Avaliação da contaminação por hidrocarbonetos do solo e da água da região de Avaré

Pós-graduação em Engenharia Civil e Ambiental - FEB

Geoquímica de radionuclídeos naturais e biomonitoramento em área de mineração de carvão no sul do Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação técnica e econômica de um biodigestor de fluxo tubular: estudo de caso do modelo implantado na etec "orlando quagliato" em Santa Cruz do Rio Pardo, SP

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Evaluation of the Concentration of Nonessential and Essential Elements in Chicken, Pork, and Beef Samples Produced in Brazil

Food safety is a global concern. Meat represents the most important protein source for humans. Thus, contamination of meat products by nonessential elements is a ready source of human exposure. In addition, knowledge of the concentration of essential elements is also relevant with respect to human nutrition. The aim of the present study was to determine the concentration of 17 elements in pork, beef, and chicken produced in Brazil. Meat samples were analyzed by inductively coupled plasma mass spectrometry. The estimated daily intake for nonessential elements including arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and antimony (Sb) through meat consumption is below the toxicological reference values. However, high levels were detected for the nonessential element cesium (Cs), mainly in beef samples, an observation that deserves future studies to identify the source of contamination and potential adverse consequences.

Anti-Toxocara spp. antibodies in an adult healthy population: serosurvey and risk factors in Southeast Brazil.

Objective: To evaluate the frequency of anti-Toxocara spp. antibodies in an adult healthy population. Methods: The study was performed by interviewing 253 blood donors, from 19 to 65 years of age, in a hematological centre in Presidente Prudente, São Paulo, southeast Brazil. A survey was applied to blood donors in order to evaluate the possible factors associated to the presence of antibodies, including individual (gender and age), socioeconomic (scholarship, familial income and sanitary facilities) and habit information (contact with soil, geophagy, onycophagy and intake of raw/undercooked meat) as well as the presence of dogs or cats in the household. ELISA test was run for detection of the anti-Toxocara spp. IgG antibodies. Bivariate analysis followed by logistic regression was performed to evaluate the potential risk factors associated to seropositivity. Results: The overall prevalence observed in this study was 8.7% (22/253). Contact with soil was the unique risk factor associated with the presence of antibodies (P=0.0178 ; OR=3.52; 95% CI=1.244-9.995) Conclusions. The results of this study reinforce the necessity in promoting preventive public health measures, even for healthy adult individual, particularly those related to the deworming of pets to avoid the soil contamination, and hygiene education of the population.

Serological, clinical and epidemiological evaluation of toxocariasis in urban areas of south Brazil.

Toxocariasis is a worldwide public-health problem that poses major risks to children who may accidentally ingest embryonated eggs of Toxocara. The objectives of this study were to investigate the occurrence of anti-Toxocara spp. antibodies in children and adolescents and the variables that may be involved, as well as environmental contamination by Toxocara spp. eggs, in urban recreation areas of north central mesoregion, Paraná State, Brazil. From June 2005 to March 2007. a total of 376 blood samples were collected by the Public Health Service from children and adolescents one to 12 years old, of both genders. Samples were analyzed by the indirect ELISA method for detection of anti-Toxocara antibodies. Serum samples were previously absorbed with Ascaris suum antigens, and considered positive with a reagent reactivity index ≥1. Soil samples from all of the public squares and schools located in the four evaluated municipalities that had sand surfaces (n = 19) or lawns (n = 15) were analyzed. Of the 376 serum samples, 194 (51.6%) were positive. The seroprevalence rate was substantially higher among children aging one to five years (p = 0.001) and six to eight years (p = 0.022). The clinical signs and symptoms investigated did not show a statistical difference between seropositive and seronegative individuals (p > 0.05). In 76.5% of the investigated recreation places, eggs of Toxocara were detected in at least one of the five collected samples. Recreation areas from public schools were 2.8 times more contaminated than from public squares. It is important to institute educational programs to inform families and educators, as well as to improve sanitary control of animals and cleaning of the areas intended for recreation in order to prevent toxocariasis.

Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Remediation of crude oil contaminated soils by means of bitumen emulsions

Effective remediation of contaminated sites with oils, heavy metals and other chemical agents is one of the most important environmental problems all over the world. Contaminated soils by petroleum from different sites and origins, might contaminate groundwater aquifers and then be spread by rain. Many years and the requirement of remedial techniques may be needed to remediate them. However, previous experiences show the uselessness of these methods for the solution of all problems. As any case of soil contamination is different, specific studies with relevant factors at financial aspects, legal limits and waste and soil characteristics are needed. In this work, a study of the use of bitumen asphalt emulsion to remediate contaminated soils by crude oils is exposed. By means of the soil stabilization technology, using the contaminated soils as aggregates and the tailor made emulsion as binder, the feasibility of the mix application to produce stable and resistant pavements is demonstrated

Intermediate hosts of Toxoplasma gondii and food safety:epidemiology, genetics and parasite survival in meat-producing animals in Italy

Toxoplasma gondii is a coccidian parasite with a global distribution. The definitive host is the cat (and other felids). All warm-blooded animals can act as intermediate hosts, including humans. Sexual reproduction (gametogony) takes place in the final host and oocysts are released in the environment, where they then sporulate to become infective. In intermediate hosts the cycle is extra-intestinal and results in the formation of tachyzoites and bradyzoites. Tachyzoites represent the invasive and proliferative stage and on entering a cell it multiplies asexually by endodyogeny. Bradyzoites within tissue cysts are the latent form. T. gondii is a food-borne parasite causing toxoplasmosis, which can occur in both animals and humans. Infection in humans is asymptomatic in more than 80% of cases in Europe and North-America. In the remaining cases patients present fever, cervical lymphadenopathy and other non-specific clinical signs. Nevertheless, toxoplasmosis is life threatening if it occurs in immunocompromised subjects. The main organs involved are brain (toxoplasmic encephalitis), heart (myocarditis), lungs (pulmonary toxoplasmosis), eyes, pancreas and parasite can be isolated from these tissues. Another aspect is congenital toxoplasmosis that may occur in pregnant women and the severity of the consequences depends on the stage of pregnancy when maternal infection occurs. Acute toxoplasmosis in developing foetuses may result in blindness, deformation, mental retardation or even death. The European Food Safety Authority (EFSA), in recent reports on zoonoses, highlighted that an increasing numbers of animals resulted infected with T. gondii in EU (reported by the European Member States for pigs, sheep, goats, hunted wild boar and hunted deer, in 2011 and 2012). In addition, high prevalence values have been detected in cats, cattle and dogs, as well as several other animal species, indicating the wide distribution of the parasite among different animal and wildlife species. The main route of transmission is consumption of food and water contaminated with sporulated oocysts. However, infection through the ingestion of meat contaminated with tissue cysts is frequent. Finally, although less frequent, other food products contaminated with tachyzoites such as milk, may also pose a risk. The importance of this parasite as a risk for human health was recently highlighted by EFSA’s opinion on modernization of meat inspection, where Toxoplasma gondii was identified as a relevant hazard to be addressed in revised meat inspection systems for pigs, sheep, goats, farmed wild boar and farmed deer (Call for proposals -GP/EFSA/BIOHAZ/2013/01). The risk of infection is more highly associated to animals reared outside, also in free-range or organic farms, where biohazard measure are less strict than in large scale, industrial farms. Here, animals are kept under strict biosecurity measures, including barriers, which inhibit access by cats, thus making soil contamination by oocysts nearly impossible. A growing demand by the consumer for organic products, coming from free-range livestock, in respect of animal-welfare, and the desire for the best quality of derived products, have all led to an increase in the farming of free-range animals. The risk of Toxoplasma gondii infection increases when animals have access to environment and the absence of data in Italy, together with need for in depth study of both the prevalence and genotypes of Toxoplasma gondii present in our country were the main reasons for the development of this thesis project. A total of 152 animals have been analyzed, including 21 free-range pigs (Suino Nero race), 24 transhumant Cornigliese sheep, 77 free-range chickens and 21 wild animals. Serology (on meat juice) and identification of T. gondii DNA through PCR was performed on all samples, except for wild animals (no serology). An in-vitro test was also applied with the aim to find an alternative and valid method to bioassay, actually the gold standard. Meat samples were digested and seeded onto Vero cells, checked every day and a RT-PCR protocol was used to determine an eventual increase in the amount of DNA, demonstrating the viability of the parasite. Several samples were alos genetically characterized using a PCR-RFLP protocol to define the major genotypes diffused in the geographical area studied. Within the context of a project promoted by Istituto Zooprofilattico of Pavia and Brescia (Italy), experimentally infected pigs were also analyzed. One of the aims was to verify if the production process of cured “Prosciutto di Parma” is able to kill the parasite. Our contribution included the digestion and seeding of homogenates on Vero cells and applying the Elisa test on meat juice. This thesis project has highlighted widespread diffusion of T. gondii in the geographical area taken into account. Pigs, sheep, chickens and wild animals showed high prevalence of infection. The data obtained with serology were 95.2%, 70.8%, 36.4%, respectively, indicating the spread of the parasite among numerous animal species. For wild animals, the average value of parasite infection determined through PCR was 44.8%. Meat juice serology appears to be a very useful, rapid and sensitive method for screening carcasses at slaughterhouse and for marketing “Toxo-free” meat. The results obtained on fresh pork meat (derived from experimentally infected pigs) before (on serum) and after (on meat juice) slaughter showed a good concordance. The free-range farming put in evidence a marked risk for meat-producing animals and as a consequence also for the consumer. Genotyping revealed the diffusion of Type-II and in a lower percentage of Type-III. In pigs is predominant the Type-II profile, while in wildlife is more diffused a Type-III and mixed profiles (mainly Type-II/III). The mixed genotypes (Type-II/III) could be explained by the presence of mixed infections. Free-range farming and the contact with wildlife could facilitate the spread of the parasite and the generation of new and atypical strains, with unknown consequences on human health. The curing process employed in this study appears to produce hams that do not pose a serious concern to human health and therefore could be marketed and consumed without significant health risk. Little is known about the diffusion and genotypes of T. gondii in wild animals; further studies on the way in which new and mixed genotypes may be introduced into the domestic cycle should be very interesting, also with the use of NGS techniques, more rapid and sensitive than PCR-RFLP. Furthermore wildlife can become a valuable indicator of environmental contamination with T. gondii oocysts. Other future perspectives regarding pigs include the expansion of the number of free-range animals and farms and for Cornigliese sheep the evaluation of other food products as raw milk and cheeses. It should be interesting to proceed with the validation of an ELISA test for infection in chickens, using both serum and meat juice on a larger number of animals and the same should be done also for wildlife (at the moment no ELISA tests are available and MAT is the reference method for them). Results related to Parma ham do not suggest a concerning risk for consumers. However, further studies are needed to complete the risk assessment and the analysis of other products cured using technological processes other than those investigated in the present study. For example, it could be interesting to analyze products such as salami, produced with pig meat all over the Italian country, with very different recipes, also in domestic and rural contexts, characterized by a very short period of curing (1 to 6 months). Toxoplasma gondii is one of the most diffuse food-borne parasites globally. Public health safety, improved animal production and protection of endangered livestock species are all important goals of research into reliable diagnostic tools for this infection. Future studies into the epidemiology, parasite survival and genotypes of T. gondii in meat producing animals should continue to be a research priority.

Potencial de fitorremediação de diferentes plantas em solo contaminado por 14C-tebuthiuron

Este trabalho teve como objetivo avaliar a tolerância e a capacidade de fitorremediação de crotalária (Crotalaria spectabilis), sorgo (Sorghum bicolor), nabo forrageiro (Raphanus sativus), amendoim (Arachis hypogaea) e alfafa (Mendicago sativa) a solos contaminados por tebuthiuron. Para determinar a tolerância das plantas ao herbicida estas foram submetidas a 5 diferentes doses (300, 600, 1200, 2400 e 4800 gramas de ingrediente ativo por hectare gi.a. ha-1) e comparadas com uma testemunha que não recebeu aplicação do herbicida. Crotalária, Nabo forrageiro e alfafa se mostraram sensíveis ao herbicida, mesmo na menor dose de aplicação, enquanto sorgo se mostrou tolerante ao herbicida até a dose de 600 gi.a. ha-1 tendo apresentado fitointoxicação de 80% na dose de 1200 gi.a. ha-1 e amendoim foi tolerante até a dose de 4800 gi.a. ha-1 para a qual apresentou apenas 40% de fitointoxicação. Plantas de amendoim e sorgo foram submetidas a dose de contaminação de 600 gi.a. ha-1 aplicada por meio de uma solução de trabalho contendo 17,47kBq (Quilobecquerels) de 14C-tebuthiuron. As duas plantas foram capazes de remediar o solo, no entanto amendoim se mostrou mais eficiente reduzindo a contaminação em 75,8% enquanto sorgo retirou do solo 44,49% do herbicida contaminante

Consumable electrode arc-melting of cold-compacted thorium powder /

The consumable electrode arc melting of cold-compacted thorium powder has been developed to produce dense, clean and soft ingots which can be hot rolled without cracking. By using a water-cooled copper crucible, contamination has been prevented and resultant ingots cleaner than the original powder have been produced.

An investigation of contaminant distribution in subsurface marine wood waste at Mill-A South Terminal, Port of Everett, Washington

This project investigates the correlation between contaminants and the wood waste present in marine sediments off the shore of the Port of Everett in the former Weyerhaeuser Mill-A pulp mill site. The investigation includes the results of two field studies, which tested contaminant levels in 22 boreholes as well as several surface samples. The contaminants include heavy metals and wood waste byproducts. These results, along with 14 other bore logs, provide the framework for a three-dimensional site model, interpolating the full extent of the depositional units and organic and inorganic chemicals found at Mill-A. The sediments of interest are divided into five depositional units defined by the percent wood content and type of wood: native material (<5% wood), intermediate (<30% wood), sawdust (<30% wood), woodchips (<30% wood), and poorly sorted sands with silt (SM-SP) (0% wood). The contaminants include arsenic, 2,4-dimethylphenol, and total organic carbon. Three-dimensional modeling software, RockWorks, interpolated the discrete borehole data of sediment and contaminants assuming horizontal continuity between sampling locations. The sediment distribution was calculated within concentration ranges for each contaminant of concern. The lowest detection limits, the screening levels, and the cleanup levels defined these ranges. Total organic carbon served as a proxy to estimate the quantity of wood waste in the sediment. As a known byproduct of wood decomposition, 2,4-dimethylphenol was expected to be more prevalent in the depositional units with more wood waste. Finally, arsenic was a proxy for other contaminants to determine if contaminants at Mill-A are dominant in sediments with high percentages of wood waste. The volumetric distribution established that high levels of total organic carbon are present in the sediment with higher percentages of wood waste. This correlation was stronger in the decomposing sawdust-rich sediment than the woodchip-rich sediment. The 2,4-dimethylphenol concentrations above cleanup standards were dominant in the sawdust-rich, intermediate and native sediments. Concentrations of 2,4-dimethylphenol below cleanup levels characterized the native sediment. The distribution of arsenic showed no statistically significant correlation to wood content in sediment. These results do not support the hypothesis of contaminant-rich wood waste, as many of the high concentrations of contaminants were not in the wood-rich sediments. This suggests that the contaminants are more distributed among all depositional units at Mill-A rather than focused within sediments with a high percent of wood waste. Understanding the distribution of potentially toxic compounds with wood waste is important for restoring the Puget Sound waterways to a more habitable environment. Future studies should include new data to validate these results and to limit the uncertainty of the extent of contaminants. Future studies may also find motive in looking for a correlation between contaminants and grain size based on previous studies linking these characteristics. These investigations will benefit the current cleanup effort as well as future cleanup efforts at similarly contaminated waterways.

Accumulation and toxicity of monophenyl arsenicals in rat endothelial cells

Clark 1 (diphenylarsine chloride) and Clark 2 ( diphenylarsine cyanide) were used as chemical weapon agents (CWA), and the soil contamination by these CWA and their degraded products, diphenyl and phenyl arsenicals, has been one of the most serious environmental issues. In a series of comparisons in toxicity between trivalent and pentavalent arsenicals we investigated differences in the accumulation and toxicity of phenylarsine oxide (PAO(3+)) and phenylarsonic acid (PAA(5+)) in rat heart microvascular endothelial cells. Both the cellular association and toxicity of PAO(3+) were much higher than those of PAA(5+), and LC50 values of PAO(3+) and PAA(5+) were calculated to be 0.295 muM and 1.93 mM, respectively. Buthionine sulfoximine, a glutathione depleter, enhanced the cytotoxicity of both PAO(3+) and PAA(5+). N-Acetyl-L-cysteine (NAC) reduced the cytotoxicity and induction of heme oxygenase-1 (HO-1) mRNA in PAO(3+)-exposed cells, while NAC affected neither the cytotoxicity nor the HO-1 mRNA level in PAA(5+)-exposed cells. The effect of NAC may be due to a strong affinity of PAO(3+) to thiol groups because both NAC and GSH inhibited the cellular accumulation of PAO(3+), but PAA(3+) increased tyrosine phosphorylation levels of cellular proteins. These results indicate that the inhibition of protein phosphatases as well as the high affinity to cellular components may confer PAO(3+) the high toxicity.

Tratamento de cascalho de perfuração utilizando sistemas microemulsionados

The oil industry is one of the activities that generates more waste to the environment. The drill cuttings is a waste generated in large quantities in the drilling process and that may cause environmental damage such as soil contamination and consequently the contamination of groundwater if disposed of without prior treatment. Arises the need to develop scientific activities and research ways to adapt these wastes the current environmental standards. In the case of solid wastes, the NBR 10004: 2004 of the Brazilian Association of Technical Standards (ABNT) classifies them into class I waste (hazardous) and class II (not dangerous), which determines which wastes may or may not be discarded in the environment without causing environmental impact. This study presents a novel alternative for treating drill cuttings, where this waste was classified as class I (Abreu & Souza, 2005), mainly by removing the n-paraffin present in it, since this arises when using drilling fluids base oil. Using microemulsion systems promotes the removal of this contaminant drill cuttings samples from wells located in Alto do Rodrigues - RN. Initially, we determined the concentration of paraffin using infrared method in samples were extracted with ultrasound, we obtained a paraffin concentration in the range from 36.59 to 43.52 g of paraffin per kilogram of cuttings. Used two microemulsion systems containing two nonionic surfactants from different classes, one is an alcohol ethoxylated (UNTL-90) and the other an nonylphenol ethoxylated (RNX 110). The results indicated that the system UNTL-90 surfactant has better efficiency than the system with RNX 110. The study of the influence of contact time at the extraction showed that for times greater than 25 minutes has a tendency to increase the percentage extraction with increasing contact time. It was also observed that the extraction is fast because at 1 minute contact has 22.7% extraction. The reuse of the microemulsion system without removing the paraffin extracted in previous steps, showed reduction of 29.32 in percentage of extraction by comparing the first and third extraction, but by comparing the first and second extractions reduction is 8.5 in percentage extraction, so the systems reuse optimization can be an option for economically viable removing paraffin from cuttings. The extraction with shaking is more effective in the treatment of cuttings, reaching the extraction percentage of 87.04%, that is, obtaining a drill cuttings with 0.551% paraffin. Using the percentage of paraffin employed in non-aqueous drilling fluids and fluid maximum limit on cuttings for disposal established by the Environmental Protection Agency of the United States (US EPA), one arrives at the conclusion that the level of paraffin on gravel cannot exceed 3.93%. Conclude that the amount of paraffin in the treated cuttings with the microemulsion system with shaking is below the established by US EPA, showing that the system used was efficient in removing the paraffin from the drill cuttings.

Passivo ambiental: estudo de caso

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Contabilidade e Finanças