Comprehensive study on dioxin contents in binder and anti-caking agent feed additives

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in some additives widely employed as binder and anti-caking agents in feedstuffs, such as kaolin, bentonite, zeolite, etc. with an special attention on sepiolite samples. Owing to their physico-chemical properties, the little information of these materials reported in the literature, the variability of PCDDs/PCDFs found in a preliminary evaluation and the absence of reference materials highlighted further research needed. Therefore, an extensive study on the analytical procedures based on the classical methods was performed with sepiolite samples. The study includes evaluation of reproducibility and repeatibility. To this end, a series of intra-day and nine inter-day analysis were made. The methodolgy was also assessed against the sample size and series of 12.5, 25, 37.5 and 50 g were analyzed. In all cases, the results confirmed good correlation with the parameters evaluated.     

Characterization of a limestone in a batch fluidized bed reactor for sulfur retention under oxy-fuel operating conditions

CO₂ and SO₂ are some of the main polluting gases emitted into atmosphere in combustion processes using fossil fuel for energy production. The former is one of the major contributors to build-up the greenhouse effect implicated in global climate change and the latter produces acid rain. Oxy-fuel combustion is a technology, which consists in burning the fuel with a mix of pure O₂ and recirculated CO₂. With this technology the CO₂ concentration in the flue gas may be enriched up to 95%, becoming possible an easy CO₂ recovery. In addition, oxy-fuel combustion in fluidized beds allows in situ desulfurization of combustion gases by supplying calcium based sorbent.In this work, the effect of the principal operation variables affecting the sulfation reaction rate in fluidized bed reactors (temperature, CO₂ partial pressure, SO₂ concentration and particle size) under typical oxy-fuel combustion conditions have been analyzed in a batch fluidized bed reactor using a limestone as sorbent. It has been observed that sulfur retention can be carried out by direct sulfation of the CaCO₃ or by sulfation of the CaO (indirect sulfation) formed by CaCO₃ calcination. Direct sulfation and indirect sulfation operating conditions depended on the temperature and CO₂ partial pressure. The rate of direct sulfation rose with temperature and the rate of indirect sulfation for long reaction times decreased with temperature. An increase in the CO₂ partial pressure had a negative influence on the sulfation conversion reached by the limestone due to a higher temperature was needed to work in conditions of indirect sulfation. Thus, it is expected that the optimum temperature for sulfur retention in oxy-fuel combustion in fluidized bed reactors be about 925–950 °C. Sulfation reaction rate rose with decreasing sorbent particle size and increasing SO₂ concentration.     

Organochlorine compounds (PCBs, PCDDs and PCDFs) in seafish and seafood from the Spanish Atlantic Southwest Coast

Concentrations and congener specific profiles of PCDD/Fs and PCBs were determined in edible fish and seafood species from the Coast of Huelva, in the Spanish southwest Atlantic coast. Five fish species, namely wegde sole (Dicologoglossa cuneata), common sole (Solea vulgaris), white seabream (Diplodus sargus), sardine (Sardina pilchardus), angler fish (Lophius piscatorius), two shellfish species (Donax trunculus and Chamelea gallina), common cuttlefish (Sepia officinalis) and prawns (Parapenaeus longirostris), frequently found and consumed in the area were analysed. Concentrations ranged from 861 to 23787pg/g wet weight for total PCBs, while 2,3,7,8-PCDD/Fs showed concentrations ranging from 0.2 to 1.18pg/g wet weight. WHO-TEQ concentrations ranged from 0.038 to 0.186pg WHO-TEQ(PCDD/Fs)/g wet weight, values well below the maximum concentrations established by the EU. When non- and mono-ortho PCBs were included the values increased to a maximum of 0.99pg WHO-TEQ(PCDD/Fs+PCBs)/g wet weight. The PCB and PCDD/F accumulation pattern found in the samples analysed showed a distribution typically reported for marine samples, and no remarkable differences were found between species. The PCBs were the ones contributing with the highest percentage to the total TEQ content in most species studied. Concerning the seafood, specially prawns and shellfish, the opposite was observed and PCDD/Fs were found to contribute with a higher percentage than PCBs. The congener specific contribution to the TEQ showed PCB 126 followed by 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF as the most abundant ones.     

Alteration in some biochemical and enzymological parameters in the snake head fish Channapunctatus, exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Improvements in dioxin abatement strategies at a municipal waste management plant in Barcelona

This study presents the results of a dioxin abatement programme undertaken in the municipal waste incineration plant of Montcada i Reixac (Barcelona, Spain) after the replacement of an obsolete air cleaning device by a new flue gas treatment system. A number of sampling campaigns were conducted with the aim of characterising stack gas emission levels of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and to evaluate initial specifications of dioxin stack gas emission values below 0.1 ng I-TEQ/Nm(3). Preliminary results revealed levels between 44 and 111 ng I-TEQ/Nm(3) when the gas-cleaning system consisted only of an old electrostatic precipitator (ESP). Decreased levels around 15 ng I-TEQ/Nm(3) were observed when the semi-dry scrubber began to operate and the ESP was switched off. Again, remarkable dioxin removal was observed after the installation of the fabric filter and levels around 0.3-0.4 ng I-TEQ/Nm(3) were soon achieved. Nevertheless, the limit of 0.1 ng I-TEQ/Nm(3) was reached by additional injection of activated carbon which helped to lower PCDD/PCDF levels to around 0.036 ng I-TEQ/Nm(3). The results also demonstrated a significant change in the dioxin distribution present in combustion-derived materials (stack gas emission, bottom ash and solid waste from gas treatment). The major dioxin fraction was found in gaseous matrices before the flue gas control system was upgraded. After this step, the major dioxin fraction content was observed in solid waste from gas treatment.     

Evaluation of Organochlorine Compounds (PCDDs,PCDFs, PCBs and DDTs) in Two Raptor Species Inhabiting a Mediterranean Island in Spain (8 pp)

Background Species that are at high levels of the food web have often been used as bioindicators to evaluate the presence of persistent contaminants in ecosystems. Most of these species are long-lived, so pollutant burdens may be integrated in some complex way over time. This makes them particularly sensitive to deleterious effects of Persistent Organic Pollutants (POPs). Birds have been suggested as useful organisms for monitoring pollutant levels. Traditionally such studies have been carried out with raptors such as osprey (Pandion haliaetus), peregrine falcon (Falco peregrinus), bald eagle (Haliaetus leucocephalus), etc. In this paper we present the results of a monitoring study conducted on two raptor species, osprey (Pandion haliaetus) and red kite (Milvus milvus), inhabiting a Mediterranean island (Menorca, Spain). These two species have different feeding habits; ospreys prey on fish and red kites feed on terrestrial species. This study constitutes a good opportunity to investigate if differences in feeding habits (aquatic vs. terrestrial) influences the contaminants pattern in two species inhabiting the same area. Methods The study was conducted in a non-destructive way, using only failed eggs, to avoid the damage of the population stability. Eggs were collected during the period 1994–2000. The contaminants examined were dichlorodiphenyltrichloroethanes (DDTs, including DDT and its main metabolite, DDE), polychlorinated biphenyls (PCBs), including ortho PCBs (PCBs with at least one Chlorine atom in the ortho position): #28, 52, 95, 101, 123+149, 118, 114, 153, 132+105, 138, 167, 156, 157, 180, 170, 189, 194; and non ortho PCBs (PCBs with no Chlorine atom in the ortho position): #77, 126, 169 and all the polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) with Chlorine atoms at the 2,3,7 and 8 position (2,3,7,8-substituted PCDDs and PCDFs). The analysis of organochlorine compounds was performed using a sample treatment based on a Solid Phase Matrix Dispersion procedure. Ortho PCBs and DDTs were determined by HRGC-μECD; non ortho PCBs and PCDD/Fs were determined by HRGC-HRMS. Results and Discussion The sum of the ortho PCB congeners analysed ranged from 0.94 to 15.03 μg/g wet weight (ww) for ospreys and from 1.0 to 11.2 μg/g ww for red kites. In both species, PCB congeners #153, #138 and #180 accounted about 75% to total ortho PCB concentrations. Regarding non ortho PCBs, for ospreys, concentrations ranged from 0.16 to 1.39 ng/g wet weight (ww) and for red kites from 0.12 to 0.51 ng/g ww, being congener #126 the most abundant. Concerning DDTs, concentration for ospreys ranged from 0.07 to 1.03 μg/g ww; and for red kites ranged from 0.90 to 2.10 μg/g ww, representing DDE more than 95% of the total DDTs, which proves a past use of DDT in the study area. Differences in contaminant levels between species are probably associated to feeding habits. The fish-eating species presents the highest PCB levels, whereas the terrestrial species exhibits the highest DDT levels. PCDD/Fs in ospreys were in the range 2.6–14.2 pg/g ww, while in red kites the range was slightly wider (22.2–43.2 pg/g ww), being PCDDs the major contributors in black kites. Ospreys had PCDDs similar to PCDF concentrations. PCDD/F profiles were mostly influenced by OCDD in both species. Non ortho PCBs were the major contributors to calculated Toxic Equivalent Quantity (TEQs) in both species. Conclusion In both species studied, ortho-PCBs could represent a problem of concern since 57% of the eggs exhibited levels higher than 4 μg/g ww, reported as the level that could cause reduced hatchability, embryo mortality, and deformities in birds. Recommendations and Outlook Results found in this study suggest that a more detailed study to clear up possible deleterious effects of PCBs on the bird populations studied here should be done. Section Editor: Prof. Dr. Paola Gramatica (paola.gramatica@uninsubria.it)     

Alteration in some biochemical and enzymological parameters in the snake head fish , exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Occurrence of PCBs, PCDD/Fs, PBDEs and DDTs in Spanish breast milk: enantiomeric fraction of chiral PCBs

Concentrations and congener specific profile of DDTs, PCBs and PCDD/Fs have been determined in a number of Spanish breast milk samples. The concentrations found indicate a decreasing tendency compared to previous data from the 1990s. Mean concentrations of 238 ng/g fat weight, 111 ng/g fat weight and 82.1 pg/g fat weight were found for DDTs, PCBs and 2,3,7,8-PCDD/Fs, respectively. When the WHO-TEQs were calculated, PCDD/Fs was the family contributing with the highest percentage to the total (62-84%), followed by the non-ortho PCBs (10-25%) and the mono-ortho PCBs (5-24%). The congener specific accumulation patterns found were comparable to those reported in other studies in industrialised countries. In addition, the levels of 9 PBDEs congeners have been also determined in the breast milk samples. The concentrations ranged from 0.04 to 1.38 ng/g fat weight. The enantiomeric enrichment of a number of chiral PCBs in the breast milk samples, including congeners 84, 91, 95, 132, 135, 149, 171, 174, 176 and 183, has also been studied, for some of them for the first time in this matrix.     

Inactivation of <Emphasis Type="Italic">Escherichia coli</Emphasis> in fresh water with advanced oxidation processes based on the combination of O<Subscript>3</Subscript>, H<Subscript>2</Subscript>O<Subscript>2</Subscript>, and TiO<Subscript>2</Subscript>. Kinetic modeling

The purpose of this work was to study the efficiency of different treatments, based on the combination of O₃, H₂O₂, and TiO₂, on fresh surface water samples fortified with wild strains of Escherichia coli. Moreover, an exhaustive assessment of the influence of the different agents involved in the treatment has been carried out by kinetic modeling of E. coli inactivation results. The treatments studied were (i) ozonation (O₃), (ii) the peroxone system (O₃/0.04 mM H₂O₂), (iii) catalytic ozonation (O₃/1 g/L TiO₂), and (iv) a combined treatment of O₃/1 g/L TiO₂/0.04 mM H₂O₂. It was observed that the peroxone system achieved the highest levels of inactivation of E. coli, around 6.80 log after 10 min of contact time. Catalytic ozonation also obtained high levels of inactivation in a short period of time, reaching 6.22 log in 10 min. Both treatments, the peroxone system (O₃/H₂O₂) and catalytic ozonation (O₃/TiO₂), produced a higher inactivation rate of E. coli than ozonation (4.97 log after 10 min). While the combination of ozone with hydrogen peroxide or titanium dioxide thus produces an increase in the inactivation yield of E. coli regarding ozonation, the O₃/TiO₂/H₂O₂ combination did not enhance the inactivation results. The fitting of experimental values to the corresponding equations through non-linear regression techniques was carried out with Microsoft® Excel GInaFiT software. The inactivation results of E. coli did not respond to linear functions, and it was necessary to use mathematical models able to describe certain deviations in the bacterial inactivation processes. In this case, the inactivation results fit with mathematical models based on the hypothesis that the bacteria population is divided into two different subgroups with different degrees of resistance to treatments, for instance biphasic and biphasic with shoulder models.

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