Water taste and odor (T&O): challenges, gaps and solutions from a perspective of the WaterTOP network.

Aesthetic aspects of drinking water, such as Taste and Odor (T&O), have significant effects on consumer perceptions and acceptability. Solving unpleasant water T&O episodes in water supplies is challenging, since it requires expertise and know-how in diagnosis, evaluation of impacts and implementation of control measures. We present gaps, challenges and perspectives to advance water T&O science and technology, by identifying key areas in sensory and chemical analysis, risk assessment and water treatment, as articulated by WaterTOP (COST Action CA18225), an interdisciplinary European and international network of researchers, experts, and stakeholders

First Report of Cylindrospermopsin Production by Two Cyanobacteria (Dolichospermum mendotae and Chrysosporum ovalisporum) in Lake Iznik, Turkey

Cylindrospermopsin (CYN) is a cytotoxic alkaloid produced by cyanobacteria. The distribution of this toxin is expanding around the world and the number of cyanobacteria species producing this toxin is also increasing. CYN was detected for the first time in Turkey during the summer months of 2013. The responsible species were identified as Dolichospermum (Anabaena) mendotae and Chrysosporum (Aphanizomenon) ovalisporum. The D. mendotae increased in May, however, C. ovalisporum formed a prolonged bloom in August. CYN concentrations were measured by LC-MS/MS and ranged from 0.12 µg·mg−1 to 4.92 µg·mg−1 as dry weight, respectively. Both species were the only cyanobacteria actively growing and CYN production was attributed solely to these species. Despite CYN production by C. ovalisporum being a well-known phenomenon, to our knowledge, this is the first report of CYN found in D. mendotae bloom

Comparative study of periphyton colonisation on common reed (Phragmites australis) and artificial substrate in a shallow lake, Manyas, Turkey

Colonisation of epiphytic algae on the common reed (Phragmites australis) and on glass slides were studied during a twenty-four week exposure period in a shallow, turbid lake, Manyas (Bird Paradise), western Turkey. Slides were used as substrate and positioned near the reed stands. To understand the effect of light on the colonisation of periphyton on P. australis and artificial substrates, three perspex frames (each frame consisted of 60 glass slides) were positioned at depths of ca. 25 cm, 50 cm and 75 cm, called 'upper', 'middle', and 'lower section', below the water surface. For the determination of periphyton and chlorophyll a content three new stems, which were cut above the rhizomes and subdivided into 25 cm, and three slides were taken from the each frame at four-weeks intervals. The rapid increase was recorded in algal species richness and biovolume on P. australis, whereas relatively slow colonisation was observed on glass slides. Filamentous centric diatoms, (mainly Aulacoseira italica and Melosira varians) was the dominant group, accounting for 29 to 82% of the total algal biovolume, and adnate diatoms (Surirella spp.), filamentous, and Chlorococcal chlorophytes (Pediastrum spp. and Oedogonium spp.) were the subdominant groups on the artificial substrate during the colonisation period. Pennate diatoms, mainly prostrate/motile and filamentous diatoms (Navicula tripunctata, Navicula radiosa, and Aulacoseira muzzanensis), and filamentous cyanobacterium (Planktolyngbya linmetica) were recorded as dominant groups on the reeds. Generally, epiphytic algal biomass was higher upon P. australis than upon glass slides. However, after the twelfth week colonisation biomass increased less than on earlier stages on the P australis. Total algal biovolume was positively correlated with chlorophyll a and with Soluble Reactive Phosphorus (SRP), and negatively correlated with the water level and Secchi disc depth

Factors influencing the phytoplankton steady state assemblages in a drinking-water reservoir (Omerli reservoir, Istanbul)

In this study, algal assemblages, phytoplankton biomass, chlorophyll-a and selected physico-chemical parameters were investigated in a drinking water reservoir in Omerli, Istanbul from October 1999 to November 2000. Water samples were collected from three sampling stations at the surface, a depth of 1 m and at 5 m depth intervals to the bottom (approximately 20 m). Particular attention was given to the ecology of steady state phytoplankton assemblages. When the euphotic depth (z(eu)) was less then 1.52 m and the ratio of the euphotic to mixing zone (z(eu)/z(mix)) was 0.2 m ( during October 1999 and September and October 2000), Microcystis aeruginosa Kutz. dominanted, accounting for 85-95% of the total phytoplankton biomass. A shift to Fragilaria crotonensis Kitton and Asterionella formosa Hass. occurred during April and early May 2000 when z(eu)>4.1 m. Other dominant species were Coelastrum microporum Nag. Pediatrum boryanum (Turp.) Menegh. and P. duplex (May to mid June 2000); C. microporum, Staurastrum spp. and Cryptomonas spp. (late June to mid July 2000); and Scenedesmus spp., S. gracile and Nitzschia holsatica Hust. (late July to late August 2000). Below 10 meters, a high biomass of Mougeotia sp. was recorded at all sites. However, in October and early November 2000, this species appeared in the surface water. During late May to late August 2000, the z(eu) depth changed between 2.7 and 3.38 m. pH and total organic carbon (TOC) concentrations were found to be relatively high in the surface waters, whereas total phosphorus (TP) and Soluble Reactive Silicate (SRSi) concentrations were high below the 5 meters. The total nitrogen (TN) concentrations were high either in the surface waters or in deep layers. It is suggested that the observed increase in cell biomass of some species was controlled by the nutrient concentrations. The changes in the phytoplankton assemblages resulted in a reduction of the euphotic depth

Effects of water quality and hydrologic drivers on periphyton colonization on Sparganium erectum in two Turkish lakes with different mixing regimes

The aim of this paper is to determine and compare the environmental factors controlling vertical colonisation of periphyton on Sparganium erectum in a shallow eutrophic turbid lake, Manyas Lake, and an oligo-mesotrophic deep lake, Sapanca Lake, Turkey during the July 1997-November 1998. To investigate the effect of the environmental factors on periphyton colonization on S. erectum, the stem was cut above the rhizomes and subdivided into three equal sections. Multivariate statistical analyses have been applied to clarify relationships between environmental variables and periphyton colonization on S. erectum. Results indicated that physical disturbance and trophic level of the lakes influenced the colonization of the periphyton. Among the measured parameters, low light intensity, total suspended solids, temperature and water level fluctuation were observed as driving factors in Manyas Lake whereas nutrient deficiency was found as key factor in Sapanca Lake. The zonation of the periphyton, density, composition and dominant/subdominant taxa were significantly different in these lakes. However, Oedogonium sp., Mougeotia sp., Cylindrocapsa sp., Cladophora glomerata (Linn.), Aulacoseira italica (Ehr.) Simonsen, Melosira varians C. Agardh, Navicula tripunctata (O.F. Muller) Bory and Fragilaria ulna (Nitzsch) Lange-Bertalot were found as dominant species at all sections of S. erectum both in Manyas Lake and Sapanca Lake. It can be thought that these species have a broad range of tolerance to several physical, chemical and hydrologic disturbances. This is the first study to introduce how much the water quality and hydrologic drivers have affected vertical colonization of periphyton on S. erectum in two lakes with different mixing regimes

DO EUTROPHIC WATERS PROMPT TO TOXIC CYANOBACTERIA IN TURKISH BLACK SEA COAST?

Cyanobacteria is known to form harmful blooms in fresh and brackish waters and also marine environments. Cyanobacteria blooms generally are the indicators of eutrophication in freshwaters as well as estuaries and marine ecosystems. European Environmental Agency rated the eutrophication in the Black Sea as highest concern in 1995. Since the Turkish coastline is also under the pollution risk, the present study was conducted to investigate whether toxic cyanobacteria were present and pose any risk hazard. Samples were taken in five sites along the Turkish coast between Igneada to Samsun, ca 928.5 km long between May October 2012 to investigate the potential of toxic cyanobacteria presence. Twenty eight samples from surface waters were analysed using 16S rRNA and sixteen of them were positive. Cyanobacteria was detected every sampling date in Sakarya river vicinity both microscopically and PCR method. BEP-PCR was used to detect the toxin genes and four samples gave positive results. In contrast, no hepatotoxin was detected with ELISA

Depth profiles of protein-bound microcystin in Kucukcekmece Lagoon

Microcystis is the most commonly found toxic cyanobacterial genus around the world and has a negative impact on the ecosystem. As a predominant producer of the potent hepatotoxin microcystin (MC), the genus causes outbreaks in freshwaters worldwide. Standard analytical methods that are used for the detection of microcystin variants can only measure the free form of microcystin in cells. Since microcystin was found as free and proteinbound forms in the cells, a significant proportion of microcystin is underestimated with analytical methods. The aim of the study was to measure protein-bound microcystins and determine the environmental factors that affect the binding of microcystin to proteins. Samples were taken at depths of surface, 1 m, 5 m, 10 m, 15 m, and 18 m in Kucukcekmece Lagoon to analyze depth profiles of two different microcystin forms from June to September 2012 at regular monthly intervals. Our findings suggest that the most important parameter affecting proteinbound microcystin at surface water is high light. Due to favorable environmental conditions such as temperature, light, and physicochemical parameters, the higher microcystin contents, both free and protein-bound MCs, were found in summer periods

Planktothrix rubescens: a perennial presence and toxicity in Lake Sapanca

Cyanobacteria are expected to adjust to new conditions better than other primary producers since they have a long history of adaptation as one of the first organisms on earth. Their ecophysiological adaptations differ widely among cyanobacterial species. As a stratified species, P. rubescens forms a population in the metalimnion during summer months in lakes with clear water and disperses in the whole water column during the period. However, after a dry season in 2006 and 2007, a prolonged surface bloom in late winter was observed in Lake Sapanca The maximum biomass of P. rubescens reached 13.9 mg L-1 in surface water in February 2007 and microcystin concentrations varied between 0.12 and 8 mu g L-1 MC-LR equiv. in the open water throughout the year. The maximum microcystin value was measured at 79 mu g L-1 when accumulations of filaments were observed on the shoreline. As P. rubescens is a shade-adapted species, lower insolation in February together with stable water conditions and lower water temperature promoted the surface bloom. In conclusion, the presence of toxic P. rubescens throughout the year with changing depths poses severe health hazards to people and also an economic burden to the water treatment facility, since the lake is used as a drinking-water reservoir

Planktothrix rubescens: a perennial presence and toxicity in Lake Sapanca

Cyanobacteria are expected to adjust to new conditions better than other primary producers since they have a long history of adaptation as one of the first organisms on earth. Their ecophysiological adaptations differ widely among cyanobacterial species. As a stratified species, P. rubescens forms a population in the metalimnion during summer months in lakes with clear water and disperses in the whole water column during the period. However, after a dry season in 2006 and 2007, a prolonged surface bloom in late winter was observed in Lake Sapanca The maximum biomass of P. rubescens reached 13.9 mg L-1 in surface water in February 2007 and microcystin concentrations varied between 0.12 and 8 mu g L-1 MC-LR equiv. in the open water throughout the year. The maximum microcystin value was measured at 79 mu g L-1 when accumulations of filaments were observed on the shoreline. As P. rubescens is a shade-adapted species, lower insolation in February together with stable water conditions and lower water temperature promoted the surface bloom. In conclusion, the presence of toxic P. rubescens throughout the year with changing depths poses severe health hazards to people and also an economic burden to the water treatment facility, since the lake is used as a drinking-water reservoir