Testing of Eluates from Waterproof Building Materials for Potential Environmental Effects Due to the Behavior of Enchytraeus albidus

In order to determine the potential environmental impact of construction products, it is necessary to evaluate their influence on organisms exposed to them or their eluates under environmental conditions. The behavior of the white worm Enchytraeus albidus is a useful tool for assessing the potential environmental impact of construction products in contact with water and soil. This study investigates the environmental effects of eluates from two construction products, a reactive waterproofing product, and an injection resin, on the reproduction and avoidance behavior of E. albidus. The eluates were prepared according to existing guidelines. The soil used for the tests was moistened with the eluates of the construction products. The reproduction results of the worms were collected after six weeks of exposure. Offsprings were counted under the microscope and statistically analyzed. Results from the avoidance behavior were collected after 48 h of exposure, and results were compared with the reproduction results. The eluates from both construction products induced significant changes in the reproduction behavior of E. albidus. Undiluted or only slightly diluted eluates of the injection resin drastically reduced the reproduction of the worms, whereas the leaches of the reactive waterproofing product only had a minor effect. The avoidance results for the injection resin indicates that its presence in the habitat is clearly detrimental to the survival of E. albidus, while the avoidance results for the waterproofing resin showed an initial avoidance of the eluates, but no harmful effects were observed. The avoidance test is a way of rapid toxicity screening of environmental samples when time is a critical parameter to measure possible environmental effects. This study shows that ecotoxicological tests using Enchytraeids are a valuable and important tool for understanding the mode of action of eluates from construction products in the environment

The problem of health: evaluating the legacy of Western biomedicine on Kenyan Health

A normative evaluation of the impact of colonialism and Western medicine on Kenyan health, using colonial administration documents and secondary literature to highlight the underlying motives of Western medical expansion, colonial introduction of disease, and the lingering legacies of profit and power in contemporary Kenyan health care systems

Ecotoxicological implications of leachates from concrete demolition debris on oligochaetes: survival and oxidative stress status

Urbanization and population growth demand the construction of structures to facilitate the need for space, and old infrastructures must make space for new ones leading to demolition and concrete debris. In addition to demolition, aging and weather are factors leading to concrete deterioration and, thus, a new challenge as an environmental pollutant. Studies on how concrete debris and leachate affect biota in the environment are limited. The present study aimed to understand the effects of leachate from various sizes of concrete debris on the three oligochaete species Enchytraeus crypticus, Tubifex, and Lumbriculus variegatus. Acute toxicity testing was carried out to determine the adverse effects over time. The oligochaetes’ survival was monitored as well as the activity of the biotransformation enzyme glutathione S-transferase and the antioxidative enzyme catalase as indicators of the oxidative stress status. Leachate from the smallest concrete particle size (<1 mm) was found to be the most toxic as it caused, on average, 6-fold increased oligochaete mortality compared to the larger pieces (2–5 cm) after 96 h of exposure, potentially due to the larger surface area facilitating the release of toxicants. Substrate buffered the toxic effect of the leachate with 42 ± 12% fewer mortalities and reduced adverse effects on the enzymes. Of the three oligochaetes, E. crypticus was the most resilient to the concrete leachate. The study is the first to investigate the effects of concrete leachate on oligochaetes.Peer reviewe

Optical SETI at Harvard-Smithsonian

A high-intensity pulsed laser, teamed with a moderate sized transmitting telescope, forms an efficient interstellar beacon. To a distant observer in the direction of its slender beam, such a laser transmitter, built with "Earth 2000" technology only, would appear (during its brief pulse) a thousand times brighter than our sun in broadband visible light; even at ranges of 1000 light years a single nanosecond laser pulse would deliver roughly a thousand photons to a 10-meter receiving telescope. We have built a photometer to search for such unresolved pulses, and are using it in a piggyback targeted search of some 2500 nearby solar-type stars. The photometer receives about 1/3 of the light focused by the 1.5-meter optical reflector, otherwise unused by the primary experiment (a stellar radial-velocity survey). A beamsplitter followed by a pair of fast hybrid avalanche detectors is triggered in coincidence to record the time and intensity profile of large pulses. In the first year of operation the system has made ~8500 observations of ~2500 separate stellar candidates, amounting to 50 days of cumulative observation time. We review those observations, and suggest follow-on experiments

Absolute diffuse calibration of IRAC through mid-infrared and radio study of HII regions

We investigate the diffuse absolute calibration of the InfraRed Array Camera on the Spitzer Space Telescope at 8.0microns using a sample of 43 HII regions with a wide range of morphologies near GLON=312deg. For each region we carefully measure sky-subtracted,point-source- subtracted, areally-integrated IRAC 8.0-micron fluxes and compare these with Midcourse Space eXperiment (MSX) 8.3-micron images at two different spatial resolutions, and with radio continuum maps. We determine an accurate median ratio of IRAC 8.0-micron/MSX\8.3-micron fluxes, of 1.55+/-0.15. From robust spectral energy distributions of these regions we conclude that the present 8.0-micron diffuse calibration of the SST is 36% too high compared with the MSX validated calibration, perhaps due to scattered light inside the camera. This is an independent confirmation of the result derived for the diffuse calibration of IRAC by the Spitzer Science Center (SSC). From regression analyses we find that 843-MHz radio fluxes of HII regions and mid-infrared (MIR) fluxes are linearly related for MSX at 8.3-microns and Spitzer at 8.0 microns, confirming the earlier MSX result by Cohen & Green. The median ratio of MIR/843-MHz diffuse continuum fluxes is 600 times smaller in nonthermal than thermal regions, making it a sharp discriminant. The ratios are largely independent of morphology up to a size of ~24 arcsec. We provide homogeneous radio and MIR morphologies for all sources. MIR morphology is not uniquely related to radio structure. Compact regions may have MIR filaments and/or diffuse haloes, perhaps infrared counter- parts to weakly ionized radio haloes found around compact HII regions. We offer two IRAC colour-colour plots as quantitative diagnostics of diffuse HII regions.Comment: 29 pages, LaTeX (aastex), incl. 31 PostScript (ps,eps) figures and 5 tables. Accepted by MNRAS (main journal). Replaced an unused file and added this URL for people wishing to download a version with high-resolution images: http://www.astro.wisc.edu/sirtf/martin.hii.accepted.pd