Treatment Station Research Articles

White-Tailed Deer Spatial Distribution in Relation to '4-Poster' Tick Control Devices in Suburbia.

Deer are keystone hosts for adult ticks and have enabled the spread of tick distributions. The ‘4-Poster’ deer bait station was developed by the United States Department of Agriculture to control ticks feeding on free-ranging deer. Although effective in certain scenarios, ‘4-Poster’ deer treatment stations require the use of bait to attract deer to one location, which may cause increased deer disease transmission rates and habitat damage. To better understand and manage the impact of baited ‘4-Poster’ stations on deer movements, we captured and GPS-monitored 35 deer as part of an integrated pest management project. Fifteen ‘4-Poster’ stations were deployed among three suburban county parks to control ticks. To quantify the effects of ‘4-Poster’ stations, we calculated deer movement metrics before and after feeders were filled with whole kernel corn, and we gathered information on visitation rates to feeders. Overall, 83.3% of collared deer visited a feeder and revisited approximately every 5 days. After feeders were refilled, collared deer were ~5% closer to feeders and conspecifics than before filling. Males used a higher percentage of available feeders and visited them more throughout the deployment periods. Although these nuanced alterations in behavior may not be strong enough to increase local deer abundance, in light of infectious diseases affecting deer populations and effective ‘4-Poster’ densities, the core range shifts and clustering after refilling bait may be a cause for concern. As such, trade-offs between conflicting management goals should be carefully considered when deploying ‘4-Poster’ stations.

Impact of the modernized technology on the quality of water supplied to the extended distribution system of the city of Pozna\u0144

The paper presents the results of a long-term study covering the development, implementation and operation of the second stage of water treatment (i.e. ozonation and subsequent granular active carbon (GAC) filtration) in the “Mosina” water treatment station supplying drinking water to the city of Poznań. The basis for the modernisation of the system was the high reactivity of the natural organic matter (NOM) present in the treated water with the disinfectant (in this case chlorine dioxide) resulting in an increased demand for ClO2 and reduced microbiological stability of the water. During the study it was shown that simple carboxylic acids are generated during ozonation and their presence can be an indicator of the microbiological stability of the treated water. However, these compounds are effectively removed from water during filtration through biologically active GAC filters. It was also shown that the best and cheapest parameter allowing to control water quality at individual stages of its treatment is UV absorbance, which shows reactive components of NOM removal efficiency in the technological sequence. The effectiveness of the modernisation of the technological system was evaluated on the basis of the disinfectant demand as well as on the basis of selected carboxylic acids concentration in the intake points on the water supply network fed with water from the WTS “Mosina”. At the last stage of the study, it was observed that the concentration of carboxylic acids in the distribution network was significantly reduced and stabilised, and a low dose of chlorine dioxide did not cause their re-formation. As a result of the modernisation, a new balance was achieved between the disinfectants used and the NOM compounds present in the treated water. Thus, the results confirmed that properly conducted pilot studies are a required element in planning of modernisation changes for water supply facilities.

Underestimated contribution of fugitive emission to VOCs in pharmaceutical industry based on pollution characteristics, odorous activity and health risk assessment

Fugitive emission has been becoming an important source of volatile organic compounds (VOCs) in pharmaceutical industry, but the exact contribution of fugitive emission remains incompletely understood. In present study, pollution characteristics, odorous activity and health risk of stack and fugitive emissions of VOCs from four functional units (e.g., workshop, sewage treatment station, raw material storage and hazardous waste storage) of three representative pharmaceutical factories were investigated. Workshop was the dominant contributor to VOCs of fugitive emission in comparison with other functional units. Extreme high concentration of VOCs from fugitive emission in unsealed workshop (94.87 mg/m3) was observed relative to sealed one (1.18 mg/m3), accounting for 31% and 5% of total VOCs, respectively. Fugitive emission of VOCs in the unsealed workshop mainly consisted of n-hexane, 1-hexene and dichloromethane. Odorous activity indexes and non-cancer hazard ratios of these VOCs from fugitive emission in the unsealed workshop were as high as that from stack exhaust. Furthermore, cancer risk of dichloromethane from fugitive emission and stack exhaust was up to (1.6-1.8) × 10−5. Odorous activity or health risk index of the VOCs from fugitive emission was up to 13 or 11 times of the corresponding threshold value, posing remarkable health threat on pharmaceutical workers. Our findings highlighted the possibly underestimated contribution of fugitive emission on VOCs in the pharmaceutical industry.

Overcoming Barriers to the Implementation of Cleaner Production in Small Enterprises in the Mechanics Industry: Exploring Economic Gains and Contributions for Sustainable Development Goals

The purpose of this study is to evaluate the economic and environmental gains that result from the implementation of cleaner production in a small enterprise (SE) from the metal and mechanics industry, allowing for overcoming barriers and contributing to sustainable development goals. The research work builds on a case study that involved several data sources, including semi structured interviewing and non-participant observation. Data analysis involved the calculation of mass balance, building solid and liquid waste that were minimized in the process. The results suggest that cleaner production led to economic gains, by allowing for reduction in losses and promoting a better use of raw materials. It also led to environmental improvements by means of the implementation of a wastewater treatment station that allowed for the reuse of water in the manufacturing process. It was concluded that the economic gain in the project played a determinant role for the SE to overcome the barriers for the implementation of CP and leading to the reduction of the environmental impact in the abiotic, biotic, water and air compartments, as estimated with the Mass Intensity Factor. The study offers a timely and relevant contribution for the literature in the field, while offering insights for o managerial practice, and the attainment of the Sustainable Development Goals defined by the United Nations Development Program.

Analysis on the Influence of Constructing Sewage Treatment Stations on Hydrological Monitoring in the Upstream and Downstream of Hydrological Stations

Analysis on the Influence of Constructing Sewage Treatment Stations on Hydrological Monitoring in the Upstream and Downstream of Hydrological Stations

Achieving partial denitrification using organic matter in brewery wastewater as carbon source

To find a cost-effective carbon source for partial denitrification (PD), brewery wastewater was utilized to test the viability of initiating PD. The Sbre (sludge from the biological treatment tank of Tsingtao Brewery Plant sewage treatment station) and Slab (sludge from laboratory) were fed with brewery wastewater at CODCr/NO3−-N (C/N) ratios of 8.0–10.0 and 5.0 for 95 days at 25 ± 1 °C, respectively. The mean NO3−-N to NO2−-N transformation ratio (NTR) in long-term operation was 40.0% in the Sbre system and 83.2% in the Slab system. Batch tests with C/N ratio of 2.2–4.4 were conducted after 95 days incubation and the result suggested that C/N ratio of 4.3 ± 0.1 contributed more to NO2−-N accumulation in both systems. Thauera bacteria, known to be beneficial for NO2−-N accumulation, became the dominant community. The relative abundances of Thauera on day 95 in the Sbre and Slab system were 83.36% and 79.11%, respectively.

Water productivity in cultivating the cowpea under different production systems

The increase in irrigated areas and the water crisis in numerous regions have encouraged the use of irrigation systems and management that afford greater efficiency in the use of water. Wastewater is one option for maximising this efficiency. The aim of this study was to evaluate the indicators of water productivity in the cultivation of irrigated cowpea under different production systems. The study was carried out in the experimental area of the Sewage Treatment Station (ETE) located in Tianguá, Ceará. The experiment consisted of six production systems (treatments) in subdivided plots distributed in a completely randomised design (CRD) with fifteen replications in a (2 x 3) factorial scheme, i.e. two sources of water and energy: drinking water + electricity from the electrical grid (conventional system) and wastewater + solar photovoltaic energy (alternative system), and the different sources of fertiliser (mineral and organic), in addition to the control treatments. The water productivity indicator that expresses the relationship between the yield of the crop and the volume of water applied was determined, and the index in economic terms between crop yield and the volume of water applied. The system using wastewater and organic fertiliser showed better water productivity, 0.422 kg m-3, while the system that used drinking water with no fertiliser showed less efficiency, 0.188 kg m-3. Water use efficiency in the systems that used wastewater was higher in relation to the systems that used drinking water. Irrigation with treated domestic effluent increases water productivity and water use efficiency, in addition to being a strategy for agricultural exploitation under conditions of water scarcity

Biogas manufacture from co-digestion of untreated primary sludge with raw chicken manure under anaerobic mesophilic environmental conditions

This work aimed to co-digest various wastes to assess the best combination of all mixing ratio, also at choosing the best ratio between untreated primary sludge (UPS) singly from two sources, (South valley University (SUPS) and Abu tesht wastewater station (AUPS) and raw chicken manure (RCM) and comparing the results in either case. The co-digestions of untreated primary sludge from Abu tesht wastewater treatment stations with different levels of raw chicken manure (0:100, 10:90, 30:70, 50:50, 90:10, and 100:0) to obtain the best mixtures. Also, co-digestion of untreated primary sludge from south valley university with different levels of raw chicken manure at the same ratios, to obtain the best mixtures. Batch digestion tests were applied in 2.5 L digester with a working volume of 2.0 L. The samples in triplicates were separately loaded into the digesters locally fabricated and kept for 20 days as a retention period and diluted with the same amount of water. Mesophilic under 35 °C was adopted for untreated primary sludge as well as mixtures with raw chicken manure based on total solids (TS) and volatile solid (VS) proportions. The average biogas yields from AUPS/RCM mixture obtained ranged from 8570 to 5600 ml, by the following descending order, 10: 90 > 90:10 and so on >100:0, and the average biogas yields from SUPS/RCM obtained ranged from 6330 to 5635 ml, in the order of 90: 10 > 10:90 and so on >100:0. The results showed highest biogas yield from AUPS/RCM and SUPS/RCM mixtures with mixing ratio of 10:90 and 90:10, respectively, however, the lowest biogas production detected in separate digestion of AUPS and SUPS. The results indicated that co-digestion between the sludge and raw chicken manure could increase total biogas production volume, enhance sludge treatment process, and produce eco-friendly sludge because of co-digestion process than separate processing of each feedstock.

Ordu ili kentsel kıyı yerleşim yerlerinden denize verilen evsel atık su deşarjlarının araştırılması

In this study, the compliance of domestic wastewater discharges to the sea from the urban coastal settlements of Ordu Province with the criteria specified in the regulations was investigated. For this purpose, in 2018, samples were taken from the wastewater inlet and wastewater outlet at 8 different domestic wastewater treatment stations located in urban coastal settlements, twice a month, every month 2018. BOD5 (Biological Oxygen Demand), COD (Chemical Oxygen Demand), TP (Total Phosphorus), TN (Total Nitrogen), TSS (Suspended Solids), and pH analysis were performed in the wastewater samp-les. In the evaluation of the data obtained, the parameters and upper limit values are given in the Urban Wastewater Treatment Regulation and in the Water Pollution Control Regulation were taken as a basis. In the research, it was determined that they were able to function smoothly in Altınordu-Durugöl, Altınordu-Kumbaşı, Gülyalı, Ünye-Doğu and Ünye-Batı treatment stations. At the domestic wastewater treatment stations in Fatsa District, wastewater is discharged into the sea after physical pretreatment. It has been determined that there is no significant difference between the wastewater inlet and wastewater outlet parameter values at the treatment stations in this district. This shows that domestic wastewater is discharged into the sea without being treated sufficiently at the treatment stations in Fatsa District. In Persembe District, domestic wastewater is directly discharged into the receiving environment. As a result, wastewater treatment plants with the capacity and characteristics to meet the needs should be established and put into operation in the districts of Perşembe and Fatsa. In addition, it is beneficial to establish pre-treatment facilities in the indust-rial zones in order to prevent the wastewater from small and large industrial sites operating in the province of Ordu and Organized Industrial Zones from mixing with domestic wastewater. Domestic wastewater and stormwater networks operating in the adjacent system throughout the province of Ordu should be converted into separate network lines.

Investigation of drying process kinetics of composite granules

Among the large number of modern environmental problems in Ukraine, waste of wastewater treatment stations occupies a special place. During biological water treatment, the separated sludge deposits are sent to the silt fields, which are the biggest problem. Today, these fields reached their capacity three times over and pose a danger, the consequences of which go far beyond environmental problems and have grown into a chain of socio-economic, technical, medical-biological and moral-ethical problems. Previously, activated sludge was used as fertilizer in the fields, but in connection with the Chornobyl Disaster, it was banned. As a result, accumulations of silt deposits were formed, which are also called obsolete. A modern solution is the compaction of sediments and the development of energy-efficient technologies for the processing of obsolete sludge and incineration in appropriate facilities. This paper presents the results of the drying process study for composite granules based on peat, sludge and biomass. The effect of coolant temperature on the drying rate shows the 1.4-fold intensification of the drying process. Theoretical studies with the construction of generalized drying curves of composite granules calculated by the method of V. V. Krasnikov showed coincidence with experimental data.

Assessment of the heavy metal sources and concentrations in the Nador Lagoon sediment, Northeast-Morocco

This study investigates the heavy metals (HM) and sulfurs concentration, enrichment level and potential sources in the bottom sediments of Nador lagoon, North-East Morocco. 50 samples of sediments from Nador lagoon heavy metals were analyzed by ICP-MS, while their spatial distribution and source identification were evaluated by Enrichment Factor (EF), QGis Inverse Distances Weighted (IDW) interpolation models, multivariate statistical techniques (Principal Component Analysis - Agglomerative Hierarchical Clustering - Pearson correlation matrix), Positive matrix factorization (PMF model) and grain size/organic matter analysis. The average heavy metal concentrations in the sediments are in the decreasing order: Sr > Ba > V > Zr > Zn > Cr > Rb > La > Cu > Pb > Ni > Ce > Nd > Co > Sc > Nb > Ga > Th > Y > Hf, and the Sulfurs. The results showed that the average concentrations of the S, Sr, Pb, and Nd in bottom sediments were higher than their background contents. The EF values demonstrated that HM contents were enriched by anthropogenic activities, especially for Sr and S, and secondly for Th, V, Ce, Nd, and Pb. The potential HM and sulfurs identified sources showed that: 1) Ga, Y, Hf, Nb, Rb, Sc, Zr, Nb, Co, Zn, Th, Ni, V, Ba, Cr, and Cu were derived industrial activities related to stealing and mining; 2) Wastewater treatment station and lagoon watershed were the main sources of Sr in the lagoon; 3) Zn, Cu, and Pb also linked to sulfurs, mostly origin from agriculture inputs and mining activities; 4) Ce, Cr, and Ni linked to sulfurs, mainly origin form metallurgical activities and solid wastes. The results suggest that heavy metal concentrations were significantly affected anthropogenic activities. Severe enrichment of Sr was found in the lagoon ecosystem with no correlation with carbonates, with four sources of heavy metals apportioned by Geostatistics and Positive matrix factorization. Solid waste, water waste and industrial activities were the main anthropogenic source. Lutite fraction and organic matter show a high accord with heavy metals concentration distribution.

Effect of turbidity on ultraviolet disinfection of domestic wastewater for agricultural reuse

Water treatment and reuse are fundamental because of the increasing demand for freshwater, especially in agriculture. Accordingly, this study evaluated the effects of turbidity of wastewater processed at the Effluent Treatment Station (ETE) of the UFSCar/Araras and of UV dose on microbial inactivation. The ETE treats up to 2000 L of wastewater daily from toilets and a university restaurant and has five components (grease box, septic tank, microalgae tank, upflow anaerobic filter, and wetlands). Pretreated effluents were used in the experiments, and sampling sites consisted of inspection boxes located after the wetlands. Sample collection, inspection, preservation, and analyses were performed according to standard methods. Sample turbidity was adjusted to 5, 50, 100, 200, and 300 nephelometric turbidity units (NTU), and UV doses of 7.2–28.8 mWs cm-2 were used. A 5 x 5 factorial design (five turbidity levels and five radiation doses) was used, totaling 25 treatments. Each treatment was performed in triplicate. The data were submitted to analysis of variance and Tukey’s test. The results showed that the increase in turbidity significantly decreased disinfection efficiency in samples with turbidity levels higher than 50 NTU. The microbial inactivation coefficients obtained here can be extrapolated to disinfection of wastewater with turbidity up to 300 NTU to eliminate thermotolerant coliforms. The UV sterilizer is feasible for wastewater treatment and its reuse in agriculture.
 Keywords: domestic effluent, sustainability, ultraviolet radiation, water reuse.

Shifts of acidogenic bacterial group and biogas production by adding two industrial residues in anaerobic co-digestion with cattle manure

Anaerobic biodigestion figures as a sustainable alternative to avoid discharge of cattle manure in the environment, which results in biogas and biofertilizer. The anaerobic bioconversion of biomass to methane via anaerobic biodigestion requires a multi-step biological process, including microorganisms with distinct roles. Here, the dynamics of acidogenic bacterial populations by classical microbiology, as well as biogas productivity by gasometer and chromatography, in the anaerobic co-digestion process were studied. This paper presents a performance evaluation of co-digestion systems for biogas production using cattle manure and wastes from the Sewage Treatment Station of a brewery and ricotta cheese whey. The search revealed that the type of substrate added in co-digestion with cattle manure, Carbon/Nitrogen ratio, and Ammonia Nitrogen were the most influential factors that explained many of the variations of the microbiota in the biodigesters fed. This study demonstrated a good potential for the use of ricotta cheese whey in the production of biogas and its further conversion into energy. These findings could provide some fundamental and technical information for the co-treatment of industrial derived wastes in centralized anaerobic biodigestion facilities in a sustainable manner with high process capacity and methane recovery.

Quality and nutritional investigation of some water sources in Sulaimani city

Several water treatment and distribution station in Sulaimani city has been investigated to discover their safety, quality and nutrition. This is to ensure public health protection. In this regard, water samples were collected from certain sites (underground and surface water). Water analysis was conducted in terms of several parameters, such pH, total dissolved solids (TDS), electric conductivity (EC), total hardness, calcium, magnesium, potassium, sodium and chloride content. The results were compared to universal standards (World and health organization (WHO) & national drinking water quality standard) and local standard (Iraqi standards). It was found that the majority of results within a safe range by both universal and local standards. However, water samples from some sites (in one or two parameters) were only acceptable by local standard, this includes some sites that was out of safe limit by both standards. Apart from acceptability and quality, the impact of drinking water from selected distribution tanks on a possible long-term health risk has been found. This investigation was confirmed data just for year 2019. Continuous analysis needs to be conducted and other water treatment and distribution stations have to be investigated to ensure full public health protection of Sulaimani city.

CARACTERISATION PHYSICO-CHIMIQUE ET MICROBIOLOGIQUE DES BOUES DE VIDANGE DESHYDRATEES ET DES DECHETS SOLIDES MENAGERS ORGANIQUES POUR UNE VALORISATION EN COMPOST AGRICOLE

In the city of Ouagadougou in Burkina Faso, faecal sludge treatment plants suffer from the lack of a process for recovering sludge after drying. Forsolid household waste, the quantities collected are mainly intended fortechnical landfill. Finding a solution for the recovery of Dewatered Faecal Sludge (DFS) and Organic Household Solid Waste (OHSW) is necessary in order to complete the faecal sludge management and solid waste management sectors. Our work aims to make a physico-chemical, microbiological and eco-toxicological study of a compost based on DFS and OHSW in order to propose a methodological approach for the sustainable production of hygienic compost. This article discusses the first step of our research, which consisted in characterizing the DFS at the Zagtouli treatment station as well as the OHSW of waste treatment and recovery center of Ouagadougou in order to identify a suitable recovery channel. To do so, a representative sample was taken from the Zagtouli DFS heap for laboratory analysis. The OHSW sample was obtained from household garbage bins from pre-collection centers in the city of Ouagadougou. The raw characteristics of DFS and OHSW (organic matter, nitrogen, pH, etc.) and their value in mineral elements (calcium, magnesium, potassium, phosphorus) show that these substrates would be ideal for the production of quality compost.

Patch-Based DCNN Method for CBCT Image Enhancement

Cone-beam computed tomography (CBCT) often has suboptimal image quality compared with standard fan-beam CT due to increased sensitivity to scattering and motion artifacts. In radiation treatment of cancers, due to the convenience in image acquisition as it is fully incorporated into the treatment station, CBCT plays a significant role in treatment plan re-evaluation and adaptation in adaptive radiation therapy but is limited by the image quality. In this paper, we propose a deep convolutional neural network (DCNN) based method for head and neck (HN) CBCT enhancement, where the network learns to transform the low-quality CBCT images to high-quality images.CT and CBCT image pairs from 50 HN cancer patients who received radiotherapy treatment were used for model training, validation and testing. An additional 22 raw CBCT images from another vendor were also used for testing. Pre-processing procedures include rigid registration, center-cropping, and Otsu's thresholding to segment the anatomical region. Data quality control was applied before training a 2D U-Net to reduce the adverse impact from the unmatched pairs. A patch-based strategy was employed during training, since the randomly extracted patches could reduce the receptive field and thus reduce the probability of overfitting based on the global anatomy. We explored the impact of patch size by varying it to be 64 × 64, 128 × 128, 192 × 192 and 256 × 256. After fixing to the optimal patch size, a Pix2Pix network combining L1 loss and conditional generative adversarial network (GAN) loss was also trained.It was found that the U-Net trained with a patch size of 128 × 128 reached the optimal performance and improved the mean absolute error (MAE) from 57.91 to 34.78 Hounsfield units (HU), peak signal-to-noise ratio (PSNR) from 30. 56 to 32.84 dB, and structural similarity (SSIM) from 0.7546 to 0.8455 compared with the original CBCT. With the addition of conditional GAN loss, the trained Pix2Pix network better kept the image details, especially on the external testing set.In this work, we developed a DCNN-based method to improve the CBCT image quality. This method has the advantages of high adaptability, vendor neutrality and low cost, since it operates purely in the image domain. Our data quality control pipeline automatically removed the unmatched CT and CBCT image pairs from the training set. The proposed DCNN-based method with the patch-based training strategy showed promising results for fast CBCT image enhancement.

Advanced treatment of drinking water from chlorine by-products in water transport and stationary facilities

Chlorination is a priority method for drinking water disinfection, since chlorine has strong bactericidal properties. However, a whole set of volatile chlorine derivatives of organic substances dangerous to humans are formed during chlorination, among which it is necessary to mention chloroform, carbon tetrachloride, chlorophenols. To reduce the concentration of organochlorine derivatives, it is necessary to supplement the current water treatment technology with an adsorption stage of advanced treatment at local sorption treatment facilities immediately before water is supplied to the consumer. It is advisable to design a third water treatment stage at water treatment stations, the capacity of which is low, since a huge number of filters will be needed for high-capacity plants, which may significantly reduce the water head when supplied to the city’s water supply networks, and this will entail huge costs associated with the construction of a workshop for the third treatment stage and the cost of the filters themselves. It makes sense to use such sorption plants in cottage estates and water transport. Besides, chlorination remains in the drinking water treatment scheme, which preserves the quality of water during transportation over long distances, and organochlorine substances, including 2-chlorophenol, are removed during sorption.

EVALUATE AND RECTIFICATE THE PERFORMANCE OF THE SPIRAL PUMP OF THE HOLLY KARBALA SEWAGE TREATMENT STATION

This paper evaluates the performance of the primary spiral (Archimedes) screw pump in the old sewage treatment station of the holly Karbala. This paper evaluates the pump according to its volumetric flow rate, determines the problems, diagnoses the defects, and finds the solutions. In addition, the paper suggests the optimum design for the pump. The results show a big effect of the side profile, pitch, and radius of the torque tube upon the discharge of the pump.

External control of fluoridation in the public water supplies of Brazilian cities as a strategy against caries: a systematic review and meta-analysis

BackgroundAmong the methods currently available to provide fluoride in population levels, fluoridated water is the most successful for presenting high efficacy, safety and good cost–benefit. However, recent studies on external control have shown great variability of fluoride concentrations in the water from treatment stations in Brazilian cities, which must present concentration between 0.6 and 0.8 mg/L to be considered acceptable in most cities. Thus, this study aimed to perform a systematic review of the literature to assess the adequacy of fluoride concentration in the water in Brazilian cities using external control.MethodsThe protocol was registered in PROSPERO. Six databases were used as primary search sources and three databases were used to partially capture the "gray literature". Only observational studies that assessed the fluoride concentration of artificially fluoridated water from the public supply network were included. The JBI Critical Appraisal Tools for Systematic Reviews was used to assess the risk of bias of the studies. A proportion meta-analyses using random-effect models were performed. The heterogeneity between studies was determined by I2 statistic. Meta-regressions were conducted to identify relevant moderators to be used in stratified meta-analyses. Publication bias was investigated by Egger’s tests.ResultsThe search provided 2038 results, from which 14 met the eligibility criteria and were included in the data extraction of the review. Overall, the water samples were collected from 449 different sources in three Brazilian regions. Thirteen studies presented a low risk of bias. The mean concentration of fluoride ranged from 0.17 to 0.89 ppmF. The meta-analyis demonstrated that more than half of the water samples analyzed had fluoride concentration levels outside the acceptable range (56.6%; 95% CI 45.5; 67.3), with high heterogeneity.ConclusionMore than half of the public water supply analyzed in the studies selected had fluoride concentration levels outside the acceptable range, which may affect the risk of developing oral diseases in the Brazilian population, having an important impact on public health.

Tidal and Physicochemical Effects on Phytoplankton Community Variability at Tagus Estuary (Portugal)

The Tagus Estuary is one of the largest estuaries in Europe and merges large urban and industrial areas. Understanding phytoplankton community variability is key for an appropriate assessment of the estuarine ecological status. The objective of the present study was to assess the importance of the tidal influence over the phytoplankton community and to evaluate its main drivers of variation. Weekly sampling was performed at two stations on the Tagus Estuary with different anthropogenic pressures (Alcântara and Barreiro). The sampling covered periods with different tidal amplitude. Alcântara presented both the lowest and highest concentrations of dissolved inorganic nitrogen (DIN) and orthophosphate concentration (DIP), depending on the tidal height. Such high variability in this sampling station is probably due to its proximity to a sewage treatment station outfall and to the estuary mouth. In the present study, both seasonal and tidal variations influenced the chlorophyll a concentration of which the tidal cycle explained up to 50% of the chlorophyll a variations. Chlorophyll a displayed a seasonal trend with two peaks of phytoplankton biomass between spring and mid-summer. The main drivers of chlorophyll a variation were radiation, water temperature, tidal amplitude, salinity, river discharge, and the inorganic nutrients DIN and DSi. The estuarine phytoplankton community was mainly dominated by Bacillariophyceae, especially at Alcântara. Bacillariophyceae were less important at Barreiro, where communities had a higher representation from other phytoplankton groups, such as Cryptophyceae and Prasinophyceae. The drivers of variability in the community composition were similar to those influencing the total biomass. In conclusion, the spring-neap tidal cycle strongly influenced the phytoplankton community, both in terms of biomass and community composition. Of the several tidal conditions, spring tides were the tidal condition that presented both higher biomass and higher Bacillariophyceae representativity in the community.