Suitability of Immobilized Pseudomonas fluorescens SM1 Strain for Remediation of Phenols, Heavy Metals, and Pesticides from Water

Immobilized microbial cells for the biological treatment have the potential to degrade toxic chemicals faster than conventional wastewater treatment systems. In the present study, suitability of immobilized Pseudomonas fluorescens SM1 strain in calcium alginate beads for remediation of the major toxicants in Indian water bodies was tested by means of GC/HPLC and AAS techniques. Roughly 80% reduction in the concentration of phenols was observed by immobilized SM1 cells compared with 60% by the free cells. Also, in the case of the bioremediation of heavy metals, immobilized SM1 cells were found to be more efficient compared with the free cells. Suspension of P. fluorescens SM1 cells in the test model water for 24 h brought down the concentrations of Cu⁺⁺, Cd⁺⁺, Ni⁺⁺, and Pb⁺⁺ by more than 75% under free cell state and 7?C9% better efficiency under the immobilized conditions. However, Cr(VI) could show only 44% removal by the cell immobilized system, whereas a mere 35% reduction in the Cr(VI) levels was shown in the test model water by the free SM1 cells under the same conditions. Moreover, a model water containing 2,000 ppb of BHC, 1,248 ppb mancozeb, and 312 ppb 2,4-D passed through the cell immobilized column resulted in the decline in their concentrations up to 362 ppb, 750 ppb, and 126 ppb, respectively. Generally, AAS, HPLC, and GC analyses of treated test model waters with the free and immobilized SM1 cells exhibited high potential of immobilized SM1 in detoxification of test water. From the results, we conclude that immobilized cells of P. fluorescens SM1 strain were quite effective in bioremediation of major toxicants present in Indian water bodies, and we also recommend the use of immobilized bacterial cells rather than the free cells for the bioremediation/detoxification process.     

Copper Biosorption by Biomass of Marine Alga: Study of Equilibrium and Kinetics in Batch System and Adsorption/Desorption Cycles in Fixed Bed Column

Copper biosorption onto chemically modified biomass of marine alga Sargassum filipendula was investigated in a batch reactor and a fixed bed column. Experiments were carried out in the batch reactor to obtain kinetic and equilibrium data and to assess the copper desorption efficiency of different eluent solutions. The pseudo-first-order, pseudo-second-order, and Langmuir kinetic models were used to correlate kinetic data. The experimental data fitted well to the pseudo first order and Langmuir kinetic models. Langmuir and Freundlich models were applied to describe the equilibrium data obtained at a fixed temperature of 30°C and at pH values of 3.0, 4.0, 5.0, and 6.0. The maximum capacities of copper biosorption onto the algal biomass were 1.43, 1.59, 2.40, and 2.36 mequiv./g at pH 3.0, 4.0, 5.0, and 6.0, respectively. The efficiencies of two eluent solutions (calcium chloride and hydrochloric acid) for copper removal from the biomass were evaluated at different concentrations (0.1, 0.2, 0.5, and 1.0 mol/L). The efficiencies of the calcium chloride solutions varied from 1% to 14%, while efficiencies varying from 95% to 99% were obtained when hydrochloric acid solutions were applied. Three adsorption/desorption cycles were carried out in a fixed bed column using 0.1 mol/L hydrochloric acid as eluent solution. The results showed that an increase in the number of cycles led to a reduction in the adsorption capacity of the alga. The desorbed copper fraction presented no significant variation, remaining around 63% in the three adsorption/desorption cycles.     

Industrial Symbiosis Between the Winery and Environmental Industry Through the Utilization of Grape Marc for Water Desalination Containing Copper(II)

A bioadsorbent formulated with a secondary raw material, consisting of grape marc, subjected to a bioxidize process and entrapped in calcium alginate beads, was used for the desalination of water containing copper(II) sulfate. Experiments were established under different experimental conditions varying the concentration of contaminant, the amount of bioadsorbent, and the extraction time through response surface methodology. The most significant variable in the removal of copper(II) sulfate was the amount of bioadsorbent employed, followed by the extraction time; whereas, the adsorbent capacity was more influenced by the amount of contaminant and the amount of bioadsorbent used. At the highest concentration of copper(II) sulfate (0.15 mol/L), the equations obtained predict that the bioadsorbent has a capacity of 2785 mg/g and produces a copper(II) removal about 43% using low adsorbent/water ratios, 1:10 (v/v), and maximum extraction times; whereas, it would remove 97.2% of copper(II) sulfate in 5 min, using adsorbent/water ratios close to 1:2 (v/v), with capacity values, in this case, around 1800 mg/g. The encapsulation of the bioxidize adsorbent increased its capacity to 30% and allowed the precipitation of sulfate ions as calcium sulfate. The results obtained in this work could presume advances for promoting the industrial symbiosis between winery and environmental industries.

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Graphical abstract Utilization of secondary raw material, consisting of bioxidize grape marc from winery industry, as bioadsorbent encapsulated in calcium alginate beads, for the removal of copper(II) sulfate from water

     

Growth,nutrient acquisition,and physiological responses of three olive cultivars to induced salt stress

Three olive (Olea europaea L.) cultivars Nabali Baladi (NB), Nabali Muhassan (NM), and Grossi Di'Espagna (GE) were evaluated under salt stress. Seedlings were treated with salinity induced by a 3:1 ratio of calcium chloride and sodium chloride to four concentration levels measured as electrical conductivity (EC) [1.2, 4.1, 7.0, and 14.0 dS/m] for 122 days. Olive seedlings varied in their response to salinity. In all treatments, NB had the highest root; stem and leaf dry weights had among the highest total plant dry weights, specific stem length (SSL) and relative water content (RWC). NB seedlings maintained the highest stomatal conductance at 7.0 dS/m and highest chlorophyll index at 14.0 dS/m. Olive seedlings that tolerated salt tolerance developed mechanisms of nutrient acquisition and distribution in the organs, by storing minimal amounts of sodium (Na⁺) and chloride (Cl^?) in the stems and loading the most in the leaves and roots.     

Production of high hydroxytyrosol yields via tyrosol conversion by Pseudomonas aeruginosa immobilized resting cells

An immobilized whole cell system was successfully performed to produce the most powerful antioxidant, hydroxytyrosol. Bioconversion of tyrosol into hydroxytyrosol was achieved via the immobilization of Pseudomonas aeruginosa resting cells in calcium alginate beads. Immobilization was advantageous as it allows immobilized cells to tolerate a greater tyrosol concentration than free cells. The bioconversion yield reached 86% in the presence of 5 g L-1 of tyrosol when cells immobilized in alginate beads were carried out in single batches. Evaluation of kinetic parameters showed the maintenance of the same catalytic efficiency expressed as Kcat/Km for both free and immobilized cells. The use of immobilized cells in repeated batches demonstrated a notable activity stabilization since the biocatalyst reusability was extended for at least four batches with a molar yield greater than 85%.     

Detoxification Potential of Pseudomonas fluorescens SM1 Strain for Remediation of Major Toxicants in Indian Water Bodies

The present investigation was carried out to evaluate the detoxification potential of Pseudomonas fluorescens SM1 strain immobilized in calcium alginate beads for some major toxicants of Indian water bodies. The toxicants selected in this study were benzene hexachloride, mancozeb, 2,4-dichloro-phenoxyacetic acid (pesticides); phenol, catechol, cresol (phenolics); and Cd⁺⁺, Cr(VI), Cu⁺⁺ and Ni⁺⁺ (heavy metals), which were taken as mixtures up to a concentration of roughly twice that usually found in highly polluted sites. Allium cepa phytotoxicity test, Ames fluctuation test and plasmid nicking assay were employed to estimate the phytotoxicity and genotoxicity of the model water containing the test toxicants under different combinations before and after exposure to our bioremediation-cum-detoxification system. The IC₅₀ of the model water containing all the test toxicants, treated with the immobilized SM1 cells, was recorded to be 0.7× compared to 0.06× for the same but untreated water sample, enhancing the IC₅₀ value by 12-fold. The IC₂₅ of the test heavy metal mixture only could enhance from 0.07 to 1.30× (18-fold). The IC₂₅ of the test pesticide mixture alone was increased from 0.07 to 1.71× (24-fold). The IC₂₅ values for the mixture of test phenolics were 0.07× and 2.18× under the pre- and post-treatment conditions, respectively, exhibiting a 31-fold increase. A mutational induction (Mi) corresponding to the 0.5 value in the Ames fluctuation test was used to evaluate the mutagenicity of the test model water containing all the toxicants before and after exposure to the immobilized SM1 cell system. The Mi (0.5) value with the TA98 tester strain was estimated to be 0.08× for the untreated and 0.6× for the treated model water, whereas the same index was calculated to be 0.48× and 1.8×, respectively, for the TA100 strain. A remarkable improvement in the quality of the test water as a result of exposure to this bioremediating system was observed in terms of the absence of the linear form of the plasmid contrary to the visible linearization with the untreated model water. In view of the above findings, it is quite clear that the test of P. fluorescens SM1 strain immobilized in the calcium alginate beads could be used as an efficient system of bioremediation and for water decontamination strategies owing to its remarkable detoxification potential.     

Evaluation of available boron content using eight methods of extraction in different soils from Córdoba and sucre in Colombia

The aim was to evaluate eight methods of boron (B) extraction in different soils from Córdoba and Sucre, Colombia. 37 samples were collected at a depth of 0–20 cm and carried to Soil and Water Laboratory of University of Córdoba for its chemical characterization. The available boron was extracted with the following methods: modified hot water, calcium chloride (CaCl₂) 0.05, hydrochloric acid (HCl) 0.05, barium chloride (BaCl₂) 0.006, manitol 0.05 + CaCl₂ 0.01, Ca(H₂PO₄)₂H₂O 0.008 in mol L^?1, mehlich-1 and ammonium acetate (NH₄OAc) (1.0 mol L^?1, pH = 7.0). The major quantity of boron was extracted with mehlich-1, HCl 0.05 mol L^?1 and hot water, extracting 0.36, 0.29 and 0.26 mg kg^?1, respectively. The extracting solution that correlated with the hot water method was HCl 0.05 mol L^?1 (r = 0.81); followed by Ca(H₂PO₄)₂H₂O 0.008 mol L^?1 (r = 0.62) and mehlich-1 (r = 0.54). According to characteristic and heterogeneity of soils, we recommend HCl method to extract available boron.     

Technical and Economical Assessment and Extrapolation of a 200-dm3 Pilot Bioreactor for Reduction of Sulphate and Metals in Acid Mine Waters

Acidity, presence of metals and high-sulphate concentration are typical characteristics found in acid mine waters (AMWs). A 200-dm³ pilot, allowing bacterial conversion of sulphate into sulphide, was designed to treat AMWs. A fixed-bed column was filled with pozzolana, inoculated with a bacterial population containing the sulphate-reducing organism Desulfomicrobium norvegicum and fed with a H₂ and CO₂ gas mixture. The pilot worked in continuous-feeding conditions during 36 days. An actual AMW was sequentially treated by neutralisation of acidity, precipitation of metals using sulphide produced by the bioreactor and bioconversion of sulphate in the bioreactor fed with the sulphide-treated effluent. The residence time in the bioreactor was decreased down to 8.5 h. The sulphate reduction rate, correlated with the temperature between 5 and 17°C, varied between 35 and 95 mg dm^?3 h^?1. On the basis of the technical assessment previously made and after setting up some extrapolation hypotheses and calculations for a 10 m³ h^?1 unit, the treatment cost per cubic meter of AMW was evaluated.     

Stress Protein Responses in South African Freshwater Invertebrates Exposed to Detergent Surfactant Linear Alkylbenzene Sulfonate (LAS)

Stress responses can be measured at various levels of biological organization, from sub-organism through to ecosystem level. This study aimed to investigate stress protein induction as a sub-organism level stress response in two South African freshwater aquatic macroinvertebrates exposed to detergent linear alkylbenzene sulfonate (LAS). Shrimp Caridina nilotica and limpet Burnupia stenochorias were exposed to a range of LAS concentrations (0, 1, 1.8, 3.2, 6.5 and 12.7 mg/L and 0, 0.6, 1.2, 1.6 and 3.2 mg/L respectively) for 96 h. Surviving organisms were prepared for sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot analysis. In C. nilotica there appeared to be induction of a putative ≈ 70 kDa protein at 12.7 mg/L LAS, and induction of putative ≈45 and ≈40 kDa proteins at concentrations of 6.5 mg/L LAS and above. However, only an Hsp70 protein was detected with anti-Hsp72/Hsc73 at 12.7 mg/L LAS. No protein induction was observed in exposed B. stenochorias, however an Hsp40 protein was detected with anti-Hsp40 in exposed and unexposed limpets.     

Hexavalent Chromium Removal by Candida sp. in a Concentric Draft-Tube Airlift Bioreactor

The main purpose of this work was to conduct a kinetic study on cell growth and hexavalent chromium [Cr(VI)] removal by Candida sp. FGSFEP in a concentric draft-tube airlift bioreactor. The yeast was batch-cultivated in a 5.2-l airlift bioreactor containing culture medium with an initial Cr(VI) concentration of 1.5 mM. The maximum specific growth rate of Candida sp. FGSFEP in the airlift bioreactor was 0.0244 h^?1, which was 71.83% higher than that obtained in flasks. The yeast strain was capable of reducing 1.5 mM Cr(VI) completely and exhibited a high volumetric rate [1.64 mg Cr(VI) l^?1 h^?1], specific rate [0.95 mg Cr(VI) g^?1 biomass h^?1] and capacity [44.38 mg Cr(VI) g^?1 biomass] of Cr(VI) reduction in the airlift bioreactor, with values higher than those obtained in flasks. Therefore, culture of Candida sp. FGSFEP in a concentric draft-tube airlift bioreactor could be a promising technological alternative for the aerobic treatment of Cr(VI)-contaminated industrial effluents.     

Effect of Waterborne Zinc on Survival, Growth, and Feed Intake of Indian Major Carp, Cirrhinus mrigala (Hamilton)

The effect of waterborne zinc on survival, growth, and feed intake of Indian major carp, Cirrhinus mrigala (Hamilton), advanced fry was studied under laboratory condition. Survival rates of C. mrigala advanced fry (2.71?±?0.49 g) after 30 days exposure to control (0.01), 0.03, 0.06, 0.10, and 0.15 mg/L zinc using the static renewal method in freshwater at pH 7.3?±?0.2, temperature 26?±?2°C, and total hardness 114?±?16 mg/L as CaCO₃ were 100%. Growth of the fish exposed to 0.10 and 0.15 mg/L of zinc was significantly lower (P?<?0.05) than in control (0.01), 0.03, and 0.06 mg/L of zinc after 30 days of exposure. However, there were no significant differences (P?>?0.05) in fish growth between 0.03 and 0.06 mg/L zinc concentrations. Feed intake rates were significantly (P?<?0.05) reduced in the fish exposed to 0.10 mg/L and higher levels of zinc. The zinc accumulation in the whole body of the fish increased with increasing concentrations of the metal.     

湿筛过程中分散液的质量对土壤团聚体稳定性影响

【目的】土壤团聚体是土壤结构的基本单元,决定着土壤在生态系统中的作用和功能。保持良好的结构状态和稳定的结构性能是确保土壤水、 肥、 气、 热肥力因子协调的基本条件。现代土壤管理中大量使用的化肥无机盐以及灌溉水体富含的离子都会造成对团聚体的破坏,本文以富含有机质的黑土为研究对象,探索湿筛过程中分散溶液的质量对团聚体稳定性的影响。【方法】以氯化钠、 氯化钙和氯化铝3种不同价态的阳离子溶液为介质,采用改进的萨维若夫（Саввинов）法进行湿筛,设置0（不加盐去离子水,CK）、 0.1、 0.3、 0.5 mol/L 4个浓度水平,研究直径0.25 mm的土壤团聚体在不同阳离子盐溶液作用下的稳定性。【结果】不同盐溶液中黑土团聚体的稳定性差异很大。在氯化钠盐溶液中,黑土团聚体的盐破坏率（PAD0.25/w）均为正值,且随钠盐溶液浓度的增大而增加,在浓度为0.1、 0.3和0.5 mol/L的氯化钠溶液中分别为0.21%、 10.7%和14.4%。在氯化钙溶液和氯化铝溶液中,黑土PAD0.25/w均为负值, 氯化钙溶液中PAD0.25/w的绝对值随着盐浓度的增大而减小,氯化铝溶液中PAD0.25/w的绝对值均在51%以上。【结论】一价盐溶液加剧了0.251 mm黑土团聚体的分散,但能够保护直径1 mm以上的团聚体,而二价盐和三价盐溶液对团聚体的分散有明显的抑制和保护作用。     

Biodegradation of Crude Oil in Contaminated Soils by Free and Immobilized Microorganisms

The efficiencies of free and immobilized bacterial cultures of petroleum hydrocarbon degraders were evaluated and compared in this study.Hydrocarbon-degrading microbial communities with high tolerance to and high degrading ability of crude oil were obtained from the soil contaminated with crude oil in the Yellow River Delta.Then,the microbial cells were immobilized in sodium alginate(SA)beads and sodium alginate-diatomite(SAD)beads.The biodegradation of crude oil in soil by immobilized cells was compared with that by free cells at three inoculation concentrations,1×10⁴ colony forming units(cfu)kg^-1(low concentration,L),5×10⁴ cfu kg^-1(medium concentration,M),and 1×10⁵ cfu kg^-1(high concentration,H).At 20 d after inoculation,the maximum degradation rate in the immobilized systems reached 29.8%(SAD-M),significantly higher(P<0.05)than that of the free cells(21.1%),and the SAD beads showed greater degradation than the SA beads.Moreover,both microbial populations and total microbial activity reached significantly higher level(P<0.05)in the immobilized systems than free cell systems at a same initial inoculation amount.The scanning effectronic microscope(SEM)images also confirmed the advantages of the immobilized microstructure of SAD beads.The enhanced degradation and bacterial growth in the SAD beads indicated the high potential of SAD beads as an effective option for bioremediation of crude oil-contaminated soils in the Yellow River Delta.     

固定化唾液链球菌生产γ-氨基丁酸的研究

以唾液链球茵嗜热亚种(Streptococcus salivarius subsp.thermophilus Y-2)为供试菌株,考察了卡拉胶、明胶和海藻酸钙等材料将此菌株固定化的效果,并通过比较固定化细胞的谷氨酸脱羧酶(glutamatedecarboxylase,GAD)活性及γ-氨基丁酸的产量和载体机械强度,确定了海藻酸钙作为固定化细胞的适宜载体.优化后得到的最适固定化条件(W/V)为:海藻酸钠2%,CaCl_2 14%,茵体25%,凝胶平均颗粒直径1.64 mm,在此条件下测得固定化细胞的GAD活性为游离细胞的1.2倍.细胞多批次应用稳定性试验证明:固定化细胞较游离细胞有着更稳定的GAD活性,反复使用60 h后,固定化细胞GAD活性仍能保持其初始活性的90%以上,γ-氨基丁酸的积累量达到7.97 g/L.     

Impact of Supplemental Calcium Chloride on Yield,Quality, Nutrient Status,and Postharvest Attributes of Tomato

Little is known regarding the impact of calcium chloride applications during growth and development on tomato postharvest quality. This trial investigated supplemental calcium chloride applications on yield, nutrient content, texture, and postharvest quality of tomato fruit. Calcium (Ca) nutrient solution concentrations were: 60, 180, and 360 mg·L^?1 calcium, while foliar applications were (0, 1, and 2% calcium chloride w/v). Plants grown with 60 mg·L^?1 Ca had a high incidence of blossom end rot, which was not affected by calcium chloride sprays. Fruit nutrient concentrations were affected by calcium delivered through the nutrient solution. As fruit cluster position increased, fruit nutrient concentrations significantly decreased. Foliar calcium chloride sprays affected fruit soluble solids content and dry weight, but did not affect texture. Pericarp elasticity increased concomitantly with calcium in the nutrient solution. Postharvest disease incidence was not affected by calcium treatment, though weight loss during storage was negatively affected by calcium chloride sprays.     

Biodegradation Kinetics and Effects of Operating Parameters on the Performance of a Methyl Tert-Butyl Ether Degrading Biofilter

The goals of the study were to determine the effectiveness of a laboratory-scale biofilter on the removal of methyl tert-butyl ether (MTBE) and investigate the operating parameter effects on biofilter performance. The experimental results show that average MTBE removals of 53.6–93.2% were observed at loads of 2.5–20.1 gm^?3 h^?1 and an empty-bed residence time of three minutes, after continuous operation for four months throughout the biofilter acclimation period. After a one-day recovery period operation, the biofilter system recovered from the introduction of a shock load. More than 99% removal efficiencies were achieved for the inlet MTBE concentration at 50 ppmv and with the highest residence time. MTBE removals at the bottom section of the biofilter were consistently lower than for the top section, which was attributed to insufficient microorganism growth in the bottom section. The parameters estimated by using the Michaelis-Menten equation were 1.116 ± 0.51 ppmv s^?1 for the maximum removal rate (V _m ), and 26.38 ± 17.21 ppmv for the half-saturation constant (Ks), evaluated at the biofilter exit.     

Growth Irradiance Effects on Productivity,Photosynthesis, Nitrate Accumulation and Assimilation of Aeroponically Grown Brassica alboglabra

Brassica alboglabra plants were first grown aeroponically with full nutrients under full sunlight with average midday photosynthetic photon flux density (PPFD) of 1200 μmol m^?2 s^?1. Thirty days after transplanting, plants were respectively, subjected to 10 days of average midday PPFD of 1200 (control, L1), 600 (L2) and 300 μmol m^?2 s^?1 (L3). Productivity, photosynthetic CO₂ assimilation and stomatal conductance were significantly lower in low-light (L2 and L3) plants than in high-light (L1) plants. Low light plants had the highest nitrate (NO₃^?) accumulation in the petioles. Low light also had an inverse effect total reduced N content. After different light treatments, all plants were re-exposed to another 10 days of full sunlight. Low-light plants demonstrated their ability to recover their photosynthetic rate, enhance productivity and reduce the NO₃^? concentration. These results have led to the recommendation of not harvesting this popular vegetable during or immediately after cloudy weather conditions.     

Radiosensitivity Studies and Radiostability of Ribulose-1,5 Bis-Carboxylase and Gas Exchange Characteristics in Wheat, Garden Pea, Field Pea, Spinach, and Okra

Implication of ureolytic biocalcification process as an efficient carbon dioxide sequestration technology was evaluated with Bacillus megaterium culture growing in a closed environment system. In three experimental sets containing either 35 % v/v CO₂ in headspace (set 1) or 50 mM urea in solution (set 3) or both (set 2), change in headspace CO₂, soluble calcium, and pH were monitored during 8 days of incubation. In absence of urea, headspace CO₂ content continued to increase in set 1 (up to 48 % v/v) without any carbonate precipitation. However, carbonate precipitation were obvious in urea containing sets (sets 2 and 3) utilizing all the added calcium (25 mM) in just 2 and 6 days, respectively. No headspace CO₂ could be detected in set 2 at the end of experimental period, and analysis suggested that this was majorly (>53 %) attributed to the solubility trapping phenomenon. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis revealed that the precipitates were made up of calcite and major fraction of vaterite polymorph of CaCO₃.     

A Comparative Study of Immobilized Nitrifying and Co-Immobilized Nitrifying and Denitrifying Bacteria for Ammonia Removal from Sludge Digester Supernatant

Bench scale kinetic experiments were conducted to examine the use of cell immobilization in calcium alginate to remove ammonia in anaerobic sludge digester supernatant. Two systems, immobilized nitrifiers and co-immobilized nitrifiers and denitrifiers, were studied with and without the addition of methanol. Results indicated that partial nitrification (to nitrite) was achieved in both systems. The co-immobilized reactors did not exhibit the extent of nitrite accumulation observed in the solely nitrifying reactors. The nitrifying reactors were unable to buffer the hydrogen ion production, during the nitrification process, to the level the co-immobilized cell reactors achieved. Both of these differences suggested the occurrence of denitrification in the co-immobilized reactors. Scanning electron microscopic images of bacteria immobilized in the alginate spherical beads support the results of the kinetic experiments. Nitrifiers colonized in the 100–200 μm peripheral layer of the beads. Large voids caused by nitrogen gas due to denitrification were found in a number of co-immobilized bead samples.     

Physiological Response of Daphnia magna to Linear Anionic Polyacrylamide: Ecological Implications for Receiving Waters

Linear anionic polyacrylamide (LA-PAM) is being considered as a soil amendment to reduce seepage and infiltration in unlined earthen canals. While polyacrylamides have been extensively used for potable water treatment, dewatering sewage sludge, coal and mine processing, paper manufacturing, and agriculture, little is known about its ecological impact to aquatic ecosystems. Acute toxicity (LC₅₀, 24 and 48 h) and chronic exposure tests (limited and continuous exposures) were conducted on Daphnia magna. In the chronic limited exposure experiments, Daphnia were exposed to LA-PAM for only 24 h whereas for the chronic continuous exposure the concentrations of 0, 0.5, 1, 5, 10, and 100 mg/L were tested and the endpoints of growth, onset to reproduction, fecundity, and mortality were measured for the duration of 32 days. There was no significant difference among the chronic, limitedly exposed organisms. The acute toxicity for LA-PAM was measured at 100, 150, 200, 250, and 300 mg/L. The acute test showed that the LC₅₀ for LA-PAM was at 152 mg/L. Overall in the chronic, continuous exposure test, D. magna was negatively impacted by LA-PAM at levels as low as 1 mg/L. Growth was reduced by 37% and 89% at 1 and 100 mg/L, respectively. Fecundity and onset to reproduction was impaired at 10 and 100 mg/L. Kinematic viscosity ranged from 0.98 cSt at 1 mg/L to 2.9 at 100 mg/L. At these levels, mechanical and physiological impairments due to the viscous properties of LA-PAM are the proposed mechanisms of reduction in the life history traits of D. magna.