Levels of polychlorinated biphenyls (PCBs) in whole milk powderand estimated daily intake for a population of children / Níveis de bifenilos policlorados (PCBs) em leite em pó integral e ingestão diária estimada para uma população infantil

ABSTRACT: Polychlorinated biphenyls (PCBs) are chemical contaminants classified as persistent organic pollutants. Although, their use has been banned for several decades, PCBs are still scattered in the environment and; therefore, all living organisms may be exposed to these compounds. Diet, especially fatty foods such as milk, has been recognized as one of the main sources of human exposure to PCBs. Hence, the aim of this study was to evaluate the residual levels of indicator PCBs in whole milk powder consumed by preschool children in the Municipality of Imbé, State of Rio Grande do Sul, Brazil and to determine the estimated daily intake of these PCBs through this food. Analyses were performed by GC-μECD and the results were confirmed by GC/MS. The PCBs 28, 52 and 153 displayed values ​​below the limit of quantification. The PCBs 138 and 180 showed mean values of 0.073 and 0.157ng.g-1 lipid, respectively. These values were below the reference limits established by the European Community. The estimated total daily intake of PCBs was 0.110ng.g-1 lipid of body weight per day, a value lower than that established by the legislations of Belgium and Norway.

RESUMO: Os bifenilos policlorados (PCBs) são contaminantes químicos classificados como poluentes orgânicos persistentes. Embora seu uso tenha sido banido há mais de décadas, os PCBs ainda encontram-se presentes no meio ambiente e portanto, todos os organismos vivos podem estar expostos a esses compostos. A alimentação, especialmente alimentos gordurosos, como leite, tem sido reconhecida como uma das principais fontes de exposição humana aos PCBs. Assim, o objetivo deste estudo foi avaliar os níveis residuais de PCBs indicadores em leite em pó integral consumido por pré-escolares no Município de Imbé, Rio Grande do Sul, e determinar a ingestão estimada desses PCBs por meio deste alimento. As análises foram realizadas em GC-µECD e os resultados foram confirmados em GC/MS. Os PCBs 28, 52 e 153 apresentaram valores abaixo do limite de quantificação. Os PCBs 138 e 180 apresentaram valores médios de 0,073 e 0,157ng.g-1 lipídio, respectivamente. Estes valores estavam abaixo dos limites de referência estabelecidos pela Comunidade Europeia. A ingestão diária total estimada de PCBs foi de 0,110ng.g-1 de peso corporal por dia, valor inferior ao estabelecido pelas legislações da Bélgica e da Noruega.

Aislamiento e Identificación de Hongos filamentosos tolerantes a aceites dieléctricos usados y los Bifenilos Policlorados (PCBs) de suelos contaminados / Isolation and Identification of Filamentous Fungi Tolerant to Used Dielectric Oils and Contaminated Soil Polychlorinated biphenyls (PCBs)

Los PCBs por sus propiedades físicas y químicas son usados en diferentes sectores industriales; sus productos de desechos y su almacenamiento inadecuado han contaminado ambientes como suelos y aguas poniendo en peligro la supervivencia en los ecosistemas. Sin embargo, algunos seres vivos son capaces de adaptarse. Los bifenilos policlorados (PCBs) son compuestos orgánicos de hidrocarburos sintéticos formados por dos anillos de benceno unidos por un enlace de carbono; comprenden una clase de 209 compuestos individuales, isómeros y congéneres. Su objetivo fue aislar e identificar hongos filamentosos capaces de tolerar y adaptarse para sobrevivir en condiciones adversas en el ecosistema suelo contaminado por el xenobiótico PCBs, presente en aceites dieléctricos usados (ADU) en un sector industrial de Barranquilla. Los hongos aislados de los géneros Aspergillus sp, Alternaría sp, Phoma sp, Rhizopus sp. sobrevivieron a concentraciones de ADU 20 %, y a 200 ppm de PCBs

PCBs for their physical and chemical properties are used in different industrial sectors; waste products and inadequate storage have polluted environments such as soils and water that endanger ecosystem survival. However, some living beings are able to adapt. Polychlorinated biphenyls (PCBs) are organic synthetic hydrocarbon compounds formed by two benzene rings bonded by a carbon bond, comprise a class of 209 individual compounds, isomers and congeners. Its objective was the isolation and identification of filamentous fungi capable of tolerating and adapting to survive in adverse conditions in the soil ecosystem contaminated by the xenobiotic PCBs, present in used dielectric oils (ADU) in an industrial sector of Barranquilla. The isolated fungi of the genus Aspergillus sp, Alternaria sp, Phoma sp, Rhizopus sp. survived concentrations of 20% ADU, and 200 ppm of PCBs.

Benefit-risk Assessment of Fish and Fish Products in the Norwegian Diet – An Update.

Request from the Norwegian Food Safety Authority (NFSA) In September 2013, the Norwegian Food Safety Authority requested VKM to update relevant parts of the benefit-risk assessment of fish in the Norwegian diet published by VKM in 2006. The background for the request was new knowledge and data on the content of some nutrients and contaminants both for wild and farmed fish since 2006. The proportion of vegetable ingredients used in farmed fish feed has in recent years increased, and new national dietary surveys for adults and children have been conducted. The Norwegian Food Safety Authority referred to VKM’s report from 2006, which pointed out that the positive impact of fish consumption on public health was especially due to the content of polyunsaturated fatty acids and vitamin D in fish. Further, VKM concluded that the contaminants that could pose a potential risk to public health through fish consumption mainly were methylmercury, dioxins and dioxin-like PCBs (dl-PCBs). The request included a reassessment of fish consumption in Norway with focus on specific nutrients; n-3 fatty acids (eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), vitamin D, and the minerals iodine and selenium, and on specific contaminants; mercury, dioxins and dl-PCBs. VKM was asked to address the main changes in the use of raw materials in farmed fish feed and how these affect the levels of nutrients, mercury, dioxins and dl-PCBs and in fish feed. Further, VKM was asked to address to what extent levels of nutrients and contaminants in fish have changed since 2006, to describe these changes and estimate the human intake of the substances in question on the basis of recent dietary data. VKM was also requested to consider the benefits of eating fish with regard to the intake of nutrients and the risks associated with the intake of mercury, dioxins and dl-PCBs and comment on whether this change the conclusions from the report in 2006. Additionally, on the basis of updated knowledge, VKM was asked to comment whether other substances, like pesticide and residues of veterinary medicinal products, could affect the conclusions with regard to the impact on public health. The Norwegian Food Safety Authority and the Directorate of Health will use the updated assessment as a basis for public recommendations concerning the consumption of fish and fish products. How VKM has Addressed the Request The VKM appointed a working group consisting of VKM members and external experts to answer the request. Several of the scientific panels of VKM reviewed the report during its preparation. The Scientific Steering Committee of VKM has given their final assessment and approval of the current report. In the current report, VKM has mainly used data from national surveillance and monitoring programs for nutrient and contaminant concentrations in fish feed, farmed fish and wild caught fish, but occurrence data have also been derived from peer reviewed articles. VKM has estimated fish consumption in three population groups (2-year-olds, adults and pregnant women). The estimated fish consumption was compared to national dietary guidelines. To assess health effects of fish consumption, the current estimated fish intakes were also compared with assessments done by recognised international bodies and results from epidemiological studies addressing possible associations between fish consumption and specific health outcomes. Literature searches were done to identify relevant epidemiological studies. VKM has not systematically assessed reviews or meta-analyses nor individual studies for weight of evidence, but merely summarised the studies retrieved from the literature search. It was considered being beyond the scope of this assessment to review individual studies included in reviews or meta-analyses. Furthermore, based on current fish consumption in the various population groups, intake of nutrients and exposure to contaminants from fish were estimated. For benefit characterisation of the specific nutrients the estimated nutrient intake was compared with national recommendations of nutrients intake and for EPA and DHA a comparison was also done with European recommendations. For risk characterization of contaminant exposure from fish, VKM used health based guidance values set by international risk assessment bodies (WHO, EFSA). VKM noted that the request from NFSA was restricted to fish, whereas the VKM report in 2006 included both fish and other seafood. VKM focused on specific nutrients and contaminants as requested by the NFSA. In addition, VKM also commented on other substances that could affect the risk assessment, such as residues of veterinary medicinal products including residues of antibiotics, new contaminants from fish feed like the pesticide endosulfan, polycyclic aromatic hydrocarbons (PAHs), mycotoxins, the synthetic antioxidants ethoxyquin, butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT), as well as environmental contaminants like brominated flame retardants and perfluorated organic compounds Background In the Norwegian diet fish is important source of well-balanced proteins, and important nutrients such as EPA and DHA, vitamin D, iodine and selenium. On the other hand, fish is also a source of exposure to chemical contaminants like dioxins, PCBs and mercury. Over the last 10 years there has been a great change in raw materials used in fish feeds, and in 2013 terrestrial plant proteins and vegetable oils accounted for 70% of the feed. The changes in concentrations of nutrients and contaminants in fish feed for farmed Atlantic salmon and trout are reflected in changed concentrations and compositions of the same nutrients and contaminants in the farmed fish fillet. The current national dietary guideline is to eat fish as dinner meals 2-3 times per week for all age groups, representing 300-450 g fish per week for adults, including at least 200 g fatty fish, such as salmon, trout, mackerel and herring. Fish is also recommended as bread spread. Further, a daily supplement of vitamin D to infants from 4 weeks of age is recommended, and if this supplement is taken as cod liver oil it will in addition ensure an adequate supply of EPA and DHA. The present benefit-risk assessment is comprised of three elements, i.e. benefit assessment, risk assessment and benefit-risk comparison. This methodology is in accordance with the guidance given by EFSA in 2010. Fish Consumption in Norway and Comparison with National Dietary Guidelines VKM has used information about fish consumption from more recent national dietary surveys among 2-year-olds (Småbarnskost 2007) and adults at 18-70 years of age (Norkost 3, 2010/2011), as well as information for pregnant women who answered the Norwegian Mother and Child Cohort Study (MoBa2, 2002-2008) food frequency questionnaire. The national food consumption survey Ungkost 2000, which covers the age groups 4-, 9-, and 13-year-old children, was considered too old to be used and it is therefore not known if their fish consumption patterns have changed, neither in amount consumed nor type of fish consumed. Even though there are methodological differences between the dietary surveys used in 2006 and 2014, the amount of fish consumed appears to be unchanged for all population groups. Furthermore, in 2014, lean fish and fatty fish contribute with about 60 and 40 percent, respectively, of the total fish consumption, which is similar to 2006. Given a portion size of 150 g fish, the average adult eats fish equivalent to 2-3 dinner servings per week and the average pregnant woman eats fish equivalent to 1-2 dinner servings per week, while the average two-year-old eats fish equivalent to 1-2 dinner servings per week given a portion size of 75 g. The table below describes fish intake in the selected populations. Fish consumption (expressed as raw fish), mean grams (g) per week in 2-year-olds (Småbarnskost 2007, n=1674), adults (Norkost 3, n=1787) and pregnant women (MoBa, n=86277) Population groups Mean fish consumption g/week Fish roe Fish, total Lean fish (≤ 5% fat) Fatty fish (> 5% fat) and liver 2-year-olds 112 70 35 7 Adults 364 210 147 7 Pregnant women 217 126 77 14 VKM concludes that of the different population groups, only adults (18-70 years of age) with an average or higher fish consumption reach the national food based dietary guidelines for total fish consumption. Mean total fish consumption and fatty fish consumption in children (2-year-olds) and pregnant women, as well as the mean fatty fish consumption in adults are lower than recommended. In pregnant women and 2-year-olds, fish consumption is too low to meet the food based dietary guidelines Health Effects of Fish Consumption VKM is of the opinion that according to epidemiological studies, the net effects of the present average fish consumption in Norway for adults including pregnant women is beneficial for specific cardiovascular diseases (particularly cardiac mortality, but also with regard to ischaemic stroke, non-fatal coronary heart disease events, congestive heart failure and atrial fibrillation), as well as for optimal neurodevelopment of foetus and infants. Furthermore, VKM is of the opinion that those with fish consumption less than one dinner serving per week may miss these beneficial effects. The health benefit of fish consumption is reported from 1-2 dinner servings per week and up to 3-4 dinner servings per week. For higher fish intake per week, the limited number of consumers in epidemiological studies does not allow for drawing firm conclusions about the actual balance of risk and benefit. More knowledge is needed to reveal the beneficial mechanisms of fish consumption. Benefit Characterisation of Nutrients in Fish VKM is of the opinion that there has been minor or no changes of the composition and concentrations of nutrients in wild caught fish since 2006. Due to replacement of fish oil and fish protein with plant prote

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Bifenilos policlorados em arroz e feijão do estado do Rio Grande do Sul / Polychlorinated biphenyls in rice and beans from Rio Grande do Sul state, Brazil

Os bifenilos policlorados (PCBs) estão entre os poluentes mais tóxicos presentes no meio ambiente, apresentando os alimentos como principal fonte de exposição humana. Com base nisso, este trabalho teve como objetivo determinar os sete PCBs indicadores de contaminação ambiental em 22 amostras de arroz e 18 de feijão do estado do Rio Grande do Sul, Brasil. Além disso, objetivou-se calcular a ingestão diária estimada de resíduos, a partir da contaminação existente no arroz e feijão, assim como determinar o teor de gordura das amostras para correlacioná-lo com os níveis de PCBs. A extração e purificação dos compostos foram realizadas pelo método QuEChERS, seguido de identificação e quantificação por CG-EM. Os PCBs 153 e 101 apresentaram as maiores concentrações médias nas amostras de arroz e feijão, respectivamente. Considerando o somatório dos PCBs, este foi de 4,39ng g-1 para o arroz e de 4,17ng g-1 para o feijão. Quanto à ingestão diária estimada, esta foi de 7,82ng kg-1 e de 3,14ng kg-1 de peso corporal por dia, para o arroz e o feijão, respectivamente. Em relação ao percentual de gordura, o arroz e o feijão apresentaram teores de gordura de 0,32% e de 1,1%, respectivamente. No entanto, a correlação com os níveis de PCBs não foi significativa. Os resultados demonstram que o estado do RS apresenta fontes importantes de contaminação desses resíduos químicos persistentes.

Polychlorinated biphenyls (PCBs) are among the most toxic pollutants in the environment showing foods as the main source of human exposure. Based on this, this study aimed to determine 7 PCBs indicators of environmental contamination in 22 samples of rice and 18 samples of beans in Rio Grande do Sul state, Brazil. Furthermore, this study aimed to calculate the waste estimated daily intake, starting from the existing contamination in rice and beans, as well as wanted to determine the samples fat content to correlate with levels of PCBs. The extraction and purification of the compounds were performed via QuEChERS method followed by identification and quantification by GC-MS. PCBs 153 and 101 showed the highest mean concentration in the samples of rice and bean, respectively. Considering the sum of PCBs in the samples, this was 4.39ng g-1 for the rice and 4.17ng g-1 for the beans. In estimated daily intake, this was 7.82ng kg-1 and 3.14ng kg-1 of body weight per day, for the rice and beans, respectively. Regarding the percentage of fat the rice and beans samples had fat contents of 0.32% and 1.1%, respectively. However, the correlation with the PCBs levels was not significant. The results demonstrate that the State of RS has important sources of these persistent chemical waste contaminations.

Live algae as a vector candidate for hydrophobic polychlorinated biphenyls translocation to bivalve filter feeders for laboratory toxicity test.

Live algae carrying hydrophobic xenobiotics can be an effective vector candidate for the chemical translocation to filter feeders in the laboratory toxicity test, but information on their application is lacking. Time-course uptake and elimination of polychlorinated biphenyls (PCBs) (0, 50, 100, and 500 ng g-1) by two key algal foods, Isochrysis galbana and Tetraselmis suecica, were measured. Both of the algae achieved maximum concentration in an hour after PCBs exposure regardless the chemical concentrations in our time-course measurements (0, 1, 5, 10, 24, 48 and 72 hrs). Once achieved the maximum concentration, the algae shortly exhibited elimination or eliminating tendency depending on the chemical concentrations. Algae exposed to the chemical for 1 and 24 hrs (hereafter 1 and 24 hr vectors, respectively) were then evaluated as a chemical translocation vector by feeding test to larval and spat Crassostrea gigas. In the feeding test the 24 hr vector, which contained lower chemicals than the 1-hr vector, appeared to be more damaging the early lives of the oyster. This was particularly significant for vectors of higher PCBs (p<0.05), probably due to algal reduction in food value by the prolonged chemical stress. These findings imply that 1 hr exposure is long enough for a generation of algal vector for laboratory toxicity test, minimizing data error resulted from reduction in food value by longer chemical stress.

Using systematic reviews and meta-analyses to support regulatory decision making for neurotoxicants: lessons learned from a case study of PCBs / Utilizando revisões sistemáticas e meta-análise de apoio às decisões regulatórias para neurotóxicos: lições de um estudo de caso dos PCBs

We examined prospective cohort studies evaluating the relation between prenatal and neonatal exposure to polychlorinated biphenyls (PCBs) and neurodevelopment in children to assess the feasibility of conducting a meta-analysis to support decision making. We described studies in terms of exposure and end point categorization, statistical analysis, and reporting of results. We used this evaluation to assess the feasibility of grouping studies into reasonably uniform categories. The most consistently used tests included Brazelton's Neonatal Behavioral Assessment Scale, the neurologic optimality score in the neonatal period, the Bayley Scales of Infant Development at 5-8months of age, and the McCarthy Scales of Children's Abilities in 5-year-olds. Despite administering the same tests at similar ages, the studies were too dissimilar to allow a meaningful quantitative examination of outcomes across cohorts. These analyses indicate that our ability to conduct weight-of-evidence assessments of the epidemiologic literature on neurotoxicants may be limited, even in the presence of multiple studies, if the available study methods, data analysis, and reporting lack comparability.

Foram examinados estudos de grupo que avaliaram a relação entre a exposição pré-natal e neonatal aos bifenilos policlorados (PCB) e o desenvolvimento neuropsicomotor em crianças a fim de avaliar a viabilidade da realização de uma meta-análise para suporte à tomada de decisão. Nós descrevemos os estudos em termos de exposição, categorizações, análise estatística e elaboração de relatórios de resultados. Nós utilizamos esta avaliação para verificar a viabilidade de agrupar os estudos em categorias razoavelmente uniformes. Os testes mais utilizados foram Brazelton Neonatal Behavioral Assessment Scale, a pontuação de otimalidade neurológica no período neonatal, as Escalas Bayley de Desenvolvimento Infantil de 5 a 8 meses de idade, e as Escalas McCarthy de habilidades das crianças em 5 anos de idade. Apesar de administrar os mesmos testes com idades semelhantes, os estudos foram muito diferentes para permitir uma análise quantitativa significativa dos resultados entre grupos. Estas análises indicam que a nossa capacidade de realizar avaliações da literatura epidemiológica sobre neurotóxicos pode ser limitada - mesmo na presença de vários estudos - se não existe nenhuma forma de comparação com os métodos de estudo disponíveis e análise dos dados.

Los contaminantes ambientales bifenilos policlorinados (PCB) y sus efectos sobre el Sistema Nervioso y la salud / The polychlorinated biphenyls (PCBS) environmental pollutants and their effects on the Nervous System and health

Environmental pollution is a world-wide issue which is a matter for concern among the international community. Great industrialized cities are the most polluted and Mexico City is among them. However, pollution affects places which are far away from contaminated urban areas, thus damaging eco-systems. Environmental pollution is responsible for an alarming and increasing list of illnesses in humans, animals and plants. This has generated an international interest in this problem. From the 187 chemical agents considered toxic for living organisms, the Inter-Government Committee for the Negotiation of Persistent Organic Pollutants (Pops) has catalogued 12 as the most hazardous for life. Among them are the so-called polychlorinated biphenyls (PCBs). PCBs are a family of 209 structurally chlorinated compounds made up of chlorine, carbon and hydrogen. These compounds are chemically and thermally stable, insoluble in water, non-flammable, electrically resistant, with low volatility at normal temperatures, and bio-degradable only at high temperatures (1200°C). One of their main disadvantages is that they are subject to a process of bioaccumulation where their concentration increases along the food chain. Their physical properties make them widely used in industry, mainly in the electrical and building areas. Not long after PCBs were manufactured, it was determined that food for human intake such as milk, fish and eggs, to mention just a few, presented higher PCBs concentrations than those allowed by the Organism for US Environmental Protection (0.0005mg/l). It has been demonstrated that PCBs can cause damage to the endocrine, immunologic and Nervous Systems, among others. The underlying mechanism of action of these compounds is through the activation of the aril hydrocarbon receptor (AhR), a ligand-dependent cytosolic transcription factor. PCBs act like ligands and, given their lipophilic properties, enter cells by passive diffusion. Two co-chaperone proteins are bound to AhR to form an oligomer which dissociates when binding to a PCB. After ligand binding, a heterodimer is formed which translocates into the nucleus and links to specific DNA regions; this in turn regulates the transcription velocity of specific genes and produces genetic alterations that modify processes and functions in the cell. PCBs belong in the group of chemicals considered endocrine disruptors. Damage caused by these compounds can be irreversible. In the endocrine system they interfere with the production and regulation of steroid and thyroid hormones, acting as agonists or antagonists of hormone receptors. They impair endocrine metabolic pathways, such as those of thyroid hormones (T3 and T4), and inhibit carrier proteins such as transthyretin. Contaminants that harm the endocrine system also affect the reproductive function and disrupt various aspects of sexuality. In males, PCBs inhibit the synthesis of testosterone, alter masculinity, reduce sperm motility and the capacity of binding and penetrating the ovule, induce changes in the shape of the penis as well as its size, retard or inhibit testicle descent, and can generate testicular cancer. In females, they can cause early menarche (first menstruation), enhanced duration of menstrual bleeding, urogenital malformations, endometriosis, spontaneous abortion, fetal death, premature delivery and low-weight in offspring. Our group, as well as other research groups, has encountered that PCB administration to gestating rats causes an increment in offspring mortality, fetal miscarriages, low bodily weight of the offspring and a reduction in the number of males per litter. The immunological system is sensitive to chemicals such as PCBs which originate an immunological response; they act as immunotoxins that cause thymus atrophy, affect innate immunity, compromise host resistance and immunity mediated by B and T cells, as well as humoral immunity. PCBs and their metabolites are carcinogenic and act as general cancer promoters by enhancing the effects of other substances through the generation of oxygen reactive compounds that can induce DNA oxidative damage. Chronic PCB exposure can cause chromosomal aberrations; these compounds have been related to all types of cancer: mammary gland, liver, biliary tract, gastrointestinal, skin (especially malignant melanomas), lung, pancreas and brain. There is evidence that organisms are more vulnerable to PCB exposure during the early embryonic stages. These compounds can cross the placenta and affect the fetus; when they are present in human milk they keep the offspring under high PCB levels thus altering development. In addition, they can contribute to the interruption of growth and development of brain, organs and tissues. As a result, malfunctions or miscarriage occur. PCBs are involved in the neurodegeneration process since they affect dopaminergic neurons in caudate nucleus, ventral tegmental area and substantia nigra. These compounds disrupt neuronal mechanisms such as vesicular transport and dopamine release which lead to cellular death similar to that described for diseases such as Parkinson's. Perinatal exposure to PCBs is associated with neurodevelopmental deficiencies of infants which consist of dysfunctions at the neuropsychological level such as in verbal learning (syllables, words and concepts), performance functions, changes in attention and psychomotor development. Acute or chronic exposure to PCBs is associated with cephalea, insomnia, nervousness, irritability, depression and anxiety; these symptoms in turn modify behavior. At the neurophysiological level, these contaminants impair excitatory and inhibitory synaptic transmission in the hippocampus, inhibit long-term potentiation and synaptic plasticity, alter some mechanisms of cell signaling (GABAergic pathway), and deteriorate learning and memory. Recently, these compounds have been related to cognitive alterations. Our group demonstrated that the administration of PCB-77 and Aroclor 1254 during gestation inhibits the enzymatic activity of nitric oxide synthase (NOS) in 10-day postnatal pups. These rats presented degenerative morphological neuronal changes such as shrinking, picnosis, loss of neurites, neuronal death and decrease in the number of nitrergic neurons in the paraventricular and supraoptic hypothalamic nuclei. We also reported that in these nuclei a decrease in immunoreactivity to vasopressin and neuronal NOS is observed. The evidence in PCB studies is conclusive. The exposure to these environmental toxins interferes with the functioning of various organs and systems such as the endocrine and Nervous Systems, not only in humans but also in animals. These contaminants pose a risk factor for a wide number of neurodegenerative alterations.

La contaminación ambiental es un grave problema mundial que actualmente preocupa a la comunidad internacional. Las grandes ciudades industrializadas, como la de México, son las más contaminadas. Sin embargo, la contaminación llega hasta zonas alejadas de donde se produce y afecta los ecosistemas. La contaminación es responsable de una alarmante y creciente lista de enfermedades en el hombre, los animales y las plantas. Los bifenilos policlorados (PCB) se catalogaron dentro de los 12 contaminantes orgánicos más tóxicos para los organismos vivos. Sus propiedades físicas hicieron que se usaran ampliamente en la industria. No son biodegradables y se acumulan en el ambiente, se transfieren dentro de la cadena alimenticia y tienden a concentrarse más al final de ésta, por lo que en los alimentos se determinaron concentraciones que sobrepasaban los límites establecidos por el Organismo de Protección del Ambiente de los Estados Unidos. Se demostró que los PCB afectan la función de los sistemas endocrino, inmunológico y nervioso, entre otros. El mecanismo de acción descrito para los PCB, es por medio de la activación del receptor aril hidrocarburo, un factor de transcripción citosólico dependiente de ligando. Los PCB actúan como ligandos y son lipofílicos, por lo que entran a la célula y llegan al núcleo para unirse al ADN, lo cual altera la trascripción de genes específicos y provoca alteraciones genéticas que conducen a cambios en los procesos y funciones celulares. Los PCB interfieren con la producción y regulación de las hormonas esteroides y tiroideas al actuar como antagonistas o agonistas de los receptores hormonales. Afectan la función reproductora y alteran diferentes aspectos de la sexualidad. Como otros grupos de investigación, el nuestro ha observado que la administración de PCB a ratas gestantes causa un incremento de la mortalidad de las crías, pérdida fetal, peso corporal bajo y una reducción en el número de machos por camada. Los PCB actúan como inmunotoxinas que causan la atrofia del timo y afectan la respuesta inmune. Los PCB y sus metabolitos son carcinogénicos debido a la generación de especies reactivas de oxígeno que pueden producir daño oxidativo al ADN, provocar aberraciones cromosómicas y generar cáncer de mama, hígado, tracto biliar, gastrointestinal, cerebral, etc. Los organismos son más vulnerables a la exposición de los PCB durante las etapas tempranas del desarrollo embrionario. Los PCB atraviesan la placenta y llegan al feto, permanecen en la leche materna y mantienen niveles altos en las crías. Los PCB afectan así el desarrollo del Sistema Nervioso, los órganos y los tejidos, y pueden llevar a la pérdida fetal. También se asocian a deficiencias en el neurodesarrollo del niño y a alteraciones neuropsicológicas en la atención, el aprendizaje y el desarrollo psicomotor. La exposición aguda o crónica a los PCB se asocia con cefalea, insomnio, nerviosismo, irritabilidad, depresión y ansiedad. Los PCB participan en el proceso de neurodegeneración al afectar el sistema dopaminérgico. En el nivel neurofisiológico, afectan la transmisión sináptica excitatoria e inhibitoria hipocampal; inhiben la potenciación a largo plazo y la plasticidad sináptica; alteran mecanismos de señalización celular como el GABAérgico, en el aprendizaje y la memoria, y producen alteraciones cognoscitivas. Nuestro grupo demostró que la administración de los PCB durante la gestación inhibe la actividad de la enzima sintasa del óxido nítrico y provoca cambios neuronales morfológicos degenerativos en los núcleos paraventricular y supraóptico hipotalámicos. Las evidencias de los estudios realizados con los PCB son concluyentes en cuanto a que la exposición a estos tóxicos ambientales interfiere con el funcionamiento de diferentes órganos y sistemas y a que son un factor de riesgo para un amplio número de alteraciones neurodegenerativas. Actualmente, las poblaciones están expuestas a concentraciones que exceden los niveles límite tolerables recomendados por la Organización Mundial de la Salud. Nuestro grupo está analizando las alteraciones de estos contaminantes en el nivel neuroendocrino y en algunos aspectos del aprendizaje y la memoria. Dada la relevancia de los efectos de los PCB en la salud y de la falta en México de una valoración de los niveles de los PCB existentes en personas y alimentos, es importante que las instituciones de salud fomenten y apoyen las investigaciones en esta área.

Possible aggravating impact of gene polymorphism in women with endometriosis.

Background & objectives: Endometriosis is one of the most commonly encountered benign problems in gynaecology. It is frequently associated with chronic pelvic pain, dysmenorrhoea, menorrhagia and dyspareunia, which lead to infertility. To determine the possible association between polychlorinated biphenyls (PCBs) and GSTM1 null (*0/*0) mutation and their possible impact in the pathogenesis of endometriosis. Methods: Ninety seven women with endometriosis mean age (28.5 ± 6.5 yr) diagnosed by laparoscopy and 102 women without endometriosis (28.4 ± 4.8 yr) were included. Heparinised blood samples were collected from all for DNA isolation and estimation of PCBs. GSTM1 genotyping was done by PCR and PCBs were estimated by gas chromatography. Results: Women with endometriosis showed significantly higher concentrations of PCBs compared with control group. Twenty six (26.8%) women with endometriosis and 15 (14.7%) of the controls had the GSTM1 null (*0/*0) genotype [odds ratio (OR = 2.12, 95% confidence interval (CI) = 1.045-4.314], which showed significant association (P=0.03) with endometriosis. The association between the concentrations of PCBs, GSTM1 null genotype and different severity of endometriosis was significant (P<0.05) for all four compounds and GSTM1 (PCB1: r = +0.5388, P<0.0001; PCB5: r = +0.6753, P<0.0001; PCB29: r = +0.6471, P<0.0001; and PCB98: r = +0.4357, P<0.0001; GSTM1: r = +0.9439, P=0.05). Interpretation & conclusions: The study results suggested that women having higher concentration of PCBs and GSTM1 null (*0/*0) polymorphism might have an increased susceptibility of endometriosis. The findings need to be confirmed in a larger sample.

Microbial dehalogenation of polychlorinated biphenyls in aerobic conditions / Dehalogenación microbiana de bifenilos policlorados en condiciones aeróbicas

From soils contaminated with polychlorinated biphenils (PCBs) a strain of Alcaligenes sp. able to grow in a mineral medium with a commercial mixture of PCBs as carbon source was isolated. This strain consumed up to 200 ppm in seven days in laboratory conditions. After 24 h of incubation, some new congeners of PCBs could be recognized by mass spectrometry. Through the identification of these compounds it was possible to postulate examples of possible transformations by dechlorinations of penta- and tetra-chlorinated congeners into tri-chlorinated ones. The properties of the isolated strain are appropriate for bioremediation of contaminated areas and also for using in bioreactors in order to remove the xenobiotic chemical.

A partir de suelos contaminados con bifenilos policlorados (PCBs) se aisló una cepa de Alcaligenes sp. capaz de crecer en medio mineral con una mezcla comercial de PCBs como fuente de carbono. Esta cepa consumió hasta 200 ppm de PCBs en siete días de incubación en condiciones de laboratorio. En 24 horas de incubación se han podido detectar nuevos congéneres de PCBs mediante espectrometria de masa. La identificación de estos compuestos ha permitido postular transformaciones de congéneres penta- y tetra-clorados que originarían derivados triclorados. Las propiedades de la cepa aislada son apropiadas para biorremediación y para su uso en biorreactores para eliminar estos compuestos xenobióticos.

Adipose Tissue and Serum Levels of PCBs and DDE in Women with Gynecologic Benign Disease / 대한산업의학회지

OBJECTIVES: This study was purposed to determine the levels of PCBs and DDE in adipose tissue and serum and to evaluate the relations with factors affecting these levels. METHODS: We analyzed adipose tissues and sera from 52 gynecologic benign disease patients aged 27-78 years, except hormonal diseases such as breast cancer and endometriosis. We also surveyed age, education, occupation, body mass index (BMI), smoking, drinking, number of children, and duration of breastfeeding by questionnaires. Tissue and serum levels of PCBs and DDE were measured using gas chromatography. RESULTS: The median and geometric mean levels of PCBs were 48. 29 ng/g, 56. 78 ng/g for adipose tissue and 4. 67 uc/L, 4. 85 m/L for serum, and those of DDE were 142.89 ng/g, 117.06 ng/g for adipose tissue and l. 75 m/L, 2.09 ua/L for serum, respectively. Adipose tissue and serum levels for DDE showed high correlation (r=0. 310, p=0. 0002), but those of PCBs didn' t (r=0.029, p=0.2582). In analyses of the differences of the means of log transformed adipose tissue and serum PCBs and DDE levels for groups of potential covariates, only adipose tissue DDE levels were significantly associated with number of children (p=0.015), age at first birth (p=0.014) and BMI (p=0.035). In multiple regression analysis, adipose tissue DDE levels were significantly increased with decreasing number of children and increasing age at first birth. CONCLUSIONS: This study suggested that parity and adiposity were associated with levels of DDE in adipose tissue, and adipose tissue is a better biomarker than serum for evaluating the long-term exposure of organochlorines.