Browsing by Author "Salgado, Ricardo"
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- Bioremediation of petroleum hydrocarbons by fungi of the genus Aspergillus in different compartmentsPublication . Pessoa, Kelly; Quintella, Cristina; Salgado, Ricardo; Mata, Ana
- Data Acquisition and Data Processing Challanges in Heavy Metal MeasurementsPublication . Pereira, José Miguel Costa Dias; Salgado, Ricardo
- Effect of pH and dissolved organic matter on the photochemical fate of acetamipridPublication . Pinto, M.I.; Salgado, Ricardo; Laia, C. A. T.; Branco, L.; Vale, C.; Cooper, William J.; Burrows, Hugh D.; Noronha, J. P.In this study the effect of pH and dissolved organic matter (DOM) on the photodegradation rate of acetamiprid (ACT) was studied. Observed photodegradation rate constants in the range of 0.0010 – 0.0026 h-1 and 24 – 36 h-1 were obtained using a solar simulator (290-800 nm) and a medium pressure mercury (MP Hg) lamp, respectively. In both experiments an increase in pH from 5 to 9 did not significantly change the photodegradation rate constant of ACT. A different behaviour was found for ACT degradation in the presence of DOM. When samples were irradiated with MP Hg lamp the observed photodegradation rate constant of ACT decreased with an increase of DOM concentration.
- IoT applied to environmental monitoring in oysters’ farmsPublication . Viegas, Vítor; Pereira, José Miguel Costa Dias; Girão, Pedro Silva; Postolache, Octavian; Salgado, RicardoNowadays, the aquaculture of oysters represents an important economical activity in coastal and estuarine areas. It is known that the growth rate of oysters is affected by several water parameters, including temperature, salinity, turbidity, pH and dissolved oxygen. In this paper, a cloud-based platform is proposed to acquire water parameters that affect oysters' growth. The paper includes the hardware and software description of the measurement system, details about the storage and processing of the acquired data, and some experimental results about the abovementioned parameters.
- Metabolite identification of ibuprofen biodegradation by Patulibacter medicamentivorans under aerobic conditionsPublication . Salgado, Ricardo; Brito, Dulce; Noronha, João P.; Almeida, Bárbara; Bronze, Maria R.; Oehmen, Adrian; Carvalho, Gilda; Crespo, Maria T. BarretoIbuprofen(IBU)is anon-steroidalanti-inflammatorydrugthatisbecomingincreasinglyrecognizedas an important micropollutant to be monitored in wastewater treatment plants (WWTP), since it has been detected in effluents at the µg L−1 level. The IBU metabolites from biological degradation are not completely understood and can represent a threat to natural aquatic systems. P. medicamentivorans was previously isolated from WWTP sludge and found to be capable of IBU degradation. The aerobic biodegradation of ibuprofen by this organism was investigated in a batch lab-scale reactor for the identification of the metabolites formed. The metabolites were analysed and putatively identified by HPLC-DAD-MS/MS and GC-MS and biodegradation pathways were proposed. The toxicity and the biodegradability potential of the metabolites were also investigated. The results showed that IBU biotransformation was achieved by hydroxylation followed by the formation of a carboxylic acid in the IBU molecule and by the formation of a catechol, allowing the aromatic ring cleavage. Two biodegradation pathways were proposed: in one, the metabolites generated from the enzymatic action correspond to a less biodegradable chemical structure of the intermediate products (isobutylbenzene and 3-isobutylphenol), with comparatively higher toxicity; in the other mechanism, more oxidable chemical structures were formed with less toxicity and higher biodegradability. This suggests that the biodegradation of IBU by P. medicamentivorans can take place by more than one mechanism regarding the enzymes formed by this Gram-positive bacterium, with subsequent oxidation of the parent compound to overall more soluble and less toxic compounds to fish, daphnia and green algae.
- Photolysis, ozonation and chlorination of flame retardants in water treatmentPublication . Salgado, Ricardo; Chanfana, Cátia; Martins, Susana; Galhanas, Dina; Epifâneo, Lisete; Noronha, João PauloFlame retardants (FR) are added to different materials to reduce the risk of fire. They save lives, prevent injuries and property losses, and protect the environment by helping to prevent fires. In Western Europe, the average annual growth rate for 2007–2012 for all flame retardant chemicals is expected to be just over 3% in volume terms. The benefits of flame retardants must necessarily be balanced with the risks posed by these high production volume chemicals for human health and ecosystems. Several studies have determined that these compounds can lead to the emergence of several diseases as hormonal problems, neurological deficit, allergies and even cancer. These compounds are difficult to biodegrade in wastewater treatment plants (WWTP), and they can absorb to the sludge and/or be discharged by the WWTP effluent in the river basin. The dynamic of the adsorption equilibrium in the environment through the adsorption soil and sediments can promote the entrance in the urban water cycle, through the surface and groundwater and reach the drinking water system. Many studies reported the detection of FR in surface and groundwater used often for drinking water source. The degradation of triphenylphosphate (TPP), Hexabromocyclododecane (HBCD), Dibromoneopenthyl glycol (DBNPG), tetrabromobisphenol A (TBBPA) and the bisphenol-A (BPA) under three different oxidation/disinfection technologies (e.g. photolysis, ozonation and chlorination) as an ex-situ water treatment (WT) technology is the main goal of this study. The degradation of the target compounds are incomplete for the hydraulic retention time normally applied for the oxidation and disinfection purposes and an additional polish step with activated carbon is convenient in the water treatment. The use of photolysis, ozone and chlorine can promote the formation of by-products, in some cases, more toxic than the target compound. This study shows an important contribution for the determination of the kinetic parameter to help in the design of the WT facilities and the by-products generated during the oxidation process can be also removed with the activated carbon and reduces the impact in human health when these compounds are present in surface and groundwater, source for drinking water systems.
- The effect of chloride ions and organic matter on the photodegradation of acetamiprid in saline watersPublication . Pinto, M. I.; Salgado, Ricardo; Laia, C.A.T.; Cooper, William J.; Sontag, J.; Burrows, Hugh D.; Branco, L.; Vale, C.; Noronha, J. P.The photodegradation kinetics of the neonicotinoid insecticide acetamiprid (ACT) was investigated under different conditions of pH, salinity and dissolved organic matter (DOM). Photodegradation of ACT in saline and freshwaters followed pseudo-first-order kinetics. Varying pH from 5 to 9 did not significantly affect the photodegradation rate constants (kp) of ACT. Addition of chloride ions increased significantly the value of kp. In the presence of AHA, 10 mg L−1, kp was reduced to approximately 34% of that in sodium chloride solutions 35 g L−1 The observed inhibition may be a consequence of the antioxidant properties of DOM and/or the shading of DOM in the solution. In coastal waters, kp showed a tendency to increase with increasing of salinity and to decrease in the presence of DOM. This is an important outcome since coastal lagoons are important and dynamic systems that are likely to be highly influenced by global climate changes.
- Wastewater matrix effect on disinfection with lp/uv and mp/uv radiationPublication . Salgado, Ricardo; Hipólito, Cláudia; Galhanas, Dina; Epifâneo, Lisete; Noronha, João PauloThe disinfection of the wastewater effluents is important to reduce the pathogenic microorganism impact in the environment. UV radiation is one of the technologies used for this purposed. The wastewater characteristics, such as dissolved organic compounds or the presence of suspended solids can affect the efficiency of the faecal coliform bacteria removal in the disinfection process by ultraviolet (UV) radiation technology. This study addresses to see the effect of the effluent wastewater matrix in the disinfection by the use of low pressure (LP/UV) and media pressure (MP/UV) lamps. Samples collected in different wastewater treatment plants show different transmittance emission profiles due mostly to the presence of the mixture of dissolved organic compounds with some effect on the faecal coliform bacteria removal.