Toxicología ambiental y analítica

In this studied ZrO₂ nano particles are prepared by glycothermal method. Characterization of the prepared nano particle was done using XRD, TEM and SEM. According to the obtained results, ZrO₂ nano particles prepared by glycothermal method are mainly t-ZrO₂ phase with tetragonal shape with an average size in the range of 30-50 nm. The formation of t-ZrO₂ as the main phase of zirconium nano particles could be related to the presence of sodium hydroxide in the generation step. The removal efficiency of ZrO₂ nano particles for adsorbing As(III) and As(V) from waste water is studied. The efficiency of removal is significantly increased with increasing the dose of zirconia nano particles till 0.5 g/L. This related to increasing in the active site which are available for the removal of arsenic species by increasing the dose of the nano particles. For both As(III) and As(V), the removal efficiency increased by decreasing pH value of the solution and increasing the contact time.

Harmful Algal Blooms are increasing worldwide problems observed in inshore ecosystems, which support a growing anthropogenic activity that impacts on resources. Results of seasonal and interannual variability of toxic phytoplankton in four bays of the Peruvian sea (Sechura 04°S, Samanco 09°S, Miraflores 12°S and Paracas 14°S), are shown during spring and summer from 2012 to 2015. Toxic species such as Pseudo- nitzschia Grupo delicatissima, Grupo P. seriata, Alexandrium peruvianum, Dinophysis caudata, D. acuminata, Gonyaulax spinifera, Azadinium sp, Karlodinium sp., Karenia sp., Protoceratium reticulatum and Prorocentrum minimum were registered, associated with the presence of toxic events, more frequently of okadaic acid (lipophilic toxin - DSP) in Sechura and Samanco for 2012, 2013 and 2014 and saxitoxin (Paralytic Toxin - PSP) in Paracas 2012. Sea surface temperature for spring fluctuated between 16.3° to 19.9°C (Sechura-Paracas), and for the summer between 19.3° to 24.1°C (Paracas - Sechura). Physical dynamics were related with seasonal variations, associated to local effects, with slow surface marine currents during austral summer and intense currents during spring, with average values of <13.91 and 25.0 cm/s, respectively, associated with clockwise gyres that influenced the harmful algal blooms. Spearman correlations (p<0.05) between the biological and physicalchemical component were found mainly with temperature (r=0.665), silicates (r=0.45), phosphates (r=0.48) and nitrates (r=0.50).

The effects of different initial concentrations of bisphenol A (BPA) on Chlorella vulgaris and removal capacity of BPA by Chlorella vulgaris were investigated under the light and the dark cultural conditions. Experiments were performed in 250 mL flasks under light and dark conditions with different BPA concentrations. Results showed that 0-20 mg·L-1 BPA concentration under the light condition and 0-10 mg·L-1 BPA concentration under dark condition plays a promoting role on the growth of Chlorella vulgaris in terms of cell density. The effect of BPA removal under light condition was obviously better than that under the dark condition. The maximum BPA removal rates were 3.425 ± 0.145 mg (L·d)-1 and 1.530 ± 0.025 mg (L·d)-1 under two conditions and were observed during 2-4 d and 0-2 d, respectively. The largest removal amounts of BPA under two conditions were all investigated in L-BPA50 and D-BPA50 groups. Both superoxide dismutase (SOD) and catalase (CAT) activities were promoted in all the treatments, which proved that C. vulgaris showed a positive response to the BPA stress condition. SOD activity showed sensitive and responsive to the new medium since it was promoted immediately on the incubation day. CAT activity was supposed to be more tightly controlled in response to BPA because its level was related to the BPA removal.

Staphylococcal food poisoning is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by the bacterium Staphylococcus aureus. SEs cause gastroenteritis and also cause activation of T cells and massive cytokine release. A current method for the detection of active SEs relies on its emetic effect on monkeys or kittens. However this costly procedure has low sensitivity and raises ethical concerns. This present study overcomes the limitations of such bioassays by providing an alternative method based on the alteration of TCR Vβ8 protein levels expressed on Jurkat T cell-line. We demonstrated that increasing concentrations of SEE, the causative agent in foodborne outbreaks in France, UK and USA, reduced TCR Vβ8 protein levels in a dose dependent manner and similarly alters the luciferase gene expression under the regulation of nuclear factor of T-cell activation (NFAT). Unlike previous studies that show accessory cells are not required for T cell activation by SEA or SEB, this present study demonstrated that accessory cells are required for T cell activation by SEE and SEE has greater affinity for the accessory cells than the Jurkat T cell. It is advantageous to use fixed dead cells where possible to reduce cell culture work. In this study we show that fixed accessory cells lacking any metabolic function without processing can present intact SEE and consequently alter TCR Vβ8 levels and the reporter gene expression.

Physico-chemical and microbiological parameters were analyzed in leachate sample obtained at different locations (Obosi public dumpsite, groundwater and agricultural soil farmland 45.6 km from Onitsha dumpsite). This is to assess the impact of leachate and the effect of heavy metals on agricultural produce, Zea mays and Phaseolus vulgaris. In addition, pH values and the concentrations of these metals (Cd, Ag, Al, Mo, As, Hg, Mn, Zn, Cu, Hi, Cr, Mg, Fe, Pb and Co) in dumpsite leachate, agricultural soil collected from a depth of 10 cm were assessed. The pH of the experimental samples ranged from 6.41-7.15. The analysis of samples for heavy metals revealed very high concentrations of Mg (14.20-20.23 ppm), Hg (0.002-2.29 ppm), Pb (0.09-0.65 ppm), Cd (0.001-0.53 ppm), but Al and As were not detected in most of the samples. Physiochemical parameters (Total dissolved Solid, Temperature, Conductivity, Turbidity, Cation Exchange Capacity, Color, Total Organic Carbon and Particle size) and Microbiological parameters (Total heterotrophic bacterial and fungal count) were analyzed using standard methods. The microbial enumeration showed heterotrophic bacterial and fungal count ranging from 12 × 105 to 2 × 105 cfu/ml for leachate and ground water samples. Heterotrophic fungal count ranged from 3 × 105 to 8 × 105 cfu/ml for leachate and ground water. Culture plate, structural form and biochemical characterization conducted on these isolates using Bergey's manual of determinative bacteriology. Fungal atlas was used to suggest possible identities of the fungal isolates. These isolates were molecularly identified by 16 S rDNA and ITS rDNA sequence analysis for bacterial and fungal isolates respectively. The bacterial identities were Lysinibacillus fusiformis and Klebsiella pneumoniae, while fungal isolates were identified as Aspergillus tamarii, and Aspergillus fumigatus. The leachate generated from Obosi overburden dumpsite has the potential to pollute the surrounding water.

The effects of rainwater on freshwater ecosystems have received increasing attention worldwide. Alkaline phosphatase activity (APA) affects the biochemical cycles of phosphorus in the water, thereby affecting the proliferation and outbreak of cyanobacteria blooms. However, it is still unclear whether the complex composition of rainwater has a significant effect on the alkaline phosphatase activity. In this study, the effects of rainfall on Microcystis aeruginosa in Kunming were evaluated based upon changes in alkaline phosphatase activity, algal growth, and chlorophyll a. The results showed that the addition of rainwater brought about different changes in alkaline phosphatase activity, algal growth, and chlorophyll a. The general trend showed that a certain amount of rainwater (equivalent to light, moderate rain, and heavy levels) had a positive effect on the alkaline phosphatase activity, algal growth, and chlorophyll a in the cultivation system. Therefore, the following preliminary inference can be drawn: in the Kunming area, a certain amount of rainwater may promote the growth of blue-green algae, exacerbating an outbreak of cyanobacteria blooms.

This paper compares the different scheduling scenarios of hybrid renewable energy system in terms of system configuration, economy, power production, biomass availability and pollutant emission. The hybrid renewable energy system comprises the solar, wind and biomass based power generating systems. This case study is carried out for a specific geographical location (village Ramgarh) in Ambala district of Haryana state, in India. The HOMER software tool is used to carry out simulations of three different scenarios viz. Generator is on or off depending on the availability of solar and wind power; the generator is on for all time; and the generator operation is optimized. Sensitivity analysis is also carried out for different maximum annual capacity storage in relation to change in net present cost (NPC) and levelized cost of energy (LCOE). The results of the analysis indicate that as the maximum annual capacity storage increases, the net present cost and levelized cost of energy decreases. The comparison of the results is presented in a tabular form.

Increasing water bodies and water inhabitants’ pollution has posed a great global concern as aquatic animals are continually endangered with effluents from various sources. Polycyclic aliphatic hydrocarbons are Poly Nuclear Aliphatic Hydrocarbons and organic matter without fused ring and contains hydrogen and carbons invariably with or without substituent attached to it, Total Petroleum Hydrocarbon (TPH) is a term used to describe a large family of several hundred chemical compounds that originally come from crude oil. In this study, Petroleum hydrocarbons such as Petroleum Aliphatic Hydrocarbon (PAHs) and Total petroleum hydrocarbons (TPHs) were analyzed for in the seven sampled aquatic animals using Gas Chromatographic technique. Petroleum Aliphatic Hydrocarbons attained higher concentrations in n-hexadecane, tetracosane and tetradecane with concentration values of 0.49 ± 0.29, 0.59 ± 0.94 and 0.97 ± 0.64 mg/kg respectively. It was found in this study that even chain aliphatic hydrocarbons were found in all the samples and dominated the odd chains aliphatic hydrocarbons. Heavy weight Aliphatic Hydrocarbons like hexacosane and triaconane were not detected in all the tested aquatic animals as Octacosane was found in only three of the aquatic animals while hexatricontane was found in only one of the samples. Odd chain aliphatic hydrocarbons like Nonane and Nonadecane attained their highest concentrations of 0.19 ± 0.15 and 0.33 ± 0.45 mg/kg respectively. It was gathered from the results of this experiment that Total Petroleum Hydrocarbons (TPH) is greater than the aliphatic petroleum hydrocarbons in all the tested aquatic faunas from the Forcados River. TPH and TAH recorded maximum concentrations of 3.64 ± 0.94 and 3.46 ± 0.91 mg/kg respectively

Environmental context: Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and polybrominated diphenyl ethers (PBDEs) in PM2.5 can be toxic to humans and ecosystems, because they will show endocrine disrupting activity. It is thus important to understand the contamination level of PBDEs and OH-PBDEs in PM2.5. In this paper, a method has been applied to the analysis and separation of trace PBDEs and OH-PBDEs in PM2.5, in order to understand the pollution levels, migration and transformation of PBDEs/OH-PBDEs in PM2.5. In this study, we demonstrate a method for simultaneously analyzing 9 OH-PBDEs and 40 PBDEs existed in PM2.5. Quantitative analysis was conducted by using gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) combined with a precolumn derivatization. To achieve accurate detection, the extraction solvents and cleanup condition were optimized. The working curves were obtained via dissolving standards in blank matrix extracts. The linear range of 9 OH-PBDEs was from 15 pg m-3 to 3875 pg m-3, and limits of detection and quantification ranged from 4.95 pg m-3 to 24.33 pg m-3 and 16.48 pg m-3 to 81.09 pg m-3, respectively. The linear range of 40 PBDEs was from 1.25 pg m-3 to 5000 pg m-3, and limits of detection and quantification ranged from 0.37 pg m-3 to 38.19 pg m-3 and 1.25 pg m-3 to 127.29 pg m-3, respectively. The results showed that the recoveries were in the range of 72.1%-104.7% and the relative standard deviations were less than 13.6%. This method was suitable for simultaneous analysis of PBDEs and OH-PBDEs in PM2.5 with the advantages of high sensitivity, time saving and easy operation. The applicability of the method has been successfully validated on atmospheric samples collected in Baoding, China. Six PBDEs and five OH-PBDEs were detected in all the samples. Among the detected PBDEs and OH-PBDEs, detection rate of BDE-47, BDE-99, BDE-100 and BDE-209 were relatively higher than that of others. The results indicated that the concentration of BDE-209 might be affected by the concentration of PM2.5.

To propose a reasonable configuration of plant measures and specific planning to improve the soil quality and the surrounding ecological environment of submerged area in Shifosi reservoir, we analyzed the soil moisture content and other key physical properties such as bulk density, maximum water-holding capacity, capillary water-holding capacity, field capacity and porosity of the submerged area. Soil samples were collected within 500 m scope from the auxiliary dam and tested using test methods in compliance with the national standard LY/T1215-1999. The correlation analysis showed that a highly significant correlation existed between the moisture content with other physical properties. The capillary water-holding capacity had the highest correlation with the soil water content, followed by the maximum waterholding capacity, porosity, field capacity, and bulk density. As the changes in soil moisture content may affect the variation of other physical properties, the immersion area was divided into three regions according to their soil water contents. In region 1, the moisture content was between 23.08% and 32.96%; in region 2, the moisture content was between 21.18% and 23.08%; and in region 3, the moisture content was below 19.85%. In each region, the adaptive plant measures and configurations were put forward on the basis of natural, social and economic conditions, as well as vegetation status. In region 1, the selected tree was Salix matsudana, shrub was Forsythia mandshurica, and suitable herb was Iris lactea var. chinensis. In region 2, the proper tree was Fraxinus velutina, shrub was Amorpha fruticosa, and herb was Festuca arundinacea. In region 3, the suitable tree was Pinus tabulaeformis var. mukdensis, shrub was Lespedeza bicolor, and herb was Eleocharis yokoscensis. The rational allocation of vegetation may prevent soil erosion, contribute to the full use of the land of the submerged area, achieve optimization of social, economic, and ecological benefits, and provide a reference for plant configuration of other reservoirs in Liaoning Province, China.

Phosphate fertilizers contain varying amounts of cadmium (Cd) and other heavy metals as contaminants from phosphate rock (PR). Periodic applications of these fertilizers could result in measurable accumulations of Cd in soils and in harvested crops. A long term field study for fifteen cropping seasons (1992-2006) was conducted on an experimental plot located at the Norwegian University of Life Sciences (Ås, Norway) to evaluate the effect of application of cadmium enriched phosphate fertilizer on Cd uptake by Oat (Avena sativa) and its accumulation and availability in soil. Treatments consisted of three NPK fertilizer sources containing 1, 90, 381 mg Cd kg-1 P and applied at the rate of 0.03, 2.7, 11.43 g Cd ha-1yr-1, respectively. Surface soil samples (0-20 cm), collected after harvesting of oat in 1992, 1995, and 2006, and were analyzed for total and extractable Cd, pH, dissolve organic carbon (DOC) and PO4 3-. Plant samples collected in 1992, 1995, 1997, 2002 and 2006 were analyzed total Cd. Plant Cd generally decreased with increased soil pH throughout the experimental period except 1992. Increased input of Cd through fertilizers increased the Cd concentration in soil but the Cd concentration in oat grain remained unaffected. Ammonium nitrate (NH4NO3 -) extractable Cd in the soil increased with increasing rate of Cd through different sources but it decreased with increased pH throughout the experimental period with minor exceptions. Plant Cd did not show any significant correlation with extractable Cd in soil and hence the Cd input through fertilizers did not significantly affect the concentration of Cd in oat grain. Model (WHAM) prediction of Cd uptake by plants showed that crop yield, pH and DOC in combination explained about 57% of the variation in Cd uptake and DOC (r2=0.47, p<0.0001) was the most important factor. However, in individual years (e.g.2006) the combination of FA-Cd and yield did in fact explain 92% of the Cd-uptake.

In this study, the isolation of a potent indigenous biosurfactant-producing bacterium with potential value in enhanced bioremediation of oil-contaminated soil and oil tertiary recovery from the soil was investigated. An indigenous biosurfactant producing Gram-negative-rod-shaped bacterial strain (KISRQC) was isolated from oil-contaminated soil in Kuwait. The strain was able to reduce the surface tension below 41.1 mN/m with all tested hydrocarbons and had excellent emulsification activity toward crude oil. The strain was identified as Burkholderia cepacia. Crude biosurfactant extract from this strain was found to contain lipid with 94.9% unsaturated fatty acids. The crude biosurfactant extract was able to reduce the surface tension to 24.6 mN/m at concentration 2 g/l. Characterization of the crude biosurfactant extract activities indicated that it was stable when exposed to high and low temperatures for a reasonable time period (>month) and in the presence of 5% NaCl. The crude biosurfactant extract was effective in recovering 99% of the residual crude oil from oil-saturated sand packs. This study shows the ability of Burkholderia cepacia KISRQC to produce a highly stable biosurfactant with the strong emulsification ability towards crude oil from non-toxic material. Suggesting its potential for commercial exploitation for enhanced bioremediation of oil-contaminated soil and oil recovery from the soil.

Electrical Resistivity in conjunction with Geographic Information System (GIS) techniques have been widely used in groundwater resource management. In this research, Vertical Electric Sounding (VES), an Electrical Resistivity method, was integrated with GIS to delineate geo-electric characteristics and evaluate groundwater potential of the Bullom group of sediments in Sierra Leone. For this assessment, a total of 5 vertical electrical sounding stations were established within the site. The Schlumberger electrode configuration and the expanding procedure were used for data acquisition. The VES curves generated were interpreted using partial curve matching. The depth sounding interpretation results were used to generate geo-electric sections from which the aquifer was delineated. The aquifer revealed four subsurface layers which comprises of sandy topsoil, clayey sand which acts as aquitard and sandy gravel (confine aquifer) that serves as a source of portable water in the study area. A GIS model was then developed to locate the suitable groundwater prospective zones which reveals the average depth to groundwater to be between 10 m to 30 m. This research concluded that the boreholes were sited in high conductivity zones in VES layers 1, 2, 3 and 4 as they contain probable aquifers with good yield.