Effects of rapid urbanisation on the urban thermal environment between 1990 and 2011 in Dhaka Megacity, Bangladesh

This study investigates the influence of land-use/land-cover (LULC) change on land surface temperature (LST) in Dhaka Megacity, Bangladesh during a period of rapid urbanisation. LST was derived from Landsat 5 TM scenes captured in 1990, 2000 and 2011 and compared to contemporaneous LULC maps. We compared index-based and linear spectral mixture analysis (LSMA) techniques for modelling LST. LSMA derived biophysical parameters corresponded more strongly to LST than those produced using index-based parameters. Results indicated that vegetation and water surfaces had relatively stable LST but it increased by around 2 °C when these surfaces were converted to built-up areas with extensive impervious surfaces. Knowledge of the expected change in LST when one land-cover is converted to another can inform land planners of the potential impact of future changes and urges the development of better management strategies

Sunscreen components are a new environmental concern in coastal waters: An overview

Since ancient times, humans have felt the need to protect their skin from the harmful effects of the sun: first with the use of vegetable oils or mud that were applied on the skin and then with the wearing of clothes, hats, or umbrellas. Today, the use of sunscreens around the world has become widespread. It has been shown that the use of these cosmetics can release large quantities of chemicals into coastal waters, either directly through bathing or indirectly through waste water treatment plants and atmospheric depositions. Due to the nature of the active ingredients of sunscreens, organic and inorganic UV filters, it has been proven that they can bioaccumulate and bioconcentrate in sediments and biota and can enter the food chain, being a problem whose true magnitude is still unknown

Environmental Risk Assessment of Sunscreens

22 pagesThe sunscreens are complex products for protecting the skin of UV radiation. These products contain active ingredients organic and inorganic UV filters. The release of some of these components can provoke negative effects to aquatic ecosystems. The UV filters have shown to be present in environmental compartments (freshwater, wastewater, groundwater, seawater, sediment, and sand) and to be ubiquitous, motivated by the use in other applications. To assess the environmental risk of these products implies to know exposure conditions and toxic effects in order to establish the risk quotient. This is calculated as the ratio between predicted environmental concentration (PEC) or measured environmental concentration (MEC) and predicted no-effect concentration (PNEC). The organic compounds that presented higher risk were benzophenone-3, ethylhexyl methoxycinnamate, and 4-methylbenzylidene camphor. Nevertheless, this risk is depending on the location and environmental compartment. The lack of a database concentration of inorganic nanoparticles (TiO2 and ZnO) makes difficult to carry out a realistic assessment of environmental risk, although using modeled data an approach was carried out. The results evidenced that certain risk can be related to the release of these nanomaterials from sunscreens, although a refinement will be necessary to reduce the uncertainties. Finally, some gaps of information have been identified in order to get a more realistic environmental risk assessment. Thus, the toxicity of the mixture of sunscreens compounds under realistic conditions and the improvement of the knowledge of their mode of actions could be the next stepsWe would like to thank to the projects CTM2016-75908-R funding by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and FEDER funds and the Junta de Andalucía PAIDI, Excellence Research Group RNM306 for their supportPeer reviewe