Composition analysis of dental solid waste in Brazil

When developing proper waste management strategies, it is essential to characterize the volume and composition of solid waste. The aim of this work was to evaluate the composition of dental waste produced by three dental health services in Belo Horizonte, Minas Gerais State, Brazil. Two universities, one public and one private, and one public dental health service were selected. Waste collection took place from March to November 2007. During this period, three samples were collected from each dental health service. The total amount of dental waste produced in one day of dental work was manually separated into three categories: infectious and potentially infectious waste, accounting for 24.3% of the total waste; non-infectious waste, accounting for 48.1%; and domestic-type waste, accounting for 27.6% (percentages are for mean weights of solid waste). Our results showed that most of the waste considered as biomedical may be misclassified, consequently making the infectious waste amount appear much larger. In addition, our results suggest that the best waste minimization method is recycling, and they help to define an appropriate waste management system in all three of the dental health services involved in this study.     

Science, Ethical Arguments, and Management in the Preservation of Land for Grizzly Bear Conservation

Abstract: Environmental groups advocate the preservation of an area within British Columbia's coastal temperate rainforest as a sanctuary for grizzly bears (    Ursus arctos horribilis ). Debate among government, industry, and environmental spokespersons has provided arguments but no resolution. We have applied to this issue available biological knowledge on grizzly bears and the arguments of a range of ethical theories. The theories of three professionally trained ethicists were included: Tom Regan, Holmes Rolston III, and Arne Naess. Aldo Leopold's prominent position in the conservation movement justifies his "land ethic" as a fourth ethical theory. All four theories agree that the area should be preserved. Contrary to this fundamental agreement, the theories diverge when tested against a "hard" conservation scenario, the conflict between the protection of the last surviving grizzly bears versus the survival of a culturally distinct human tribe. Application of the principles developed by Regan and Naess recommend that human interests should override the preservation of grizzly bears, whereas Leopold's and Rolston's arguments favor the preservation of the area for the bears. Our work can be used as a model of how the gap between biological sciences, ethical theories, and ecosystem management can be bridged successfully.     

Kill before being killed: an experimental approach supports the predator-removal hypothesis as a determinant of intraguild predation in top predators

Intraguild predation (IGP) has been explained in terms of competitor-removal, food-stress and predator-removal hypotheses. Only the first two hypotheses have been fairly well studied. To test the predator-removal hypothesis as a force determining IGP in avian predators, we performed a field experiment to simulate the presence of an IG predator (eagle owl Bubo bubo dummy) in the surrounding of the nests of four potential IG prey (black kite Milvus migrans, red kite Milvus milvus, booted eagle Aquila pennata and common buzzard Buteo buteo). To discard the possibility that an aggressive reaction towards the eagle owl was not related to the presence of the IG predator, we also presented a stuffed tawny owl Strix aluco, which is a potential competitor but cannot be considered an IG predator of the studied diurnal raptors considered in the experiment. While almost always ignoring the tawny owl, raptors chiefly showed an interspecific aggressive behaviour towards their IG predator. Our results seem to support the predator-removal hypothesis, as the IG prey may take advantage of the diurnal inactivity of the IG predator to remove it from their territory. However, the recorded behaviour may be also considered as a special variety of mobbing (i.e. a prey’s counter-strategy against its predator), where the mobber is sufficiently powerful to escalate predator harassment into deliberate killing attempts. In their turn, eagle owls can respond with an IG predatory behaviour aimed at removing IG prey species which are highly aggressive mobbers.     

Environmental–sanitary risk analysis procedure applied to artificial turf sports fields

Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In this paper, the authors performed a Tier 2 environmental–sanitary risk analysis on five artificial turf sports fields located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat, inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10^?6 and the cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to playing soccer on an artificial field.     

The application of the vermicomposting process in the bioremediation of diesel contaminated soils

Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are among the environmental pollutants that have very high carcinogenic and mutagenic activity. Among hundreds of different PAHs, 17 are considered priority pollutants and routinely monitored for regulatory purposes. Extended periods of exposure and expensive clean-up costs are typically associated with the vast majority of processes used for the remediation of areas contaminated with PAHs. The results of this study indicate that bioremediation via vermicomposting could be an effective method for remedying soils contaminated with toxic organic compounds, such as PAHs. This study was conducted over 90?days in the presence of various quantities of organic matter (cattle manure) to recover soils contaminated with PAHs. High-performance liquid chromatography (HPLC) was applied to identify PAHs. An evaluation of the toxicity of the final material and the transformation of the organic matter throughout the process was also conducted. The data presented here suggest a relationship between the molar mass of the PAHs and the ability of the vermicomposting process to promote biodegradation. These results suggest that vermicomposting has great potential to be utilized as a tool for the bioremediation of soils impacted by PAHs.     

Levels and risks of particulate-bound PAHs in indoor air influenced by tobacco smoke: a field measurement

Considering tobacco smoke as one of the most health-relevant indoor sources, the aim of this work was to further understand its negative impacts on human health. The specific objectives of this work were to evaluate the levels of particulate-bound PAHs in smoking and non-smoking homes and to assess the risks associated with inhalation exposure to these compounds. The developed work concerned the application of the toxicity equivalency factors approach (including the estimation of the lifetime lung cancer risks, WHO) and the methodology established by USEPA (considering three different age categories) to 18 PAHs detected in inhalable (PM₁₀) and fine (PM_2.5) particles at two homes. The total concentrations of 18 PAHs (Σ_PAHs) was 17.1 and 16.6 ng m^?3 in PM₁₀ and PM_2.5 at smoking home and 7.60 and 7.16 ng m^?3 in PM₁₀ and PM_2.5 at non-smoking one. Compounds with five and six rings composed the majority of the particulate PAHs content (i.e., 73 and 78 % of Σ_PAHs at the smoking and non-smoking home, respectively). Target carcinogenic risks exceeded USEPA health-based guideline at smoking home for 2 different age categories. Estimated values of lifetime lung cancer risks largely exceeded (68–200 times) the health-based guideline levels at both homes thus demonstrating that long-term exposure to PAHs at the respective levels would eventually cause risk of developing cancer. The high determined values of cancer risks in the absence of smoking were probably caused by contribution of PAHs from outdoor sources.