Main Water Quality Parameters Research Articles

Water quality assessment and evaluation of human health risks in the Pusur River, Klaten Regency, Central Java, Indonesia.

This research examines the condition of the water characteristics of the Pusur River to provide data regarding water quality status and risks to human health. In determining the water quality use the NSF-WQI, or National Sanitation Foundation-Water Quality Index based on the main water quality parameters, including temperature, fecal coliform, turbidity, pH, DO, COD, and nitrate. The WQI at the Sudimoro Village location is 37.50, Cokro is 43.54, Wangen is 39.51, Delanggu is 35.45, Juwiring is 38.05, and Taji Village is 34.92. From these six locations, the WQI values are all included in the bad criteria (scores of 26-50). The low WQI values at the six locations were influenced by the low values of the DO, nitrate, temperature, and fecal coliform sub-indices. This low value is related to anthropogenic activities in the region. Furthermore, the data were subjected to applications of the Chronic Daily Index (CDI) Hazard Quotient (HQ), and Hazard Index (HI) to reveal possible non-carcinogenic health risks from nitrate and cadmium contaminants. The hazard quotient through exposure to ingestion from each sampling point includes low risk, namely the value range of 0.1 < HI < 1 for adults and children. Water from rivers must be adequately treated before being used for domestic purposes.

ARIMA and TFARIMA Analysis of the Main Water Quality Parameters in the Initial Components of a Megacity’s Drinking Water Supply System

The objective of this paper is to use autoregressive, integrated, and moving average (ARIMA) and transfer function ARIMA (TFARIMA) models to analyze the behavior of the main water quality parameters in the initial components of a drinking water supply system (DWSS) of a megacity (Bogota, Colombia). The DWSS considered in this study consisted of the following components: a river, a reservoir, and a drinking water treatment plant (WTP). Water quality information was collected daily and over a period of 8 years. A comparative analysis was made between the components of the DWSS based on the structure of the ARIMA and TFARIMA models developed. The results show that the best water quality indicators are the following: turbidity &gt; color &gt; total iron. Increasing the time window of the ARIMA analysis (daily/weekly/monthly) suggests an increase in the magnitude of the AR term for each DWSS component (WTP &gt; river &gt; reservoir). This trend suggests that the turbidity behavior in the WTP is more influenced by past observations compared to the turbidity behavior in the river and reservoir, respectively. Smoothing of the data series (moving average) as the time window of the ARIMA analysis increases leads to a greater sensitivity of the model for outlier detection. TFARIMA models suggest that there is no significant influence of past river turbidity events on turbidity in the reservoir, and of reservoir turbidity on turbidity at the WTP outlet. Turbidity outlier events between the river and reservoir occur mainly in a single observation (additive outliers), and between the reservoir and WTP also have a permanent effect over time (level shift outliers). The AR term of the models is useful for studying the transfer of effects between DWSS components, and the MA term is useful for studying the influence of external factors on water quality in each DWSS component.

Conjugation of deep learning and de noising data methods for short-term water turbidity forecasting

Water turbidity is a critical index of water quality due to its high correlation with the five main water quality parameters (electrical conductivity, nitrogen, dissolved oxygen, phosphorus, and pH). The exact measurement of water turbidity is a difficult process because many conditions affect the reading of turbidity. Although many researchers applied decomposition-based techniques for preprocessing, it is difficult to use these approaches in real estimation because the newly acquired data greatly affect the initial decomposed subsequent values. In this study, the threshold-based wavelet denoising method, as a data pre-processing, coupled with the deep learning models (i.e., ANN and ANFIS) was employed to enhance the performance of the water turbidity modeling. The results showed that deep learning techniques in temporal modeling of water turbidity have good accuracy and can be used with reasonable confidence. Also, data denoising increases the accuracy of deep learning methods in estimating the amount of water turbidity. ANFIS method is more accurate in both calibration and validation modes as well as in noisy and denoised conditions. Based on the results, data denoising in the ANN method has a more significant impact than in the ANFIS technique. For example, in Comb. 5, which is the best case, the improvement rate of the results in the ANN is 12% and in the ANFIS method is 4%. This could be due to the fuzzy system in handling uncertainties in the model.

Effects of source-sink landscape proximity on the spatial–temporal water quality from the perspective of cost distance in an agricultural watershed

Spatial patterns of source-sink landscapes play a critical role in assessing surface water quality. However, this relation may be different due to various proximity of source-sink landscapes. The effect of the source-sink landscape proximity on surface water quality remains poorly understood. The impact of source-sink landscape proximity on the spatial–temporal water quality were quantified based on field monitoring data (2013–2019) in an agricultural watershed. A new approach considering the cost distance of landscape types, slope, and vegetation on the transformation of nutrients from one point to water bodies was used to construct different buffer zones which reflected very high, high, moderate, low, very low proximities, while the subwatershed represented the very low proximity. Then the effects of the source-sink landscape proximity were assessed based on sub-watershed and other four buffers. The resutls showed that the TN and NO3−-N were the main non-point source pollution indices with significant spatial variation (p < 0.05). The water quality index (WQI) was higher during the dry season than during the wet season, indicating that the sampling sites also experienced seasonal variations. The multi-scale analysis demonstrated the significance of the source-sink landscape proximity in improving the quality of surface water. A stronger correlation between the ratios of sink landscape and the main water quality parameters (the TN and NO3−-N) was observed in the low proximity zone, suggestiong that the low proximity zone with moderate non-point source pollution risk was a critical region in water quality management. The results provide important insights into understanding the effects of the source-sink landscape proximity on water quality and how scientific and effective measures can be made to improve water quality.

Turbidity Reduction by Using Variations of Filtration Media Sizes (Case Study of Treated Water PT. X Jakarta)

Turbidity is one of the main water quality parameters in drinking water quality. One way to reduce turbidity levels is by filtration. The filtration unit in the water treatment plant must use appropriate media so that the processed raw water meets World Health Organization (WHO) standards. WHO states that the turbidity of processed water before disinfection is 1 NTU. This research was conducted to know the efficiency of filtration processing with various media in reducing the concentration of turbidity in raw water. This study used three types of media, namely 50% silica sand with a mesh size of 12-16 and 50% silica sand with a mesh size of 8-12 (C), 100% silica sand with a mesh size of 12-16 (K), and 100% silica sand in mesh size. 8-12 (B). Porosity value for each sample C, K, and B is 0.412; 0.423; and 0.388. The detention time at maximum discharge for samples C, K, and B was 3.6, respectively; 3.76; and 3.45 minutes. The flow rates used for media samples C, K, and B were 4125 L/s and 2500 L/s, respectively. The removal efficiency produced by the highest turbidity was obtained in medium C with values of 90.8% and 89.9%, respectively. Meanwhile, media B gave the lowest turbidity removal efficiency, namely 86.3% and 86.4%. The results of all variations of the media used have met WHO standards, where the processed results have produced turbidity concentrations of 0.25 - 0.32 NTU.

Groundwater quality assessment for sustainable human consumption in arid areas based on GIS and water quality index in the watershed of Ain Sefra (SW of Algeria)

Groundwater quality in arid areas is an issue that requires attention, as often the only source of irrigation and drinking. In this manuscript, a research area of 4590.2 Km2, which depicts important problems of water scarcity and water-poor quality in an arid environment, was assessed. Therefore, GIS-based mapping of the region was carried out to examine the adequacy of groundwater quality. Forty-three (43) groundwater samples were gathered in the fieldwork in March 2022, and various physicochemical limits were analysed within Gibbs and Piper diagrams. Likewise, spatial distribution maps of twelve (12) main water quality parameters were performed using the Inverse Distance Weighted interpolation method (IDW) in the ArcGIS tool. The Water Quality Index (WQI) has been calculated considering Algerian drinking water quality standards and to know the suitability of water for human consumption. A Pearson’s test was carried out to explore the correlations among the different variables. Major results of the study showed that, among anions and cations, sulphates (SO_{4}^{ - 2}) and calcium (Ca) were the most common ions. The WQI showed that 30.23% of the samples have excellent water quality, 62.79% belong to the good water category, and 6.97% fall into the poor water quality category. Thus, the correlation study between many physicochemical properties also showed significant positive relationships between WQI, TDS, EC, TH, {text{SO}}_{4}^{ - 2}, {text{Ca}}^{ + + }, and {text{Mg}}^{ + + }. In agreement with the Gibbs diagram, most of the samples fall into the field of rock-water interaction dominance. Hence, this research shows that using GIS and WQI as joint approaches could be useful tools for the decision-making process of local and international authorities and water resources management.

Regional Models for Sentinel-2/MSI Imagery of Chlorophyll a and TSS, Obtained for Oligotrophic Issyk-Kul Lake Using High-Resolution LIF LiDAR Data

The development of regional satellite bio-optical models for natural waters with high temporal and spatial variability, such as inland seas, reservoirs, and coastal ocean waters, requires the implementation of an intermediate measuring link in the chain, “water sampling—bio-optical models”, and this link must have certain intermediate characteristics. The most crucial of them are the high-precision measurements of the main water quality parameters, such as the concentration of chlorophyll a (Chl a), colored dissolved organic matter (CDOM), and total suspended sediments (TSS) in the upper water layer, together with a high operational rate and the ability to cover a large water area in a short time, which corresponds to a satellite overpass. A possible solution is to utilize laser-induced fluorescence (LIF) of water constituents measured by a marine LiDAR in situ with a high sampling rate from a high-speed vessel. This allows obtaining a large ground-truth dataset of the main water quality parameters simultaneously with the satellite overpass within the time interval determined by NASA protocols. This method was successfully applied to the oligotrophic Issyk-Kul Lake in Kyrgyzstan, where we obtained more than 4000 and 1000 matchups for the Chl a and TSS, respectively. New preliminary regional bio-optical models were developed on the basis of a one-day survey and tested for archive Sentinel-2A data for 2022. This approach can be applied for regular monitoring and further correction in accordance with seasonal variability. The obtained results, together with previously published similar studies for eutrophic coastal and productive inland waters, emphasize the applicability of the presented method for the development or adjustment of regional bio-optical models for water bodies of a wide trophic range.

Establishing a Telemetry-Based Management System for Distant Supervision of Water Quality Parameters in a Laboratory Dedicated to Shrimp Larvae Cultivation

A management platform was developed for the monitoring, registration and alarm of the main water quality parameters: PH, dissolved oxygen, salinity and temperature, which are supervised in the cultivation of shrimp larvae (nauplius). With the platform, the person in charge of the laboratory will have a tool to analyze, determine and detect possible conditions that are dangerous to the animal's health.

Monitoring of Surface Water Quality in King Talal Dam Using GIS: A Case Study

King Talal Dam is the largest surface water reservoir in Jordan. Zarqa River and some springs are the major flow contributors to this dam. The other inflow comes in the form of effluents from Al-Samra, Baqa'a, and Jerash wastewater treatment plants, and industries located in Amman and Zarqa. These effluents dramatically deteriorate the water quality of the dam. This study applied Geographical Information System to monitor the temporal and spatial changes in the water quality of King Talal Dam. The parameters included toxicity and infiltration risks, clogging in irrigation systems (drip), soil degradation through soluble salt accumulation, and excessive nitrogen-associated issues. The study expanded from winter 2014 to summer 2016. The final integrated maps revealed two suitable and unsuitable classes for irrigation purposes. The study also provided essential information about the main water quality parameters and pollution sources such as EC, and E. coli. They were recorded throughout the study period in unsuitable zones whereas TSS and bicarbonate (HCO3-) were found in the spring of 2015 and spring of 2016, respectively. Autumn 2014 was found to be the worst season among all the study years. During that season, the unsuitable area expanded up to 93% of the total reservoir area. Then, the unsuitable zone reached up to 68.4% of the total area during the winter of 2016. The mapping results indicated that site 100 remained polluted during all the study seasons. This was expected as site 100 is in Zarqa River where Al-Samra and Jerash wastewater treatment plants are discharged.

Growth Performance and Survival of Climbing Perch (Anabas testudineus Bloch) Raised in Conventional and Bioflocs System

The aim of this research is to analyze the performance of growth and survival of climbing perch (Anabas testudineus Bloch) which was raised in bioflocs and conventional systems. It investigated the difference in the initial size of the fry stocked with climbing perch has effect. The experimental design used in this study was a Factorial Completely Randomized Design (CRD) with 2 factors and 3 replications: Factor A: climbing perch aquaculture Systems; A1: climbing perch in conventional system of; A2: the climbing perch in bioflocs system; Factor B: Initial Size of fry Stocking; B1: fry size 3 ± 0.5cm; B2: fry size 5 ± 0.5cm and B3: fry size 7 ± 0.5cm. The research was conducted for 90 days with daily growth parameters (SGR), weight and length growth, survival rate, food conversion, flocsvolume density (FVD), and main water quality parameters (water temperature, pH, dissolved oxygen and dissolved ammonia).The results showed that the bioflocs system was able to increase the average growth in the range of 12-67% with an average of 29.73% when compared to conventional systems. The highest value for the daily growth rate or Specific Growth Rate (%/day) was for fry with a size of 7 cm in the bioflocs system (8,419%). The fry size of 3 ± 0.5cm in the bioflocs system had the highest difference in standard length (4.33 cm) while the highest average length during maintenance was the seed size of 7 ± 0.5 cm in the bioflocs system. The survival results of climbing perch fish during the study were based on the highest score on the seed size of 3 ± 0.5cm in the bioflocs system. The survival range of the bioflocs system is 94.89 - 99.67% and that of the conventional system is 82.00 - 94.26%. Thus the bioflocs system is able to increase survival in the range of 5-14% when compared to conventional systems. The bioflocs system is able to provide better feed efficiency than conventional systems in the range of 34-39%. The average value of floc volume density (FVD) in the bioflocs system is in the range of 5.35 – 8.16 ml/L, which is still ideal but can still be improved. Water temperature during the study period, air and water temperatures ranged from 28.54 to 28.71 (ºC), the degree of acidity in all treatments was in the range 6.34 – 7.27, dissolved oxygen levels were in the range 5.77 – 6.90 mg /L) while the average measurement results for ammonia levels (mg/L) were in the range of 0.49 – 0.57 mg/L. The temperature ranges in the studies on conventional and bioflocs systems are within the acceptable range for fish farming Water temperature during the study period, air and water temperatures ranged from 28.54 to 28.71 (ºC), the degree of acidity in all treatments was in the range 6.34 – 7.27, dissolved oxygen levels were in the range 5.77 – 6.90 mg /L) while the average measurement results for ammonia levels (mg/L) were in the range of 0.49 – 0.57 mg/L.

Ecological Health Status of the Yitong River, China, Assessed with the Planktonic Index of Biotic Integrity

The Yitong River Basin is the main northern urban river basin in China, and its ecological health has become an important issue of public interest. In 2021, the plankton community and main water quality parameters of the Yitong River were monitored quarterly. An evaluation system was established based on the Planktonic Index of Biotic Integrity (P–IBI) to assess the spatial and temporal variability in river health. To verify the feasibility of the P–IBI, its assessment results were compared with those of the water quality index (WQI), and the main factors affecting the P–IBI in different seasons were analyzed using correlation analysis between P–IBI metrics and environmental factors. Seasonal comparisons showed that most sampling sites exceeded the “moderate” level in spring and autumn, followed by winter. The worst assessment results occurred in summer. Urban river reaches were more polluted than reaches in rural areas. Regarding driving factors, hydraulic effects on the P–IBI in spring and autumn were significantly stronger than other environmental factors. In summer and winter, special attention should be paid to the input of nitrogen compounds and organic pollutants. Trends based on the P–IBI and the WQI differed in winter, but site patterns were consistent between both indices. The results provide a theoretical basis and data support for the health maintenance of the Yitong River.

Performance assessment of data driven water models using water quality parameters of Wangchu river, Bhutan

Multifarious anthropogenic activities triggered by rapid urbanization has led to contamination of water sources at unprecedented rate, with less surveillance, investigation and mitigation. The use of artificial intelligence (AI) in tracking and predicting water quality parameters has surpassed the use of other conventional methods. This study presents the assessment of three main models: adaptive neuro fuzzy inference system (ANFIS), artificial neural network (ANN) and multiple linear regression (MLR) on water quality parameters of Wangchu river located at capital city of Bhutan. The performance and predictive ability of these models are compared and the optimal model for predicting the parameters are recommended based on the coefficient correlation (CC), root mean square error (RMSE) and Nash–Sutcliffe efficiency (NSE) evaluation criteria. Overall NSE and RMSE, the ANN model predicted parameters with maximum efficiency of 97.3 percent and minimum error of 8.57. The efficiency of MLR and ANFIS model are 95.9 percent and 94.1 percent respectively. The overall error generated by MLR and ANFIS are 10.64 and 12.693 respectively. From the analysis made, the ANN is recommended as the most suitable model in predicting the water quality parameters of Wangchu river. From the six-training function of ANN, trainBR (Bayesian Regularization) achieved the CC of 99.8%, NSE of 99.3% and RMSE of 9.822 for next year data prediction. For next location prediction, trainBR achieved CC of 99.2%, NSE of 98.4% and RMSE of 6.485, which is the higher correlation and maximum efficiency with less error compared to rest of the training functions. The study represents first attempt in assessing water quality using AI technology in Bhutan and the results showed a positive conclusion that the traditional means of experiments to check the quality of river water can be substituted with this reliable and realistic data driven water models.Article highlightsTotal dissolved solids (TDS), electrical conductivity (EC), potential of hydrogen (pH) and dissolved oxygen (DO) are selected as main water quality parameters as data for modeling.Artificial neural network model gives highest efficiency and accuracy compared to MLR and ANFIS model.Use of artificial intelligence shows better performance to provide water quality and future predictions over conventional methods leading to conservation of water resources and sustainability.

Evaluation of water quality index and geochemical characteristics of surfacewater from Tawang India

In this study,the water samples were collected from 31 sites of Tawang, Arunachal Pradesh, India (North-Eastern Himalaya), during the winter season to check the suitability of water for drinking and irrigation purposes.The study scientifically demonstrates the estimation of Water quality index (WQI) andhydrogeochemical characteristics of surface water samples by utilizing multivariate statistical methods. The main water quality parameters considered for this study were TDS, conductivity, salinity, pH, hardness, cations and anions. WQI was calculated in order to find out the deviation in the water quality parameters particularly with respect to BIS permissible limits.The major influencing factors responsible for the variation in these parameters were derived by using Principal component analysis (PCA) and Correlation matrix.To check the suitability of water for drinking purpose, hydrogeochemical facies and rock water interaction was derived by using well established methods such as Piper Plot (determine water type), WQI (Quality monitoring), and saturation index (for mineral dissolution). The results revealed that the silicate weathering was the main ionic source in comparison to carbonate weathering which is due to the higher dissolution capacity of silicate minerals.The results of the scattered plot between (Ca2+ + Mg2+)–(HCO3ˉ + SO42ˉ) versus (Na+ + K+)–Clˉ (meq/L) highlighted thation exchange occurs between Mg2+ and Ca2+ofsurface water with Na+ and K+of rock /soil. This means that calcium ion was getting adsorbed, and sodium ion was getting released. The Ca2+–Mg2+–HCO3ˉ, Na+–HCO3ˉand Na+–Clˉ type of surface water suggested permanent and temporary hardness respectively in the studied region. The dominant cations of this study were Na+ and Ca2+ while the dominant anions were HCO3ˉ and SO42ˉ. In order to check the suitability of water sources for irrigation, parameters like, Magnesium hazard (MH), Total hardness (TH), Permeability Index (PI), Kelly Index (KI), Sodium adsorption rate (SAR), Sodium percentage (Na%), and Residual sodium carbonate (RSC) were determined. The results showed that 93% of the samples had PI score < 75, which indicates the suitability of the water for irrigation. Also the WQI calculation showed an average WQI value of 82.49, amongst which 61% samples were in the range of 0–50 being considered as good for drinking, while 39% were catageorised as unsuitable for drinking showing a value of > 50. Hence the above findings reveal that geogenic activities play a major role in influencing the water quality of Tawang region. Hence suitable water treatment technologies or methods might be used to eliminate thenon desirable elements and minerals present in surface water.

On the Development of Long-Range Water Quality Monitoring System for Outdoor Aquaculture Objects

Abstract The paper is dedicated to the development of hardware and software components for the autonomous water quality monitoring system (WQMS) for fishing farms. The system can measure main water quality parameters, storing and processing data on the remote server. The LoRaWAN technological solutions and infrastructure are utilized, providing the optimal tradeoff between data transmission range and adaptive power consumption. The main implementation and exploitation issues are described, and the proposed solutions are provided.

A simpler statistical approach to estimate the allowable effluent discharge into a low monitored river network

The goal of the study was to illustrate how the variation in streamflow patterns affects the magnitude of pollutants that can be loaded into the hydrography in a more straightforward manner. For that, two basins in the Doce River basin (Brazil) were evaluated in order to estimate the variation in the allowed wastewater in streamflow units (m3s−1) into the hydrography without impairing the rivers' water quality. The main water quality parameters of the basin were considered for the analysis: E. coli, total phosphorus (P), nitrate‑nitrogen (N-NO3−), and biochemical oxygen demand (BOD). Because the already existing E. coli in the system is too high, the allowable streamflow, considering this pollutant, was null. For N-NO3−, the model was not valid because the concentration of it the wastewater is smaller than the allowed in the legislation. For last, considering P and BOD, it was observed that, for most gauges, it was possible to load more wastewater in the hydrography during wet months, especially when the effluent goes through some treatment. For example, considering P, a significant difference between the allowable pollutants in the wet season in comparison to the dry season, indicating that for one gauge, more wastewater is allowed in the dryer season. For BOD, contrarily, the allowable wastewater in the hydrography increased by about 50% in both seasons, without much variation. With that, we conclude that the dilution capacity in the waters is variable, so should be the allowed amount of pollutants into the river network throughout the year.

Assessment of recent rehabilitation projects’ impact on water quality improvement in Lake Burullus, Egypt

Lake Burullus, the second largest coastal lake and wetland in Egypt, is suffering environmentally and economically under the tremendous pressure of rapid urbanization and increase of agriculture, aquaculture and industrial activities for more than 4 decades. This caused significant reduction of the lake’s area and sever degradation of its ecological system, including the decrease in fishing yield, which consequently led to serious socio-economic challenges for the local fisheries communities as well as affecting the national fish production of Egypt. Recently, the Egyptian Government has made great efforts for the rehabilitation and restoration of the northern lakes and wetlands in attempt to improve their environmental conditions and restore their economic value. Among these efforts is Burullus Lake Rehabilitation Project, which has started in 2018 covering the inlet and the eastern part of the lake and aims to improve the water quality and fish production in the lake mainly by enhancing water exchange between the lake and the sea through dredging and side protection works. The current study provides an update of the water quality conditions over Burullus lake by carrying out a wide water sampling program that covers the entire perimeter of the lake with an emphasis on the most problematic areas. The main water quality parameters were measured and analyzed spatially in order to provide a quantitative assessment of the efficiency of the implemented rehabilitation and restoration works and provide recommendation for further improvement works. The results show that there was a significant improvement of investigated water quality parameters over the lake inlet and the eastern part where the dredging works were carried out while less improvement was found over the western part. This indicates that water exchange with the sea and the circulation pattern in the lake have the most significant influence on the lake’s water quality, which should be considered in future rehabilitation projects.

Composition and structure of benhtic macroinvertebrate communities in watercourses of Donji Vakuf

Zoobenthos are one of the most significant communities in aquatic habitats. Remediation of aquatic ecosystems depends on maintaining a healthy zoobenthos community. The first step in restoring aquatic ecosystems is to understand the hydrology and water quality parameters that influence zoobenthos variation. Based on field sampling of the river zoobenthos in the watercourses of Donji Vakuf, the current study used principal component analysis to identify the key habitat elements affecting zoobenthic communities. Bray-Curtis similarity was used to compare analyzed zoobenthic communities. The findings in this study demonstrate that water temperature, dissolved oxygen, total Phosphourous and total Nitrogen were the main physical and chemical water quality parameters affecting the zoobenthic populations in investegated watercourses. The highest similarity of analyzed macrozoobenthos communities was observed between Semešnica river and Sokolinski stream. All of the approaches described in this work can be used for studies on different communities, such as fish, algae, and zooplankton in aquatic ecosystems. Managers can use the techniques and findings in this report as important references to safeguard and revitalize deteriorated water ecosystems.

Variância de parâmetros de qualidade da água e análise de agrupamentos na bacia hidrográfica do rio Goiana, Pernambuco

A qualidade das águas superficiais consiste em um tema de interesse da comunidade científica, dos órgãos gestores e de toda sociedade civil, principalmente devido a velocidade de degradação dos corpos hídricos. Dessa forma, objetivou-se nesse estudo realizar a análise sobre alguns dos principais parâmetros da qualidade da água na bacia hidrográfica do rio Goiana. Os parâmetros analisados (pH, oxigênio dissolvido, demanda bioquímica de oxigênio, turbidez, amônia, fósforo total, coliformes termotolerantes e condutividade elétrica) correspondem a pontos amostrais em sete localidades inseridas dentro da bacia hidrográfica do rio Goiana, distribuídas em seis períodos distintos, considerando a estação chuvosa, e seca. Os dados foram submetidos a avaliação de variância e ao teste de Fisher, com nível de significância de p ≤ 0,05, bem como análise de agrupamentos. Considerando os efeitos da sazonalidade, os testes estatísticos realizados permitiram concluir que na estação chuvosa, os parâmetros de pH (p = 0,0097) e oxigênio dissolvido (p = 0,0352) apresentaram médias com valores estatisticamente distintos, já no período seco, isso ocorreu com a turbidez (p = 0,0058). Deste modo, constata-se que pode haver diferenças na qualidade da água em determinados pontos, entre as estações do ano, em detrimento do comportando da precipitação local. Em relação aos agrupamentos estabelecidos, houve algumas diferenças, considerando a sazonalidade, obtendo 2 ou 3 agrupamentos para os pontos em estudo, evidenciando diferentes níveis de poluição, principalmente nas proximidades de áreas urbanas. Diante disso, os resultados obtidos são essenciais para auxiliar na elaboração de políticas públicas para mitigação de impactos ambientais.Palavras-chave: recursos hídricos, análise de água, efeitos da sazonalidade, ferramentas estatísticas. Variance of water quality parameters and cluster analysis in Goiana river watershed, Pernambuco A B S T R A C TThe quality of surface water is a subject of interest to the scientific community, the management bodies and all civil society, mainly due to the speed of degradation of water bodies. Thus, the aim of this study was to analyze some of the main water quality parameters in the Goiana river basin. The parameters analyzed (pH, dissolved oxygen, biochemical oxygen demand, turbidity, ammonia, total phosphorus, thermotolerant coliforms and electrical conductivity) correspond to sampling points in seven locations within the Goiana river watershed, distributed over six distinct periods, considering the rainy season and the dry season. The data were submitted to variance evaluation and Fisher's test, with a significance level of p ≤ 0.05, as well as cluster analysis. Considering the effects of seasonality, the statistical tests performed allowed us to conclude that in the rainy season, the parameters pH (p = 0.0097) and dissolved oxygen (p = 0.0352) presented means with statistically different values, whereas in the dry season, this occurred with turbidity (p = 0.0058). Thus, it can be seen that there may be differences in water quality at certain points, between the seasons of the year, as a result of the behavior of the local rainfall. In relation to the groupings established, there were some differences, considering the seasonality, obtaining 2 or 3 groupings for the points under study, showing different levels of pollution, especially near urban areas. Therefore, the results obtained are essential to assist in the development of public policies for the mitigation of environmental impacts.Keywords: water resources, water analysis, seasonality effects, statistical tools

Effect of rainfall seasonality and land use on the water quality of the paraíba do sul river

Monitoring water quality is important for the suitable management of water resources. Therefore, this study aims to assess the main water quality parameters and the National Sanitation Foundation-Water Quality Index (WQINSF) of four locations on the Paraíba do Sul River basin, in the state of Rio de Janeiro, influenced by different land use and land cover, and in the dry and rainy seasons. The following quality parameters were evaluated: total phosphorus (TP), nitrate (NO3-), dissolved oxygen (DO), potential of hydrogen (pH), turbidity (Turb), thermotolerant coliforms (Col), total dissolved solids (TDS), biochemical oxygen demand (BOD), water temperature (Twater) and air temperature (Tair). Statistical differences (p &lt; 0.05) were observed between the dry and rainy seasons for the parameters: TP, Col, Turb, TDS, Twater, Tair, NO3-, DO, and WQINSF. The concentration of rainfall was effective in water quality parameters behavior. WQINSF was lower in the rainy season and possibly the runoff was the major cause of water quality degradation. Land use and land cover influenced the concentration of DO and Col and, consequently, WQINSF. Despite statistical differences, in most cases, the Paraíba do Sul River basin lies in medium water quality index according to the classification of the National Water and Sanitation Agency (ANA).

Can shrimp farming wastewater negatively affect water quality and zooplankton community structure of a Neotropical estuary? A case study during a productive cycle of Litopenaeus vannamei

Aquaculture wastewater can influence various communities’ structures in both marine and freshwater environments. This study describes the zooplankton community structure and environmental variables in both Passos River estuary (Northeast Atlantic, Brazil) and commercial shrimp farming ponds associated with this estuary. Samples for water quality analysis and quantification and identification of zooplankton were taken during a shrimp culture cycle (July to September 2014) from eight sites (two across the main channel, downstream and upstream, and six shrimp farming ponds). The main water quality parameters showed difference between the shrimp farming ponds and the Passos River estuary – higher levels of total phosphorus and chlorophyll-a were observed in the shrimp ponds. The zooplankton structure at different environments was dominated by the copepods (53.3 to 83.7%) and rotifers (9.2 to 35.5%) but no significant difference was observed among the individual densities. Meanwhile, nutrients availability was a key for high plankton densities in shrimp ponds. These findings have suggested that wastewater from shrimp farming did not influence the zooplankton community on a Neotropical estuary on a short-time scale.