Fractal and multifractal characterization of the scaling geometry of an urban bus-transport network

A FD around D = 1.5 characterizes the fractal nature of the bus-transport network of Cordoba (Spain) for small spatial scales. MF analysis is a suitable method for characterizing the heterogeneity distribution of bus stops across a transport network. Multifractal analysis determines the relevance of each route for maintaining the heterogeneity across the network. Multifractal analysis adds useful information when connections and distances among bus stops are modified.Ministry of Economy and Competitiveness [ERDF Project CGL2014-54615-C2-1-R

Food contamination on flame retardants

Analyses of all kinds of foodstuffs consistently detect halogenated flame retardants (HFRs) in most of the samples, with seafood and meat as the most contaminated. The banned BDE-47 and BDE-209 are still the most frequently found. The levels of emerging HFRs are usually below the levels of polybrominated diphenyl ethers (PBDEs). However, organophosphorus flame retardants (OPFRs) are observed at higher concentrations, even some orders of magnitude higher, with EHDPP and TCIPP as the main contributors to OPFR profiles in food. The literature shows that regulation on e-waste recycling areas and the use of flame retardants in general are effective in decreasing the levels of these contaminants. Conversely, the fact that OPFRs are applied as plasticisers in addition to the widespread use of plastic materials in the production sites and in food packaging means that these compounds are almost deliberately delivered to food. In regards to food safety, different reports point out at BDE-99 as a possible health hazard based on the margin of exposure (MOE) approximation and exclusively via consumption of seafood, excluding other pathways of exposure. However, estimations of daily intake of flame retardants are safely below the set thresholds, even for BDE-99. Lastly, further studies on food processing or cooking and the bioaccessibility of flame retardants are required as risk assessment is typically performed based on the concentrations in raw food, ignoring that food is rarely consumed raw and that not all the contaminants ingested might be fully assimilated.Peer reviewe