Distribution and availability of potentially toxic metals in soil in central area of Belgrade,Serbia

Belgrade, capital city of Serbia, has over 1,600,000 inhabitants and over 400,000 vehicles trafficking every day on its streets. The investigation of soil pollution was performed by sequential extraction analysis to investigate the availability of potentially toxic metals (Zn, Cd, Pb, Co, Ni, Cu, Cr and Mn) under different oxidation and pH conditions. All investigated metals were mainly extracted from soils with neutral or acidic extractants. Serious pollution was observed along roads and streets with high traffic frequency, but Pb and Ni pollution was the highest since their concentrations exceed both soil Serbian standard and Canadian guidance values and is characteristic for all investigated sites. Cd, Cu, Cr and Zn concentrations are moderately high since they are between Canadian guideline and Serbian standard.     

Screening of phthalic acid esters in raw materials,premixes and feed additives

Phthalates are animal carcinogens and may cause death or tissue deformities. Samples of feedstuffs collected in 2005 and 2006 from industrial feed manufacturers in the Czech Republic were analysed for contamination with phthalic acid esters (PAEs), specifically di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP). Samples of feed additives, premixes and raw materials were collected (year 2005, n = 26). For soybean oil, the total volume of phthalates measured (DBP + DEHP) reached a level of 131.42 mg kg⁻¹; for rapeseed oil, fish meal and animal fats, the levels measured were 15.00, 7.96 and 58.87 mg kg⁻¹, respectively. The lowest level of DBP + DEHP was found in corn (2.03 mg kg⁻¹). Since phthalates were detected, samples of feed additives (n = 28) and raw materials (n = 28) were collected again in 2006. The highest levels of DBP + DEHP were found in raw materials containing fat. Phthalate levels in rapeseed oil samples ranged from 1.38 to 32.40 mg kg⁻¹ DBP + DEHP. For feed additives, contamination levels in vitamins and amino acids ranged from 0.06 to 3.15 and 1.76 to 4.52 mg kg⁻¹ DBP + DEHP, respectively. Here, we show that the levels of PAEs found in cereals such as wheat, barley and corn may be regarded as being alarmingly high, because cereals make up the largest proportion of compound feed of farm animals.     

Recycling glass-polishing sludge and aluminum anodising sludge in polyurethane and cement composites: fire performance and mechanical properties

Journal of Material Cycles and Waste Management - This article aims to study the mechanical strength and fire resistance of polyurethane/cement (PuCem) composites containing glass sludge and sludge...     

The Impact of Biodegradable Plastics in the Properties of Recycled Polyethylene Terephthalate

Journal of Polymers and the Environment - Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some...     

A new simple methodology for evaluation of explosion risk in underground coal mines

The key objective of this paper is the presentation of a new risk assessment tool for underground coal mines based on a simplified semi-quantitative estimation and assessment method.In order to determine the risk of explosion of any work process or activity in underground coal mines it is necessary to assess the risk. The proposed method is based on a Risk Index obtained as a product of three factors: frequency of each individual scenario P_ucm, associated severity consequences C_ucm and exposure time to explosive atmospheres E_ucm. The influence of exposure time is usually not taken into account up to now. Moreover, the exposure to explosive atmospheres may affect factors of hazardous event probability as much as its consequences. There are many definitions of exposure to explosive atmospheres but in the case of underground coal mines the exposure is defined as frequency risk of firedamp and coal dust. The risk estimation and risk assessment are based on the developed of a risk matrix.The proposed methodology allows not only the estimation of the explosion risk but also gives an approach to decide if the proposal investment is well-justified or not in order to improve safety.     

Convergent evolution in the antennae of a cerambycid beetle, <Emphasis Type="Italic">Onychocerus albitarsis,</Emphasis> and the sting of a scorpion

Venom-injecting structures have arisen independently in unrelated arthropods including scorpions, spiders, centipedes, larval owlflies and antlions, and Hymenoptera (wasps, ants, and bees). Most arthropods use venom primarily as an offensive weapon to subdue prey, and only secondarily in defense against enemies. Venom is injected by biting with fangs or stinging with a specialized hypodermic structure used exclusively for the delivery of venom (usually modified terminal abdominal segments). A true sting apparatus, previously known only in scorpions and aculeate wasps, is now known in a third group. We here report the first known case of a cerambycid beetle using its antennae to inject a secretion that causes cutaneous and subcutaneous inflammation in humans. Scanning electron microscopy revealed that the terminal antennal segment of Onychocerus albitarsis (Pascoe) has two pores opening into channels leading to the tip through which the secretion is delivered. This is a novel case of convergent evolution: The delivery system is almost identical to that found in the stinger of a deadly buthid scorpion.     

Why do <Emphasis Type="Italic">Manduca sexta</Emphasis> feed from white flowers? Innate and learnt colour preferences in a hawkmoth

Flower colour is an important signal used by flowering plants to attract pollinators. Many anthophilous insects have an innate colour preference that is displayed during their first foraging bouts and which could help them locate their first nectar reward. Nevertheless, learning capabilities allow insects to switch their colour preferences with experience and thus, to track variation in floral nectar availability. Manduca sexta, a crepuscular hawkmoth widely studied as a model system for sensory physiology and behaviour, visits mostly white, night-blooming flowers lacking UV reflectance throughout its range in the Americas. Nevertheless, the spectral sensitivity of the feeding behaviour of naïve moths shows a narrow peak around 450 nm wavelengths, suggesting an innate preference for the colour blue. Under more natural conditions (i.e. broader wavelength reflectance) than in previous studies, we used dual choice experiments with blue- and white-coloured feeders to investigate the innate preference of naïve moths and trained different groups to each colour to evaluate their learning capabilities. We confirmed the innate preference of M. sexta for blue and found that these moths were able to switch colour preferences after training experience. These results unequivocally demonstrate that M. sexta moths innately prefer blue when presented against white flower models and offer novel experimental evidence supporting the hypothesis that learning capabilities could be involved in their foraging preferences, including their widely observed attraction to white flowers in nature.     

Unexpected high PCB and total DDT levels in the breeding population of red kite (Milvus milvus) from Doñana National Park, south-western Spain

This study provides information on the current status of contamination by organochlorines (DDTs, PCBs, PCDDs and PCDFs) in the declining red kite (Milvus milvus L.) population breeding in the Do?ana National Park (DNP), south-western Spain. Analyses were performed in addled eggs collected between 1999 and 2001. DDE concentrations ranged from 0.1 to 33.5 microg/g ww, representing more than 86% of the total DDTs. Of the samples studied, 50% showed DDE levels above those associated with reproductive impairment in other raptor species. Concentrations of ortho PCBs (average 36.8 microg/g ww+/-37.7) in 50% of the eggs were much higher than levels reported to cause reduced hatching success, embryo mortality, and deformities in birds (>20 microg/g ww). It is remarkable that average ortho PCB and DDE concentrations showed an increase of one order of magnitude compared to previous data for the species during the 80s. Total PCDD/Fs showed levels in the low pg/g range (7.2-42 pg/g ww), having PCDDs and PCDFs similar contributions in most samples. Total mean TEQs were 238 pg/g (ww), being the range 7.02-667 pg/g (ww). Spatial variation within DNP was observed for PCBs, DDTs, as well as for TEQs. Since some eggs exceeded the NOEL (67%) and LOEL (33%) reported for other raptor species, we would expect the red kite to experience detrimental effects to dioxin-like toxicity. Our results suggest that organochlorine contaminants should be regarded as an element of concern in the population under study, in addition to other conservation problems already reported. Further investigations should be undertaken to identify potential sources of these chemicals in DNP, and to find out if organochlorine contamination is present in other predator species in the area, as well as their potential health effects on individuals and/or populations.     

Thyroid disruption at birth due to prenatal exposure to beta-hexachlorocyclohexane

OBJECTIVE: Thyroid hormones play an important role in human brain development, and some organochlorine compounds (OCs) act as thyroid disruptors. The objective of the present study was to evaluate the association between prenatal exposure to organochlorine compounds and thyroid function in newborns from a general population birth cohort in Menorca, with an a-priori specific focus on beta-HCH. METHODS: Levels of polychlorinated biphenyls (PCB congeners 28, 52, 101, 118, 138, 153 and 180), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), dichlorodiphenyl dichloroethylene (p'p'-DDE) and dichlorodiphenyl trichloroethane (p'p-DDT) in cord serum, and thyrotropin (TSH) concentration in plasma three days after birth were measured in 387 newborns from Menorca. The TSH concentration was categorized (high or low), except for 27 children whose TSH levels were quantified. RESULTS: Levels of beta-HCH and PCB-153 were positively related to TSH concentrations (gestational age-adjusted coefficient (p-value): 0.26 (p = 0.006) and 0.31 (p = 0.050), respectively). CONCLUSIONS: beta-HCH is potentially a new thyroid disrupting compound, deserving special interest in future studies given its high body burden in humans.     

Calibration of a portable HPGe detector using MCNP code for the determination of 137Cs in soils

In situ gamma spectrometry provides a fast method to determine (137)Cs inventories in soils. To improve the accuracy of the estimates, one can use not only the information on the photopeak count rates but also on the peak to forward-scatter ratios. Before applying this procedure to field measurements, a calibration including several experimental simulations must be carried out in the laboratory. In this paper it is shown that Monte Carlo methods are a valuable tool to minimize the number of experimental measurements needed for the calibration.