Sub-soil contamination due to oil spills in zones surrounding oil pipeline-pump stations and oil pipeline right-of-ways in Southwest-Mexico

Oil spills due to oil pipelines is a very frequent problem in Mexico. Petroleos Mexicanos (PEMEX), very concerned with the environmental agenda, has been developing inspection and correction plans for zones around oil pipelines pumping stations and pipeline right-of-way. These stations are located at regular intervals of kilometres along the pipelines. In this study, two sections of an oil pipeline and two pipeline pumping stations zones are characterized in terms of the presence of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs). The study comprehends sampling of the areas, delimitation of contamination in the vertical and horizontal extension, analysis of the sampled soils regarding TPHs content and, in some cases, the 16 PAHs considered as priority by USEPA, calculation of areas and volumes contaminated (according to Mexican legislation, specifically NOM-EM-138-ECOL-2002) and, finally, a proposal for the best remediation techniques suitable for the contamination levels and the localization of contaminants.     

Urban Development and Air Quality in San Luis City, Argentina

Some factors such as the high population growth, along with insufficient housing, health and sanitary services, obsolete industrial technology and the lack of environmental management programs, give rise to contamination in Latin-American cities. Owing to the urban characteristics of San Luis, a detailed analysis of air quality was planned as part of a more comprehensive study, in order to make an environmental diagnosis of the city after the demographical and economic upgrowth over the last 15 years. It has been concluded that air pollution levels in San Luis are higher than those expected for a medium-size city. The reported high levels were attributed to important industrial activity, responsible not only for the direct of polluting gases to the atmosphere but also as the principal cause of the urban expansion. The levels of CO and SO₂ (ppm) found in the city can be considered as high. Some weeks during the sampling measure values were appreciably higher than the maximum tolerance levels established. The urban area under study was separated into five defined areas, which allowed to make comparisons in order to identify specific contamination problems. The slopes corresponding to the plot polluting substances concentration vs. wind speed were lower than the expected values. Because of the urban area characteristics, different micrometeorological effects facilitating a low air exchange can be generated, and consequently increasing the contamination levels. Thus, it is correct to conclude that the degradation processes are not occurring in a single environmental plane. Accordingly, air contamination rate in San Luis city could be considered as evidence of other upper-scale regional environmental degradation processes.     

Phytoremediation of polyaromatic hydrocarbons, anilines and phenols

Phytoremediation technologies based on the combined action of plants and the microbial communities that they support within the rhizosphere hold promise in the remediation of land and waterways contaminated with hydrocarbons but they have not yet been adopted in large-scale remediation strategies. In this review plant and microbial degradative capacities, viewed as a continuum, have been dissected in order to identify where bottle-necks and limitations exist. Phenols, anilines and polyaromatic hydrocarbons (PAHs) were selected as the target classes of molecule for consideration, in part because of their common patterns of distribution, but also because of the urgent need to develop techniques to overcome their toxicity to human health. Depending on the chemical and physical properties of the pollutant, the emerging picture suggests that plants will draw pollutants including PAHs into the plant rhizosphere to varying extents via the transpiration stream. Mycorrhizosphere-bacteria and -fungi may play a crucial role in establishing plants in degraded ecosystems. Within the rhizosphere, microbial degradative activities prevail in order to extract energy and carbon skeletons from the pollutants for microbial cell growth. There has been little systematic analysis of the changing dynamics of pollutant degradation within the rhizosphere; however, the importance of plants in supplying oxygen and nutrients to the rhizosphere via fine roots, and of the beneficial effect of microorganisms on plant root growth is stressed. In addition to their role in supporting rhizospheric degradative activities, plants may possess a limited capacity to transport some of the more mobile pollutants into roots and shoots via fine roots. In those situations where uptake does occur (i.e. only limited microbial activity in the rhizosphere) there is good evidence that the pollutant may be metabolised. However, plant uptake is frequently associated with the inhibition of plant growth and an increasing tendency to oxidant stress. Pollutant tolerance seems to correlate with the ability to deposit large quantities of pollutant metabolites in the 'bound' residue fraction of plant cell walls compared to the vacuole. In this regard, particular attention is paid to the activities of peroxidases, laccases, cytochromes P450, glucosyltransferases and ABC transporters. However, despite the seemingly large diversity of these proteins, direct proof of their participation in the metabolism of industrial aromatic pollutants is surprisingly scarce and little is known about their control in the overall metabolic scheme. Little is known about the bioavailability of bound metabolites; however, there may be a need to prevent their movement into wildlife food chains. In this regard, the application to harvested plants of composting techniques based on the degradative capacity of white-rot fungi merits attention.     

Evaluation of copper-induced DNA damage in Vitis vinifera L. using Comet-FISH

The contamination of soils and water with copper (Cu) can compromise the crops production and quality. Fungicides containing Cu are widely and intensively used in viticulture contributing to environmental contamination and genotoxicity in Vitis vinifera L. Despite the difficulty in reproducing field conditions in the laboratory, hydroponic solutions enriched with Cu (1, 10, 25 and 50 μM) were used in forced V. vinifera cuttings to evaluate the DNA damage in leaves of four wine-producing varieties (‘Tinta Barroca’, ‘Tinto Cão’, ‘Malvasia Fina’ and ‘Viosinho’). Alkaline comet assay followed by fluorescence in situ hybridisation (Comet-FISH) was performed with the 45S ribosomal DNA (rDNA) and telomeric [(TTTAGGG)_n] sequences as probes. This study aimed to evaluate the tolerance of the four varieties to different concentrations of Cu and to determine which genomic regions were more prone to DNA damage. The comet assay revealed comets of categories 0 to 4 in all varieties. The DNA damage increased significantly (p < 0.001) with the Cu concentration. ‘Tinto Cão’ appeared to be the most sensitive variety because it had the highest DNA damage increase in 50 μM Cu relative to the control. Comet-FISH was only performed on slides of the control and 50 μM Cu treatments. Comets of all varieties treated with 50 μM Cu showed rDNA hybridisation on the head, ‘halo’ and tail (category III), and their frequency was significantly higher than that of control. The frequency of category III comets hybridised with the telomeric probe was only significantly different from the control in ‘Malvasia Fina’ and ‘Tinta Barroca’. Comet-FISH revealed partial damage on rDNA and telomeric DNA in response to Cu but also in control, confirming the high sensitivity of these genomic regions to DNA fragmentation.

     

Non-immunological hydrops fetalis and intrapericardial teratoma: Case report and review

A large intrapericardial teratoma was found at necropsy in a 38−week stillborn fetus, in which prenatal diagnosis of hydrops fetalis and an ehogenic cardiac mass had been made. Clinical and pathological data are reported. In utero intrapericardial teratomata lead to different outcomes depending on whether fetal hydrops is associated. When generalized fetal hydrops is not present, the outcome is good, even in cases with large pericardial effusions. When generalized fetal hydrops occurs, it often results in a poor outcome. In our literature review, we have found eight perinatal deaths in nine similar cases reported.     

Variability of the frequency of male neoteny in Ostrea puelchana (Mollusca: Bivalvia)

Ostrea puelchana (D'Orbigny), a larviparous oyster from the Atlantic coast of South America, comprises two types of individuals: (1) adults which live for several years and become sexually developed after one year, these show a rhythmic successive hermaphroditism with male, hermaphroditic and female phases; (2) neotenic individuals settled on the adults, which live for only about one year and function exclusively as males. Adult oysters were collected in February 1982 from a natural bed in the San Matias Gulf, Argentina, and were transferred to two sites 200 km to the south of their original habitat, where they were maintained under culture conditions. At the beginning of the study, 17% of adult oysters were observed bearing neotenic individuals. After two years, the number of adults in the female phase had decreased, and neotenic individuals had entirely disappeared. The presence of female-phase adults would seem to be necessary for the existence of neotenic males. Further analysis of the results revealed high adult density to be directly associated with greatly decreased numbers of adults in the female phase; this may play a role in the decrease of neotenic individuals.     

Prediction of SO2 levels using neural networks

In this paper, we present an adaptation of the air pollution control help system in the neighborhood of a power plant in As Pontes (A Coru?a, Spain), property of Endesa Generación S.A., to the European Council Directive 1999/30/CE. This system contains a statistic prediction made half an hour before the measurement, and it helps the staff in the power plant prevent air quality level episodes. The prediction is made using neural network models. This prediction is compared with one made by a semiparametric model.     

Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates

Published data on nitrate (NO3-) toxicity to freshwater and marine animals are reviewed. New data on nitrate toxicity to the freshwater invertebrates Eulimnogammarus toletanus, Echinogammarus echinosetosus and Hydropsyche exocellata are also presented. The main toxic action of nitrate is due to the conversion of oxygen-carrying pigments to forms that are incapable of carrying oxygen. Nitrate toxicity to aquatic animals increases with increasing nitrate concentrations and exposure times. In contrast, nitrate toxicity may decrease with increasing body size, water salinity, and environmental adaptation. Freshwater animals appear to be more sensitive to nitrate than marine animals. A nitrate concentration of 10 mg NO3-N/l (USA federal maximum level for drinking water) can adversely affect, at least during long-term exposures, freshwater invertebrates (E. toletanus, E. echinosetosus, Cheumatopsyche pettiti, Hydropsyche occidentalis), fishes (Oncorhynchus mykiss, Oncorhynchus tshawytscha, Salmo clarki), and amphibians (Pseudacris triseriata, Rana pipiens, Rana temporaria, Bufo bufo). Safe levels below this nitrate concentration are recommended to protect sensitive freshwater animals from nitrate pollution. Furthermore, a maximum level of 2 mg NO3-N/l would be appropriate for protecting the most sensitive freshwater species. In the case of marine animals, a maximum level of 20 mg NO3-N/l may in general be acceptable. However, early developmental stages of some marine invertebrates, that are well adapted to low nitrate concentrations, may be so susceptible to nitrate as sensitive freshwater invertebrates.     

Contribution of Spanish-American silver mines (1570-1820) to the present high mercury concentrations in the global environment: a review

In this review I evaluate the contribution of Spanish-American silver mines during the period 1570-1820 (a Spanish colonial period of 250 years) to the present high mercury concentrations in the global environment. The evaluation is based upon the following bibliographic information: (1) total amount of mercury consumed in Spanish-American silver mines between 1570 and 1820; (2) percentage of the total amount of mercury consumed in Spanish-American silver mines that may have been emitted to the atmosphere; (3) global natural input of mercury to the atmosphere; (4) worldwide anthropogenic emissions of mercury to the atmosphere; (5) residence time of mercury in the atmosphere; and (6) capacity of mercury to be deposited in the sediments of aquatic systems. From all this information, and owing to the relatively long time that has passed since Spanish-American silver mines were operational, I conclude that most of the mercury lost during the refining of silver via the patio amalgamation process is now sequestered into the sediments of aquatic systems, mainly in marine sediments. The high mercury concentrations now being reported in the global environment essentially are a consequence of the huge pollution caused by human activities during the past 20th century.