Air-vegetation transfer of PCDD/PCDFs: an assessment of field data and implications for modeling

This study was designed to evaluate soil and air (gas and particle) transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) to vegetation in residential and industrial areas. In a first part, soil-vegetation transfer was assessed. The levels of PCDD/Fs in 120 soil and 120 herbage samples collected from 1996 to 2002 in an industrial area of Montcada (Barcelona, Spain), near a municipal solid waste incinerator (MSWI), were determined. Some additional individual samples were also evaluated. It was concluded that high soil concentrations, which are not at steady state with the air layer above it, show a tendency for PCDD/Fs to escape via volatilization. In a second part of the study, air-vegetation transfer was examined. PCDD/F concentrations from 24 herbage samples were used, while PCDD/F concentrations were also measured in seven high-volume air samples and seven passive air-vapor samples. Scavenging coefficients (m3 air "sampled"/g grass d.m.) ranged from 1.9 to 11.3 m3/g. A good trend with K(OA) was observed for PCDDs (R=0.82), while it was lower for PCDFs (R=0.55). The current results corroborate that PCDD/F concentrations in vegetation are associated with atmospheric deposition. For the highest substituted PCDD/F congeners, the air-particle uptake from plants is the principal pathway. In regions impacted by combustion emission sources, PCDD/F gas-particle partitioning is influenced by a higher concentration of particles in the air. Particles and associated particle-bound PCDD/Fs would sorb to leaf surfaces, and are subject to removal via wash off. However, in areas where emissions to air are not very notable, vapor absorption would be the principal source of vegetation pollution. The results of this investigation can have a potential interest in risk assessment studies and environmental fate models.     

Assessing water quality in rivers with fuzzy inference systems: a case study

In recent years, fuzzy-logic-based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental problems. In the present study, a methodology based on fuzzy inference systems (FIS) to assess water quality is proposed. A water quality index calculated with fuzzy reasoning has been developed. The relative importance of water quality indicators involved in the fuzzy inference process has been dealt with a multi-attribute decision-aiding method. The potential application of the fuzzy index has been tested with a case study. A data set collected from the Ebro River (Spain) by two different environmental protection agencies has been used. The current findings, managed within a geographic information system, clearly agree with official reports and expert opinions about the pollution problems in the studied area. Therefore, this methodology emerges as a suitable and alternative tool to be used in developing effective water management plans.     

Estimating the environmental impact of micro-pollutants in the low Ebro River (Spain): an approach based on screening toxicity with Vibrio fischeri

The aim of this study was to assess the likely impacts on the ecosystems due to agricultural, human, and industrial activities carried out in an ecologically important area of the Ebro River (Spain). For it, a screening site specific ecological risk assessment was conducted. Considering the presence of high levels of potentially toxic substances, such as metals and chlorinated organic compounds, aqueous and organic extracts were used to assess toxicity in sediments by using the photo-luminescent bacteria Vibrio fischeri (Microtox) as screening response variable. Sediment samples collected during 2005-2006 in the last course of the Ebro River and its Delta have been analyzed. Toxic responses have shown strong relationships to the levels of pollutants in the area. Moreover, various sites presented some toxicity level, probably because of other factors associated with reducing environments into the sediments. Results indicate that Microtox bioassay is an appropriate tool to perform risk assessment studies at screening level.     

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.     

Species-dependent chromium accumulation, lipid peroxidation, and glutathione levels in germinating kiwifruit pollen under Cr(III) and Cr(VI) stress

The accumulation of chromium by germinating kiwifruit pollen appears to be significantly affected by Cr species, Cr concentration and calcium availability. Cr(III) accumulation always occurred in a linear manner while Cr(VI) uptake followed a logarithmic model. In the absence of exogenous calcium, Cr(III) accumulation was much higher than that of Cr(VI). It was observed that, as the Cr(III) concentration increased, there was a significant decrease in the endogenous calcium content of pollen, ultimately leading to complete calcium depletion after 90 min of incubation at 150 microM Cr(III). This loss of calcium could be responsible for the strong inhibition of tube emergence and growth following exposure of pollen to Cr(III). Indeed, when exogenous calcium was added to the kiwifruit pollen culture medium, significant growth recovery and reduced Cr(III) uptake occurred; the opposite was true in Cr(VI)-treatments. A significant rise in lipid peroxide production occurs in the presence of both Cr species; the effect was more pronounced following Cr(VI) exposure. Finally, glutathione pool dynamics appears to be differentially affected by chromium species and concentrations. In conclusion, results of the present study have provided important information regarding the different activity profiles of Cr(III) and Cr(VI) in relation to kiwifruit pollen performance, and have also demonstrated differences in some biochemical responses of pollen to metal stress.     

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.     

Establishing the link between ammonia emission control and measurements of reduced nitrogen concentrations and deposition

In the context of international efforts to reduce the impactsof atmospheric NH₃ and NH₄ ⁺ (collectively, NH_x), it is important to establish the link between NH₃emissions and monitoring of NH_x concentrations and deposition. This is equally relevant to situations where NH₃emissions changes are certain (e.g. due to changed source sectoractivity), as to cases where NH₃ abatement technologies havebeen implemented. Correct interpretation of adequate atmosphericmeasurements is essential, since monitoring data provide the onlymeans to evaluate trends in regional NH₃ emissions.These issues have been reviewed using available measurements and modelling from nine countries. In addition to historic datasets,the analysis here considers countries where NH₃ source sector activity changed (both increases and decreases) and countries where NH₃ abatement policies have been implemented.In The Netherlands an `ammonia gap' was identified between the expected reduction and results of monitoring, and was attributedinitially to ineffectiveness of the abatement measures. The analysis here for a range of countries shows that atmospheric interactions complicate the expected changes, particularly sinceSO₂ emissions have decreased at the same time, while at manysites the few years of available data show substantial inter-annual variation. It is concluded that networks need to beestablished that speciate between NH₃ and aerosol NH₄ ⁺, in addition to providing wet deposition, and sample at sufficient sites for robust regional estimates to be established. Such measurements will be essential to monitor compliance of the international agreements on NH₃ emission abatement.     

Influence of weight on the content of trace metals in tissues of Mytilus galloprovincialis (Lamarck, 1819): a forecast model

Fifty seven samples of Mytilus galloprovincialis (Lamarck, 1819) collected along the breakwater barriers of Fano (station 1) and Pesaro (station 2), Adriatic Sea, Marche Region, central Italy, were analyzed by atomic absorption spectrometry and Cd, Cu, Pb and Zn concentrations in the soft tissues were measured. The aims of this work were the statistical analysis of Cd-weight, Cu-weight, Pb-weight, Zn-weight relationships, and the building of a tendency function that allows assessing with a good approximation the concentrations of a metal in different weight organisms. In Mytilus galloprovincialis the content of Cd proportionally grew with the weight and therefore its concentration was independent from this factor; while the concentration of Pb decreased as the weight increased. In both cases the accuracy of multiple regression models improved considering the variable ‘site’, while the same approach appeared not reliable for Cu and Zn, that were two essential metals. Our results showed that a tendency function was reliable, solid and able to predict to a very satisfying extent the concentration of non-physiological metals, like Cd and Pb; while it did not show a good approximation with real Cu and Zn contents.