| 1. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
Exposure assessments of nanoparticles in aquatic environments – considerations, review and recommendations
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Synthetic nanoparticles are new forms of chemical substances. They can be found in several different forms, such as free particles, surface bound and dissolved in liquid. Nanoparticles can also exist as free, individual particles or agglomerate consisting of multiple particles. This report discusses the assessment of possible risks of nanoparticles. Chemical risk is usually considered to consist of two elements: (1) Exposure to the substance, and (2) the substance's toxicity. So far, the risk-related research on nanoparticles has had a strong focus on the particles ' toxic effects. In this report, we would instead focus on how exposure to nanoparticles can be calculated and assessed, with focus on nanoparticles in water. In the report, we provide an initial background and definitions of nanomaterials and nanoparticles, and describe briefly a standard method of risk assessment of chemicals in the environment. Then we go through important considerations that should be made in the exposure assessment of nanoparticles. First we discuss three considerations related to the emissions of nanoparticles, namely the lack of data for annual production of nanoparticles, the importance of applying a substance flow perspective, and lack of data for so-called emission factors for nanoparticles of various products and materials. Furthermore, we discuss considerations for modeling of nanoparticles behavior in water, mainly by listing a number of key processes with large influence. These are agglomeration, sedimentation, and dissolution. Related to that, we discuss how natural organic materials, coatings and aging of particles can affect these processes. We note here three particle properties that are important in order to describe nanoparticles dispersion in water, in a similar way that the octanol-water partition coefficient and half-life is important to describe the fate of organic chemicals in the environment. For nanoparticles these are the particle size (a) and the density (ρ). We also identify a number of more complex parameters affecting particle behavior in the environment, but not only because of the different particle characteristics, but also depending on characteristics related to the environment. These are the collision efficiency (α), point of zero charge (pHpzc), Hamaker constant (A) and a so-called form factor (β) that affect the sedimentation. In addition to the general difficulty to measure or calculate these parameters they also co-vary. Furthermore, we make a review of 11 currently available exposure models for nanoparticles in aquatic environment. We note that the studies differ regarding modeling method, which sources of emissions that are included, the nanoparticles taken into account, estimated concentrations in the environment, and whether the results are presented as mass or particle concentration. Only two studies trying to model the nanoparticle exposure based on particle properties in a manner similar to standard methods for chemical risk assessment. The other modeling studies are instead based on data on flows of specific nanomaterials, and not on generic algorithms. Next, we describe a number of challenges that occur when measuring nanoparticles in the environment. Finally, we provide the following recommendations to ensure good exposure assessment of nanoparticles in the future: 1. Information of flows and stocks of nanoparticles in society need to be collected. 2. Emission factors would need to be developed for each product that makes use of nanoparticles. 3. Emissions should be reported both as mass and particle number until it becomes clearer which one is most relevant. 4. More research is needed in order to determine which particle properties need to be known in order to calculate the concentration of nanoparticles in the environment. 5. At least the particle size and particle size distribution, as well as the specific particle density should be reported. 6. More research is required to improve the experimental measurements of nanoparticles to be able to validate exposure models.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Molander, Sverker, 1957, et al.
(författare)
-
Förnybara energikällors inverkan på de svenska miljömålen
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna rapport beskrivs olika förnybara energikällors negativa påverkan på desvenska miljömålen. Resultatet har presenterats i form av ett antal konceptuellabilder som länkar miljöpåverkan i energislagens livscykelsteg till specifika miljömål.De energislag som studerats är vattenkraft, vindkraft, tunnfilmssolceller, kiselbaseradesolceller, solfångare, värmepumpar samt odlade biobränslen (såsometanol och raps metylester), biobränslen från avfall (såsom biogas) och biobränslenfrån skogsråvara (såsom flis och pellets). Miljöpåverkan har inte kvantifierats idenna studie, och ingen jämförelse energislagen emellan har utförts. Vad som dockvisats är att de ovan listade energislagen påverkar många svenska miljömål, ochden påverkan kommer att växa om de aktuella svenska målen för förnybar energiförverkligas. Mer detaljerade studier kring de förnybara energislagens påverkan påmiljömålen krävs således för att undvika negativ miljöpåverkan från förnybar energii framtiden. Denna rapport har utifrån dagens vetenskapsläge kartlagt de viktigasteverkningarna på de svenska miljömålens uppfyllelse från förnyelsebar energiteknik,och utgör således en grund för ett sådant mer omfattande arbete. Avslutningsvisges ett antal rekommendationer inför fortsatta studier på området.
|
|
| 8. |
- Ahlborg, Helene, 1980, et al.
(författare)
-
A background on social context and renewable energy sources in Mozambique and Tanzania - An initial report from the STEEP-RES project
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This initial research report, appearing before the formal commencement of the STEEP-RESproject, focuses on the background and context of the project which is intended to make asocio-technical-ecological assessment of prerequisites to and effects of introducing renewableenergy sources (RES) into rural communities of the coastal Tanzania and Mozambique. Thereforea short review of the scientific literature is made dealing with societal prerequisites andrepercussions of electrification. Technical aspects related to the availability of natural resourcesand technologies for renewable energy resources utilisation are also briefly coveredalong with some very brief remarks on possible environmental repercussions.The review of the social context covers > 45 papers dealing with different experiencesof electrification in developing countries relating to renewable energy applicable for povertyalleviation in rural settings. The primary energy sources in rural East Africa are biofuels andelectricity plays a limited role. Electrification influences the composition of the energy mix,but during early development it has very limited impact on the use of wood for cocking andheating purposes. The institutional and financial frameworks are currently major barriers tosmall-scale RES-projects, although local technical and financial capacities are slowly increasing.Social and cultural settings create important drivers and barriers to introduction and diffusionof new technologies. Further, poverty and gender inequality are considered key issues forelectrification projects and create important barriers to success. Participatory and needorientedapproaches are considered necessary by most researchers for successful RES-projects.The more technical review is based on ~50 papers covers the existing renewable energysources (RES) - biofuels, solar, hydro, geothermal, wind, wave and tide. The technologicalstate and resource abundance of each source is discussed briefly in a regional context,along with environmental considerations on each technology.As large scale hydropower is being used in the region since long, it is noticeable thatsmall- and micro-scale hydropower is now advancing and will contribute to electrification inmany smaller river-bound areas. Bioenergy, in terms of firewood is widely used for cookingpurposes, although not environmentally sustainable and not with potential for electricity generation.Biofuels from plantations is rapidly increasing in Africa as well as the global trend.Also here, environmental considerations are of great importance for sustainability. Other RESof potential in the region, and with perhaps less environmental constrains, may be solar photovoltaicand tidal energy. Of less importance, according to regionally sparse resource abuniidance, seem to be wind and wave energy. The potential of geothermal energy is geographicallyrestricted to a few good locations.An inventory of actors within the field of East-African RES based on internet resourcesreveals a “top-heavy” information situation with many and well-designed information sourcesand active networks on global and African regional level while less web-information is availablefrom local levels in Tanzania and Mozambique, where only few companies working inthe field has been identified. More direct investigations are needed starting from the actorsidentified in this initial inventory.
|
|
| 9. |
|
|
| 10. |
|
|
