Toxicity of chromated copper arsenate: a study in mice

Chromated copper arsenate (CCA) was widespread used as a chemical wood preservative with application in the construction of playground equipment, fences, jetties, and naval. Environmental protection agency (EPA) had limited the use of CCA-treated wood on 2002, due to probable implications on both human and environmental health. Although this fact, several industries pursue the use of this product within their manufactories. In addition, the durability of this wood for 60 years, makes these treated products an hazard to the public health. In the present work, studies were explored exposing mice to CCA, during 14, 24, 48, and 96 h for the assessment of acute toxicity of CCA. Kidney and liver were removed, prepared for histology and for metalloid, and copper content evaluation by high resolution inductively coupled plasma mass spectroscopy. The histological results evidenced apparently normal structures for control animals and group exposed to As2O5. On the contrary, the renal sections of the animals treated with CCA revealed epithelium cells desquamation, hyaline, and granular casts in renal tubules lumen. Furthermore, high levels of arsenic were detected in the kidney of animals treated with CCA over 14 and 48 h, being significantly greater than controls. Although this approach underlines the potential hazard of CCA on some vital organs, further testing may be required to establish the impacts on other functions.

Determina����o do teor de compostos arom��ticos polic��clicos de ��leos minerais isolantes para transformadores

Mestrado em Engenharia Qu��mica - Ramo Optimiza����o Energ��tica na Ind��stria Qu��mica

Monitoriza����o do consumo de energia em centros de dados

Disserta����o de Mestrado em Engenharia Inform��tica

Trace metals in size-fractionated particulate matter in a Portuguese hospital: exposure risks assessment and comparisons with other countries

Hospitals are considered as a special and important type of indoor public place where air quality has significant impacts on potential health outcomes. Information on indoor air quality of these environments, concerning exposures to particulate matter (PM) and related toxicity, is limited though. This work aims to evaluate risks associated with inhalation exposure to ten toxic metals and chlorine (As, Ni, Cr, Cd, Pb, Mn, Se, Ba, Al, Si, and Cl) in coarse (PM2.5���10) and fine (PM2.5) particles in a Portuguese hospital in comparison with studies representative of other countries. Samples were collected during 1 month in one urban hospital; elemental PM characterization was determined by proton-induced X-ray emission. Noncarcinogenic and carcinogenic risks were assessed according to the methodology provided by the United States Environmental Protection Agency (USEPA; Region III Risk-Based Concentration Table) for three different age categories of hospital personnel (adults, >20, and <65 years) and patients (considering nine different age groups, i.e., children of 1���3 years to seniors of >65 years). The estimated noncarcinogenic risks due to occupational inhalation exposure to PM2.5-bound metals ranged from 5.88��10���6 for Se (adults, 55���64 years) to 9.35��10���1 for As (adults, 20���24 years) with total noncarcinogenic risks (sum of all metals) above the safe level for all three age categories. As and Cl (the latter due to its high abundances) were the most important contributors (approximately 90 %) to noncarcinogenic risks. For PM2.5���10, noncarcinogenic risks of all metals were acceptable to all age groups. Concerning carcinogenic risks, for Ni and Pb, they were negligible (<1��10���6) in both PM fractions for all age groups of hospital personnel; potential risks were observed for As and Cr with values in PM2.5 exceeding (up to 62 and 5 times, respectively) USEPA guideline across all age groups; for PM2.5���10, increased excess risks of As and Cr were observed particularly for long-term exposures (adults, 55���64 years). Total carcinogenic risks highly (up to 67 times) exceeded the recommended level for all age groups, thus clearly showing that occupational exposure to metals in fine particles pose significant risks. If the extensive working hours of hospital medical staff were considered, the respective noncarcinogenic and carcinogenic risks were increased, the latter for PM2.5 exceeding the USEPA cumulative guideline of 10���4. For adult patients, the estimated noncarcinogenic and carcinogenic risks were approximately three times higher than for personnel, with particular concerns observed for children and adolescents.

Avalia����o da carga poluente afluente a uma massa de ��gua ��� rio de S. Domingos

Disserta����o para obten����o do Grau de Mestre em Engenharia do Ambiente ��� Perfil de Engenharia Sanit��ria

Avalia����o do papel da glutationa e do vac��olo como mecanismos de defesa contra a toxicidade induzida pelo chumbo na levedura Saccharomyces cerevisiae

A presen��a de metais pesados no meio ambiente deve-se, principalmente, a actividades antropog��nicas. Ao contr��rio do Cu e do Zn, que em baixas concentra����es s��o essenciais para o normal funcionamento celular, n��o se conhece para o chumbo nenhuma fun����o biol��gica. O chumbo apresenta efeitos t��xicos, e considerado poss��vel agente carcinog��neo, sendo classificado como poluente priorit��rio pela Agencia de Protec����o Ambiental dos EUA (US-EPA). O presente trabalho teve como objetivo avaliar o papel da glutationa e do vac��olo, como mecanismos de defesa, contra os efeitos t��xicos induzidos pelo chumbo, usando como modelo a levedura Saccharomyces cerevisiae. A levedura S. cerevisiae quando exposta a varias concentra����es de chumbo, durante 3h, perde a viabilidade e acumula esp��cies reativas de oxig��nio (ROS). O estudo comparativo da perda de viabilidade e acumula����o de ROS em c��lulas de uma estirpe selvagem (WT) e de estirpes mutantes, incapazes de produzir glutationa devido a uma defici��ncia no gene GSH1 (���gsh1) ou GSH2 (���gsh2) mostrou que as estirpes ���gsh1 ou(���gsh2 n��o apresentavam um aumento da sensibilidade ao efeito toxico do chumbo. No entanto, o tratamento de c��lulas da estirpe WT com iodoacetamida (um agente alquilante que induz a deple����o de glutationa) aumentou a sensibilidade das c��lulas a presen��a de chumbo. Pelo contr��rio, o enriquecimento em GSH, atrav��s da incuba����o de c��lulas WT com glucose e uma mistura de amino��cidos que constituem a GSH (acido L-glut��mico, L-ciste��na e glicina), reduziu o stress oxidativo e a perda de viabilidade induzida por chumbo. A import��ncia do vac��olo, como mecanismo de defesa, foi avaliada atrav��s da utiliza����o de um mutante sem qualquer estrutura vacuolar (���vps16) ou de mutantes deficientes na subunidade catal��tica A (���vma1) ou B (���vma2) ou no proteol��tico - subunidade C (���vma3) da V-ATPase. As c��lulas da estirpe ����vps16 apresentaram uma elevada suscetibilidade a presen��a de chumbo. As c��lulas das estirpes deficientes na subunidade A, B ou c da V-ATPase, apresentaram uma maior perda de viabilidade, quando expostas a chumbo, do que as c��lulas da estirpe WT, mas menor do que a da estirpe ���vps16 Em conclus��o, os resultados obtidos, no seu conjunto, sugerem que a glutationa esta envolvida na defesa contra a toxicidade provocada por chumbo; todavia, a glutationa, por si s��, parece n��o ser suficiente para suster o stress oxidativo e a perda de viabilidade induzida por chumbo. O vac��olo parece constituir um importante mecanismo de defesa contra a toxicidade provocada por chumbo. A V-ATPase parece estar envolvida na compartimenta����o de chumbo no vac��olo.

Exposure to polycyclic aromatic hydrocarbons and assessment of potential risks in preschool children

As children represent one of the most vulnerable groups in society, more information concerning their exposure to health hazardous air pollutants in school environments is necessary. Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority air pollutants due to their mutagenic and carcinogenic properties that strongly affect human health. Thus, this work aims to characterize levels of 18 selected PAHs in preschool environment, and to estimate exposure and assess the respective risks for 3���5-year-old children (in comparison with adults). Gaseous PAHs (mean of 44.5��������12.3 ng m���3) accounted for 87 % of the total concentration (��PAHs) with 3���ringed compounds being the most abundant (66 % of gaseous ��PAHs). PAHs with 5 rings were the most abundant ones in the particulate phase (PM; mean of 6.89��������2.85 ng m���3) being predominantly found in PM1 (78 % particulate ��PAHs). Overall child exposures to PAHs were not significantly different between older children (4���5 years old) and younger ones (3 years old). Total carcinogenic risks due to particulate-bound PAHs indoors were higher than outdoor ones. The estimated cancer risks of both preschool children and the staff were lower than the United States Environmental Protection Agency (USEPA) threshold of 10���6 but slightly higher than WHO-based guideline.

Modela����o din��mica de sistemas de drenagem em meio urbano

Disserta����o para obten����o do Grau de Mestre em Engenharia do Ambiente, perfil Engenharia Sanit��ria

Distribui����o geoqu��mica e biodisponibilidade de metais tra��o em sedimentos no Rio Bento Gomes, Pocon�� - MT, Brasil

RESUMO O sedimento �� um dos compartimentos mais importantes dos ecossistemas aqu��ticos, possui papel importante no transporte e acumula����o de metais. Este estudo teve por objetivo determinar a concentra����o de metais nas fra����es geoqu��micas de sedimentos do Rio Bento Gomes, Pantanal de Pocon�� (MT) por meio da extra����o seletiva e sequencial, a fim de avaliar a distribui����o e mobilidade dos metais. Os sedimentos foram coletados nos per��odos seco e chuvoso em oito pontos distintos, e os metais (Fe, Mn, Cr, Cu, Zn e Ni) extra��dos dos sedimentos por procedimentos de extra����o sequencial (baseada no protocolo proposto por BCR -Community Bureau of Reference) e de extra����o seletiva (baseada no protocolo 3050B da Environmental Protection Agency of the United States), utilizando-se materiais de refer��ncia certificados para valida����o do m��todo anal��tico. Todos os metais apresentaram teores abaixo do limite previsto na Resolu����o CONAMA n�� 454/2012 no per��odo seco, com exce����o do Ni no per��odo chuvoso (maior que 18 mg kg-1). Os estudos de fracionamento indicaram que os metais foram encontrados nas fra����es mobiliz��veis do sedimento, especialmente associados aos ��xidos de ferro. Os metais mais m��veis e, consequentemente, mais biodispon��veis, foram o mangan��s, zinco e n��quel, principalmente na ��poca chuvosa. Maiores teores de cobre foram encontrados nas fra����es residuais do sedimento, indicando baixa mobilidade no meio aqu��tico. A sequ��ncia de mobilidade dos metais estudados foi Mn > Zn > Ni > Cr > Cu > Fe.

An analysis of the use of photogrammetric sorting to audit construction and demolition waste production on site

This study analyses the area of construction and demolition waste (C & D W) auditing. The production of C&DW has grown year after year since the Environmental Protection Agency (EPA) first published a report in 1996 which provided data for C&D W quantities for 1995 (EPA, 1996a). The most recent report produced by the EPA is based on data for 2005 (EPA, 2006). This report estimated that the quantity of C&DW produced for that period to be 14 931 486 tonnes. However, this is a ���data update��� report containing an update on certain waste statistics so any total provided would not be a true reflection of the waste produced for that period. This illustrates that a more construction site-specific form of data is required. The Department of Building and Civil Engineering in the Galway-Mayo Institute of Technology have carried out two recent research projects (Grimes, 2005; Kelly, 2006) in this area, which have produced waste production indicators based on site-specific data. This involved the design and testing of an original auditing tool based on visual characterisation and the application of conversion factors. One of the main recommendations of these studies was to compare this visual characterisation approach with a photogrammetric sorting methodology. This study investigates the application of photogrammetric sorting on a residential construction site in the Galway region. A visual characterisation study is also carried out on the same project to compare the two methodologies and assess the practical application in a construction site environment. Data collected from the waste management contractor on site was also used to provide further evaluation. From this, a set of waste production indicators for new residential construction was produced: ��� 50.8 kg/m2 for new residential construction using data provided by the visual characterisation method and the Landfill Levy conversion factors. ��� 43 kg/m2 for new residential construction using data provided by the photogrammetric sorting method and the Landfill Levy conversion factors. ��� 23.8 kg/m2 for new residential construction using data provided by Waste Management Contractor (WMC). The acquisition of the data from the waste management contractor was a key element for testing of the information produced by the visual characterisation and photogrammetric sorting methods. The actual weight provided by the waste management contractor shows a significant difference between the quantities provided.