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Equilibrium partitioning theory to predict the sediment toxicity of the anionic surfactant C12-2-LAS to Corophium volutator Texte intégral
2009
Rico-Rico, Angeles | Temara, Ali | Hermens, Joop L.M.
The study of the effect of the sorption of linear alkylbenzene sulfonates (LAS) on the bioavailability to marine benthic organisms is essential to refine the environmental risk assessment of these compounds. According to the equilibrium partitioning theory (EqP), the effect concentration in water-only exposure will be similar to the effect concentration in the sediment pore water. In this work, sorption and desorption experiments with two marine sediments were carried out using the compound C12-2-LAS. The effect of the sediment sorption on the toxicity of benthic organisms was studied in water-only and in sediment bioassays with the marine mud shrimp Corophium volutator. In addition, three common spiking methods were tested for its application in the toxicity tests, as well as the stability of the surfactant during the water-only and sediment-water test duration. LC50 values obtained from water-only exposure showed a good correspondence with the pore water concentrations calculated from the sorption and desorption isotherms in the spiked sediments.
Afficher plus [+] Moins [-]Assessment of present and future risk to Italian forests and human health: Modelling and mapping Texte intégral
2009
A review of ozone pollution in Italy shows levels largely above the thresholds established by EU regulation for vegetation and human health protection. The Italian air quality monitoring network appears quantitatively inadequate to cover all the territorial surface, because of scarcity and unequal distribution of monitoring sites. By applying the integrated assessment model RAINS-Italy to the year 2000, the whole of Italy exceeds the AOT40 critical level for forest, while Northern and central areas show strong potential of O3 impact on human health with 11% of territory >10 O3-induced premature deaths. Two scenarios for the year 2020, the Current Legislation and the Maximum Technical Feasible Reduction, show a reduction of AOT40Forest by 29% and 44%, SOMO35 by 31% and 47%, and O3-induced premature deaths by 32% and 48%, compared to 2000. RAINS-Italy can be used to improve the map quality and cover areas not reached by the national monitoring network. AOT40 and SOMO35 are and will be high enough to affect forest and human health all over Italy.
Afficher plus [+] Moins [-]Pesticide transport via sub-surface drains in Europe Texte intégral
2009
Brown, Colin D. | Van Beinum, Wendy
Transport of pesticides from point of application via sub-surface drains can contribute significantly to contamination of surface waters. Results of 23 field drainage experiments undertaken at sites across Europe were collated and analysed by residual maximum likelihood. Both maximum concentration of pesticide in drainflow (n = 167) and seasonal loss of pesticide to drains (n = 97) were significantly related to strength of pesticide sorption to soil, half-life of the pesticide in soil, the interval between application and first drainflow and the clay content of the soil. The statistical models accounted for 71% of the variability in both maximum concentration and seasonal load. Next, the dataset was used to evaluate the current methodology for assessment of aquatic exposure used in pesticide registration in Europe. Simulations for seven compounds with contrasting properties showed a good correspondence with field measurements. Finally, the review examines management approaches to reduce pesticide transport via sub-surface drains. Despite a large amount of work in this area, there are few dependable mitigation options other than to change application rate or timing or to restrict use of a compound in the most vulnerable situations. Chemical and environmental factors influence pesticide transfer to water via drains.
Afficher plus [+] Moins [-]Polycyclic aromatic hydrocarbon (PAH) contamination of surface sediments and oysters from the inter-tidal areas of Dar es Salaam, Tanzania Texte intégral
2009
Gaspare, Lydia | Machiwa, John F. | Mdachi, S.J.M. | Streck, Georg | Brack, Werner
Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low. PAH contamination may pose hazards to benthos but limited risks to humans
Afficher plus [+] Moins [-]Prediction of Cadmium uptake by brown rice and derivation of soil-plant transfer models to improve soil protection guidelines Texte intégral
2009
Römkens, P.F.A.M. | Guo, H.Y. | Chu, C.L. | Liu, T.S. | Chiang, C.F. | Koopmans, G.F.
Cadmium (Cd) levels in paddy fields across Taiwan have increased due to emission from industry. To ensure the production of rice that meets food quality standards, predictive models or suitable soil tests are needed to evaluate the quality of soils to be used for rice cropping. Levels of Cd in soil and rice grains were measured in 19 paddy fields across the western plains in Taiwan. Cadmium levels in soil range from less than 0.1 mg kg⁻¹ to 30 mg kg⁻¹. Measured Cd levels in brown rice were predicted very well (R² > 0.8) based on Cd and Zinc in a 0.01 M CaCl₂ extract or a soil-plant transfer model using the reactive soil Cd content, pH, and cation exchange capacity. In contrast to current soil quality standards used in Taiwan, such models are effective in identifying soils where Cd in rice will exceed food quality standards. Cadmium uptake by 12 rice cultivars is predicted well by a single soil-plant transfer model based on 0.01 M CaCl₂ or a combination of pH, CEC, and the 0.43 N HNO₃-extractable soil Cd concentration.
Afficher plus [+] Moins [-]Persistence of organochlorine chemical residues in fish from the Tombigbee River (Alabama, USA): Continuing risk to wildlife from a former DDT manufacturing facility Texte intégral
2009
Hinck, Jo Ellen | Norstrom, Ross J. | Orazio, Carl E. | Schmitt, Christopher J. | Tillitt, Donald E.
Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations were measured in largemouth bass from the Tombigbee River near a former DDT manufacturing facility at McIntosh, Alabama. Evaluation of mean p,p'- and o,p′-DDT isomer concentrations and o,p'- versus p,p'-isomer proportions in McIntosh bass indicated that DDT is moving off site from the facility and into the Tombigbee River. Concentrations of p,p'-DDT isomers in McIntosh bass remained unchanged from 1974 to 2004 and were four times greater than contemporary concentrations from a national program. Total DDT in McIntosh bass exceeded dietary effect concentrations developed for bald eagle and osprey. Hexachlorobenzene, PCBs, and toxaphene concentrations in bass from McIntosh also exceeded thresholds to protect fish and piscivorous wildlife. Whereas concentrations of DDT and most other organochlorine chemicals in fish have generally declined in the U.S. since their ban, concentrations of DDT in fish from McIntosh remain elevated and represent a threat to wildlife.
Afficher plus [+] Moins [-]Do earthworms impact metal mobility and availability in soil? - A review Texte intégral
2009
Sizmur, Tom | Hodson, Mark E.
Do earthworms impact metal mobility and availability in soil? - A review Texte intégral
2009
Sizmur, Tom | Hodson, Mark E.
The importance of earthworms to ecosystem functioning has led to many studies on the impacts of metals on earthworms. Far less attention has been paid to the impact that earthworms have on soil metals both in terms of metal mobility and availability. In this review we consider which earthworms have been used in such studies, which soil components have been investigated, which types of soil have been used and what measures of mobility and availability applied. We proceed to review proposed reasons for effects: changes in microbial populations, pH, dissolved organic carbon and metal speciation. The balance of evidence suggests that earthworms increase metal mobility and availability but more studies are required to determine the precise mechanism for this. We review the impact of earthworms on metal mobility and availability and suggest areas for further investigation.
Afficher plus [+] Moins [-]Do earthworms impact metal mobility and availability in soil? A review Texte intégral
2009
Sizmur, Tom | Hodson, M. E.
The importance of earthworms to ecosystem functioning has led to many studies on the impacts of metals on earthworms. Far less attention has been paid to the impact that earthworms have on soil metals both in terms of metal mobility and availability. In this review we consider which earthworms have been used in such studies, which soil components have been investigated, which types of soil have been used and what measures of mobility and availability applied. We proceed to review proposed reasons for effects: changes in microbial populations, pH, dissolved organic carbon and metal speciation. The balance of evidence suggests that earthworms increase metal mobility and availability but more studies are required to determine the precise mechanism for this. (C) 2009 Elsevier Ltd. All rights reserved.
Afficher plus [+] Moins [-]A flux-based assessment of the effects of ozone on foliar injury, photosynthesis, and yield of bean (Phaseolus vulgaris L. cv. Borlotto Nano Lingua di Fuoco) in open-top chambers Texte intégral
2009
Stomatal ozone uptake, determined with the Jarvis' approach, was related to photosynthetic efficiency assessed by chlorophyll fluorescence and reflectance measurements in open-top chamber experiments on Phaseolus vulgaris. The effects of O₃ exposure were also evaluated in terms of visible and microscopical leaf injury and plant productivity. Results showed that microscopical leaf symptoms, assessed as cell death and H₂O₂ accumulation, preceded by 3-4 days the appearance of visible symptoms. An effective dose of ozone stomatal flux for visible leaf damages was found around 1.33 mmol O₃ m⁻². Significant linear dose-response relationships were obtained between accumulated fluxes and optical indices (PRI, NDI, ΔF/Fm'). The negative effects on photosynthesis reduced plant productivity, affecting the number of pods and seeds, but not seed weight. These results, besides contributing to the development of a flux-based ozone risk assessment for crops in Europe, highlight the potentiality of reflectance measurements for the early detection of ozone stress. Ozone stomatal fluxes affect leaf cell viability, photosynthetic performance, optical properties and crop yield of bean.
Afficher plus [+] Moins [-]Hg concentrations and related risk assessment in coral reef crustaceans, molluscs and fish from New Caledonia Texte intégral
2009
Chouvelon, Tiphaine | Warnau, Michel | Churfaud, Carine | Bustamante, Paco
There is a dramatic lack of data on Hg levels in marine organisms from tropical areas, and in particular from New Caledonia. For the first time, this study reports the total Hg concentrations in the tissues of several marine taxa from the New Caledonian lagoon. Seafood from both wild and farmed populations was considered. Hg concentrations varied over three orders of magnitudes according to factors including species, age (size/weight), trophic level, lifestyle and geographical origin. Taking into account the edible tissues, estimations of the amount of flesh that should be consumed by a 60-kg person to reach the Hg Provisional Tolerable Weekly Intake (PTWI) reveal acceptable risk for Human health in general. However, a risk was clearly identified in one site of the lagoon (i.e. Grande Rade) where high Hg concentrations were measured. These concentrations were higher than values reported in the current literature. This work reports the first assessment of Hg levels in edible organisms from the New Caledonian lagoon and the associated risk linked to their consumption by Human.
Afficher plus [+] Moins [-]Organohalogen compounds in human breast milk from mothers living in Payatas and Malate, the Philippines: Levels, accumulation kinetics and infant health risk Texte intégral
2009
Malarvannan, Govindan | Kunisue, Tatsuya | Isobe, Tomohiko | Sudaryanto, Agus | Takahashi, Shin | Prudente, Maricar | Subramanian, Annamalai | Tanabe, Shinsuke
Human breast milk samples (n = 33) from primipara and multipara mothers from Payatas a waste dump site, and Malate a reference site in the Phillipines were collected in 2004 and analyzed for eight organohalogen compounds, viz., PCBs, DDTs, CHLs, HCHs, HCB, TCPMe, PBDEs and HBCDs. DDTs and PCBs were predominant in all the samples. Overall mean concentrations of PBDEs found in our study were higher (7.5 ng/g lipid wt.) than those reported for Japan and many other Asian countries. Primipara mothers had significantly higher levels of DDTs, CHLs and HCHs than multipara mothers, but not PBDEs and HBCDs. A few individuals accumulated CHLs close to or even higher than the tolerable daily intake guidelines proposed by Health Canada. First comprehensive study on organohalogen contaminants in human breast milk from the Philippines.
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