Physicochemical Parameters Of Water Research Articles

Characteristics of the Stone Crayfish Population along a Disturbance Gradient—A Case Study of the Kustošak Stream, Croatia

The stone crayfish, Austropotamobius torrentium, is a native European freshwater species sensitive to habitat alterations such as stream channelization and urban development, putting its populations at risk. This study aims to assess how habitat alteration and subsequent water quality changes affect the stone crayfish population in the Kustošak Stream (Croatia) through three selected sites under different levels of anthropogenic disturbance: (1) undisturbed; (2) recently modified, and (3) long-time modified sites. At each site, crayfish were captured, measured, and marked to estimate population size, structure, and crayfish condition. Additionally, we examined whether water quality (18 measured physicochemical parameters) affects relative crayfish abundance. We also used mitochondrial sequencing and microsatellite genotyping to assess species genetic diversity and population connectivity and to compare results among the sites. The results showed that habitat alteration caused an overall reduction in population abundance and changes in size structure; however, it had not yet resulted in detectable genetic differences. Partial least squares regression showed that crayfish abundance was affected by the physicochemical parameters of water, including, among others, oxygen, calcium ions, nitrates, pH, and water temperature. We discuss our findings in the context of the effects of anthropogenic disturbance on the viability and persistence of this EU priority species.

Evaluating the treatment performance of filtration & real-time UV irradiation processes for bacteria and pathogens in fresh ballast water

Ballast water (BW) is fresh water or seawater taken onboard to stabilize ships. By traveling with the vessels, different species can be introduced into a new area, which has potential impact on human health, economy, and environment. Bacteria are transferred in large numbers through BW. Owing to their diversity and potential pathogenicity, they could pose a direct threat to the prevailing microbiome in the recipient waters and human health. The aim of this paper is to examine the effects of real-time ultra-violet (UV) irradiation on the survival, activity, and diversity of bacterioplankton in fresh water. The treated water was held in the treatment tanks for one day or five days before discharged. After treatment, the density of total viable bacteria and indicator bacteria decreased significantly in discharge water compared with control water, and the density of indicator bacteria met the D-2 standard. The sequencing of 16S rRNA amplicons showed that α-proteobacteria was dominant in Inlet water. In the treated water, γ-proteobacteria was dominant in UV_PD_1d, while α-proteobacteria became the most abundant class again in the UV_PD_5d. Shannon and Simpson indices confirmed the declining trend in bacterial diversity. Further, our result indicated that real-time UV irradiation was likely to cause the change of assemblage of bacteria, and there were still several pathogen bacteria after treatment. By monitoring the physicochemical parameters of ballast water, we found that pH positively correlated with the dominant phylum Proteobacteria. This study provides a further idea for type approval of ballast water management systems.

Physicochemical characteristics of soil and water in electronic waste dump site, Alaba Lagos, Nigeria

Determination of physicochemical characteristics of soil and water adjoining dumpsites is important to ascertain the fitness of drinkable water and their public health implications. Following the paucity of information on this area of study, physicochemical characteristics of water and soil in electronic waste dump site, Alaba, Lagos, Nigeria. Six samples from the dumpsite made up of three soil and water respectively were collected and extracted using USEPA methods. One soil and water sample far from the dumpsite served as control. Physicochemical parameters of water and soil samples were determined using standard methods. Results show that pH of the water samples ranged from 4.81 to 7.30. SW1 had highest pH (slightly alkaline) while SW3 had lowest pH and was acidic. The electrical conductivity of SW1, SW2 and SW3 ranged from 61 µS to 1421 µS respectively. Water temperature was between 29.53 and 29.57oC. Total dissolved solid of the water ranged from 32.33 to 722 mg/L. Sulphate ranged from 238 mg/L to 314 mg/L. Phosphate ranged from 41.92 to 60 mg/L. Dissolved oxygen ranged from 0.93 to 2.4 mg/L. Similarly, soil pH ranged from 6.57 to 7.44. Soil temperature ranged from 28.43 to 30.7. Soil organic carbon ranged from 13.75% to 20.25% while the soil organic matter ranged from 17.88% to 26.32%. Soil particle distribution ranged from 58.56 – 87.52% sand, 3.22 – 13.79% clay and 8.84 – 27.65% slit. Some physicochemical characteristics of soil and water in sampled location did not follow the WHO standard. This study has informed the state of water available for consumption as well as the state of soil contamination. Proper care is required to checkmate this location to avoid future contaminations.

The Effects of Humic Acids on the Early Developmental Stages of African Cichlids during Artificial Breeding.

The aim of this study was to compare the effect of humic acid (HA) obtained by extraction from alginate on the incubation of roes and fry development in African cichlids, Labidochormis caeruleus, as well as their influence on the stabilization of the physicochemical parameters of water in an aquarium during artificial breeding. The roes were obtained by extruding from a female buccal cavity immediately after fertilization. For the experiment, 4 groups of 40 roes were formed in an incubator with an artificial hatchery. Groups 1-3 were exposed to 1%, 5%, and 10% concentrations of HA, respectively. The control group C was not exposed to HA. In all groups, the mortality and size differences of the fry, as well as the temperature, pH, hardness, nitrite, and nitrate levels in the tanks, were determined during a 30-day monitoring period until the resorption of the yolk sac. The results of this study indicated the ability of HA in 5% and 10% concentrations to reduce nitrite and nitrate levels in the aquatic environment, which significantly reduced the mortality of roes and the survivability of the fry. The determination of the morphological measurements of the fry revealed an increased body length in the groups exposed to 5% and 10% HA concentrations compared to the control group by the end of the monitored period. It was also noted that the yolk sac was resorbed two days earlier in the same groups than in the control. Thus, the results showed that HAs are suitable for use in the artificial aquarium incubation of roes and fry development, which are increasingly exposed to adverse environmental factors. The knowledge obtained in this study and its transfer into practice can allow even less experienced aquarists to successfully breed aquarium fish species that could not normally be bred under artificial conditions without the addition of HA.

Assessment of Physicochemical Parameters of Water from Selected Boreholes Around Nnewi Industrial Area, Anambra State, Nigeria

The study seeks to evaluate the quality of borehole water around the Nnewi industrial area of Anambra State, Nigeria, and to determine the extent of its deterioration due to waste from nearby industries. Samples were collected from 16 different borehole sampling sites around 8 industries for twelve consecutive months (May 2019 to April 2020) and analysed for various physicochemical parameters such as pH, temperature, biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), etc., using standard methods. The results were compared with World Health Organisation (WHO) standards. In both seasons, data acquired indicate COD ranges of 4.50 – 20.50 mg/L (mean value 9.63±5.28 mg/L), temperature 27.00 – 30.00°C (mean value 28.59±0.99°C), pH 5.60–7.99 (mean value 6.97±0.47), DO 2.00 – 6.60 mg/L (mean3.99±0.76 mg/L), BOD 4.00 – 9.60 mg/L (mean 6.54±1.33mg/L). All the physicochemical parameters examined, with exception of BOD and COD, are within the WHO standard limits. Pearson’s correlation showed that physicochemical parameters were strongly and moderately correlated with each other at either <i>p </i>< 0.01 or < 0.05. The BOD and COD results revealed that the borehole water was found to be contaminated, unfit for drinking, and likely health hazards to users. It is, therefore, recommended that water from these study areas will be properly treated before human consumption, to rid it of contaminants.

Circadian (re)colonisation dynamics of macroinvertebrates in an isolated karst spring.

Freshwater ecosystems, especially springs, are highly sensitive to environmental changes. They are also excellent natural laboratories because of their stable conditions, reducing the number of variables to be considered in field studies. We examined the composition, dynamics and colonisation patterns of macroinvertebrates with respect to canopy coverage and time of day in which available areas are actively colonised. We used artificial substrates that mimicked the natural habitat structure at an isolated karst spring and recovered exposed substrates every 12 h. Physico-chemical parameters of water did not differ significantly regardless of canopy cover. The most numerous representatives and the pioneering champions were larvae of Baetidae (Ephemeroptera) and Chironomidae (Diptera). Simuliidae were also among the most successful pioneering species. Most observed groups more actively colonised substrates in the closed canopy area. Oligochaeta and Gammarus fossarum were more numerous on substrates in the open canopy area. Individuals of all analysed groups showed day-night migration patterns and were more active at night. Coleoptera (Elmis sp.) were the poorest (re)colonisers among the analysed taxa.

Distribution of Foraminiferal Assemblages in Contemporary Bottom Sediments of Qua-Iboe River Estuary, Southeast Nigeria

Abstract Qua-Iboe River estuary, Southeast Nigeria, was studied to determine the relationship between foraminiferal distribution and bottom water physicochemical parameters including salinity, temperature, depth, dissolved oxygen, pH, tidal energy, and sediment. Fifty-five bottom sediment samples from geo-referenced stations were collected at water depths of 0–10 m across the channel. Ten species of foraminifera were identified in the estuary. Q-mode cluster analysis resulted in two biotopes (1 and 2), each representing distinct sub-environments. Biotope 1 included two sub-groups namely, 1a and 1b. Biotope 1a represents the upper estuary environment and is distinguished by the non-recovery of foraminifera. It has a maximum water depth of 8.3 m and occurs in freshwater conditions (0 ppt) with slightly acidic to neutral pH and fine- to medium-grained sands. Biotope 1b is found in the mid-estuarine environment and has a maximum water depth of 4 m. It is distinguished by an abundance of Arenoparrella mexicana. Biotope 2 occurs within the subtidal lower estuarine environment with a maximum water depth of 4 m. It is characterized by slightly acidic to slightly alkaline (pH = 6–8), brackish to marine waters, with fine to very fine-grained sands. Foraminiferal species commonly found in this biotope include Ammonia beccarii, Pseudononion japonicum, and Cribroelphidium excavatum. As salinity increased seawards, agglutinated taxa were gradually replaced by calcareous species. Foraminiferal assemblages in bottom sediments are strongly influenced by salinity.

Особливості росту дволіток веслоноса (Polyodon spathula Walbaum, 1792) в умовах ставового господарства Лісостепу України

Purpose. To investigate the peculiarities of growth of age-1+ paddlefish depending on water temperature and quantitative parameters of zooplankton development in ponds of the forest-steppe zone of Ukraine. Methodology. Age-1+ paddlefish, a North American zooplanktophagus were reared in polyculture with cyprinids in a 72-hectare pond using semi-intensive technology. The stocking density of age-1 paddlefish with an average weight of 86.5 g was 59 fish/ha, with a total stocking density of 2,402 fish/ha for all objects of polyculture. The intensification measures included fertilization of ponds with traditional organic fertilizers and feeding of carp with feed mixtures based on waste from the processing of agricultural raw materials of plant origin. The study of the intensity of development of the natural food supply and physicochemical parameters of water was carried out according to the methods generally accepted in hydrobiology and hydrochemistry. Determination of piscicultural parameters and growth characteristics of age-1+ paddlefish was carried out using methods common in ichthyology based on the dynamics of body weight gains in absolute and relative values. Findings. The conditions of the pond environment during most of the period of rearing of age-1+ paddlefish met the biological requirements of this species. A periodic decrease in the content of oxygen dissolved in water to 3.3-3.5 mgO2/dm3 was noted, which could negatively affect the growth of fish. Water temperature during the fish breeding period varied between 9.8-26.5oC. The average seasonal biomass of phytoplankton and zooplankton of the pond was 16.49 mg/dm3 and 3.92 g/m3, respectively, with a predominance of Cladocera and Copepoda (respectively, 61.0 and 34.5% in the average seasonal biomass) in the quantitative composition of zooplankton. As a result, age-1+ paddlefish reached an average weight of 1318.3 g with a fish productivity of 45.6 kg/ha and a total pond fish productivity of 1162.6 kg/ha. Maximum relative weight gains of paddlefish of 4.25–4.37% per day were observed during the first half of the growing season (mainly in June) at a water temperature of 22–25oC during the period of increase in zooplankton biomass from 3.79 to 10.11 g/m3. Originality. New data were obtained on the growth characteristics of paddlefish depending on environmental conditions of the ponds of the Forest-Steppe zone of Ukraine. Practical value. The study results can be used in the process of improving pond aquaculture technologies in Ukraine. Key words: pond aquaculture, paddlefish, growth, zooplankton, water temperature.

Seasonal Variation and Pollution Assessment of Some Physicochemical Parameters of the Surface Water of Mahin Lagoon and Its Adjoining creeks, South-Western Nigeria

Indiscriminate discharge of untreated wastes from into the aquatic ecosystem may result in deterioration of water quality, as well as poses a great threat to the balance of aquatic ecosystems and human health. This study investigated the seasonal variation in physicochemical characteristics and assessed the pollution status of Mahin Lagoon and its adjoining creeks using standard method. Results of physico-chemical parameters varied significantly (p&lt;0.05) across seasons and stations, with the following mean values: Temperature (27.79±0.96oC), salinity (7.65±0.99‰), conductivity (15.23±17.63µS/cm), pH (7.74±6.57), DO (7.65±0.99 mg/L), BOD (7.74±6.57mg/L), nitrate (8.00±3.67mg/L), sulphate (8.60±5.01mg/L), phosphate (3.88±1.55mg/L). Heavy metals were with the following mean values: Zn (7.15±6.31mg/L), Pb (0.04±0.21mg/L), Fe (10.63±6.02mg/L), Cu (1.16±1.72mg/L), Cr (0.02±0.00mg/L), Cd (0.01±0.08mg/L), Ni (0.28±0.45mg/L) and Co (0.26±0.44mg/L). The physic-chemical parameters were within the permissible limits recommended by International Organizations for lotic ecosystem. However, the single-factor pollution index (PI) classified pH, DO, BOD, Cu and Zn within the ‘medium pollution’ category while nitrate and phosphate indicated heavy pollution status. The PI also revealed that Cu, Fe and Ni were at serious pollution level while Co and Cr were at non-pollution level. The comprehensive pollution index revealed that the water was severely polluted (CPI &lt; 2). The Hazard Quotients of heavy metals in the surface water were less than 1 (HQ &lt; 1) indicating there was no risk to human health through ingestion or dermal contact. Therefore, the water from the Mahin lagoon and its adjoining creeks may still be suitable for domestic use and conducive for survival of aquatic life.

COMPARATIVE INVESTIGATION OF THE IMPACT OF EFFLUENT FOOTPRINT ON THE BONNY ESTUARY

The study, comparative investigation of the impact of effluent footprint on the Bonny estuarywas to assess the impact of wastewater on the Bonny estuary and its environment by analyzing the physicochemical and microbial parameters of surface water in four different locations and a control point. The study found that almost all locations exhibited some level of contamination, particularly hydrocarbons and heavy metals. The findings underscore the importance of regular monitoring of the Bonny Estuary and its environment to detect changes in water quality that could be detrimental to aquatic life and human health.Therefore, regular monitoring of these locations is necessary to discover changes in water quality that could harm marine life consumed by the human community in these areas.

KEPADATAN, KARAKTER MORFOLOGI, DAN PERTUMBUHAN LAMUN Cymodocea rotundata DI PANTAI YANKARWAR, MANOKWARI, PAPUA BARAT: APAKAH ADA PERBEDAAN DIANTARA ZONA INTERTIDAL?

Cymodocea rotundata is a seagrass species that occupy habitats in the intertidal zone. The ability of this species to occupy the intertidal zone is thought to be related to its particular morphological adaptations in response to fluctuations in local aquatic environmental conditions. This study aims to describe habitat conditions, distribution related to density, morphological differences, and growth among C. rotundata seagrass stands in the upper, middle, and lower intertidal zones of Yankarwar Beach, Manokwari, West Papua. Transects and quadrats methods were used to collect seagrass samples, so information on their distribution and density could be obtained. The seagrass samples collected were also analyzed (counted and measured) for their morphological characters including the number of leaves, leaf length, leaf width, horizontal sheath internode length, root length, stand weight, leaf weight, rhizome weight, and root weight. Seagrass growth was obtained by marking the leaves and observing them for 10 days. The results of this study indicate that the conditions of the physicochemical parameters of the intertidal waters are still suitable for the growth of this seagrass species. The highest density was found in the upper intertidal zone (3,161.73 stands.m-2) and followed by the middle intertidal zone (962.04 stands.m-2). Although most of the morphological characters of seagrasses and seagrass parts were relatively the same between the three intertidal zones, larger leaf widths and lengths of horizontal rhizome internodes were found in stands in the two upper intertidal zones. Differences in growth as reflected by the increase in leaf length and dry leaf weight also showed greater values in the upper and middle intertidal zones. This condition shows the adaptability of this seagrass species to variations in environmental parameter conditions in the middle and upper intertidal zone. In addition, the results of this study indicate the presence of C. rotundata, especially in the intertidal aquatic environment which has an important ecological role, including as a substrate stabilizer. Therefore, this vegetation conservation effort is very important.&#x0D; &#x0D; Keywords: intertidal zone, morphological adaptation, seagrass growth

Effects of physicochemical parameters of water on byproduct formation during electrolysis of ballast water

Introduction: Disinfection byproducts (DBPs) generated during ballast water treatment using active substances have gained increasing interest owing to their potential impact on the marine environment. This study aimed to investigate the occurrence and distribution of DBPs, which are secondary products generated during electrolysis, using land-based tests.Methods: DBP levels were compared under various water conditions, including chloride and bromide ion compositions, hold time, and organic matter-related parameters.Results: After electrolysis, trihalomethane (THM) and haloacetic acid (HAA) levels increased from day 0 to day 5 under all salinities, whereas haloacetonitrile (HAN) level decreased. THMs were found to be the most dominant DBP group, followed by HAAs and HANs. In marine water and brackish water, brominated DBPs were dominant owing to high levels of bromide ions, while chlorinated DBP concentrations were relatively high in fresh water.Discussion: After electrolysis, the specific ultraviolet absorption of the treated water was &amp;gt;4, indicating a high likelihood of generating carbonaceous DBPs such as THMs and HAA. These findings contribute to a better understanding of the general mechanisms through which physicochemical factors affect the formation of DBPs during electrolysis treatment of ballast water. This understanding is valuable in addressing issues related to the treatment and release of treated ballast water into the marine environment, which is an emerging environmental concern.

The Effect of Sausage Tree Fruit (Kigelia africana) on Gonadal Development and Growth Performance of Oreochromis andersonii

In Zambia fish farms, Oreochromis andersonii is an important common indigenous fish species. Naturally, safe phytochemicals can effectively improve fish reproduction performance and their production potential. Therefore, this study was conducted to determine the effect of Kigelia africana on the gonadal development and the performance of Oreochromis andersonii. A total of 96 male fingerlings were randomly assigned to four dietary treatments (D1-D4), and each treatment group had three replicates. The D1, D2, D3, and D4 groups were formulated to receive 0, 50, 100, and 150 g of powdered Kigelia africana/kg, respectively. The fish were fed the diets for 9 weeks, followed by the study parameter measurements at the end of the experiment. The highest mean body weight and gonadal weight were (29.8 ± 0.63 and 0.09 ± 0.010 g, respectively) for fish in the D2 group. There was no significant difference between the mean body weight of fish in different groups, but their mean gonadal weights differed significantly. The gonadal somatic index of fish differed significantly among treatment groups, with those in D2 having the highest mean value (0.36 ± 0.060). The highest mean standard length (103.3 ± 0.63 mm) and total length (126.0 ± 0.11 mm) of fish were observed for D1 and D2 groups, respectively. Additionally, the mean values for those parameters decreased with increasing Kigelia africana in the diet. The physicochemical parameters of water, including temperature and dissolved oxygen, ranged 16.8-23.1℃ and 0.6-2.2 mg/L, respectively; these were generally at low levels considering the optimum requirements for this fish species. In conclusion, Kigelia africana improved gonadal growth and development but did not promote overall fish growth. The best gonadal growth/development results of Kigelia africana powder were observed at a level of 50 g/kg, which can be used as a performance booster in the aquaculture production of Oreochromis andersonii.

Spatial and temporal variation of physicochemical parameters of coastal waters in the southwestern region of Sri Lanka

Physicochemical parameters of coastal water in the southwestern area of Sri Lanka were studied from January to November 2016. Surface water samples from 15 selected locations were analysed according to standard methods. The ranges of the values recorded were; water temperature (WT) 26.5-33.9 ºC, pH 7.1-8.4, dissolved oxygen (DO) 4.4-7.4 mg L-1, salinity 14-38 ppt, electrical conductivity (EC) 27.1-53.8 mS cm-1, total suspended solids (TSS) 50.2-403.4 mg L-1, turbidity 1.2-64.9 NTU, nitrate nitrogen (NO3--N) 0.00-0.57mg L-1, nitrite nitrogen (NO2--N) 0.00-0.035mg L-1, ammoniacal nitrogen (NH4+-N) 0.00-1.72mg L-1, dissolved inorganic phosphorous (DIP) 0.00-0.65 mg L-1, biochemical oxygen demand (BOD) 0.1-11.6 mg L-1 and chemical oxygen demand (COD) 40-768 mg L-1. Results of Two-way ANOVA showed that there was a seasonal variability in parameters such as water temperature (p&lt;0.001), dissolved oxygen (p&lt;0.001), BOD (p&lt;0.001), COD (p&lt;0.001), nitrite nitrogen (p&lt;0.001), nitrate nitrogen (p&lt;0.001), dissolved inorganic phosphorous (p&lt;0.001), turbidity (p&lt;0.001), TSS (p&lt;0.001) and Chlorophyll a (p&lt;0.001). Spatial variation was identified in parameters, pH (p&lt;0.001), turbidity (p&lt;0.001), dissolved oxygen (p=0.004) and nitrite nitrogen (p&lt;0.001) whereas the interaction between time and location was significant in pH (p=0.005) and turbidity (p=0.007). However, EC, salinity and ammoniacal nitrogen were not significant by either of the factors of consideration. In conclusion, the physicochemical characteristics of water are highly variable over time and location due to both natural and human factors. Water quality near fish processing areas such as fishery harbours and fish markets relatively deteriorated in terms of pH, DO, turbidity and nitrite nitrogen compared to recreational beaches. It is recommended to regulate any discharges of sewage and industrial wastewater directly into the sea. A long-term coastal water quality monitoring programme is vitally important to comprehensively characterise the coastal segments for a long-term strategic plan for sustainable development.

Combined effect of physico-chemical and microbial quality of breeding habitat water on oviposition of malarial vector Anopheles subpictus.

Mosquitoes prefer diverse water bodies for egg laying and larval survival. Present study was performed with an objective to characterize physico-chemical properties and microbial profiling of breeding habitat water bodies of Anopheles subpictus mosquitoes. A field survey was accomplished to check the presence of An. subpictus larvae to record per dip larval density in various breeding habitats throughout the year. Physico-chemical and bacteriological properties in relation to mosquito oviposition were assessed. Dissolved oxygen content, pH and alkalinity were found to have major impacts and ponderosity on the prevalence of An. subpictus larvae. Larval density showed significant positive correlation with dissolved oxygen content of water and significant negative correlation with pH and alkalinity of habitat water. Comparatively higher population (cfu/mL) of Bacillus spp. competent with starch hydrolyzing and nitrate reducing properties were recorded all the breeding habitat water bodies of An. subpictus. Higher amplitude of anopheline larvae was portrayed during monsoon and post-monsoon season in clear water with an inclining trend to high dissolved oxygen content and neutral pH. B. cereus, B. megaterium, B. subtilis and B. tequilensis prevalent in all habitat water bodies were marked as oviposition attractants of gravid An. subpictus mosquitoes. Microbial population played key roles in the modulation of physico-chemical parameters of habitat water with a view to enhance its acceptability by gravid mosquitoes in relation to their oviposition. Better understanding of the interactions along with the control of oviposition attractant bacterial strains from mosquito breeding habitats might contribute to the vector management programme.

HeadwaterstreamSNevada: Data on riparian vegetation and water parameters of headwater streams in Sierra Nevada, Spain.

Providing historical data on riparian plant biodiversity and physico-chemical parameters of stream water in Mediterranean mountains helps to assess the effects of climate change and other human stressors on these sensitive and critical ecosystems. This database collects data from the main natural headwater streams of the Sierra Nevada (southeastern Spain), a high mountain (up to 3479 m above sea level [m asl]) recognized as a biodiversity super hotspot in the Mediterranean basin. On this mountain, rivers and landscapes depend on snowmelt water, representing an excellent scenario for evaluating global change's impacts. This dataset covers first- to third-order headwater streams at 41 sites from 832 to 1997 m asl, collected from December 2006 to July 2007. Our goal is to supply information on the vegetation associated with streambanks, the essential physico-chemical parameters of stream water, and the physiographic features of the subwatersheds. Riparian vegetation data correspond to six plots sampled at each site, including total canopy, individual number, height and DBH (diameter at breast height) in woody species, and cover percentage for herbs. Physico-chemical parameters were measured in situ (electric conductivity, pH, dissolved O2 concentration, stream discharge) and determined in the laboratory (alkalinity, soluble reactive phosphate-phosphorus [SRP], total phosphorus [TP], nitrate-nitrogen [ -N], ammonium-nitrogen [ -N], total nitrogen [TN]). Watershed physiographic variables comprise drainage area, minimum altitude, maximum altitude, mean slope, orientation, stream order, stream length, and land cover surface percentage. We recorded 197 plant taxa (67 species, 28 subspecies, and 2 hybrids), representing 8.4% of the Sierra Nevada vascular flora. Due to the botanical nomenclature used, the database can be linked to FloraSNevada database, contributing to Sierra Nevada (Spain) as a laboratory of global processes. This data set can be freely used for non-commercial purposes. Users of these data should cite this data paper in any publications resulting from its use.

Predicting Legionella contamination in cooling towers and evaporative condensers from microbiological and physicochemical parameters.

Inhalation of Legionella-containing aerosols generated by cooling towers (CT) and evaporative condensers (EC) where water risk management is not performed correctly has been linked to a high percentage of community outbreaks of Legionnaires' disease (LD). Likewise, microbiological and physicochemical characteristics of the water in these facilities have been associated with this bacterium. The main aim of this study was to assess the risk of Legionella colonization in CT and EC based on the data for microbiological and physicochemical water quality provided by the Environmental Health Department and Laboratory of the City Council of L'Hospitalet de Llobregat (Barcelona, Spain). Legionella was analysed in 789 samples collected from 127 CT and EC in 46 companies in Catalonia from 2002 to 2019. A two-step logistic regression analysis was carried out to assess the risk of colonization by Legionella in the studied facilities according to the microbiological (aerobic heterotrophic bacteria) and physicochemical (pH, alkalinity, hardness, turbidity, conductivity, total iron and Langelier Index) water parameters. The optimal cut-off points for the water parameters predictive of Legionella contamination were defined as the values on the receiver operating characteristic (ROC) curve where sensitivity and specificity were jointly maximized. Legionella was isolated in 8.49% of the 789 analysed samples, 22.39% of which were heavily contaminated (with counts higher than 1.0×104CFU/l). L. pneumophila was isolated in 82.09% of the samples, with 41.82% belonging to serogroup 1. Logistic regression analysis revealed that aerobic heterotrophic bacteria concentrations ≥6.90×102CFU/ml [Odds ratios (OR) (95% CI)=3.56 (1.39-9.43), p=0.01], a pH≥8.70 [OR (95% CI)=3.60 (1.34-10.09), p=0.01], and water hardness ≥5.72×102mg/l [OR (95% CI)=6.30 (2.34-18.56), p<0.001] were each independently associated with a higher risk of CT and EC colonization by Legionella. The present study shows the importance of risk assessment for improving the control measures aimed at preventing or reducing Legionella populations in CT and EC, thus minimizing potential dangers for public health.

Bioflocs enriched with lyophilized açaí (Euterpe oleracea) improved the survival and weight gain of Litopenaeus vannamei post-larvae cultivated in the BFT system

This study evaluates the bioflocs capacity to assimilate and transfer the bioactive compounds present in açaí to post-larvae of Litopenaeus vannamei cultured in the BFT system. In the first experiment, 21 experimental units (1 l) were randomly distributed among seven treatments (control, 2.5, 5.0, 10.0, 20.0, 40.0, and 80.0 mg açaí L−1) in the BFT system without the inclusion of post-larvae and no water change. Every 24 h, for seven days, the respective concentrations of açaí were added to bioflocs. Initial characteristics of the biofloc used were of 0.13 mg TAN L−1, 0.51 mg N-NO2− L−1, 60.5 mg N-NO3− L−1, 245 mg CaCO3 L−1 and 330 mg TSS L−1. In the second experiment, 12 experimental units (20l), all in triplicate, were randomly distributed in four treatments (control, 5.0, 20.0, and 80.0 mg açaí L−1) with 600 post-larvae (twenty-three day-old PL) per tank cultivated in the BFT system for 27 days. The biofloc inoculum used in the second experiment contained 0.52 mg TAN L−1, 0.13 mg N-NO2− L−1, 35.70 mg N-NO3− L−1, 177.5 mg CaCO3 L−1 and 330 mg TSS L−1. Water changes during post-larvae cultivation were performed when the concentration of nitrite and total suspended solids in the water exceeded the safe levels of 1.38 mg L−1 and 500 mg L−1, respectively. In the first experiment, an increase in the antioxidant capacity was observed against peroxyl radicals of bioflocs (p < 0.05) at concentrations of 5.0 and 20.0 mg açaí L−1 and a decrease in lipid peroxidation (TBARS) at a concentration of 20.0 mg açaí L−1. In the second experiment, the mean values of the physicochemical parameters of water remained within the range considered adequate for post-larval culture. Shrimp from treatments with açaí showed greater survival, weight gain, and FCR at the concentration of 20.0 mg açaí L−1 (p < 0.05). Bioflocs and shrimp lost antioxidant capacity with increasing açaí concentration (p < 0.05). The TBARS levels of the biofloc were lower at concentrations of 5.0 and 20.0 mg açaí L−1 compared with 80.0 mg açaí L−1 (p < 0.05). It is concluded that bioflocs can assimilate part of the antioxidant compounds, allowing the addition of up to 80.0 mg of lyophilized açaí in BFT systems, and are an alternative to minimize oxidative stress during culture and influence the quality and growth success of post-larvae.

Growth Performance and Proximate Composition of African Catfish (Clarias gariepinus) Cultured in Cages and Pens in Northern Benin Water Reservoirs Exposed to Cotton-field Effluents

The potential use of water reservoirs exposed to cotton-fields effluents in northern Benin was explored for African catfish (Clarias gariepinus) production. A 120-day experiment was conducted to evaluate the rearing performance of C. gariepinus in two culture systems (cage and pen) tested each in two water reservoirs, one located within the cotton basin (Batran) and the other outside (Songhaï). Measured water physico-chemical parameters were within the tolerable limits for C. gariepinus. Survival rates were similar among treatments and above 92%. Water reservoir, culture system and their interaction influenced significantly the final mean body weight (g), specific growth rate (%/day), and condition factor (%). The highest values of these parameters were observed in fish from cages at Batran (701.09±38.82 g, 2.88±0.05, and 0.84±0.00), while the same culture system displayed the lowest values (296.83±19.95 g, 2.16±0.06, and 0.67±0.02), statistically similar to those obtained in pens at Songhaï. Feed utilization parameters were similar between the culture systems. Fish with high mean final body weight contained less water and more ash and gross energy (p&lt;0.05). We recommend cage culture for improved rearing of African Catfish in northern Benin water reservoirs.

Surface Water Contamination by Mining Wastes: Case of the Sidi Kambar Region (Skikda North-East Algeria)

Abstract The objective of this work is to assess the contamination of the Essouk stream, under acid drainage from the Sidi Kambar mine (southwest of Skikda, Algeria), which has been widely exploited during the previous decades. The methodology was conducted to control the current state of water chemistry, its evolution in space and time according to the variation of water physicochemical parameters and the content of trace metals (Pb, Fe, and Zn). In general, Essouk stream are highly sulphated (reached 598.56 mg/L) and have an elevated salinity, resulting in a high conductivity (1925 µS/cm) and presented a low pH (3.01). In addition, Fe, Pb and Zn contents reached 5.17 mg/L, 2.05 mg/L and 4.05 mg/L, respectively. Such results were linked to the bedrock of Sidi Kambar that is composed of galena, pyrite and sphalerite.