Search results for "POLLUTANTs"
showing 10 items of 1125 documents
EDTA excess Zn(II) back-titration in the presence of 4-(2-pyridylazo)-resorcinol indicator and naphthol green beta as inert dye for determining Cr(II…
2006
The colour changes of 4-(2-pyridylazo)-resorcinol and naphthol green beta as new screening metallochromic indicator in back-titration of EDTA excess with Zn(II) to determine Cr(III)/EDTA complex was investigated with the help of tristimulus colorimetry. Specific colour discrimination (SCD) and L*, a*, b* 1976 parameters were successfully applied to evaluate the quality of colour transition at the end-point in non-alkaline media and in the presence of Zn(II) and Ca(II) which resulted in non-interfering species at 1x10(-3) M and 2x10(-3) M, respectively. The above concentrations are comparable with those used for Cr(III). Validation of the fast and accurate reported method was performed by at…
Distribution of Cr and Pb in artificial sea water and their sorption in marine sediments: an example from experimental mesocosms
2016
The uptake of two heavy metals (chromium and lead) in sediments in experimental mesocosms under exposure to different metal concentrations was evaluated by monitoring their concentrations over time both in seawater and in sediment. Two separate experiments under laboratory-controlled conditions were carried out for the two metals. Sediments were collected from a protected natural area characterized by low anthropic influence and were placed in mesocosms that were housed in aquaria each with seawater at a different metal concentration. At pre-established time intervals, seawater and sediment samples were collected from each mesocosm for chemical analyses. Quantification of chromium and lead …
Effects of temperature on the acute toxicity of heavy metals (Cr, Cd, and Hg) to the freshwater crayfish, Procambarus clarkii (Girard).
1987
Chromium, an essential trace element for humans and animals is involved in normal carbohydrate metabolism; however, it is toxic at high concentrations. There is no evidence that cadmium and mercury are biologically essential but their toxicity for organisms is well known. Both cause toxic effects at low concentrations to most organisms, especially in combination with other environmental variables such as temperature. Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues (including heavy metals) from the many urban and waste waters in this area. In 1978, the American red crayfish Procambarus clarkii appeared in lake Albu…
Statistical characterisation of heavy metal contents inParacentrotus lividusfrom Mediterranean Sea
2014
This work focuses on the estimation of Hg, As, Cr, Ni, Cu, V, Cd and Pb by inductively coupled plasma mass spectrometry in 135 adult specimens of Paracentrotus lividus collected in different coastal areas of Sicily (Gela, Punta Secca, Ragusa (RG), Siracusa, Priolo, Catania, Messina, Milazzo, Brolo and Filicudi), in order to monitor the Mediterranean marine ecosystem by use of sea urchin as bioindicator. Moreover, the paper deals with the statistical classification of the tested samples according to the sampling area based on metal concentrations. The descriptive statistics findings were obtained and, a starting multivariate matrix was built. Data-sets were subjected to Kruskal-Wallis test t…
Removal of trivalent chromium from tannery waste waters using bone charcoal
2002
International audience; The ability of bone charcoal to remove Cr(III) from aqueous solutions by adsorption has been investigated. The adsorbent used was first characterised and then the adsorption was studied as a function of time and amount of charcoal. Tests were carried out with synthetic solutions whose Cr concentrations (500 mg L-1) were similar to those found in some effluents of Moroccan tannery industries. Cr removal efficiencies higher than 90% were obtained at pH 3.5 using 3 g of bone charcoal and a stirring time of about 30 min. Results of Cr removal by all sieved fractions of bone charcoal had shown the same interesting capabilities for Cr(III) retention. The cross interference…
Congener profile, occurrence and estimated dietary intake of dioxins and dioxin-like PCBs in foods marketed in the Region of Valencia (Spain).
2011
During 2006-2008, a monitoring program was conducted on 29 target compounds, including PCDD/Fs and dl-PCBs, comprising 150 randomly collected individual food samples marketed in the Region of Valencia, Spain, grouped into 8 categories (vegetables, cereals, fats and oils, eggs, milk and dairy products, fish products, meat and meat products and fish oil). For PCDD/Fs, the highest frequency of detection corresponds to 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,4,7,8-PeCDF; and PCBs 118, 105 and 156 were the more frequent dl-PCBs. The food groups presenting higher contamination, expressed as toxic equivalents (WHO-TEQs), were fish oil (6.38 pg WHO-TEQ g(-1)fat), fish (1.21 pg WHO-TEQ g(-1)w.w.) and milk an…
Occurrence of biomarkers of pesticide exposure in non-invasive human specimens.
2015
Biomonitoring has been used in many types of investigations, including national programmes and epidemiological studies, to explore the occurrence of biomarkers of pesticide exposure in the general population or relevant groups. This review discusses recent studies that measure levels of biomarkers of pesticide exposure in non-invasive human specimens such as urine, breast milk, meconium and hair. Specific and non-specific metabolites of organophosphate and pyrethroid insecticides have been widely investigated in urine, where some of the suitable biomarkers present rates of detection higher than 80%, which stand for an ongoing chronic exposure to traces of these chemicals. Hair is a promisin…
Ischemic cardiovascular disease in workers occupationally exposed to urban air pollution – A systematic review
2018
Introduction Cardiovascular disease is the first cause of morbidity and mortality worldwide. Among several known risk factors, researchers also focus their attention on the chronic exposure to air pollution. There is much evidence that exposure to air pollution, especially to ultrafine particles, can damage the endothelium and can favour cardiovascular diseases in the general population. Occupational exposition could be an additive risk factor for the cardiovascular system. This article presents a scientific review of the linkage between occupational exposure to air pollution and ischemic heart disease. Material and methods A scientific review was undertaken, followed by PRISMA Statements. …
Thiourea Organocatalysts as Emerging Chiral Pollutants: En Route to Porphyrin-Based (Chir)Optical Sensing
2021
Environmental pollution with chiral organic compounds is an emerging problem requiring innovative sensing methods. Amino-functionalized thioureas, such as 2-(dimethylamino)cyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea (Takemoto’s catalyst), are widely used organocatalysts with virtually unknown environmental safety data. Ecotoxicity studies based on the Vibrio fischeri luminescence inhibition test reveal significant toxicity of Takemoto’s catalyst (EC50 = 7.9 mg/L) and its NH2-substituted analog (EC50 = 7.2–7.4 mg/L). The observed toxic effect was pronounced by the influence of the trifluoromethyl moiety. En route to the porphyrin-based chemosensing of Takemoto-type thioureas, their s…
Genotoxicity of citrus wastewater in prokaryotic and eukaryotic cells and efficiency of heterogeneous photocatalysis by TiO(2).
2012
Abstract The presence of (±)α-pinene, (+)β-pinene, (+)3-carene, and R-(+)limonene terpenes in wastewater of a citrus transformation factory was detected and analyzed, in a previous study, by using Solid Phase Micro-extraction (SPME) followed by GC analyses. Purpose of that research was to compare the genotoxic responses of mixtures of terpenes with the genotoxicity of the individual compounds, and the biological effects of actual wastewater. Genotoxicity was evaluated in the Salmonella reversion assay (Ames test) and in V79 cells by Comet assay. Ames tests indicated that the four single terpenes did not induce an increase of revertants frequency. On the contrary, the mixtures of terpenes ca…