acceleration of production-related industrial activities, the expansion of the city with construction activities, and the decrease in precipitation. The purpose of this study was to reveal the situations of surface sediments collected from Istanbul water reservoirs in terms of PCDD/Fs and DL-PCBs, to identify possible sources, and to conduct their ecological risk assessment. Total PCDD/Fs and DL-PCBs concentrations varied between 28.13 and 457.4pg/g (average 136.8pg/g) and 12.19-340.1pg/g (average 72.09pg/g). The corresponding TEQ values of PCDD/Fs and DL-PCBs were between 0.53 and 5.37pg TEQ/g (average 2.23pg TEQ/g) and 0.02-0.44pg TEQ/g (average 0.12pg TEQ/g), respectively. Octachlorodibenzo-p-dioxin (OCDD) is the dominant congener by constituting about 75% of the total PCDD/Fs on average, while congener distributions of DL-PCBs showed the dominance of PCB-118 and PCB-105. The sediments taken from Kazandere dam have the lowest pollution levels for both PCDD/Fs and DL-PCBs. The highest PCDD/F and DL-PCB amounts were measured in sediments of Alibey and Elmalı dams (closest to highly populated settlements of Istanbul), which are most affected by the air pollution caused by the traffic, commercial/industrial combustion (like waste incineration facility) and combustion for residential heating. Almost all the sediments have total dioxin-like toxicity levels higher than the safe threshold level (with two exceptions) of 0.85pg TEQ/g dw, proposed for ecological risk. Health risk assessment shows that levels of dioxin-like compounds would result in a total intake of 0.33pg TEQ/kg bw/day even in the worst-case scenario, not exceeding the tolerable daily intake value of 1pg TEQ/kg bw/day. Among exposure pathways, consumption of fish constitutes almost all the total intake, while contributions of other pathways are minimal.

Water in Istanbul: Rising to the Challenge?

Water in Istanbul: Rising to the Challenge?

Analysis of Eutrophication Potential in Main Drinking Water Basins of Istanbul

AbstractEutrophication potential in three main drinking water reservoirs of Istanbul is investigated. The eutrophication analysis is conducted by a phosphorus mass balance model using the point and nonpoint sources of pollution with the data provided by the Istanbul Water and Sewerage Administration. In addition to the mass balance model, the reservoirs are also evaluated based on trophic state index calculations. The results indicate that Istanbul's main drinking water reservoirs are either under eutrophication danger or already under eutrophic conditions. While reduction of nonpoint source loads using a series of best management practices is recommended for Omerli and Buyukcekmece Reservoirs, additional measures to mitigate internal eutrophication is necessary for Terkos Reservoir. Results of this study provide insight into management and control scenarios to prevent impacts of eutrophication in these reservoirs.

Isolation and identification of free-living amoebae isolated from well water in Istanbul.

Free-living amoebae (FLA) are ubiquitous protozoa commonly found in water and soil environments. FLA belonging to various genera, including Acanthamoeba, Balamuthia, Naegleria, and Vermamoeba, can cause opportunistic and non-opportunistic infections in humans and animals such as keratitis or meningoencephalitis. In addition, some of them serve as hosts for a large number of pathogenic bacteria, yeasts, and viruses. The purpose of the present study was to assess the prevalence and molecular characterization of FLA in well water samples in İstanbul. Ten well water samples were collected from the taps and the presence of FLA was monitored both by the culture and polymerase chain reaction methods. FLA were isolated in 8 out of the 10 samples (80%) included in this study. Morphological analysis and partial sequencing of the 18S rDNA revealed the presence of Acanthamoeba genotypes T3 and T4, and Vermamoeba vermiformis in the investigated well water samples. This study reports for the first time the detection of Acanthamoeba genotype T3 in well water samples in İstanbul. The presence of potentially pathogenic amoebae in habitats related to human activities supports the relevance of FLA as a potential public health concern.

İçme Suyu Dağıtım ve Atıksu Toplama Şebekelerinde Maliyet Analizi: İstanbul Asya Yakası Örneği

Türkiye’de su temini ve atıksu hizmetleri özerk bütçeli Su ve Kanalizasyon İdareleri (SUKİ) tarafından yürütülmektedir. SUKİ’ler üzerine düşen sorumluluğu gerçekleştirebilmek için büyük yatırımlar yapmaktadır. Bu çalışmada, İstanbul şehri için İstanbul Su ve Kanalizasyon İdaresi (İSKİ) sorumluluk alanında bulunan içme suyu dağıtım ve atıksu toplama şebekeleri için maliyet analizi yapılmıştır. Çalışma sonuçlarına göre; içme suyu dağıtım şebekelerinde, Ø(100-600) mm anma çaplı hatların birim inşaat maliyeti ortalama kaplamasız borularda ~98 $/m iken, kaplamalı borularda ise ~107$/m olduğu bulunmuştur. Atıksu toplama şebekelerinde ise Ø(300-600)mm anma çaplı borularda birim fiyat 200 $/m ile 276$/m aralığında değişmektedir. İçme suyu dağıtım ve atıksu toplama şebekeleri için hesaplanan hektar başına düşen mal varlığı ile hektar başına toplam şebeke uzunluğu arasında doğrusal bir ilişki olduğu görülmüştür. İçme suyu dağıtım ve atıksu toplama şebekelerinde, birim şebeke uzunluğu başına düşen ortalama birim maliyet sırasıyla yaklaşık 77.825 $/km ve 294.664 $/km olarak bulunmuştur. Kişi başına ortalama birim maliyet ise içme suyu dağıtım şebekeleri için 68 $/kişi, atıksu toplama şebekesi için ise 254 $/kişi’dir. Çalışmada elde edilen özgül maliyet verilerinin yatırım planlamalarında değerlendirilmesinde yol gösterici olması beklenmektedir.

Retrofitting of Five Preliminary Wastewater Treatment Plants in Istanbul (Turkey) to High-Rate Activated Sludge System and/or Post Oxidation

ABSTRACTThis study investigated the environmental and technical feasibility of the high-rate activated sludge (HRAS) system and post oxidation for five large wastewater treatment plants (WWTPs) of Istanbul Water and Sewerage Administration (ISKI) already discharging effluents into the lower stratum of the Bosporus. A two-year HRAS pilot-scale study was conducted in ISKI Baltalimanı Preliminary WWTP and the results from a semi-technical scale chemical post oxidation (by ozone and ozone + hydrogen peroxide) study were presented. It was found that the proposed treatment configuration is quite energy efficient and could remove chemical oxygen demand (COD) and total suspended solids (TSS) significantly.

Identification of free-living amoebae isolated from tap water in Istanbul, Turkey

Free-living amoebae (FLA) are widely spread in the environment and also known to cause rare but often serious infections. The present work focuses on a local survey on FLA. It is essential to know the prevalence and distribution of these microorganisms in order to get infections caused by them under control. In this study, FLA isolated from domestic tap water samples from homes of contact lens wearers were identified by morphology and by 18S rRNA gene sequence analysis. Morphological analysis and partial sequencing of the 18S rDNA revealed the presence of Acanthamoeba genotype T4 and Vermamoeba vermiformis in the investigated tap water samples. Naegleria fowleri, Balamuthia mandrillaris, and Sappinia spp. were not detected during this study. It was shown that species of FLA known to cause eye infections in humans are widely distributed in tap water in Istanbul, Turkey. Contact lens wearers should be aware of the risk of contamination from tap water and strictly apply stringent contact lens hygiene. With this study, we established Acanthamoeba genotype T4 and Vermamoeba vermiformis as contaminants of tap water in Istanbul.

Fungal contaminants in man-made water systems connected to municipal water.

Water-related fungi are known to cause taste and odor problems, as well as negative health effects, and can lead to water-pipeline clogging. There is no legal regulation on the occurrence of fungi in water environments. However, much research has been performed, but further studies are needed. The main objectives of this study were to evaluate the fungal load and the presence of mycotoxigenic fungi in man-made water systems (for homes, hospitals, and shopping centers) connected to municipal water in Istanbul, Turkey. The mean fungal concentrations found in the different water samples were 98 colony-forming units (CFU)/100 mL in shopping centers, 51 CFU/100 mL in hospitals, and 23 CFU/100 mL in homes. The dominant fungal species were identified as Aureobasidium pullulans and Fusarium oxysporum. Aflatoxigenic Aspergillus flavus and ochratoxigenic Aspergillus westerdijkiae were only detected in the hospital water samples. Alternaria alternata, Aspergillus clavatus, Aspergillus fumigatus, and Cladosporium cladosporioides were also detected in the samples. The study reveals that the municipal water supplies, available for different purposes, could thus contain mycotoxigenic fungi. It was concluded that current disinfection procedures may be insufficient, and the presence of the above-mentioned fungi is important for people with suppressed immune systems.

Batch cultivation of marine microalgae Nannochloropsis oculata and Tetraselmis suecica in treated municipal wastewater toward bioethanol production

Algae have come into prominence over the last decade as a commercial biofuel feedstock due to their high production efficiencies compared to first and second feedstocks. However, algal investment is not economically feasible currently due to the operational and capital cost. There is still need for innovations for both high productivity and green productions. In order to decrease the cost of the algal processes, usage of some wastes as cultivation medium for algal productions and novel biofuel production methods should be considered according to green chemistry principals. In this study, seawater and wastewater supplied from Istanbul Water and Sewerage Administration (ISKI) were used and combined at different ratios to be utilized as a growth medium for Nannochloropsis oculata and Tetraselmis suecica microalgae strain under the same growth conditions, and its effect on cell proliferation and growth kinetics were investigated. It was found that, both N. oculata and T. suecica can tolerate and utilize the wastewater and, the specific growth rate of the cultures can up to 0.5430 d−1 (75% of wastewater) for N. oculata and 0.4778 d−1 (25% of wastewater) for T. suecica. Different concentrations show different results for the growth of two species due to the effect of higher concentrations of the fundamental sources on growth stage and change of ionic composition of the culture medium. To evaluate bioethanol production performance of these two strains, samples which included maximum carbohydrate content as well as control groups were chosen for further studies. The results showed that T. suecica is much suitable for ethanol production using municipal wastewater as a culture medium.

Perchlorate Exposure Through Water and Milk in Istanbul.

Perchlorate is a chemical pollutant that inhibits iodide uptake and may possibly impair thyroid function. Our previous study found widespread perchlorate exposure in non-pregnant, non-lactating, healthy women residing in Istanbul. The aim of this study is to assess the relative amounts of perchlorate exposure attributable to consumption of municipal water, bottled water and boxed milk available in Istanbul. Only trace levels of perchlorate were found in treated municipal water (58% detectable, mean=0.13µg/L, maximum=0.75µg/L) and bottled water (7.4% detectable, mean=<LOD, maximum=0.19µg/L). Conversely, all 30 boxed milk samples contained measurable levels of perchlorate (mean=4.53µg/L; maximum=6.21µg/L). Median perchlorate exposure attributable to water and milk (0.007µg/kg/day) is small compared both to the reference dose (0.7µg/kg/day) and to total perchlorate exposure (0.13µg/kg/day) in Istanbul. Therefore, additional studies are needed to identify the major sources of perchlorate exposure in Istanbul.

Amoebicidal efficacy of a novel multi-purpose disinfecting solution: First findings

Free-living amoebae of the genus Acanthamoeba can cause a sight-threatening corneal infection, Acanthamoeba keratitis, mostly in contact lens wearers. The use of ineffective contact lens disinfecting solutions is one of the most important risk factors for this infection. This study concerns a new multi-purpose contact lens disinfecting solution, OPTI-FREE® PureMoist®, tested for its efficacy against Acanthamoeba trophozoites and cysts by using the most probable number technique for amoebic enumeration. Acanthamoeba castellanii ATCC 50373 and an environmental strain of Acanthamoeba genotype T4 isolated from tap water in Istanbul were used during the experiments. OPTI-FREE® PureMoist® achieved total kill (more than a 3-log reduction) of trophozoites of both strains before the manufacturer-recommended disinfection time (6h). In contrast, this solution had limited cysticidal activity against the ATCC strain but more against the environmental strain, with log reductions of 0.75 and 2.20, respectively, after 6h of exposure.

Urban climate change impact and Istanbul Water Consensus

Climate change impacts especially on major cities of the world are expected to cause inter-sectoral interactions concerning environmental, socio-economic, cultural, and technological developments and their implementations. This paper presents a methodology to predict future monthly rainfall amounts and surface runoff volumes on decadal basis from 2000–2050 and accordingly interpretation of monthly dry and wet periods, which are the most important gradients for the management of future water supply problems in major cities. It also presents significant articles for combating the climate change impacts on major cities through Istanbul Water Consensus Local and Regional Authorities Declaration on the occasion of the Fifth World Water Forum in Istanbul, which expressed the awareness and responsibility of local and regional leaders concerning climate change impacts on major cities.

Analysis, occurrence and fate of commonly used pharmaceuticals and hormones in the Buyukcekmece Watershed, Turkey

The occurrence of 14 mostly used pharmaceuticals from different classes (antibiotics, β-blockers, non-steroidal anti-inflammatory drugs, and stimulant) and hormones in surface water in Istanbul, Turkey was investigated in this study. An important drinking water source, Buyukcekmece Lake and main rivers flowing into the lake were selected for the monitoring of the compounds. Sampling was conducted five different times in a year in order to observe seasonal changes. A rapid, robust and sensitive method using solid phase extraction and ultra-performance liquid chromatograph coupled with triple quadrupole tandem mass spectrometer was established for quantification of both pharmaceuticals and hormones. Limit of quantifications were between 0.5 and 1.1ngL−1. Recoveries were between 72–119% and 61–98% for ultra-pure water and for surface water, respectively. All selected compounds were detected at least once in the samples. Some pharmaceuticals were detected as high as a few of micrograms per liter levels in the rivers. Most frequently detected compounds were caffeine and antibiotics (amoxicillin, ciprofloxacin, erythromycin and sulfamethoxazole). Synthetic hormone (17α-ethynylestradiol) was detected only 4times corresponding least detected compound in whole sampling period. Field data confirms that amoxicillin is more prone to degradation with respect to other antibiotics. Estrone and 17-β estradiol are converted to estriol by natural processes in surface water.

A comparative study on the control of disinfection by-products (DBPs) and toxicity in drinking water

In this work, ozone oxidation combined with ferric chloride and aluminum sulfate (Alum) coagulations was employed to investigate the optimum conditions for the control of the toxicity to Daphnia magna and Pseudokirchneriella subcapitata and disinfection by-products (DBPs) formation potential of Buyukcekmece (BC) lake water in Istanbul, Turkey. The effi ciency of the treatment was determined by means of UV absorption at 254 nm (UV254) and dissolved organic carbon (DOC) parameters. Four species of trihalomethanes (THMs) and eight species of haloacetic acids (HAAs) were identified and quantifi ed for the evaluation of treatment methods on the formation of DBPs. It was observed that pre-ozonation enhanced DOC removal efficiency of alum and ferric chloride coagulations. 40 mg/l optimal alum and ferric chloride doses respectively exhibited 51% and 56% DOC reduction after 5 min pre-ozonation. As a result, THMs formation potential (THMFP) decreased approximately 43% after ozone enhanced alum and ferric chloride c...

Monitoring Differential Urbanization to Integrate with Basin Management and a Basin Information System Modeling for Istanbul

This article intends to give the outline of a basin information system to be generated and managed in order to monitor the increase of urbanization and trend of pollution potential over seven major basins (watersheds) of Istanbul, Turkey. The data from basin monitoring studies of Istanbul Water and Wastewater Management Authority (Istanbul) was used to evaluate the differential settlement and construction. After the urbanization increase is evaluated by means of building/facility areas, the pollution trends are assessed for different time intervals in terms of five parameters by making certain unit load assumptions. The results indicate that residential settlement increased 0.124–0.003% during 29 months. Also in the same period, mean pollution potential of the basins is found to increase 8.747, 3.578, 5.970, 0.922, and 0.145 in terms of tons/day for Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Suspended Solids (SS), Total Kjeldahl Nitrogen (TKN), and Total Phosphorus (TP), respectively, considering domestic wastewater and diffuse pollution loadings (from urban runoff and feedlots). These results state that monitoring of basins, especially those exposed to intense urbanization, must be conducted periodically and continuously by means of the basin information system as the first step to be able to control the pollution and to take measures against the threats that come with urbanization.

Critical evaluation of wastewater treatment and disposal strategies for Istanbul with regards to water quality monitoring study results

Urban Wastewater Treatment and Marine Outfall Facilities are being planned in accordance with Istanbul Water Supply and Wastewater Treatment and Disposal Master Plan prepared for Istanbul Water and Sewerage Administration (ISKI) in 1999. According to the Master Plan, ISKI initiated in 1996 the water quality monitoring program of receiving water bodies conducted by the Istanbul University (IU) Institute of Marine Sciences and Management and Istanbul Technical University (ITU) Environmental Engineering Department. The monitoring program has been carried out for 10 years in 28 stations in the marine environment. In this paper, the results of experimental investigations conducted for parameters including dissolved oxygen, total organic carbon (TOC), particulate organic carbon (POC), Total-N, Total-P, chlorophyll a, structure of benthic community, turbidity and coliforms have been critically analysed taking into consideration the marine outfall and surface water discharges from Istanbul's major wastewater treatment plants together with the transboundary pollution sourced by the Black Sea. The studies reveal that the water quality in the Marmara Sea is deteriorated more than anticipated before, and it is a necessity to develop international cooperation aimed for taking more effective measures in the area.

Investigation of bromide ion effects on disinfection by-products formation and speciation in an Istanbul water supply

Recent epidemiological studies reported that brominated DBPs may be more carcinogenic than their chlorinated analogs. Thus, this research was designed to investigate the role of bromide ion in the formation and speciation of disinfection by-products (DBPs) during chlorination of Buyukcekmece Lake Water (BLW) in Istanbul. Chlorination of BLW samples was carried out at pH 7.0 with 5 and 12 mg/l chlorine dosages. For each chlorine dosage, six bromide concentrations ranging from 0.05 to 4.0 mg/l were added to form a 2 × 6 experimental matrix. In general, increasing bromide concentration gradually shifted trihalomethanes (THMs) and haloacetic acids (HAAs) speciation from chlorinated species to the mixed bromochloro species during chlorination. The halogen substitution ability of HOBr and HOCl during the formation of THMs and HAAs can be estimated through the use of probability theory. It was concluded that, in both halogen substitution for THM and dihalogenated HAA formation, HOBr was found to be 20 times more reactive than HOCl.

Prevalence and Antimicrobial Resistance Patterns of Aeromonas Strains Isolated from Drinking Water Samples in Istanbul, Turkey

The aim of this study was to determine the prevalence and the resistance patterns of Aeromonas spp. in drinking water in Istanbul, Turkey. We investigated a total of 1,680 drinking water samples (840 tap water and 840 domestic water tank samples) for Aeromonas strains between June 2002 and October 2005. A total of 147 Aeromonas strains were isolated from 49 (6%) of 840 tap water samples and from 98 (12%) of 840 domestic water tank samples. Antibiotic susceptibility of Aeromonas strains was determined by the disc diffusion method, according to the CLSI (Clinical Laboratory Standards Institute) recommendation. Among the 147 Aeromonas strains, the prevalence was: A. hydrophila 68 (46%), A. sobria 50 (34%), A. caviae 11 (8%), A. salmonicida 9 (6%), A. veronii 5 (3%) and A. jandaei 4 (3%). Approximately 55% of the strains were resistant to ampicillin, 48% to erythromycin, 41% to amoxicillin-clavulanic acid, 28% to ceftazidime, 27% to cefoxitin, 26% to ceftriaxone and cefotaxime, 22% to piperacillin, 14% to trimethoprim-sulfamethoxazole, 12% to tetracycline, 11% to aztreonam, 8% to meropenem, 6% to imipenem, 2% to nalidixic acid, 1% to ciprofloxacin, tobramycin and gentamicin. None of the strains were resistant to amikacin and netilmicin. In conclusion, Aeromonas spp. isolated from drinking water in Istanbul have a resistance potential and the antibiotic resistance rates of A. hydrophila, A. sobria and A. caviae were usually higher than those of other Aeromonas strains. It should be kept in mind that these microorganisms in drinking water might be a potential risk for public health.

Disinfection by-product precursors reduction by various coagulation techniques in Istanbul water supplies

Coagulation process can be used to control natural organic matter (NOM) during drinking water production. The effectiveness of the coagulation process appeared to depend on the pH of coagulation rather than coagulant dosages. Jar tests conducted with depressed pH levels at different coagulation conditions removed more dissolved organic carbon (DOC) than those at moderate pH levels. For low DOC waters, like Omerli Lake Water (OLW), additional treatment would be necessary to achieve enhanced removal of NOM. In this study, three different coagulation techniques were used to remove disinfection by-products (DBP) precursors from three Istanbul surface water supplies. Jar test results indicate that optimize coagulation (OC) can enhance the removal of DBP precursors, and the removal of DOC could be improved from the current average of 15% to an average of 56% at the three sites tested. At lower pH, ferric coagulants generally performed better for removal of DBP precursors than did alum.