Heavy Metal Content and Health Risk Assessment of Urban Road Dust from the Historical Center of Havana, Cuba

7 Street road dust samples were collected at 33 stations of the Historical center of Old Havana. Samples were 8 analyzed for the determination of some (Co, Ni, Cu, Zn and Pb) heavy metal concentrations using an X-ray 9 fluorescence (XRF) instrument. The mean concentrations of the elements are Zn (548.7 mg/kg), Pb (60.8 10 mg/kg), Co (7.0 mg/kg) Ni (60.6 mg/kg) and Cu (73.6 mg/kg) were Zn and Pb showed higher values of the 11 background. The study of the Enrichment Factor ( EF ), the Pollution Index ( IP ) and the Integral Pollution Index 12 (IPI), showed some stations with high values of contamination close to construction places. Zn was identified 13 as the major pollutant fallowed by the Pb. Nevertheless, the Hazard Index ( HI ) and Carcinogenic Risks ( CR ) 14 values do not show risk of getting non-carcinogenic or carcinogenic diseases associated to the analyzed 15 pollutants.


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Cities are the centers with the greatest amount of anthropogenic activities. Due to rapid urbanization and 39 industrialization, about half of the world population now lives in cities, where the population density, the 40 automotive traffic, industry and economic activities, cause large amounts of pollutants that are discharged 41 into the urban environment. So a lot of environmental problems are arising from air, soil and water pollution.

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Heavy metal contamination is a major problem, especially in urban atmospheric particles, soil and dust (Lu et

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The degree of contamination present in dust samples was evaluated using the dimensionless variable 98 denominated Enrichment Factor (EF). EF is estimated as:

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where Cn is the concentration of the potentially enriched metal and Cref is the reference metal concentration. An 100 EF>1 means the existence of a non-natural contribution to the concentration determined of an element. The 101 degree of enrichment depending on the EF value according to Sutherland (2000) is: EF < 2, minimal 102 enrichment; 2 < EF < 5, moderate enrichment; 5 < EF < 20, significant enrichment; 20 < EF < 40, very high 103 enrichment; and EF > 40, extremely high enrichment.

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Generally, EF less than 2 it is not considered significant, since a small value of EF may be due to fluctuations 105 relative to the used natural background, or for the accuracy and precision of the analytical technique used 106 (Sinem Atgin et al. 2000). In this research, iron was used as reference metal for the normalization as it is hardly 107 influenced by anthropogenic sources due to the high natural levels of this element (Villares et al. 2003).
108 Additionally, the dust contamination level was evaluated using the Integral Pollution Index (IPI) (Cheng et al.  130 years for children; PEF is the particle emission factor, that is, the relationship between the concentration of a 131 pollutant in the dust with the concentration of particles of these pollutants that are suspended in the air we 132 breathe: 1.36 x10 9 m 3 kg -1 ; SA it is the exposed skin area: 5700 cm 2 for adults and 2800 cm 2 for children; SL is 133 the skin adhesion factor: 0.7 mg.

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The highest Pb-content (422 mg.kg -1 ) was found at station 2. At this place there is small seaport for fisher boats 169 that use oil as fuel and it is the main exit of all the vehicles that cross the Havana bay tunnel. The average / 170 median ratios for Fe and Co are close to 1, so there are not outliers and it can be stated that its origins must be 171 predominantly natural. Figure 2 shows the spatial distribution for the determined heavy metals.

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However, the use of Pb-doped fuels for many years, must be the reason of the significant EF level for Pb in the 198 city since lead exhausts could have been accumulated in parks, walls and streets for years.

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The EF and PI show the same behavior (Zn> Pb> Ni> Cu> Co) with almost all the stations in the range of 218 moderate or less enrichment and pollution for Co, Ni and Cu. Pb has a significant enrichment but only three 219 stations show considerably or more pollution index. Zn shows a significant or higher enrichment in almost all 220 the stations and in correspondence the pollution index goes from moderately to highly pollution.

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Health risk assessment shows that HI and CR are in safe ranges. That confirm that the HCH city is a safe place 222 for visitors and habitants independently the great reconstruction movement performed in the last years.

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However, taking into account that the reconstruction movement will continue in the next years, the check of the 224 heavy metal content will be continued as well as the health risks assessments in order to guaranteed safe levels. Figure 1 Location of the sampling stations in Historical Center of Havana Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.   Hazard Index averages and ranges of values for children and adults and the Carcinogenic Risk