Golden Horn Research Articles

Presence and distribution of selected pharmaceutical compounds in water and surface sediment of the Golden Horn Estuary, Sea of Marmara, Turkey

The presence and distribution of ketoprofen, fenoprofen, diclofenac ibuprofen, naproxen, gemfibrozil, clofibric acid, estrone, 17β-estradiol, 17α-ethinylestradiol, and carbamazepine were investigated in water and surface sediment of the Golden Horn Estuary (Sea of Marmara, Turkey). Water samples were collected seasonally from different depths in nine sampling stations. Surface sediment samples were taken at four stations once a year. Liquid–liquid and solid-phase extraction (SPE) methods were performed on water samples. Sediment samples were extracted by ultrasonic extraction and then SPE method was applied for clean-up. Subsequently, all samples were analyzed by High-Performance Liquid Chromatography (HPLC). The most dominant compounds were found as gemfibrozil (<0.054-3.18 μg L−1), fenoprofen (<0.017-1.28 μg L−1), ibuprofen (<0.015-2.46 μg L−1) and 17α-ethinylestradiol (<0.010-1.49 μg L−1) in water samples. Only five of these eleven studied pharmaceuticals in surface sediments of the Golden Horn Estuary were able to identify. 17α-ethinylestradiol (319 ng g−1), fenoprofen (242 ng g−1), ibuprofen (215 ng g−1), gemfibrozil (124 ng g−1), carbamazepine (118 ng g−1) were detected in the surface sediments. Diclofenac, ketoprofen, naproxen, clofibric acid, estrone and 17β-estradiol were found below the method detection limits in surface sediments. Generally, the environmental concentrations of pharmaceuticals in water and surface sediment were much higher than those reported worldwide.

Community Structure of Tintinnids (Protozoa: Ciliophora) in the Eutrophic Environment (the Golden Horn Estuary, Turkey)

Community Structure of Tintinnids (Protozoa: Ciliophora) in the Eutrophic Environment (the Golden Horn Estuary, Turkey)

A Landscape Matrix Proposal For Haliç (Golden Horn) Coastal Zone

The impacts of urbanization on landscapes andecosystems have been increasing globally. Howurban landscape is shaped, in other wordsdesigned, is a fundamental human activity interms of urban sustainability. Landscape is oftendealed with mostly by aesthetic concerns whichpresents sustainable/ecological/naturalqualities only at formal level, is limited bylegislative framework, hardly responds tohuman needs and behavioral patterns and lacksa holistic approach within the Turkish spatialdesign practice. This study aims to develop alandscape matrix in the example of Istanbul(Golden Horn) region as an open spaceoperation model within the existing urbantexture, which the built environment has beenrepresented with different layers of historicaldevelopments. The matrix presented in thisstudy presents a design process on the basis ofurban ecology as well as the physical and socialrelations of the study area located in the GoldenHorn, one of the cultural identity values ofIstanbul, formed by urban layers belonging todifferent historical periods. It is thought that theconstruction of the coastal and hinterlandrelationship through the open space system bothcontributes to the dissolution of the urbantexture towards the coastal zone andstrengthens the character of the waterfront.

Golden Horn Unkapanı Highway Tube Tunnel – Istanbul: Underwater bridge design in seismic environment

The Golden Horn in Istanbul is being crossed by several bridges, one of them to be replaced by a tunnel. The river has a steep profile with densely populated banks. Because of the planned connections to the boulevards, traditional solutions (immersed tunnel in a trench, TBM tunnel) proved not feasible. Commissioned by the Istanbul Metropolitan Municipality (IBB), Arcadis designed a shallow tunnel above the river bed. Because of the severe seismic conditions, the ability to respond to dynamic soil displacements without leakage or collapse was key in the design. The basic design philosophy was ‘limited flexibility’: flexible enough to follow the movements without build-up of detrimental forces, but limited in order to avoid detrimental joint openings. The reference design was supported by piers consisting of steel tubes founded in the bedrock, 30–50 m below the tunnel axis. The tunnel would consist of short immersion elements, connected to the transition structures with a flexible seismic joint. The contractor followed the same design philosophy, but chose for longer elements to reduce the number of immersion operations. Additionally, the contractor proposed a design alternative in the form of an SFT (submerge floating tunnel), which could have been the very first SFT in the world. Because of changing economic and political situation, the project was put on hold after contract close.The article describes the reference design, the bid design and the design alternative with emphasis on the seismic influence on general concept, details and construction methodology.

Microplastic inventory in sediment profile: A case study of Golden Horn Estuary, Sea of Marmara

Assessment of microplastics (MPs) in sediment cores is necessary to unveil global plastic pollution since most of the plastic litter might have been stored in sediment columns. In the current study, MPs inventory was determined in a 105 cm sediment core, collected in the Golden Horn Estuary, Sea of Marmara. Radiodating of sediment profile by using naturally occurring 210Pb and fission product 137Cs allowed us to couple the retrospective of global MP production to sediment MPs inventory. More than 90% of total MPs inventory was found in the deep layer of the sediment column (below 15 cm). Small MPs (20–200 μm) were more abundant than large ones (200–4000 μm). Elevated concentrations of MPs were attributed to industrial and municipal effluent of Istanbul metropolitan. On a local scale, this study suggests that the Golden Horn Estuary was polluted with MPs before the 1950s, and the abundance of MPs reached a maximum in the 1980s. We also propose on a global scale that “the missing” plastics might have been buried in deep sediment and radiodating of sediment is useful to reveal their historical input records.

Polished Memories, Liquid Histories: A Meditation on Istanbul’s Sveti Stefan Church

On an embankment in the Istanbul neighborhood Fener-Balat, a striking edifice looms over the waters of the Golden Horn: Sveti Stefan Church, a cast-iron house of worship that constitutes the most visible legacy of Ottoman Istanbul's Bulgarian Orthodox community. The warm welcome that one is likely to receive at the visitor's cubicle near the entrance to the church contrasts sharply with its solemn architectural atmosphere. Since the completion of renovations in 2018, the so-called Iron Church is open to visitors as a site that celebrates a multicultural image of the Ottoman past. In this essay, I meditate on the convoluted history of Sveti Stefan and its community in order to unsettle the sanitized collective memory and discourse of interreligious tolerance that has come to rest in the church today.

Microplastic pollution in seabed sediments at different sites on the shores of Istanbul-Turkey: Preliminary results

Despite recent increase in microplastics-related studies, little is known about their abundance in seabed sediment areas. However, the quantity of microplastics (MPs) in sediments is imperative for an overall understanding of worldwide MPs pollution. To address the above-mentioned gap, this study was performed on 43 seabed sediment stations from the Marmara Sea of Turkey. Studied stations vary between marine (MRN), pier (PIER), stream (STR), sea discharge (SD), and deep-sea discharge (DSD) stations. Collected seabed sediment samples were analyzed for MPs abundance, shape, size and color distribution. Besides, an investigation on the effect of sea depth on MPs' total abundance, size, and shape was investigated using Pearson's and Spearman's product momentum correlation coefficient. Empirical data analysis showed that the highest MPs abundance at STR stations changed between 1956.5 ± 3031.8 and 3256.2 ± 5168.2 particle/kg (dry weight: d.w.) for small MPs particles (SMP) and large MPs particles (LMP), respectively. Contrarily, the lowest abundance was found as 224.8 ± 423.05 and 287.68 ± 218.6 particle/kg (d.w.) for SMP and LMP fractions, respectively at DSD stations. The MPs abundance were found at 5 categorized stations in the following order; STR>PIER>MRN>SD>DSD, noted that the highest MPs quantity was found at STR-6 station located in Golden Horn. The isolated MPs were predominantly filament and fragment in shape (42.34 ± 6.10% and 33.91 ± 6.92%), blue and white in color (40.46 ± 4.66% and 24.75 ± 3.83%). Mean MPs abundance was determined to be 1957.37 ± 4079.96 particle/kg (d.w) at all 43 stations and sizes between 1 and 5 mm was found to be predominant at depths between 5 and 71m. Furthermore, a negative correlation was found between sea depth and parameters such as total MPs abundance, shape, and size. The overall results revealed the widespread presence of MPs in the seas surrounding Istanbul.

Main tendencies of temporal changes for concentration of priority pollutants in sediments of the coastal areas at Vladivostok (Peter the Great Bay, Japan Sea)

Concentrations of hydrocarbons, phenols, DDT and its metabolites, Cu, Pb, Fe, Ni, DDD/DDE and DDD+DDE/DDT ratios, and total level of chemical contamination (TPF index) in the bottom sediments are traced for 16 stations in the coastal areas at Vladivostok in 1982−2017. Temporal variations of the concentrations and derived indices are classified to 4 types of dynamics, using the methods of exploratory and confirmatory factor analysis, crosscorrelation analysis, and fuzzy set classification procedure. They are: primary contamination; secondary contamination; exponential growth; and polymodal dynamics. These variations are induced by two main sources of pollution, such as the industrial influx including wastes from Vladivostok and nearby settlements, aeolian transfer and polluted precipitations, and the terrigenous influx with polluted freshwater discharge. Impact of the first source prevails in the Golden Horn Bay, Diomid Inlet and Eastern Bosphorus Strait, and the second source is important for the Amur and Ussuri Bays (the coast of Vladivostok in these bays is influenced by both sources with predominance of the second). The terrigenous impact has two modes depended on certain processes of contamination: the permanent pollution inherent in the types of secondary contamination and exponential growth and the extreme pollution that forms the polymodal dynamics. The secondary contamination follows the primary one with a lag of 6–7 years. The secondary contamination of terrigenous usually has inverse correlation with the Razdolnaya/Suifen River discharge; for instance, strengthening of the freshwater inflow causes lower concentrations of Cu and Pb in the bottom sediments due to dilution effect. On the contrary, contamination depends directly on the Razdolnaya/Suifen River discharge for the exponential growth of terrigenous — the stronger the freshwater inflow, the higher the concentrations of Fe, Ni, and phenols (the latter is a sign of eutrophication). The types of dynamics change following the balance between pollution and self-cleaning of the sediments that is determined by external factors, as a drop in economic activity and its subsequent recovery, limitation and finally ban for using of tetraethyl lead additive, extreme floods on rivers, etc.

Settling particles in the Golden Horn estuary, Sea of Marmara: Concentrations and fluxes of trace elements and radionuclides

The Golden Horn estuary, which is located along the Sea of Marmara adjacent to the center of Istanbul, has been heavily polluted for centuries due to concentrated shipping activities, and a legacy of industrial and municipal discharges. The municipalities and associated governments have implemented environmental rehabilitation projects for over 25 years. However, the Golden Horn estuary is still exposed to various pollutants such as vehicle emissions including from fossil-fuel combustion. In this study, two sediment traps were deployed in the Golden Horn estuary to obtain information on settling particle (SP) composition and fluxes, trace element and radionuclide concentrations, and fluxes thereof. Conventional sediment traps (Trap-1 and Trap-2) were installed side-by-side, at a depth of 15-m and moored for 18 months during which time the sediment traps were periodically sampled. Over this time period, settling particle fluxes (SPFs) were calculated. The concentrations and fluxes of radionuclides (137Cs, 226Ra, 228Ra, 210Po, and 210Pb) and trace elements (Ag, Al, As, Cd, Cu, Fe, K, Mn, Mo, Ni, Pb, Sb Sn, Tl, V, and Zn) were determined in SPs for each sampling period. Normalized enrichment factors (EF) and a Geoaccumulation Index (Igeo) showed that Ag, Cd, and Pb were statistically enriched in SPs. Together, the results of this study show that the Golden Horn estuary is still enriched in some environmental pollutants which could be a source term for the water column and associated marine animals.

Dewatering of Golden Horn sludge with geotextile tube and determination of optimum operating conditions: A novel approach

Environmental concerns about Golden Horn's polluted sediments have led to 320,000 m3 of sea dredging, generated annually by bucket dredgers to be stored in landfills without dewatering. This study presents an efficient dewatering methodology and a beneficial alternative to store the sludge. In this scenario, the sludge of a suction-cutter dredger is transported to a pond. The beneficial use of geotextile tubes filled with the sludge at circumferential embankments of pond is evaluated. An anionic polyacrylamide (APAM) is used for conditioning the high plastic silt sludge with 10% solid content. APAM dosage is optimized by Rapid Dewatering Test (RDT) for geotextile material. Microscale SEM-EDS analyzes depicted the flocculated form of the sludge. Laboratory-scale Geotextile Dewatering Test (GDT) shows improvements in the turbidity of filtrate, the quantity of solid particles retained in the tube, and the filtration efficiency, determined to be 92 NTU, 18.5% and 90.5% respectively. In accordance with the ICP-OES analysis, the discharge of the filtrate to the aquatic media is admissible. Undrained shear strength of the dewatered sludge is assessed as low, by Vane and undrained unconsolidated triaxial compression tests. Further improvements of the dewatered sludge with vacuum preloading method were projected by completion of the consolidation tests.

Assessment of phytoplankton group composition in the Golden Horn Estuary (Sea of Marmara, Turkey) determined with pigments measured by HPLC-CHEMTAX analyses and microscopy

AbstractPhtytoplankton group composition determined by microscopy was compared with high performance liquid chromatography (HPLC) derived from pigment signatures in surface water samples taken bi-weekly and monthly between October 2018 and September 2019 in the Golden Horn Estuary (Sea of Marmara). A total of 80 eukaryotic phytoplankton taxa belonging to eight algal classes were identified in surface water during the study period. Forty-three taxa (54%) were diatoms, 29 taxa (36%) were dinoflagellates and eight taxa (10%) were other phytoflagellates. The average contribution of diatoms to total phytoplankton abundance decreased considerably (41 to 25%), while the average contribution of dinoflagellates and other phytoflagellates increased markedly (59 to 75%) from the lower to the middle estuary. Chlorophyll-a and seven other group-specific pigments, including fucoxanthin, peridinin, chlorophyll-c1 + c2, alloxanthin, 19′-hexanoyloxyfucoxanthin, 19′-butanoyloxyfucoxanthin and divinyl chlorophyll-a were identified in the study area. The relative contribution of the major phytoplankton groups to chlorophyll-a was estimated on three different initial ratio matrices by CHEMTAX. The results obtained were compared with those from microscopic examination. It was concluded that the CHEMTAX method was not accurate enough to characterize the phytoplankton community in the Golden Horn Estuary ecosystem and microscopic analysis was essential to determine the major contributing species to chlorophyll-a.

Urban resilience for transformation: Clustering of hospitality services in the Golden Horn region

In this study, the clustering trend of the accommodation along with the urban renewal process in the Golden Horn region in recent years is investigated. After the districts that are mainly chosen for tourism-oriented accommodation are determined, the location selection processes of accommodation is analyzed and the reasons behind the preference of said districts are examined. The present study aims to investigate the relationship between urban policies regarding the Golden Horn region and the location selection process and to detect how the factors affecting the preference of locations regarding tourism-oriented accommodation differ in different districts. In order to deduce the factors that play an active role in the clustering process in the region, first, the distribution pattern of the accommodation activities in the two sides of the Golden Horn and the districts that are mostly preferred were determined, and then the data obtained in the field studies from semi-structured questionnaires and in-depth interviews conducted with the people representing these facilities in the determined districts, namely Balat-Ayvansaray, and Sütlüce, were interpreted. The findings of the study revealed the following original results regarding the location selection process of the tourism function in the Golden Horn: i) It was determined that there has been an increase in tourism-oriented accommodation investments in the districts in the Golden Horn region in the last 5 years; ii) The tourism-oriented accommodation facilities tend to cluster in the Golden Horn region and are predominantly located in the districts of Balat-Ayvansaray and Sütlüce; iii) Factors affecting the location selection processes of investments in two different districts differ according to the characteristics of the districts and the qualifications and preferences of the visitors. While tourism-oriented accommodation facilities are clustered in certain districts in the Golden Horn region, the reasons for clustering and the quality of the facilities that clusters vary according to the advantages of the district and the preferences of the visitors. The spatial effects caused by clustering also differ according to districts. In addition, it is observed that the location selection for accommodation in Sütlüce supports urban renewal in the district. As a result of the findings of the study, it is understood that the clustering of accommodation activity in the Golden Horn plays an important role in increasing urban resilience.

Exchange of water and contaminants between the Strait of Istanbul and the Golden Horn

The Golden Horn (Estuary) is a hotspot for marine pollution because of its close proximity to the Strait of Istanbul (Strait) with dense maritime traffic and high pollution risk of oil spill. Transport and fate of water and contaminants in Strait and Estuary are analyzed by three-dimensional numerical models. Eddies forming at the Golden Horn junction (Junction), either on a single layer or distributed over the entire water column, block the water exchange partly or entirely across the Junction. In case of an oil spill in adjacent waters, the size and distribution of eddies at Junction control the transport and fate of contaminants inside Estuary. Using twenty test cases, the exchange flows at Junction are classified in four types based on sea level difference between north and south boundaries of Strait and Reynolds number of surface flow. Eddies may prevent the natural water exchange between Strait and Estuary but also block the contaminants penetrating to Estuary. Under predominant conditions of mild and moderate southward net flow in Strait, surface waters enter Estuary. During very strong southward flow, Junction is blocked to Black Sea water and surface contaminants. Strait hydrodynamics control water exchange with Estuary through eddy formation. When horizontal eddies are formed at Junction, their size and distribution control the transport and fate of contaminants in branching inlets and estuaries by blocking the water exchange either entirely or partly in specific layers.

Geomagnetic Survey for Solving Ecology Problems on Aquatory Seaport with High Level of Electromagnetic Noise (Golden Horn Bay, Peter the Great Gulf, Sea of Japan)

The crucial task of geomagnetic survey is detecting of magnetic anomalies coming from local object with ferromagnetic properties on aquatory seaport with high level of electromagnetic noise. We developed magnetic survey and data interpretation procedure which is necessary for expanding level of results authenticity under the conditions of limited size of aquatory and high vessel traffic. We used measuring equipment and software produced in Russia. Results of magnetic anomalies quantitative interpretation certified by side-scanning sonar and diver’s works.

Occurence and Variability of Domoic Acid in Mussel (Mytilus galloprovincialis) Samples from the Golden Horn Estuary, Sea of Marmara (Turkey).

The occurrence and variability of domoic acid (DA) levels in wild Mytilus galloprovincialis samples, compared with the Pseudo-nitzschia spp. abundance and particulate DA (pDA) concentrations in relation to the environmental changes in the Golden Horn Estuary, Turkey from October 2018 to September 2019. Biotoxin analysis were performed by high-performance liquid chromatography with diode-array detection (HPLC-DAD). DA concentrations in particulate matter (pDA) and mussel samples were found between 0.090-0.685µg L-1 and 0.905-2.413µgg-1, respectively. Accumulation of DA in wild mussel samples could be the result of the increasing tendency of P.nitzschia spp. abundances between April and May. Maximum DA levels were detected in particulate matter when the salinity was measured as the lowest in May. Thus, it can be said that the DA production was driven by the significant salinity decrease in the GHE. This is the first attempt regarding the presence of DA in M. galloprovincialis samples collected from Turkish coasts.

The cult of Saint Zotikos Orphanotrophos and his images in Byzantium and beyond

St. Zotikos Orphanotrophos acquired great renown in Constantinople owing to his efforts in the establishment of two singularly important philanthropic institutions in the Byzantine Empire - Orphanotropheion (??????????????) on the Acropolis of Constantinople and the Leprosarium in Pera (Golden Horn at Elaiones). The paper discusses an underexplored aspect of the veneration of St. Zotikos - his representations in art. It uses available liturgical sources, hagiographical testimonies and the scarce visual evidence to investigate and determine the reach of the cult of St. Zotikos Orphanotrophos, first in the wider framework of Eastern Christian art and then in Serbian medieval art.

The State of the Planktonic and Benthic Components of the Ecosystem of the Golden Horn Bay (Peter the Great Bay, Sea of Japan) in the Area of the Coal Terminal

Monitoring study of the state of the planktonic and benthic components of the ecosystem of the Golden Horn bay, Peter the Great Bay of the Sea of Japan in the area of the coal terminal was carried out in the autumn of 2020. Phytoplankton in the studied area was characterized by a depleted species composition. In September 2020, phytoplankton bloom was noted at the monitoring points, due to the massive development of diatom microalgae of the Chaethoceros genus, which accounted for 90% of the total phytoplankton. In November, the amount of phytoplankton was an order of magnitude lower, and the role of dinophytic algae increased in the community. Changes in the species composition and quantitative parameters of phytoplankton correspond to the seasonal dynamics in the eastern part of the Amursky bay, which is subject of anthropogenic pollution. Based on the study carried out, it can be concluded that the activities of the coal terminal in the Golden Horn bay had no effect on the structure of communities and, in general, there was no over-normative effect on the state of aquatic biological resources.

Transformation and Continuity of Sacred Places: The Case of Galata (Istanbul)

In historical city centers that are constantly inhabited for centuries, it is a predictable phenomenon that sacred places of different periods often share the same location. This is the case not only for the Historical Peninsula of Istanbul but also Galata, which is the former capital's another ancient district opposite the Golden Horn. Accordingly, Arap Mosque is perhaps the most renowned example to this issue that it shares the same location with two former churches from the Byzantine and Genoese periods. While similar origins of other monuments in Galata like Yeni Mosque have also been discussed by scholars, those cases lacked elaboration from a more comprehensive urban perspective. Following a historical research methodology for specific urban aims, it was seen that spatial connections between the shrines of Galata from its Byzantine, Genoese and Ottoman periods are even stronger on the same plots, which better display a spatial continuity within a historical urban layout for centuries. Moreover, it can be seen that even if a sacred place had a new function, some certain traces still reveal its origins, which stress the multilayered ancient settlement.

ADZHIDERE / HADZHIDERE: TO THE QUESTION ON THE OTTOMAN NAME OF THE VILLAGE OF OVIDIOPOL

The purpose of this article is to study the use of the Ottoman name of the modern village of Ovidiopol from the first mention of the settlement to its final renaming by the Russian government (1756 - 1794). The examples show the designation of the settlement in Ottoman-Turkish sources and the transformation of the name when translated into other languages and in particular into Russian. One of the first known written mentions of the name of Adzhidere can be found in Ottoman-Turkish sources of the middle of the XVIII century. from the Government Ottoman Archives in Istanbul. In particular, the oldest designation of the settlement on the site of the modern village of Ovidiopol is in an extract from the port log / defter, which contains information on loading and dispatching merchant ships from Adzhidere Pier to Istanbul's harbor Kapan-i Dakik - the coastal quarter in Golden Horn Bay. The annotation to this document states that the port log / defter is the register of loading and dispatch of grain from the port of Adzhidere since the beginning of the month of Muharram in 1170 AH, which corresponds to the date from September 26, 1756. In the report of the Russian intelligence of 1758 Ovidiopol is already mentioned as Gadzhidere. In particular, it is reported about the purchase of wheat and rye by Turks, Crimean Tatars, Nogai, Greeks and Wallachians, and its transportation to “different cities such as Ochakov, Belgorod and Hadzhidere, Bender, Kiliya, Smailov (Izmail) and the Wallachian city Iasi” The next source, with the designation Adzhidere, are the Ottoman-Turkish documents of the Governmental Ottoman Archive in Istanbul from the collection “State Administration”, dated 1765. The documents contain several different texts from public institutions and resolutions to be implemented. A number of sources of the next period of 1780-90s indicate the Ottoman name of modern Ovidiopol both Adzhidere and Hadzhidere. Thus, in the travel description of the French engineer Lafitte-Clave, who worked for the military department of the Ottoman Empire in 1784-87, “Hadzhi Dere” was mentioned. In the description of the Ochakov land made by the Russian engineer De Volan in 1791, it is said about Adzhidere after the Russo-Turkish wars. Such double names of settlements are sometimes found in Ottoman documents due to the ignorance of the Ottoman bureaucracy of toponyms of remote regions of the Ottoman state. Such a document is the Ottoman map of 1790, as evidenced by the content of inscriptions and explanations to the settlements. A new source has been put into scientific circulation - a cartographic image of the Dniester estuary with marked key settlements on its shores and defined areas of navigation through the estuary straits with the Black Sea.

Occurrence of a human-associated microbial source tracking marker and its relationship with faecal indicator bacteria in an urban estuary.

One of the main impacts of urban sprawl in rapidly growing countries has been contamination of coastal environments by waterborne pathogens, posing a critical risk to ecosystem and human health. Microbial source tracking (MST) has been a robust tool to identify the origin of these pathogens globally. This study compared the occurrence of a human-associated Bacteroides marker (BT-α) with faecal indicator bacteria (FIB) in an urban estuary (Golden Horn, Istanbul, Turkey). Faecal coliform (culture method), enterococci (both culture and qPCR method) concentrations and physicochemical variables were compared with the BT-α concentrations in monthly collected samples for a year (n=108). Enterococci concentrations detected by culture and qPCR were positively correlated (r=0·86, P<0·01) suggesting that qPCR can be an alternative method for monitoring. BT-α marker was positive for 30% of the samples and positively correlated with enterococci (r=0·61 and r=0·64 for culture and qPCR methods respectively, P<0·01). Rainfall had a moderate positive correlation with all faecal/MST indicators suggesting combined sewer overflows also severely impacted estuarine water quality. The high FIB and BT-α concentrations at upper estuary suggested that faecal pollution mainly originated from the peri-urban settlements around two creeks entering the estuary.