Persistent organic pollutants such as polychlorinated biphenyls (PCBs), DDT and polybrominated diphenyl ethers (PBDEs) tend to accumulate in biota and are transferred through the aquatic food web, which result in a high accumulation in marine mammals. In recent years various novel flame retardants (nBFRs), which have replaced the banned PBDEs, have also started to occur in the environment. These nBFRs have similar properties as PBDEs, such as long-range transport and accumulation in biota. The purpose with this study was to evaluate a method by using pre-packed silica columns for quantification of PCBs, DDT, PBDEs and nBFRs in seal blubber, in order to facilitate the pre-treatment and decrease the time. To elute the different POPs from the pre-packed silica column; hexane, toluene and dichloromethane were used in different stages. By using this method levels of PCB and DDT were determined. For DDT the concentration was 8.28 ng/g lipid and 8.94 ng/g lipid for the two samples that was analysed, and the analysis of the PCBs showed a higher trend for the higher chlorinated PCBs. As the pre-packed silica columns are a relative new method. Further studies are therefore needed on these columns to further improve the sample clean-up and fractionation of the different POPs in environmental samples.

The issue of lead exposure through drinking water was re-examined in light of modern public health goals, recent high-profile cases of elevated lead in water, and emerging concerns regarding the efficacy of legally mandated remedial strategies. A critical literature review revealed that serious lead-in-water hazards are present at many US schools and homes, and that the threat to individuals is not eliminated by existing regulations. Health studies have provided strong links between lead in water and lead in blood of exposed populations, even at relatively low levels of exposure compared to reported lead occurrence in US tap water samples. As efforts shift from addressing pervasive lead sources that once elevated the blood lead of large percentages of the population, to more isolated individual cases requiring exceptional attention, the importance of carefully considering lead in water as a potential source for elevated blood lead increases. Consistent with decades of prior research linking elevated water lead to elevated blood lead (EBL), lead-contaminated water in the high-profile case of Washington DC markedly increased the incidence of EBL for very young children. Specifically, incidence of EBL for children aged ≤ 1.3 years increased more than 4 times during 2001-2003 when lead in water was high, compared to 2000 when lead in water was low. The incidence of EBL for children aged ≤ 1.3 years was highly correlated (R² = 0.81) to 90th percentile lead-in-water levels from 2000-2007, and the risk of exposure to high water lead levels varied markedly in different neighborhoods of the city. Analysis conducted herein focused on identifying "worst-case" neighborhoods and populations. Specifically, this was the first study of the Washington DC case to focus on infants who are most vulnerable to harm from lead in water, and to perform smaller area analysis at the neighborhood (i.e., zip code) level in order to capture pockets of high risk among local communities. Prior biokinetic modeling efforts, examining the potential adverse impacts of lead-in-water exposure, were re-examined to explicitly consider new public health goals. This included impacts on the most sensitive population groups (e.g., young children and particularly formula-fed infants), the potential variability in blood lead levels (BLLs) amongst exposed individuals within those groups (e.g., most sensitive children at the upper tail of the BLL distribution), more conservative BLL thresholds reflecting low-level adverse effects (e.g., 5, 2 and 1 µg/dL versus 10 µg/dL), and the possibility of acute health impacts. This re-evaluation creates a paradigm shift, in that levels of lead in water that were previously considered inconsequential are demonstrated to be of concern in specific circumstances. The replacement of lead service lines in front of consumers' homes is a costly, federally mandated remedial action if a water utility exceeds the US EPA lead action level. Because utilities do not own the entire lead service line, they often only replace the portion of the service line up to the property line, typically with copper pipe. Experiences in Washington DC, as revealed by Freedom of Information Act requests, indicated that partial pipe replacements were not decreasing lead in water, and were actually associated with relatively high incidence of childhood lead poisoning. This prompted the first comprehensive investigation of potential long-term problems arising from galvanic corrosion between the remaining lead pipe and the newly installed copper pipe. Bench-scale experiments demonstrated that galvanic connections between lead pipe (new or aged) and copper pipe increased lead release into the water by 1.1-16 times, when compared to a full length of lead pipe alone. The small area of lead pipe adjacent to the copper joint (<0.5 ft) was gravely affected by galvanic corrosion, and accumulated a thick lead-rust layer (1 inch wide) that constituted a reservoir for semi-random particulate lead detachment into the water. The work on simulated partial pipe replacements revealed that under worst-case scenarios of highly contaminated water samples, most of the lead was not quantified if water samples were not mixed thoroughly after standard preservation (i.e., after addition of 0.15% v/v HNO₃), or if water samples were transferred from one bottle to another prior to preservation. While there is no reason to believe that sample handling and pre-treatment dramatically skew regulatory compliance with the US EPA lead action level, slight variations from one approved protocol to another may cause lead-in-water health risks to be dramatically underestimated. This is of special concern in unusual situations of "worst-case" individual exposures to highly contaminated water, associated with childhood lead poisoning. This work provides the water industry and health agencies with important new insights and perspectives on an old problem. Results can improve strategies to detect and mitigate lead-in-water hazards for individuals or populations, and inform future revisions to the US EPA Lead and Copper Rule. / Ph. D.

This work deals with the development and optimization of conditions of pretreatment of two industrial surface finishing baths containing chromium(III) ions and oxalic, maleic, acetic or citric acid and their electrophoretic analysis. Some model mixtures containing known amounts of components of industrial solutions have been made for simulation of complex matrices of the real samples. Prior to analysis a sample pre-treatment consisting of different dilution and addition of fluoride, hydroxide or EDTA anions as suitable agent releasing acid out of the stable chromium complex were studied. Determination of organic anions was accomplished by indirect UV detection at 350 nm with a reference at 230 nm. A commercially available background electrolyte, pH 5.7, was used for separation of analytes. The most appropriate pre-treatment to release acids have been achieved by precipitation of chromium(III) hydroxide. The method of standard additions was used for the quantification. The concentrations of oxalate and citrate in the real samples were calculated as 96,50 % (S.D. = 0,71 %) and 97,53 % (S.D. = 0,79 %), respectively, of declared amount. Satisfactory repeatabilities were obtained for both analytes with R.S.D. values (n = 5) for migration times lower than 0,51 %, R.S.D. for peak areas of oxalic acid were...

68 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-05T17:50:29Z No. of bitstreams: 1 Dissertacao - Wdson Costa Santos.PDF: 1066509 bytes, checksum: 0409b0432c52d5bd01e90ebcf214766a (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-06-06T14:53:28Z (GMT) No. of bitstreams: 1 Dissertacao - Wdson Costa Santos.PDF: 1066509 bytes, checksum: 0409b0432c52d5bd01e90ebcf214766a (MD5) / Made available in DSpace on 2013-06-06T14:53:28Z (GMT). No. of bitstreams: 1 Dissertacao - Wdson Costa Santos.PDF: 1066509 bytes, checksum: 0409b0432c52d5bd01e90ebcf214766a (MD5) Previous issue date: 2012 / CAPES / No presente trabalho foram investigados os efeitos sobre a recuperação de elementos causados por modificações em processos prévios a amostragem laboratorial e lixiviação dos analitos das polpas de abóbora e batata. Inicialmente, foi avaliado o efeito da inversão na ordem de operações do procedimento de tratamento preliminar das amostras brutas das polpas sobre as recuperações dos elementos. As amostras das polpas foram secas para posterior trituração (PA) ou as amostras foram trituradas antes de serem submetidas à secagem (PB). Os resultados obtidos empregando ambos os procedimentos foram comparados para 95% de confiança e eles mostraram diferenças significativas para alguns elementos determinados na amostra de batata. As concentrações de K, P e Mn, na polpa de batata, determinadas aplicando o primeiro procedimento de pré-tratamento (PA) foram 13,6±0,4 mg K g-1, 1,95±0,04 mg P g-1 e 5,7±0,2 μg Mn g-1, enquanto 12,2±0,3 mg K g-1, 1,62±0,03 mg P g-1 e 2,6±0,2 μg Mn g-1 foram determinadas quando a mesma amostra bruta foi submetida ao pré-tratamento PB para a obtenção da amostra teste. Em contraposição, no caso da amostra bruta de polpa de abóbora, os resultados para os elementos (K, P, Mn, Mg) foram maiores quando a polpa foi previamente esmagada antes da secagem. Em um estudo independente, a eficiência da extração de metais de amostras de polpas trituradas de abóbora ou batata para soluções diluídas de HNO3 foi avaliada variando o modo (agitação mecânica ou irradiação ultrassônica) e o período (de 10 a 30 min) de agitação, bem como a concentração da solução de HNO3 na solução de lixiviação (de 0,7 a 2,1 mol L-1). Os resultados foram também comparados com aqueles obtidos nas digestões assistidas por micro-ondas das amostras teste v em meio nítrico-peróxido. Foi observado que para ambas as amostras teste (abóbora e batata) e independentemente do modo ou período de agitação que a eficiência de extração de Ca, K, Mg e Mn foi diminuída para solução para 2,1 mol L-1 HNO3. Uma melhora no nível de recuperação de P foi obtida quando a lixiviação foi realizada com soluções diluídas de HNO3 (0,7 e 1,4 mol L-1) e sob irradiação ultrassônica. Esse efeito foi relacionado à presença de átomos de fósforo em moléculas estruturais de células de abóbora e batata, bem como à cominuição (ou fragmentação) das partículas submetidas a um campo ultrassônico intenso. Contudo, efeitos indesejados foram também observados para alguns elementos quando submetidos às lixiviações assistidas com ultrassom, como exemplificado pelo teor de cálcio determinado após a lixiviação da amostra teste de batata ter atingido valor 2,3 vezes maior que o valor obtido após a mineralização da amostra em micro-ondas. Muitos desses efeitos foram relacionados à erosão da superfície interna frascos irradiados. / Salvador

In analytical chemistry the main goal is normally to determine the identity and/or concentration of one or more species in a sample. The samples analyzed are often natural samples, containing numerous different species in a complex matrix and the choice of technique for multi-elemental detection is in general inductively coupled plasma spectrometry. The chemical forms of an element can affect many of its characteristics e.g. toxicity, which makes speciation analysis important. Therefore, determination of the identity and quantity of an element is still important, but for many applications measurements of total element concentration provides insufficient information. To be able to perform speciation analysis, separation, identification and/or characterization of the various forms of elements in the sample has to be accomplished. Speciation analysis has been employed in a wide range of disciplines, including for example environmental science, biology and clinical chemistry. This thesis describes work to improve and understand the elemental speciation analysis with liquid chromatography coupled to plasma spectrometry and also highlights the importance and potential of the synergy between atomic spectrometry and molecular mass spectrometry. The combination of the matrix tolerant, robust and very sensitive plasma spectrometry used together with molecular mass spectrometry, which provides structural information and the possibility to identify unknown species, is demonstrated to be a very powerful tool for speciation analysis. In this thesis methods are developed for on-line sample clean-up and pre-concentration coupled to liquid chromatography and plasma spectrometry, which makes handling of small sample volumes easier and also decreases the risk of contamination. The problems associated with organic modifiers in plasma spectrometry are also addressed. Applications of speciation analysis are exemplified by analysis of aluminium-chelated siderophores in field-soil solutions and organic phosphorous species in aquatic sediments. The possibility to analyze un-dissolved samples as slurries with minimal sample preparation is also discussed.