Concentrations of PCDD/PCDFs in plasma of subjects living in the vicinity of a hazardous waste incinerator: follow-up and modeling validation

In 2007, the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) were determined in plasma of non-occupationally exposed subjects living near the only hazardous waste incinerator (HWI) in Spain (Constantí, Tarragona County, Catalonia). These data were compared with the levels found in two previous surveys performed in 1998 (baseline) and 2002. The current mean PCDD/PCDF concentration in plasma was 9.36pg I-TEQg(-1) of lipid (range: 1.76-23.44pg I-TEQg(-1) of lipid). It means a significant reduction of the mean PCDD/PCDFs levels in plasma in comparison to the concentrations found in 1998 and 2002 (27.01 and 15.70pg I-TEQg(-1) of lipid, respectively). This important decrease agrees well with the notable reduction in the dietary intake of PCDD/PCDFs recently noted for the population of the same area (210.1pg I-TEQd(-1), 63.8pgWHO-TEQd(-1), and 27.8pgWHO-TEQd(-1), in 1998, 2002 and 2007, respectively). The current data were also used to predict theoretical PCDD/PCDF concentrations in plasma by executing a single-compartment empirically-based pharmacokinetic model on the basis of the daily intake of these pollutants by the local population.     

Evaluation of stream ecological integrity using litter decomposition and benthic invertebrates

Biomonitoring programs to access the ecological integrity of freshwaters tend to rely exclusively on structural parameters. Here we evaluated stream ecological integrity using (a) benthic macroinvertebrate derived metrics and a biotic index as measures of structural integrity and (b) oak litter decomposition and associated fungal sporulation rates as measures of functional integrity. The study was done at four sites (S1, S2, S3 and S4) along a downstream increasing phosphorus and habitat degradation gradient in a small stream. The biotic index, invertebrate metrics, invertebrate and fungal communities' structure and sporulation rates discriminated upstream and downstream sites. Decomposition rates classified sites S4 and S2 as having a compromised ecosystem functioning. Although both functional and structural approaches gave the same results for the most impacted site (S4), they were complementary for moderately impacted sites (S2 and S3), and we therefore support the need for incorporating functional measures in evaluations of stream ecological integrity.     

Ecotoxicological evaluation of industrial port of Venice (Italy) sediment samples after a decontamination treatment

This work assesses the ecotoxicological effects of polluted sediment after a decontamination treatment process using a new sediment washing technique. Sediment samples were collected from four sites in Marghera Port industrial channels (Venice, Italy). Ecotoxicological evaluations were performed with Vibrio fischeri and Crassostrea gigas bioassays. Whole sediment and elutriate were deemed as the most suitable environmental matrices for this study. Toxicity scores developed in the Lagoon of Venice for V. fischeri on whole sediment and for C. gigas on elutriate were considered for the final ranking of samples. Ecotoxicological results showed that the treated sediment samples presented both acute and sub-chronic toxicities, which were mainly attributed to the presence of some remaining chemicals such as metals and polyaromatic hydrocarbons. The acute toxicity ranged from low to medium, while the sub-chronic one from absent to very high, suggesting that treated sediments could not be reused in direct contact with seawater.     

Human health risks of petroleum-contaminated groundwater

BACKGROUND, AIM AND SCOPE: The volatile organic compounds Benzene, Toluene, Ethylbenzene and Xylene (BTEX) are commonly found in petroleum derivatives and, at relatively high levels, can be associated with human health risks. Due to industrial activities, accidental petroleum spills are the main route of soil and groundwater contamination. The aim of the present study was to evaluate the indoor health risks due to tap water consumption contaminated by BTEX. MATERIALS AND METHODS: BTEX indoor exposure can occur through three principal pathways: inhalation, ingestion and dermal absorption. A multiphase and multicomponent model was used to simulate BTEX transport in groundwater. For evaluation of human risks due to the use of contaminated tap water, a mathematical model was elaborated. RESULTS: BTEX concentrations in a drinking well were obtained as a function over time. These concentrations were used to obtain the exposure due to the use of water from the contaminated drinking well. In addition to showing the highest concentration in water, benzene was the compound that remained for a longer period before being completely degraded. For all the evaluated BTEX, oral ingestion was also the main pathway of exposure for adults, whereas the contribution of inhalation and oral exposition in children were seen to be of the same magnitude. The sensitivity analysis of BTEX total dose for adults showed that direct ingestion was the most significant factor, followed by shower time, volume of the shower room, inhalation rate, and shower flow rate. For children, the most significant variable was also direct ingestion, followed by shower time, volume of the shower room, and body weight. DISCUSSION: In the current design situation, there would not be any health risks by the use of BTEX-contaminated water to the general population living in the neighborhood of the petroleum spill. Therefore, no remediation measures in the area of the spill would be necessary. CONCLUSIONS: The present results indicate that the design of a good scenario can perform an accuracy risk assessment. This model can serve as a useful tool for predicting indoor exposure to substances for which no direct data are available, reducing monitoring efforts and observing how different processes affect outcomes. RECOMMENDATIONS AND PERSPECTIVES: These preliminary data allow the establishment of a basis for further investigations focusing on efficiently recovering petroleum from contaminated sites.     

Rhizosphere localized cationic peroxidase from barley roots is strongly activated by cadmium and correlated with root growth inhibition

The activity of Cd-induced POD isozyme isolated from the surface of intact barley roots growing under some abiotic stress conditions (toxic metals: Al, Co, Cu, Hg; drought, NaCl, extreme temperatures: heat, cold) and compounds activating (2,4-D) or inhibiting (SHAM) POD activity as well as H(2)O(2) and H(2)O(2) scavenger (DTT) was characterized. Strong Cd concentration-dependent accumulation of one cationic POD isozyme was observed on PAGE, which correlated with Cd- and other stress induced root growth inhibition. This isoPOD is basic with isoelectric point about 9 and its localization is restricted only to the apical part of the barley root tip.     

Depuration of PCBs and DDTs in mullet under captivity clean conditions

Contaminated mullet (Mugil cephalus) from Douro estuary was allowed to depurate in clean water and fed with uncontaminated food. Levels of PCBs and DDTs in muscle and liver, and ethoxyresorufin O-deethylase (EROD) activity were measured at day 0, 21, 120 and 270. In specimens captured in the estuary total PCB and total DDT concentrations were 311 and 65 ng g(-1) in muscle and 686 and 115 ng g(-1) in liver, respectively. At day 21, after an initial 10-15 days period of starvation, organochlorines levels increased in both analyzed tissues. Thereafter levels of all PCB congeners and DDT compounds decreased in muscle, and at the end of the 270 days were 49 ng g(-1) and 13 ng g(-1), respectively. These decreases were correlated to the lipids consumption. In liver no relationship between those variables was observed, suggesting different elimination processes and eventual exchange of contaminants between muscle and liver. EROD activities decreased in the first days of depuration experiment, but showed no relations with analysed organochlorines.     

Evaluation of genotoxicity and toxicity of water and sediment samples from a Brazilian stream influenced by tannery industries

This paper reports results of genotoxicity and toxicity studies of water and sediment samples collected from the Estancia Velha stream of southern Brazil, a stream transporting both domestic sewage and effluents from regional factories working in the leather industry. Three sites were selected: in the stream headwaters (Site 1), located downstream of an urban area (Site 2), and near the basin outfall (Site 3). Results obtained with Allium cepa showed no evidence of chromosomal mutation, either in water or in sediment, during winter or summer seasons, but samples collected below Site 1 showed high toxicity. Physical and chemical analyses showed high concentrations of pollutants at these sites. Ecotoxicity tests with Daphnia magna and Ceriodaphnia dubia measured toxicity in water from Sites 2 and 3 in summer 2004. A toxic effect on Hyalella azteca was only found in sediment from Site 3 during winter 2003 and summer 2004. The results suggest that the synergy among different compounds in domestic and industrial sewage discharges can make it difficult to maintain system stability.     

Ozone stress and antioxidant substances in Trifolium repens and Centaurea jacea leaves

Ozone-sensitive (NC-S clone) and resistant plants (NC-R clone) of Trifolium repens and Centaurea jacea were exposed to moderate ozone concentrations in ambient air. The aim of this study was the investigation of the relation between ozone-sensitivity and leaf concentrations of antioxidants (ascorbic acid, total phenolics and total antioxidant capacity). NC-R clone showed the highest concentrations of antioxidants with 50-70% more ascorbic acid than NC-S. NC-R had about 5 times more ascorbic acid in the young leaves and 9 times more in the old leaves than Centaurea. In a fumigation experiment with acute ozone stress (100 nl L(-1)) the antioxidant levels changed profoundly. The ozone-injured leaves of NC-S had 6-8 times more total phenolics than uninjured leaves. Generally older leaves had lower antioxidant concentrations and were more prone to ozone injury than younger leaves. Ascorbic acid concentrations were closer related to the appearance of visible ozone injury than the other antioxidative parameters.     

Mitigating construction safety risks using prevention through design

Introduction

Research and practice have demonstrated that decisions made prior to work at construction sites can influence construction worker safety. However, it has also been argued that most architects and design engineers possess neither the knowledge of construction safety nor the knowledge of construction processes necessary to effectively perform Construction Hazards Prevention through Design (CHPtD).

Method

This paper introduces a quantitative methodology that supports designers by providing a way to evaluate the safety-related performance of residential construction designs using a risk analysis-based approach. The methodology compares the overall safety risk level of various construction designs and ranks the significance of the various safety risks of each of these designs. The methodology also compares the absolute importance of a particular safety risk in various construction designs.

Results

Because the methodology identifies the relevance of each safety risk at a particular site prior to the construction stage, significant risks are highlighted in advance. Thus, a range of measures for mitigating safety risks can then be implemented during on-site construction.

Impact on industry

The methodology is specially worthwhile for designers, who can compare construction techniques and systems during the design phase and determine the corresponding level of safety risk without their creative talents being restricted. By using this methodology, construction companies can improve their on-site safety performance.     

A prototype printer for laser driven micro-transfer printing

This paper demonstrates a new mode of automated micro transfer printing called laser micro transfer printing (LμTP). As a process, micro-transfer printing provides a unique and critical manufacturing route to extracting active microstructures from growth substrates and deterministically assembling them into a variety of functional substrates ranging from polymers to glasses and ceramics and to metallic foils to support applications such as flexible, large-area electronics, concentrating photovoltaics and displays. Laser transfer printing extends micro-transfer printing technology by providing a non-contact approach that is insensitive to the preparation and properties of the receiving substrate. It does so by exploiting the difference in the thermo-mechanical responses of the microstructure and transfer printing stamp materials to drive the release of the microstructure or ‘ink’ from the stamp and its transfer to substrate. This paper describes the process and the physical phenomena that drive it. It focuses on the use of this knowledge to design and test a print head for the process. The print head is used to demonstrate the new printing capabilities that LμTP enables.