Effect Of Water pH Research Articles

Comparison of the efficiency and mechanism of catalytic ozonation of 2,4,6-trichloroanisole by iron and manganese modified bauxite

The efficiency and mechanism of catalytic ozonation of 2,4,6-trichloroanisole (TCA) by metal oxide modified bauxite were studied. TCA was effectively degraded by catalytic ozonation in the presence of iron- or manganese-modified bauxite (IMB or MMB). The effect of water pH on catalytic ozonation indicated that surface property was the key factor that influenced the activity of catalyst. Analysis results of the isoelectric point (IEP) and zeta potential for catalyst further confirmed that a lower zeta potential for modified bauxite enhanced catalytic activity. Results of both catalytic ozone decomposition and radical scavengers experiments indicated that catalytic ozonation by IMB or MMB followed a hydroxyl radical (OH) reaction pathway. The main reaction pathway was proposed that adsorption of both ozone and TCA in the micropores and subsequent interaction (direct and indirect oxidation) between them that was confirmed by the analysis of the surface pore volume and surface hydroxyl groups, being followed by the diffusion of ozone and TCA on the mesoporous surface, in which surface hydroxyl groups covering mesoporous surface initialed ozone decomposition to generate OH, resulted in TCA degradation.

Dietary salt and water pH effects on growth and Na+ fluxes of silver catfish juveniles

This study verified the optimum dietary salt level for the growth and ion regulation of silver catfish juveniles at different water pH levels (5.5, 7.0 and 9.0). The control diet was supplemented with NaCl to yield experimental diets with 0.5, 1.0 and 2.0% NaCl. Juveniles were collected at 15 and 35 days after the beginning of experiment for analyses of Na + net fluxes. Exposure of silver catfish juveniles to alkaline or acidic water did not affect their survival. Fish fed with diets without NaCl supplementation and exposed to pH 7.0 showed significantly higher weight, length, specific growth rate and biomass per tank than those exposed to pH 5.5. Ionoregulatory disturbances of silver catfish maintained at all pH are less pronounced when fed higher dietary salt supplementation (1.0-2.0% NaCl). The increase of dietary NaCl reduced body Na + loss and protected against the impact of acidic water on growth.

Effects of Water pH and Hardness on Infection of Silver Catfish, Rhamdia quelen, Fingerlings by Ichthyophthirius multifiliis

The aim of this study is to determine the effect of (1) different pH levels (5, 6, 7, 8, and 9) with water hardness 20 mg/L CaCO3 and (2) pH 5 and 7 with varying water hardnesses (20, 60, and 120 mg/L CaCO3) on the intensity of infection by Ichthyophthirius multifiliis in fingerlings of the silver catfish, Rhamdia quelen. In Experiment 1, the lowest and highest mortality rates were observed in fingerlings exposed to pH 5 and 9, respectively; in Experiment 2, fish kept at pH 5 and 7 with hardness 20 mg/L CaCO3 showed significantly lowest and highest cumulative mortality, respectively, than those maintained in other conditions. The lowest intensity of trophonts/fingerling was observed at pH 5 and hardness 20 mg/L CaCO3 in both experiments. We conclude that infection by I. multifiliis is less severe in silver catfish maintained at pH 5 and hardness 20 mg/L CaCO3. High water hardness led to an increased intensity of trophonts and decreased survival in silver catfish kept at pH 5, but decreased intensity of trophonts and improved survival when the fish were kept at pH 7.

Water parameters affect anaesthesia induced by eugenol in silver catfish, Rhamdia quelen

The present study investigated the effects of water pH (5.0, 7.0 and 9.0), hardness (0, 20 and 120 mg CaCO3 L−1) and temperature (15, 23 and 30 °C) on the induction of sedation and anaesthesia, and subsequent recovery, of silver catfish exposed to eugenol. Moreover, the blood gas tensions (PvO2 and PvCO2) and blood pH in silver catfish acclimated to these temperatures were investigated after exposure to eugenol. Water pH, hardness, temperature and fish size affect the efficacy of eugenol in silver catfish, particularly at the lower concentrations tested (20 and 30 mg L−1). Sedation of this species can be induced at concentrations as low as 20 mg L−1, but for anaesthesia, a concentration of at least 40 mg L−1 of eugenol must be used to compensate for the influence of fish size and water quality. Blood gas tension and pH were affected by eugenol anaesthesia, but only in fish acclimated to 30 °C.

Bonding Property of Bituminous Crack Sealants in the Presence of Water

Problem statement: Crack sealing and filling is the most widely used maintenance activity for in-service pavements. If an appropriate sealant material is selected and properly installed at the appropriate time of the pavement life, it retards pavement deterioration and increases its service life at a relatively low cost. However, in some cases it is reported that sealants failed prematurely, mainly due to environmental factors and water exposure. While there have been several studies on environmental factors, water related factors has not received appropriate attention. Nevertheless, various sealants have different water resistance property; hence, they perform differently when exposed to large amount of rain and humidity. Approach: Currently, there is no standard test method to evaluate sealant water resistance. Therefore, there is a need for a standard test method to precisely predict sealant performance when exposed to water. Such a test method can help examine various sealants in terms of their water resistance. This study introduces water conditioning procedure and a test method to measure bond strength of sealant under dry and wet condition. The effect of water on the Interfacial Fracture Energy (IFE) of bituminous sealants was measured by means of a blister test. This test allows the calculations of two fundamental parameters: tensile modulus and the Interfacial Fracture Energy (IFE). Results: Experimental results showed water exposure caused a significant drop in adhesion strength. However, no significant difference was observed between adhesion strength of specimens conditioned for 8 and 12 h of conditioning. Conclusion/Recommendations: The proposed approach and testing method can be used by the sealant manufacturers to improve their sealants’ adhesion properties at the presence of water. However, further research works are needed to examine how sealant adhesion strength varies with water exposure duration. Also, the effect of water pH on sealant adhesion strength can be studied.

Comprehensive analysis of surface free energy of asphalts and aggregates and the effects of changes in pH

Moisture damage is a major factor in the deterioration of asphalt pavements. In order to combat this problem, it is essential to understand the effects of moisture on the adhesive and cohesive bonds in asphalt concrete mixtures. These effects can be quantified through the use of surface free energy, which is a thermodynamic material property that has been successfully used to select asphalt binders and aggregates that have the necessary compatibility to firm strong bonds and resist moisture damage. This study aimed at understanding the effects of material characteristics and additives on surface energy and the resulting bond between asphalt binders and aggregates. As such, the study involved measuring the surface free energy of 37 neat and polymer modified asphalt binders and 11 aggregates were measured. In addition, the surface free energy was measured for three asphalt binders after two anti-strip agents were added separately (six binder-anti-strip agent combinations) and for nine asphalt binders that were both short and long-term aged. The study also examined the effect of water pH on surface energy and water-aggregate adhesive bond. It was found that anti-strip agents, in general, reduced the cohesive bond energy of asphalt binder, allowing better wetting and adhesion to aggregates and increase in resistance to moisture damage. Aging of the asphalt either increased or decreased the cohesive bond depending upon the chemical composition of the unaged asphalt binder. Statistical analysis was conducted to rank the moisture resistance of asphalt binders and asphalt–aggregate combinations, respectively. The results showed that the pH of the water increased slightly due to contact with the aggregates, but did not significantly alter the total surface tension of the water or surface free energy components of the asphalt binder.

Mechanism investigation of catalyzed ozonation of 2-methylisoborneol in drinking water over aluminum (hydroxyl) oxides: Role of surface hydroxyl group

In this investigation, the mechanism of catalyzed ozonation of MIB by aluminum oxides (γ-AlOOH and γ-Al 2O 3) was studied. It was concluded that the roles of surface hydroxyl groups in adsorption and catalyzed ozonation determined catalyzed ozonation mechanism. The removal efficiency of MIB in catalyzed ozonation by γ-Al 2O 3 or γ-AlOOH was 98.4% and 27.5%, respectively. Effect of water pH on catalyzed ozonation indicated that surface hydroxyl group, of which surface net charge was zero, was the active site of catalysts. Radical scavenger experiments results indicated that catalyzed ozonation by γ-Al 2O 3 followed a hydroxyl radical ( OH) reaction-pathway and the reaction-pathway of catalyzed ozonation by γ-AlOOH followed solid surface mechanism. However, both γ-AlOOH and γ-Al 2O 3 can enhance ozone decomposition to generate hydroxyl radical in catalytic ozone decomposition (without MIB). The inconsistent results between radical scavengers and catalytic ozone decomposition were mainly due to the interaction between MIB and surface hydroxyl groups. According to MIB adsorption on γ-AlOOH or γ-Al 2O 3, MIB interacted with surface hydroxyl group by chemical adsorption, and surface hydroxyl group was the main adsorption site. The adsorption capability of γ-AlOOH was higher than that of γ-Al 2O 3. The participation of surface hydroxyl group in adsorption restrained its capability of catalyzed ozone decomposition to generating OH. γ-AlOOH that was covered with more surface hydroxyl groups, adsorbed MIB more stronger and inhibited generation of OH in catalyzed ozonation of MIB, resulting in lower removal efficiency of MIB in catalyzed ozonation. In addition, the surface texture and chemical properties of catalyst that can help to understand the catalyzed mechanism.

Deterministic assembly of land snail communities according to species size and diet

1. We investigated whether coexisting snail species in 145 treeless fen communities in the Western Carpathian Mountains differed more in size and diet than would be expected by chance, as predicted for traits commonly associated with competition and differential resource acquisition under limiting similarity theory. 2. Contrary to expectations, coexisting snail species were no more different in body size than expected by chance under a null model. However, variation in body size played a significant role in structuring snail communities: coexisting snail species were significantly more similar with respect to body size. 3. We developed two new test statistics to expand our investigation of limiting similarity to include diet, a nominal trait. We tested whether communities of snails were characterized by a greater richness of diet, and whether different diets were represented more or less evenly within communities. Communities of snails were significantly less evenly distributed than expected by chance, with detritivores being over-represented relative to predatory strategies. 4. We also examined the effect of water pH and conductivity, herbaceous cover, and bryophyte and vascular plant richness, on these trends by examining how the effect size of our tests varied across these gradients. Convergence in species size increased with increasing habitat pH. Specifically, smaller snail species were over-represented in fen communities in general, and this effect was accentuated in increasingly calcareous fens. 5. Theory predicts that traits related strongly to environmental conditions are more likely to be convergent. Our findings support this suggestion, as small snail species have an advantage in tolerating freezing conditions over winter when refuges are limited. 6. These results add to the growing body of literature demonstrating that variation in body size and diet play a strong role in structuring communities, although frequently in ways not predicted by limiting similarity theory. Finally, our results increase our understanding of how species are assembled non-randomly into communities with respect to important traits.

The combined effect of copper and low pH on antioxidant defenses and biochemical parameters in neotropical fish pacu, Piaractus mesopotamicus (Holmberg, 1887)

Copper sulfate is widely used in aquaculture. Exposure to this compound can be harmful to fish, resulting in oxidative metabolism alterations and gill tissue damage. Pacu, Piaractus mesopotamicus, (wt = 43.4 +/- 3.35 g) were distributed in experimental tanks (n = 10; 180 l) and exposed for 48 h to control (without copper addition), 0.4Cu (0.4 mg l(-1)), 0CupH (without copper addition, pH = 5.0) and 0.4CupH (0.4 mg l(-1), pH = 5.0). In liver and red muscle, the superoxide dismutase (SOD) was responsive to the increases in the aquatic copper. The plasmatic intermediary metabolites and hematological variables in the fish of group 0.4Cu were similar to those of the control group. Conversely, the exposure to 0.4CupH caused an increase in the plasmatic lactate, number of red blood cells (RBC) and hemoglobin (Hb). Plasmatic copper concentration [Cu(p)] increased in group 0.4Cu and 0.4CupH, which is higher in group 0.4CupH, suggests an effect of water pH on the absorbed copper. Exposure to 0.4Cu and 0.4CupH resulted in a reduction in the Na(+)/K(+)-ATPase activity and an increase in metallothionein (MT) in the gills. Exposure to 0CupH caused a decrease in glucose and pyruvate concentrations and an increase in RBC, Hb, and the branchial Na(+)/K(+)-ATPase activity. These responses suggest that the fish triggered mechanisms to revert the blood acidosis, save energy and increase the oxygen uptake. MT was an effective biomarker, responding to copper in different pHs and dissolved oxygen. Combined-factors caused more significant disturbance in the biomarkers than single-factors.

Formation of N-Nitrosodiphenylamine and Two New N-Containing Disinfection Byproducts from Chloramination of Water Containing Diphenylamine

N-nitrosodiphenylamine (NDPhA) is a disinfection byproduct (DBP) in drinking water. However, it is not known what governs the formation of NDPhA and which precursor(s) in the raw water is responsible for its formation. We report here diphenylamine (DPhA) as a key precursor of NDPhA, and we describe the effect of water pH and chloramination conditions on the formation of NDPhA. To identify precursors of NDPhA, raw water samples were collected from the same drinking water system in which NDPhA was previously detected. Analysis of the raw water samples showed the presence of 1.3 ng/L of DPhA and no detectable NDPhA. Seven hours after the treatment of the raw water with chloramines, the concentration of DPhA decreased to 0.4 ng/L with corresponding formation of NDPhA (0.4 ng/L). Controlled experiments involving chloramination of DPhA in water showed that chloramines were essential to the formation of NDPhA, and that increasing the pH from 4 to 10 resulted in 64-fold enhancement in NDPhA formation. Removal of DPhA and formation of NDPhA was found by mass imbalance, which led to the identification of two new DBPs, phenazine (MW 180 Da) and a chlorinated phenazine derivative (MW 216 Da), using liquid chromatography tandem mass spectrometry and gas chromatography mass spectrometry. Both new DBPs were detected only in the treated water and not in the raw water. Phenazine and N-chlorophenazine have never been reported as DBPs and neither their occurrence in drinking water nor their health effects are known.

Effect of Water pH on Yield and Nutritional Status of Greenhouse Cucumber Grown in Recirculating Hydroponics

ABSTRACT Cucumbers are produced in integrated hydroponic and aquaculture systems (aquaponics). Aquaponics balances pH for plants, fish, and nitrifying bacteria. Nitrification prevents buildup of toxic waste ammonia by conversion to nitrate (NO3 −)- nitrogen (N). The pH for hydroponic cucumbers (5.5–6.0) and nitrification (7.5–9.0) requires reconciliation to improve systems integration. Cucumbers were grown at pH of 5.0, 6.0, 7.0, and 8.0 with additional foliar sprays at pH 7.0 and 8.0. Plant shoot dry weight, length, N, and phosphorus (P) content at 14 DAT were similar from pH 5.0 to 7.0, but reduced at pH 8.0. Nutrient solution and shoot dry matter Mn and Fe decreased as pH increased. Foliar sprays had no effect on cucumber fruit yield. Early yield was higher at pH 5.0 compared to pH 8.0 but total yield was unaffected by pH. Cucumbers in recirculating culture may be maintained at pH levels more optimum for nitrification (7.5–8.0) except during production for early season markets.

Energy-efficient production system for ultrapure water targeted

A chemical-less process using vacuum-UV (VUV) as radiation source was used for direct oxidation of ammonium to N2 from the contaminated water. The effect of water pH, aeration, initial ammonium concentration, reaction time, and water anions on ammonium oxidation was evaluated in batch experiments. The oxidation of ammonium improved with the increase in water pH and the highest oxidation level obtained at the pH 8. Although the aeration partly improved ammonium oxidation efficiency, it inhibited the selective oxidation of ammonium to N2. The complete oxidation of ammonium at concentrations of 25, 50, 75 and 100 mg NH4+/L was obtained at the reaction times of 5, 6, 7.5 and 10 h, respectively, following pseudo first-order kinetic model. In addition, the selectivity to nitrate and N2 formation obtained in the range of 7.7–14.8% and 85.2–92.3%, respectively. In continuous flow experiments, the complete oxidation of 50 mg/L ammonium observed at HRT of 8 h with N2 selectivity above 99%. Sulfate had the lowest and carbonate had the highest scavenging effect among the selected anions on radicals species generated in the VUV photoreactor. Accordingly, the VUV photoreactor is an efficient and promising chemical-less advanced process for selective oxidation of ammonium to N2.

Effect of water pH and total dissolved solids on the species diversity of pelagic zooplankton in lakes: A statistical analysis

Statistical analysis of the combined influence of lake surface area (S), water pH, and total dissolved solids (TDS) on the formation of zooplankton communities in lakes has been made on the basis of available data on the number of species (N sp ) of pelagic zooplankton in 256 lakes of the temperate zone of Europe, Asia, and North America. Graphic analysis and analysis of variance have shown that extremely high or extremely low values of pH and TDS inhibit lake zooplankton. If the value of one of these factors is extremely high, any increase in the other factor is favorable for the inhibited zooplankton, and this second factor determines the value of N sp .

Combined effects of water pH and alkalinity on the accumulation of lead, cadmium and chromium to Labeo rohita (Hamilton)

Influence of pH (5.5, 7.0 and 8.5) and alkalinity (40 to 200 mg/L as CaCO 3 ) on the accumulation of Pb (NO 3 ) 2, CdCl 2 , H 2 O and K 2 Cr 2 O 7 to Labeo rohita (Hamilton) was investigated in the laboratory. Highest accumulation of Pb and Cr in whole fish occurred at pH 5.5 and at alkalinity level of 40 to 46 mg/L as CaCO 3 compared to 7.0 and 8.5. In case of Cd maximum accumulation occurred at pH 7.0 and at alkalinity of 100 mg/L as CaCO 3 than that of pH 5.5 and 8.5 and alkalinity 42 and 156 mg/L as CaCO 3 . Maximum accumulation of lead and chromium occurred at total alkalinity level of 40 and 46 mg/L as CaCO 3 , respectively while maximum accumulation of cadmium occurred at an alkalinity level of 200 mg/L as CaCO 3 . A significant (p<0.05) linear relationship was demonstrated between increasing pH/ alkalinity and decreasing accumulation in Pb and Cr treatment at all exposure period while for Cd there was no significant linear relationship established.

Haematological changes in the three Indian major carps, Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton) exposed to acidic and alkaline water pH

The effect of water pH on certain haematological parameters was studied in the three species of Indian major carps, catla ( Catla catla), rohu ( Labeo rohita) and mrigal ( Cirrhinus mrigala) for 21 days by subjecting fingerlings of these fishes to acidic (pH 5.5, 6.5) and alkaline (pH 8.0, 8.5 and 9.0) water, control groups were maintained at neutral pH. A change in water pH either to acidic or alkaline conditions exerted stress in fish characterized by swelling of erythrocytes, production of immature erythrocytes, and reductions in the total erythrocyte counts, haemoglobin and serum protein content. There were also increases in total leukocyte counts and blood glucose. However, the degree of these responses varied among the three species. Rohu was found to be least affected followed by mrigal to the stress of altered water pH, while catla was the most vulnerable to pH changes.

Na+ and K+ body levels and survival of fingerlings of Rhamdia quelen (Siluriformes, Pimelodidae) exposed to acute changes of water pH.

The objective of this study was to investigate the effect of water pH on survival and Na+ and K+ body levels of fingerlings of Rhamdia quelen, a freshwater catfish. Survival was 100% at pH 4.00 to 9.0 throughout the experiment (96h), and death of all fingerlings was observed only at pH 3.75 or lower and at pH 10.50. There was a significant correlation between water pH and body Na+ levels (but not K+ levels) 72h after transfer. There was a clear reduction in Na+ levels when the transfer was to pH outside the 5.0 - 9.0 range, which is in agreement with the fact that fishes exposed to such pH’s present loss of ions by diffusion and/or a decrease in absorption. Growth experiments with this species probably would present best results within the 5.0 - 9.0 pH range, in which the decrease of body Na+ levels is reduced.

Effect of water pH on the survival rate of larvae of the American tadpole shrimp, Triops longicaudatus (LeConte) (Notostraca : Triopsidae).

Survivorship of the larvae of American tadpole shrimp, Triops longicaudatus, was examined in the paddy water of organic farming soil which was adjusted to different pH values by NaOH solution. Among the range of pH 4.4 to 5.3, all inoculated larvae died within 12 h. In the range of pH 5.9 to 6.6, the survival rate of the larvae until 24 h was more than 50% and the rate increased with increasing pH. The effect of rectifying the acidity of organic farming paddy soil by adding Ca(OH)2 was examined in artificial paddy containers. The water pH without Ca(OH)2 was 4.9 during the first 10 days, and all larvae died within 6 days after inoculation. About 60% of larvae survived until 22 days after inoculation in paddy water adjusted to over pH 6.7 by adding Ca(OH)2. The brooding individuals appeared from 14 days after inoculation and ovipositing behavior was frequently observed. It was determined that the boundary of suitable and unsuitable water pH for larval survival was between 5.7 and 5.9, and the larvae can grow to the ovipositional stage by rectification of soil acidity.

Effects of water pH and calcium concentration on ion balance in fish of the Rio Negro, Amazon.

We examined the effects of acute low-pH exposure on ion balance (Na+, Cl-, K+) in several species of fish captured from the Rio Negro, a dilute, acidic tributary of the Amazon. At pH 5.5 (untreated Rio Negro water), the four Rio Negro species tested (piranha preta, Serrasalmus rhombeus; piranha branca, Serrasalmus cf. holandi; aracu, Leporinus fasciatus; and pacu, Myleus sp.) were at or near ion balance; upon exposure to pH 3.5, while Na+ and Cl- loss rates became significant, they were relatively mild. In comparison, tambaqui (Colossoma macropomum), which were obtained from aquaculture and held and tested under the same conditions as the other fish, had loss rates seven times higher than all the Rio Negro species. At pH 3.0, rates of Na+ and Cl- loss for the Rio Negro fish increased three- to fivefold but were again much less than those observed in tambaqui. Raising water Ca2+ concentration from 10 micromol L-1 to 100 micromol L-1 during exposure to the same low pH's had no effect on rates of ion loss in the three species tested (piranha preta, piranha branca, aracu), which suggests that either they have such a high branchial affinity for Ca2+ that all sites are saturated at 10 micromol L-1 and additional Ca2+ had no effect, or that Ca2+ may not be involved in regulation of branchial ion permeability. For a final Rio Negro species, the cardinal tetra (Paracheirodon axelrodi), we monitored body Na+ concentration during 5 d of exposure to pH 6.0, 4.0, or 3.5. These pH's had no effect on body Na+ concentration. These data together suggest that exceptional acid tolerance is a general characteristic of fish that inhabit the dilute acidic Rio Negro and raise questions about the role of Ca2+ in regulation of branchial ion permeability in these fish.

Combined effects of water pH and salinity on the bioaccumulation of inorganic mercury and methylmercury in the shore crab Carcinus maenas

Tissue mercury concentrations were analysed in the whole organism and various organs of the euryhaline shore crab Carcinus maenas after 3 and 15 days of exposure to inorganic mercury (Hg(II)) and methylmercury (MeHg) at a nominal concentration of 1 μgHg l −1. Chemical speciation of the metals was varied by using four pH/salinity conditions (combinations between pH 7.0 and 8.5/salinity 560 and 140 mM NaCl). In all conditions, the results showed a particularly important Hg accumulation in gill tissue, smaller levels in the carapace and internal organs, and very low concentrations in circulating haemolymph. For Hg(II), accumulation was generally favoured at low salinity, but the data revealed complex pH/salinity interactions. Positive correlations were found between tissue metal levels and the abundance of some inorganic Hg species: HgCl 2, HgCl − 3, Hg 2+, HgCl +, indicating that chemical speciation may be an important factor governing metal uptake. The balance of evidence favours HgCl 2 and CH 3HgCl as the most bioavailable species for uptake of Hg(II) and MeHg, respectively.

Water Quality I: The Effect of Water Nitrate and pH on Broiler Growth Performance

Broiler chickens grown to 6 wk of age, received water treatments of pH 5.75, 6.25, or 6.75 and nitrate-nitrogen (NO3-N) levels of 1.90, 2.72, 3.55, or 5.19 mg/L. Low NO3-N, 2.72 to 5.19 mg/L, depressed (P < .05) 6-wk body weights when averaged across all pH treatments (x = ph 6.25). The compounded effect of water pH 5.75 and low NO3-N levels of 3.55 or 5.19 mg/L significantly (P < .05) lowered broiler weights. Lowering the pH of the drinking water to 5.75 decreased water consumption (P < .05) and may have contributed to the lower body weights during the final finisher period. Thymus and spleen weights were reduced (P < .05) due to overall water nitrate treatment. As with body weights, thymus, liver, and spleen weights were lowest (P < .05) among birds consuming water of pH 5.75 or 5.19 mg/L NO3-N. This study shows that in the presence of low water pH (5.75) very low NO3-N levels (≤5.19 mg/L) will adversely affect broiler growth.