Remote sensing reveals unprecedented sublethal impacts of a 40-year-old oil spill on mangroves.

Oil spills cause long-lasting mangrove loss, threatening their conservation and ecosystem services worldwide. Oil spills impact mangrove forests at various spatial and temporal scales. Yet, their long-term sublethal effects on trees remain poorly documented. Here, we explore these effects based on one of the largest oil spills ever recorded, the Baixada Santista pipeline leak, which hit the mangroves of the Brazilian southeastern coast in 1983. Historical, Landsat-derived normalized difference vegetation index (NDVI) maps over the spilled mangrove reveal a large dieback of trees within a year following the oil spill, followed by a eight-year recolonization period and a stabilization of the canopy cover, however 20-30% lower than initially observed. We explain this permanent loss by an unexpected persistence of oil pollution in the sediments based on visual and geochemical evidence. Using field spectroscopy and cutting-edge drone hyperspectral imaging, we demonstrate how the continuous exposure of mangrove trees to high levels of pollution affects their health and productivity in the long term, by imposing permanent stressful conditions. Our study also reveals that tree species differ in their sensitivity to oil, giving the most tolerant ones a competitive advantage to recolonize spilled mangroves. By leveraging drone laser scanning, we estimate the loss of forest biomass caused by the oil spill to be 9.8-91.2 t ha-1, corresponding to 4.3-40.1 t C ha-1. Based on our findings, we encourage environmental agencies and lawmakers to consider the sublethal effects of oil spills on mangroves in the environmental cost of these accidents. We also encourage petroleum companies to use drone remote sensing in monitoring routines and oil spill response planning to improve mangrove preservation and impact assessment.

Adapting the WEPP Hillslope Model and the TLS Technology to Predict Unpaved Road Soil Erosion.

Unpaved road erosion have been recognized as important sediment sources in a watershed. To evaluate where and when road erosion occurs, the soil loss along road segments should be precisely predicted with process-based erosion models. Methods: The hillslope version of the Water Erosion Prediction Project (WEPP) was used to estimate soil loss from 20 typical road segments in the red soil region of South China. Terrestrial laser scanning (TLS)-measured soil losses were used to validate the model simulations. The results showed that the WEPP model could reasonably predict the total soil loss in relatively short (less than 100 m) and gentle (slope gradient lower than 10%) road segments. In contrast, soil loss would be underestimated for long or steep road segments. Detailed outputs along roads revealed that most of the peak soil loss rates were underestimated. It might due to the linear critical shear stress theory in the WEPP model. Additionally, the lack of upstream flow was found to be connected to the relatively low model efficiency. Nevertheless, the WEPP simulation could accurately fit erosion trend and predict the peak soil loss positions along road segments. Conclusions: The WEPP model could be adopted to evaluate the erosion risk of unpaved roads in the red soil region of South China.

Occurrence and Temporal Variation of Technology-Critical Elements in North Sea Sediments-A Determination of Preliminary Reference Values.

As interest in the investigation of possible sources and environmental sinks of technology-critical elements (TCEs) continues to grow, the demand for reliable background level information of these elements in environmental matrices increases. In this study, a time series of ten years of sediment samples from two different regions of the German North Sea were analyzed for their mass fractions of Ga, Ge, Nb, In, REEs, and Ta (grain size fraction < 20 µm). Possible regional differences were investigated in order to determine preliminary reference values for these regions. Throughout the investigated time period, only minor variations in the mass fractions were observed and both regions did not show significant differences. Calculated local enrichment factors ranging from 0.6 to 2.3 for all TCEs indicate no or little pollution in the investigated areas. Consequently, reference values were calculated using two different approaches (Median + 2 median absolute deviation (M2MAD) and Tukey inner fence (TIF)). Both approaches resulted in consistent threshold values for the respective regions ranging from 158 µg kg-1 for In to 114 mg kg-1 for Ce. As none of the threshold values exceed the observed natural variation of TCEs in marine and freshwater sediments, they may be considered baseline values of the German Bight for future studies.

Gas y electricidad. La evolución de su tecnología a partir de los artículos y noticias aparecidas en publicaciones periódicas de carácter técnico en España y Francia entre 1855 y 1910 / Gas and electricity. The evolution of its technology based on the papers and news appeared in periodical technical publications in spain and france between 1855 and 1910

Tanto el proceso de obtención del gas de hulla como los fenómenos eléctricos fueron estudiados de una forma metódica a partir del siglo XVIII. Pero, fue a principio del siglo siguiente que el gas empezó a utilizarse en el alumbrado, y años después, en desarrollar trabajo mecánico, o en calentar fluidos. En el último tercio del siglo, el desarrollo de la electricidad fue sustituyendo algunas de las aplicaciones que proporcionaba el gas. Este proceso quedó reflejado en una gran cantidad de escritos y publicaciones que difundieron los nuevos conceptos y las formas de obtención y de utilización de estas fuentes. En este artículo mostramos los resultados de un estudio cuantitativo de los artículos sobre gas y electricidad en la literatura industrial en un periodo en que los caminos de ambas fuentes empezaban a divergir. Como ejemplo nos detenemos también en dos casos concretos: algunos procedimientos alternativos de producción de gas y el auge de la electricidad.(AU)

Both the process of obtaining coal gas and electrical phenomena were studied in a methodical way from the eighteenth century. But it was at the beginning of the following century that gas began to be used in lighting, and years later, in developing mechanical work, or in heating fluids. In the last third of the century, the development of electricity was replacing some of the applications that gas provided. This process was reflected in many writings and publications that spread the new concepts and the ways of obtaining and using these sources. In this article we show the results of a quantitative study of the articles on gas and electricity in the industrial literature in a period when the paths of both sources were beginning to diverge. As an example, we also look at two specific cases: some alternative gas production procedures and the electricity boom.(AU)

Research on application of a new bottom trap technology to catch particles rich in nutrients in a large shallow lake.

The resuspension and sedimentation of particulate matter and the release of nutrients from sediment are important factors affecting the eutrophication of shallow lakes. The capture and removal of particles rich in nitrogen, phosphorus, and other nutrients at the bottom of lakes is of great significance for improving the management and eutrophication status of lakes. This study investigated the feasibility of applying lake bottom trap technology in seven different locations in Lake Chaohu, which is the fifth largest freshwater lake in China. The results showed that the trap in the western part of Lake Chaohu had the highest sedimentation rate and could capture most of the nutrients. The sedimentation rates were higher in spring and summer than in autumn and winter. The bottom trap effectively collected and preserved chlorophyll a, organic matter, total nitrogen, and total phosphorus. The trap per meter length (15-20 m wide) could catch 20.7-27.6 m3 of particles rich in nutrients with a water content of 50-70%, organic matter content of 281.9-375.8 kg, total nitrogen content of 24.5-32.6 kg, and total phosphorus content of 10.5-14 kg. The proposed bottom trap had little impact on the benthic organism system of the lake. The bottom trap technology used in this study could solve the problem of nitrogen, phosphorus, and algae accumulation in lakes and reservoirs, broaden the utility of lake hydrodynamics in environmental pollution control, and provide new ideas and strategies for the control and management of cumulative pollution in shallow lakes and reservoirs.

A Scoping Review of Technologies and Their Applicability for Exposome-Based Risk Assessment in the Oil and Gas Industry.

INTRODUCTION: Oil and gas workers have been shown to be at increased risk of chronic diseases including cancer, asthma, chronic obstructive pulmonary disease, and hearing loss, among others. Technological advances may be used to assess the external (e.g. personal sensors, smartphone apps and online platforms, exposure models) and internal exposome (e.g. physiologically based kinetic modeling (PBK), biomonitoring, omics), offering numerous possibilities for chronic disease prevention strategies and risk management measures. The objective of this study was to review the literature on these technologies, by focusing on: (i) evaluating their applicability for exposome research in the oil and gas industry, and (ii) identifying key challenges that may hamper the successful application of such technologies in the oil and gas industry. METHOD: A scoping review was conducted by identifying peer-reviewed literature with searches in MEDLINE/PubMed and SciVerse Scopus. Two assessors trained on the search strategy screened retrieved articles on title and abstract. The inclusion criteria used for this review were: application of the aforementioned technologies at a workplace in the oil and gas industry or, application of these technologies for an exposure relevant to the oil and gas industry but in another occupational sector, English language and publication period 2005-end of 2019. RESULTS: In total, 72 articles were included in this scoping review with most articles focused on omics and bioinformatics (N = 22), followed by biomonitoring and biomarkers (N = 20), external exposure modeling (N = 11), PBK modeling (N = 10), and personal sensors (N = 9). Several studies were identified in the oil and gas industry on the application of PBK models and biomarkers, mainly focusing on workers exposed to benzene. The application of personal sensors, new types of exposure models, and omics technology are still in their infancy with respect to the oil and gas industry. Nevertheless, applications of these technologies in other occupational sectors showed the potential for application in this sector. DISCUSSION AND CONCLUSION: New exposome technologies offer great promise for personal monitoring of workers in the oil and gas industry, but more applied research is needed in collaboration with the industry. Current challenges hindering a successful application of such technologies include (i) the technological readiness of sensors, (ii) the availability of data, (iii) the absence of standardized and validated methods, and (iv) the need for new study designs to study the development of disease during working life.

Particle jet impact deep-rock in rotary drilling: Failure process and lab experiment.

Aimed at the technical problems of low drilling speed and difficult rock-breaking in deep-well and hard rock-stratum, particle waterjet coupled impact rock-breaking technology in rotary drilling is put forward in this paper. Firstly, the working principle of particle jet impact rock-breaking in rotary drilling was introduced, and the acceleration model of particle jet and the damage model of rock were established. The acceleration mechanism of particles and dynamic damage evolution process of rock under particle jet were studied, which showed that the broken pit and rock damage would increase with time gone on, and damage evolution of rock presented the radial expansion. Then, experimental device of particle jet coupled impact rock-breaking in rotary state was developed, and the effect of jet parameters on penetration depth and failure volume was analyzed with comparison of la experiment and numerical simulation. The results showed that drilling speed with particle jet impact is twice that of conventional drilling, and combination nozzles layout of impact angle with 8°and 20° can achieve rock-drilled rapidly, which also demonstrated the correctness of simulation method. The device development and the rock-breaking results analysis would be of great value for engineering application.

Aboriginal artefacts on the continental shelf reveal ancient drowned cultural landscapes in northwest Australia.

This article reports Australia's first confirmed ancient underwater archaeological sites from the continental shelf, located off the Murujuga coastline in north-western Australia. Details on two underwater sites are reported: Cape Bruguieres, comprising > 260 recorded lithic artefacts at depths down to -2.4 m below sea level, and Flying Foam Passage where the find spot is associated with a submerged freshwater spring at -14 m. The sites were discovered through a purposeful research strategy designed to identify underwater targets, using an iterative process incorporating a variety of aerial and underwater remote sensing techniques and diver investigation within a predictive framework to map the submerged landscape within a depth range of 0-20 m. The condition and context of the lithic artefacts are analysed in order to unravel their depositional and taphonomic history and to corroborate their in situ position on a pre-inundation land surface, taking account of known geomorphological and climatic processes including cyclone activity that could have caused displacement and transportation from adjacent coasts. Geomorphological data and radiometric dates establish the chronological limits of the sites and demonstrate that they cannot be later than 7000 cal BP and 8500 cal BP respectively, based on the dates when they were finally submerged by sea-level rise. Comparison of underwater and onshore lithic assemblages shows differences that are consistent with this chronological interpretation. This article sets a foundation for the research strategies and technologies needed to identify archaeological targets at greater depth on the Australian continental shelf and elsewhere, building on the results presented. Emphasis is also placed on the need for legislation to better protect and manage underwater cultural heritage on the 2 million square kilometres of drowned landscapes that were once available for occupation in Australia, and where a major part of its human history must lie waiting to be discovered.

Arcobacter peruensis sp. nov., a Chemolithoheterotroph Isolated from Sulfide- and Organic-Rich Coastal Waters off Peru.

Members of the epsilonproteobacterial genus Arcobacter have been identified to be potentially important sulfide oxidizers in marine coastal, seep, and stratified basin environments. In the highly productive upwelling waters off the coast of Peru, Arcobacter cells comprised 3 to 25% of the total microbial community at a near-shore station where sulfide concentrations exceeded 20 µM in bottom waters. From the chemocline where the Arcobacter population exceeded 106 cells ml-1 and where high rates of denitrification (up to 6.5 ± 0.4 µM N day-1) and dark carbon fixation (2.8 ± 0.2 µM C day-1) were measured, we isolated a previously uncultivated Arcobacter species, Arcobacter peruensis sp. nov. (BCCM LMG-31510). Genomic analysis showed that A. peruensis possesses genes encoding sulfide oxidation and denitrification pathways but lacks the ability to fix CO2 via autotrophic carbon fixation pathways. Genes encoding transporters for organic carbon compounds, however, were present in the A. peruensis genome. Physiological experiments demonstrated that A. peruensis grew best on a mix of sulfide, nitrate, and acetate. Isotope labeling experiments further verified that A. peruensis completely reduced nitrate to N2 and assimilated acetate but did not fix CO2, thus coupling heterotrophic growth to sulfide oxidation and denitrification. Single-cell nanoscale secondary ion mass spectrometry analysis of samples taken from shipboard isotope labeling experiments also confirmed that the Arcobacter population in situ did not substantially fix CO2 The efficient growth yield associated with the chemolithoheterotrophic metabolism of A. peruensis may allow this Arcobacter species to rapidly bloom in eutrophic and sulfide-rich waters off the coast of Peru.IMPORTANCE Our multidisciplinary approach provides new insights into the ecophysiology of a newly isolated environmental Arcobacter species, as well as the physiological flexibility within the Arcobacter genus and sulfide-oxidizing, denitrifying microbial communities within oceanic oxygen minimum zones (OMZs). The chemolithoheterotrophic species Arcobacter peruensis may play a substantial role in the diverse consortium of bacteria that is capable of coupling denitrification and fixed nitrogen loss to sulfide oxidation in eutrophic, sulfidic coastal waters. With increasing anthropogenic pressures on coastal regions, e.g., eutrophication and deoxygenation (D. Breitburg, L. A. Levin, A. Oschlies, M. Grégoire, et al., Science 359:eaam7240, 2018, https://doi.org/10.1126/science.aam7240), niches where sulfide-oxidizing, denitrifying heterotrophs such as A. peruensis thrive are likely to expand.

Remote sensing assessment of oil spills near a damaged platform in the Gulf of Mexico.

An oil platform in the Mississippi Canyon 20 (MC-20) site was damaged by Hurricane Ivan in September 2004. In this study, we use medium- to high-resolution (10-30 m) optical remote sensing imagery to systematically assess oil spills near this site for the period between 2004 and 2016. Image analysis detects no surface oil in 2004, but ~40% of the cloud-free images in 2005 show oil slicks, and this number increases to ~70% in 2006-2011, and >80% since 2012. For all cloud-free images from 2005 through 2016 (including those without oil slicks), delineated oil slicks show an average oil coverage of 14.9 km2/image, with an estimated oil discharge rate of 48 to ~1700 barrels/day, and a cumulative oil-contaminated area of 1900 km2 around the MC-20 site. Additional analysis suggests that the detected oil slick distribution can be largely explained by surface currents, winds, and density fronts.

20 años de investigaciones y aplicaciones en Cuba de los radiotrazadores y el perfilaje en la industria y el medioambiente / 20 years of Cuban radiotracer and scanning researches and applications at the industry and the environment

Las tecnologías de radiotrazadores y de escaneo son herramientas bien consolidadas para el estudio, análisis y evaluación de los procesos industriales y medioambientales. En este trabajo se sintetizan los principales resultados alcanzados por el Grupo de Aplicaciones Industriales y Medioambientales de los Radiotrazadores en el Departamento de Radioquímica. La tecnología de radiotrazadores se ha empleado con éxito para la caracterización del mezclado en reactores discontinuos, los estudios sobre el comportamiento del 99mTc en aguas naturales y residuales, la calibración y validación del modelo de calidad de agua del río Almendares, la caracterización de un reactor anaerobio para el tratamiento de los residuales en el CAI “Pablo Noriega”, la verificación y validación del modelo DFC en un cristalizador azucarero, el desarrollo de un generador radisotópico de ? / ?, la modelación de la calidad del agua en el segmento medio del río Luyanó, y para la modelación de la calidad del agua en el río Guaire, Caracas, Venezuela. En los últimos años el grupo ha desarrollado y evaluado a nivel de laboratorio radiotrazadores para fluidos orgánicos, particularmente relacionados con la industria del petróleo y para sólidos, empleando como precursor al ?. Mientras la técnica de escaneo se ha utilizado para el perfilaje gamma en torres de destilación de alcohol de los CAI "Héctor Molina”“Heriberto Duquesne" y "Jesús Rabí".

Los halos de inhibición en la remediación de suelos amazónicos contaminados con petróleo / Inhibition halos in the remediation of Amazon soils contaminated with petroleum

Resumen Se analiza la historia de la biorremediación de suelos contaminados con petróleo en la Amazonía ecuatoriana desde 1994 hasta 2014. Constatamos que si bien hubo “éxitos” tecnocientíficos, la oportunidad de cimentar un proceso de excelencia científica se vio frustrada por la carencia de voluntad política para gestionar la investigación. Parecen haber influido la dependencia de tecnología extranjera, la poca articulación interna entre programas de investigación e instituciones, la corrupción, la poca tradición innovadora en la biotecnología nacional, el predominio de biobraceros y una dicotomía construida entre petróleo y ambiente. Se articulan estos resultados en torno a debates sobre ciencia y tecnología en la periferia y se reflexiona sobre aspectos necesarios para consolidar procesos tecnocientíficos de excelencia en estos territorios.

Abstract We analyze the history of bioremediation of soils contaminated with petroleum in the Ecuadorian Amazon from 1994 to 2014. Although there were some technoscientific “successes,” we argue that the opportunity to develop a process of scientific excellence was thwarted by lack of an institutional framework and the political will to oversee research and innovation. Dependence on foreign technology, insufficient internal coordination among research programs and institutions, corruption, lack of a national tradition of biotechnological innovation, the predominance of “biopeons,” and a dichotomy between oil and the environment all influenced this process. We discuss these issues in relation to science and technology on the periphery and examine what is needed to consolidate technoscientific processes of excellence in those territories.

Green remediation and recycling of contaminated sediment by waste-incorporated stabilization/solidification.

Navigational/environmental dredging of contaminated sediment conventionally requires contained marine disposal and continuous monitoring. This study proposed a green remediation approach to treat and recycle the contaminated sediment by means of stabilization/solidification enhanced by the addition of selected solid wastes. With an increasing amount of contaminated sediment (20-70%), the 28-d compressive strength of sediment blocks decreased from greater than 10MPa to slightly above 1MPa. For augmenting the cement hydration, coal fly ash was more effective than lime and ground seashells, especially at low sediment content. The microscopic and spectroscopic analyses showed varying amounts of hydration products (primarily calcium hydroxide and calcium silicate hydrate) in the presence of coal fly ash, signifying the influence of pozzolanic reaction. To facilitate the waste utilization, cullet from beverage glass bottles and bottom ashes from coal combustion and waste incineration were found suitable to substitute coarse aggregate at 33% replacement ratio, beyond which the compressive strength decreased accordingly. The mercury intrusion porosimetry analysis indicated that the increase in the total pore area and average pore diameter were linearly correlated with the decrease of compressive strength due to waste replacement. All the sediment blocks complied with the acceptance criteria for reuse in terms of metal leachability. These results suggest that, with an appropriate mixture design, contaminated sediment and waste materials are useful resources for producing non-load-bearing masonry units or fill materials for construction uses.

A first European scale multimedia fate modelling of BDE-209 from 1970 to 2020.

The European Variant Berkeley Trent (EVn-BETR) multimedia fugacity model is used to test the validity of previously derived emission estimates and predict environmental concentrations of the main decabromodiphenyl ether congener, BDE-209. The results are presented here and compared with measured environmental data from the literature. Future multimedia concentration trends are predicted using three emission scenarios (Low, Realistic and High) in the dynamic unsteady state mode covering the period 1970-2020. The spatial and temporal distributions of emissions are evaluated. It is predicted that BDE-209 atmospheric concentrations peaked in 2004 and will decline to negligible levels by 2025. Freshwater concentrations should have peaked in 2011, one year after the emissions peak with sediment concentrations peaking in 2013. Predicted atmospheric concentrations are in good agreement with measured data for the Realistic (best estimate of emissions) and High (worst case scenario) emission scenarios. The Low emission scenario consistently underestimates measured data. The German unilateral ban on the use of DecaBDE in the textile industry is simulated in an additional scenario, the effects of which are mainly observed within Germany with only a small effect on the surrounding areas. Overall, the EVn-BTER model predicts atmospheric concentrations reasonably well, within a factor of 5 and 1.2 for the Realistic and High emission scenarios respectively, providing partial validation for the original emission estimate. Total mean MEC:PEC shows the High emission scenario predicts the best fit between air, freshwater and sediment data. An alternative spatial distribution of emissions is tested, based on higher consumption in EBFRIP member states, resulting in improved agreement between MECs and PECs in comparison with the Uniform spatial distribution based on population density. Despite good agreement between modelled and measured point data, more long-term monitoring datasets are needed to compare predicted trends in concentration to determine the rate of change of POPs within the environment.

'Frankie the Frog': the total transformation of a river basin as 'totalitarian' technology (Spain, 1946-1961).

After the Spanish Civil War (1936-1939), Francisco Franco's emphasis on dam building became so intense that it is still today associated with his dictatorial rule. Rather than being purely a personal obsession, however, this intensive period of reservoir construction was the result of the influential political role played by engineers from the early years of the regime. During the years 1946-1961 some of these engineers undertook the 'total transformation' of the Noguera Ribagorzana river basin in the Catalonian Pyrenees. But this explicitly 'totalitarian' project encountered important limitations posed both by competing state agencies and by the basin's geology. Analysing the efforts of these engineers allows for new understandings of the Francoist regime and of the place of science, technology, and the landscape within it.

A comparison of wound healing between a skin protectant ointment and a medical device topical emulsion after laser resurfacing of the perioral area.

BACKGROUND: Currently, there is no standard of care for postlaser resurfacing treatment of the face. Ideally, treatment should speed re-epithelialization and reduce downtime, with minimal irritation. OBJECTIVE: This study compared the wound healing efficacy and safety of Aquaphor Healing Ointment (AHO) (Beiersdorf Inc, Wilton, CT) and Biafine Topical Emulsion (BTE) (OrthoNeutrogena, Los Angeles, CA) treatment after laser resurfacing of the perioral area. METHODS: In this double-blind, split-face study, 20 subjects with perioral rhytides received fractional carbon dioxide laser resurfacing. AHO and BTE were applied to opposite sides of the face 4 times daily after the resurfacing procedure. Clinical grading of erythema, edema, epithelial confluence, crusting/scabbing, subjective irritation, and general wound appearance were assessed using 5-point scales on days 2, 4, 7, and 14. Subjects ranked the two treatment sites daily as to which side of their face looked better. RESULTS: AHO resulted in significantly less erythema (days 2 and 7) and crusting/scabbing (days 2, 4, and 7) and higher epithelial confluence (day 4) than BTE (P ≤ .042). Subjective irritation assessments demonstrated significantly less stinging, itching, and tightness at day 2 and tightness at day 7 with AHO than with BTE (P ≤ .049). General wound appearance was graded significantly higher for AHO on days 2 and 7 (P ≤ .049). Significantly more subjects preferred AHO to BTE (P ≤ .046). LIMITATIONS: This was a small study in a homogenous population of white women. CONCLUSIONS: AHO exhibited superiority to BTE in several wound healing parameters and in overall wound condition.

Energy and public health: the challenge of peak petroleum.

Petroleum is a unique and essential energy source, used as the principal fuel for transportation, in producing many chemicals, and for numerous other purposes. Global petroleum production is expected to reach a maximum in the near future and to decline thereafter, a phenomenon known as "peak petroleum." This article reviews petroleum geology and uses, describes the phenomenon of peak petroleum, and reviews the scientific literature on the timing of this transition. It then discusses how peak petroleum may affect public health and health care, by reference to four areas: medical supplies and equipment, transportation, energy generation, and food production. Finally, it suggests strategies for anticipating and preparing for peak petroleum, both general public health preparedness strategies and actions specific to the four expected health system impacts.

History of bioengineering techniques for erosion control in rivers in Western Europe.

Living plants have been used for a very long time throughout the world in structures against soil erosion, as traces have been found dating back to the first century BC. Widely practiced in Western Europe during the eighteenth and nineteenth centuries, bioengineering was somewhat abandoned in the middle of the twentieth century, before seeing a resurgence in recent times. Based on an extensive bibliography, this article examines the different forms of bioengineering techniques used in the past to manage rivers and riverbanks, mainly in Europe. We compare techniques using living material according to their strength of protection against erosion. Many techniques are described, both singly and in combination, ranging from tree planting or sowing seeds on riverbanks to dams made of fascine or wattle fences. The recent appearance of new materials has led to the development of new techniques, associated with an evolution in the perception of riverbanks.

Fibre-optic bacterial biosensors and their application for the analysis of bioavailable Hg and As in soils and sediments from Aznalcollar mining area in Spain.

Fibre-optic biosensors for Hg and As were developed by attaching alginate-immobilised recombinant luminescent Hg- and As-sensor bacteria onto optical fibres. The optimised biosensors (consisting of seven layers of fibre-attached bacteria pre-grown till mid-logarithmic growth phase) enabled quantification of environmentally relevant concentrations of the target analytes: 2.6 microg l-1 of Hg(II) and 141 microg l-1 of As(V) or 18 microg l-1 of As(III). The highest viability and sensitivity for target analyte was obtained when fibre tips were stored in CaCl2 solution at -80 degrees C. Applicability of the fibre-optic biosensors in parallel to the respective non-immobilised sensors was assessed on 10 natural soil and sediment samples from Aznalcollar mining area (Spain). On the average 0.2% of the total Hg and 0.87% of the total As proved bioavailable to fibre-attached bacteria. Interestingly, about 20-fold more Hg and 4-fold more As was available to non-immobilised sensor bacteria indicating the importance of direct cell contact (possible only for non-immobilised cells) for enhanced bioavailability of these metals in solid samples.

The use of rocks to improve family agriculture in Brazil

During the second half of the 20th century, the introduction of new chemical agriculture technologies brought about a revolution in food production, but this has also cause deep deterioration in our relationships with the natural environment. In developing tropical countries, record yields were accompanied by rural exodus, widespread deforestation and loss of topsoil. The stonemeal research described herein is an alternative to such practices as it is an environmental friendly and socially responsible technology based on soil rejuvenation and conservation by means of the addition of natural rock powders that are rich in phosphorous, calcium, magnesium, potassium and micronutrients. The research adopted an inter-disciplinary approach and was conducted among small farmers of a rural community located in the state of Minas Gerais, Brazil. The major goal was to demonstrate that there is a harmless cheap and simple alternative to fertilizing degraded or impoverished soils, which allow farmers to sustain high productivity and to remain on their plots of land. Results have confirmed the economic, environmental and productive feasibility and advantage of the stonemeal technique for corn, rise, manioc, sugar cane and horticultural species, when compared to the use of chemical fertilizers. The fertilization of the soil with rocks, allows the understanding of the natural processes, which maintain production levels while building a sustainable fertile soil.

Durante a segunda metade do século 20, a introdução de novas tecnologias agrícolas viabilizou a revolução naprodução de alimentos, mas este fato causou também uma profunda deterioriazação na relação dos homens com o ambiente natural. Nos países tropicais, especialmente aqueles em desenvolvimento, os recordes de safras foram acompanhados de êxodo rural, devastação e erosão dos solos. A pesquisa sobre o uso da técnica de Rochagemaqui descrita pretende ser uma alternativa tecnológicaambientalmente correta e socialmente responsável para os problemas mencionados. A técnica de Rochagem está baseada no rejuvenescimento e conservação de solos por meio da adição de pós de determinados tipos de rochas enriquecidas em fósforo, cálcio, magnésio, potássio e micronutrientes. A pesquisa foi desenvolvida segundo os pressupostos interdisciplinares e foi conduzida em meio aos agricultores familiares de um assentamento rural localizado no Estado de Minas Gerais, Brasil. Os principais resultados demonstraram que essa tecnologia é uma alternativa de baixo custo e extremamente simples para fertilizar ou recuperar solos degradados, que pode conduzir a sustentabilidade e, também, produções compatíveis de forma que os agricultores possam permanecer em seus lotes. Os resultados da pesquisa mostram que o uso da Rochagem apresenta vantagens econômicas, ambientais e produtivas significativas, em culturas de milho, arroz, mandioca, cana-de-açúcar, e hortifrutigranjeiros em comparação à adubação convencional. A fertilização da terra pela própria terra segue os ensinamentos da natureza (processos naturais), mantendo os níveis de produção comsustentabilidade e preservação dos solos.