The Fouling Effect on Commercial Ceramic Membranes during Filtration of Microalgae Chlorella vulgaris and Monoraphidium contortum

Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (>70% and <50%), and steady-state permeate fluxes were <5% (for MF) and <25% (for UF) of initial (in m3 m−2 s−1) 6.2 × 10−4 (for MF) and 1.7 × 10−4 (for UF). Total resistances (in m−1) were in the ranges of 4.2–5.4 × 1012 (UF) and 2.6–3.1 × 1012 (MF) for M. contortum and C. vulgaris, respectively. DOC reduction was higher for UF membrane (>80%) than for MF (<66%) and DOC concentrations (mg C L−1) in permeates following MF and UF were about five and two, respectively. In conclusion, we demonstrated: (i) higher irreversible resistance for UF and reversible resistance for MF; (ii) permeate flux higher for UF and for M. contortum; (iii) the significant role of dissolved organic compounds in the formation of reversible resistance for MF and irreversible resistance for UF

Selected elements in surface waters of Antarctica and their relations with the natural environment

The aim of the study was to specify the concentration of selected chemical elements in surface waters of King George Island, off the western coast of the Antarctic Peninsula. The research encompassed six streams, a lake and an artificial water reservoir located on the western coast of Admiralty Bay. Measured hydrochemical parameters included pH, conductivity, total dissolved solids (TDS), and total and dissolved forms elements such as Al, Co, Ni, Cu, Zn, Cd, Pb, Mn, Fe, As and Se. The values of pH, conductivity and TDS had the following ranges: 6.09–8.21, 6.0–875 µS cm−1 and 7.0–975 mg/L, respectively, and were typical for surface waters of Antarctica. Wide disparities were discovered regarding concentrations of the investigated elements, ranging from <0.01 µg/L for Cd to 510 µg/L for Fe, and differing from one water body to another. The investigated elements are discussed with reference to environmental conditions and anthropogenic factors. Concentrations of total and dissolved forms of elements are considered in connection with the composition of soil in their surroundings and with atmospheric deposition, mostly such as that took place locally. The increased levels of Pb and Zn concentrations in the immediate proximity of a research station suggested anthropogenic contamination.Keywords: Antarctic surface waters; total and dissolved elements; baseline elements values; anthropogenic metal contamination(Published: 21 March 2014)To access the supplementary material for this article, please see Supplementary files in the column to the right (under Article Tools).Citation: Polar Research 2014, 33, 21417, http://dx.doi.org/10.3402/polar.v33.2141

Trophic Status of Lake Niesłysz (Poland) and Related Factors

In order to ensure the protection of lakes against eutrophication, an ongoing global problem, its causes should be determined on an individual basis. In this study, we investigated Lake Niesłysz in northwestern Poland in terms of (i) the impact of nitrogen and phosphorus on primary production, (ii) the Trophic State Index (TSI), and (iii) the hydromorphological characteristics and watershed features. We determined the thermal conditions, dissolved oxygen, organic matter, and selected forms of nitrogen and phosphorus. TSI was determined using Secchi depth (SD), chlorophyll a, total phosphorus (TP), and total nitrogen (TN). Hypolimnetic anoxia was observed in summer. Surface concentrations of chlorophyll a and organic carbon, total inorganic nitrogen (TIN), and total reactive phosphorus (TRP) were 5 μg L−1, 11.7 mg C L−1, 0.049 mg N L−1, and 0.018 mg P L−1, respectively. The TN:TP ratio was >30, while TIN:TRP was a, SD, and TP ranged from 42 to 59, and for TN it was >145. The total trophic state index (T-TSI) exceeded 72. In conclusion, Lake Niesłysz has an average resistance to degradation and the catchment has little influence on the release and transport of biogenic matter into the lake. The limiting nutrient for primary production was phosphorus, but the influence of nitrogen or covariates of nitrogen cannot be excluded. Based on the oxygen conditions in the hypolimnion, the lake should be classified as eutrophic. Most of the TSIs were in the mesotrophic range, while the TSIs for TN and T-TSI classified the lake as hypertonic. The results show that Lake Niesłysz is currently at a critical stage of progressive degradation, and it is advisable to develop and implement protective measures immediately

Invasive Round Goby (<i>Neogobius melanostomus</i>) Fish from the Southern Baltic as a Source of Arsenic and Selenium—Food Safety Aspects

Minimizing human exposure to arsenic (As) and ensuring an adequate dietary intake of selenium (Se) are significant issues in research on food sources. This study measured the content of As and Se in the muscles, gills, liver, and gonads of the fish round goby (Neogobius melanostomus) to assess the benefits and risks associated with their consumption. This was achieved by using dietary reference intake (DRI), estimated daily intake (EDI), target hazard quotient (THQ), and carcinogenic risk (CR). The elements were analyzed by atomic absorption spectrometry. The mean concentrations of As and Se (in μg kg−1 wet weight) were 25.1 and 161.4 in muscle, 58.8 and 367.4 in liver, 47.4 and 635.3 in gonads, and 16.4 and 228.5 in gills, respectively. Arsenic in the muscle portion of fish accounted for up to 0.5% of the DRI, while Se constituted approximately 30% of the DRI. The EDI values were below the reference oral dose (RfD). The THQ were much below the permissible levels (THQ −4). With regard to the As content, round goby muscles can be deemed safe for consumers. They may also be a valuable source of Se in the human diet. However, round goby consumption should be monitored for the proper and safe intake of these elements

The Fouling Effect on Commercial Ceramic Membranes during Filtration of Microalgae <i>Chlorella vulgaris</i> and <i>Monoraphidium contortum</i>

Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (>70% and 3 m−2 s−1) 6.2 × 10−4 (for MF) and 1.7 × 10−4 (for UF). Total resistances (in m−1) were in the ranges of 4.2–5.4 × 1012 (UF) and 2.6–3.1 × 1012 (MF) for M. contortum and C. vulgaris, respectively. DOC reduction was higher for UF membrane (>80%) than for MF (−1) in permeates following MF and UF were about five and two, respectively. In conclusion, we demonstrated: (i) higher irreversible resistance for UF and reversible resistance for MF; (ii) permeate flux higher for UF and for M. contortum; (iii) the significant role of dissolved organic compounds in the formation of reversible resistance for MF and irreversible resistance for UF

Concentrations of selected metals (NA, K, CA, MG, FE, CU, ZN, AL, NI, PB, CD) in coffee

The health benefits and detrimental effects of coffee consumption may be linked to chemical compounds contained in coffee beans. The aim of our study was to evaluate the concentration of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), zinc (Zn), aluminum (Al), nickel (Ni), lead (Pb) and cadmium (Cd) in green and roasted samples of coffee beans purchased in Bosnia and Herzegovina, and to determine the potential health implications at current consumption level

Природные ценности и туристическое использование Иньского Поозерья, а также озер Восьвин и Иньско как факторы, определяющие туристическую активность

Praca łączy aspekty klasycznych badań limnologicznych z wieloaspektowymi czynnikami determinującymi aktywność turystyczną. Dla realizacji tak ujętego problemu dokonano 1) oceny ruchu turystycznego na tle analizy stanu zagospodarowania turystycznego, 2) oceny istniejących walorów przyrodniczych i antropogenicznych okolic dwóch największych jezior Pojezierza Ińskiego: Woświn i Ińsko, 3) wskazano kierunki dalszego rozwoju potencjału turystycznego. Wykorzystano informacje dostępne w masowych środkach przekazu oraz przeprowadzono badania ankietowe wśród turystów wypoczywających nad badanymi jeziorami. Pojezierze Ińskie to obszar o wybitnych walorach przyrodniczych, umożliwiających uprawianie różnych form turystyki. W rejonie tym istnieje jednak duża dysproporcja w zagospodarowaniu turystycznym. Głównym centrum turystycznym jest gmina Ińsko – posiada ona największą i najatrakcyjniejszą bazę noclegowo-gastronomiczną i rekreacyjną. Za istotną przeszkodę w rozwoju ruchu turystycznego należy postrzegać ogólnie słabe zagospodarowanie turystyczne obszaru poza głównym centrum turystycznym tego rejonu. Baza noclegowa jest słabo rozwinięta, występują duże braki w zakresie usług gastronomicznych i usług rekreacyjno-sportowych. Mimo wykazanych braków rejon ten, w dobie kształtowania nowych trendów w turystyce związanych z chęcią przebywania w nieskażonym, mało przekształconym środowisku naturalnym, posiada duży potencjał turystyczny, który jest w stanie sprzyjać podejmowaniu aktywności fizycznej przez turystów. Ważnym czynnikiem dalszego rozwoju turystyki Pojezierza Ińskiego powinna być mało inwazyjna dla środowiska przyrodniczego wiejska agroturystyka, jednocześnie sprzyjająca rekreacji ruchowej oraz rozwojowi ekonomicznemu regionu.The study combines the aspects of classical limnological surveys with multiaspect factors determining tourist activity. To resolve the so treated problem the author 1) assessed tourism against the background of analysis of the tourist development status, 2) assessed the existing natural and anthropogenic values of the environs of the two biggest lakes of the Ińsko Lakeland: Woświn and Ińsko, 3) indicated the directions of a further development of the tourist potential. He used the information accessible in the mass media and carried out surveys among tourists resting at the lakes in question. The Ińsko Lakeland is an area of outstanding natural values enabling exercising various forms of tourism. However, there is in this region a great disproportion in terms of tourist development. The main tourist centre is Ińsko Municipality – it has the biggest and the most attractive lodging, catering and recreational base. As a major obstacle in tourism development there should be perceived a generally poor tourist development of the area beyond the main tourist centre of this region. The lodging base is underdeveloped; there are serious deficits in the field of catering, recreational and sport services. Despite the indicated deficiencies, this region, in the period of formation of new trends in tourism connected with the desire to stay in an unpolluted, low-transformed natural environment, has got a great tourist potential which enables undertaking by tourists physical activity. An important factor of a further development of tourism in the Ińsko Lakeland should be the rural lowinvasive agritourism, facilitating at the same time physical recreation and the region economic development.Работа объединяет аспекты классических лимнологических исследований со многаспектными факторами, определяющими туристическую активность. Для осуществления так выраженной проблемы провели: 1) оценку туристического движения на фоне анализа состояния туристического использования, 2) оценку существующих природных и антропогенных ценностей двух круп- нейших озер Иньского Поозерья: Восьвин и Иньско, а также 3) указали направления дальнейшего развития туристического потенциала. Использовали информацию, доступную в средствах массовой информации, и провели опросы среди туристов, отдыхающих на исследуемых озерах. Иньское Поозерье – территория с великолепными природными ценностями, предоставляющими возможность заниматься разными формами туризма. В этом районе, однако, существует большая диспропорция в туристическом использовании. Основным туристическим центром является гмина Иньско – она располагает самой большой и наиболее привлекательной базой с точки зрения гостиничного хозяйства, общественного питания и отдыха. Существенным препятствием в развитии туризма следует признать в общем слабое туристическое использование территории за пределами основного туристического центра этого района. Ночлежная база слабо развита, выступает большой дефицит в области услуг общепита и услуг отдыха и спорта. Несмотря на указанные недостат- ки, этот район, в период формирования новых тенденций в туризме, связанных с желанием пребывать в незагрязненной, в небольшой степени преобразованной естественной среде, имеет большой туристический потенциал, который в состоянии способствовать занятиям туристами физической активностью. Важным фактором дальнейшего развития туризма Иньского Поозерья должен быть необременительный для природной среды агротуризм, заодно способствующий активному отдыху и экономическому развитию региона

Effect of Filter Medium on Water Quality during Passive Biofilter Activation in a Recirculating Aquaculture System for <i>Oncorhynchus mykiss</i>

High-performance biofilters for water purification in recirculating aquaculture systems (RAS) ensure the safety of cultures of highly nutritious fish. As the most critical step in the functioning of biofilters is their activation, the objective of this study was to evaluate the suitability of commercial artificial media, namely RK Plast (BR-1), Mutag-BioChip30 (BR-2), and LevaPor (BR-3), for the passive activation of biofilters used in rainbow trout farming. Changes in NH4+-N, NO2−-N, NO3− -N, phosphorus, and carbon concentrations were analyzed. In the first period, an increase in NH4+-N concentration was recorded, before an increase in NO2−-N concentration (maximum concentrations ranged 0.728–1.290 and 0.982–5.198 mg N dm−3, respectively), followed by a reduction and stabilization to a level safe for the fish (both below 0.100 mg N dm−3). Concurrently, a steady increase in NO3−-N concentration was noted, with a maximum concentration between 6.521 and 7.326 mg N dm−3. Total phosphorus and total carbon ranged from 0.423 to 0.548 mg P dm−3, and from 43.8 to 45.2 mg C dm−3. The study confirmed the feasibility of using the tested artificial biofilter media for rainbow trout farming in RAS with passive biofilter activation. Biofilter activation efficiency was highest for the media with the highest specific surface area (BR-2 and BR-3). The removal of ammonium nitrogen and nitrite nitrogen was above 90%. Nitrogen biotransformation was not limited by phosphorus or carbon concentrations

Effect of Filter Medium on Water Quality during Passive Biofilter Activation in a Recirculating Aquaculture System for Oncorhynchus mykiss

High-performance biofilters for water purification in recirculating aquaculture systems (RAS) ensure the safety of cultures of highly nutritious fish. As the most critical step in the functioning of biofilters is their activation, the objective of this study was to evaluate the suitability of commercial artificial media, namely RK Plast (BR-1), Mutag-BioChip30 (BR-2), and LevaPor (BR-3), for the passive activation of biofilters used in rainbow trout farming. Changes in NH4+-N, NO2&minus;-N, NO3&minus; -N, phosphorus, and carbon concentrations were analyzed. In the first period, an increase in NH4+-N concentration was recorded, before an increase in NO2&minus;-N concentration (maximum concentrations ranged 0.728&ndash;1.290 and 0.982&ndash;5.198 mg N dm&minus;3, respectively), followed by a reduction and stabilization to a level safe for the fish (both below 0.100 mg N dm&minus;3). Concurrently, a steady increase in NO3&minus;-N concentration was noted, with a maximum concentration between 6.521 and 7.326 mg N dm&minus;3. Total phosphorus and total carbon ranged from 0.423 to 0.548 mg P dm&minus;3, and from 43.8 to 45.2 mg C dm&minus;3. The study confirmed the feasibility of using the tested artificial biofilter media for rainbow trout farming in RAS with passive biofilter activation. Biofilter activation efficiency was highest for the media with the highest specific surface area (BR-2 and BR-3). The removal of ammonium nitrogen and nitrite nitrogen was above 90%. Nitrogen biotransformation was not limited by phosphorus or carbon concentrations

Hydrochemical conditions of three lakes located in the West Pomeranian region in the annual cycle

The objective of the study was to trace the variability of the hydrochemical conditions in three lakes of the West Pomeranian Voivodeship (Poland) - Starzyca, Maszewskie and Nowogardzkie in the annual cycle. The research was done in 2018-2019, and samples for analysis were collected 4 times a year. All analyses were performed applying standard methods. Such hydrochemical indices were determined as dissolved oxygen, chemical oxygen demand, content of orthophosphates, total phosphorus, nitrite, nitrate, ammonium, chlorophyll a and iron. The study showed that all lakes in the research cycle were characterised by a polymictic type of water mixing, and the trophic level, based on the adopted criteria, indicated advanced eutrophy, which may also be caused by anthropogenic pressure. Oxygen conditions characterised by deoxidation of the waters in the bottom layer in the spring and summer seasons, and clear oxygenation in the surface water layer (in Lake Maszewskie reaching even 188.5% in the spring) confirm the significant advancement of the eutrophication process. The supply of phosphorus and nitrogen in spring from pelagic waters in the waters of the examined lakes influences concentrations of chlorophyll a in the summer. The influence of “internal supply” (bottom waters and bottom sediments) on the amount of nutrients available for autotrophs is clearly visible in the analysed lakes - an increase in nitrogen and mineral phosphorus concentrations in relation to surface waters was observed in the bottom layer