Bricks reveal recent history of heavy metal pollution in soil around a north Indian city

The aim of this work was to determine the type of weathering suffered by bricks belonging to a number of historic buildings in Toledo, Spain. These bricks had been exposed to either aerial or burial environments, came from different places in the selected buildings, were of different mineralogical composition, and had been fired at different temperatures. X-ray diffraction, scanning electron microscopy and the analysis of their physical properties showed the best conserved to be those that had been buried. Buried Roman bricks made from non-calcareous materials fired at 4900 1C and with a vitrified matrix showed few signs of weathering. Buried Islamic and Mudejar-Romanesque bricks made from calcareous clays and fired at temperatures of o800 1C were similarly well conserved. These showed calcareous cementation of their pore systems, which improved their physical properties. Bricks from the external and internal walls of buildings (e.g., Islamic-Mudejar and Romanesque bricks from inner courtyards and cellars) that had been exposed to aerial conditions were less well conserved. These were made from calcareous materials and had been fired at high temperatures (4900 1C). They showed a number of weathering traces but overall were still in relatively good condition. The worst conserved of all were neoclassical bricks from upper storey internal walls. These were made of calcareous material and had been fired at temperatures of between 800 and 900 1C.The mineralogical composition of the raw materials, the firing temperature, the location of the bricks in the buildings, the environments to which they had been exposed, the action of natural or polluted filtration water, the action of microorganisms and the reigning environmental conditions, all contributed towards the state of conservation of the bricks. Such knowledge may help in the choice of appropriate cleaning or restoration treatments for architectural heritage of brick construction. r

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“…Analysing samples of different ages collected from old monuments can reveal the recent history of heavy metal pollution [8,9].…”

Section: Introductionmentioning

confidence: 99%

Weathering traces in ancient bricks from historic buildings

López-Arce

García-Guinea

2005

Building and Environment

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“…Historical trend of heavy metals accumulation in soil can be reconstructed by measuring the heavy metal contents in bricks manufactured at different time periods, moss/leaf collections from museums, downstream sediments, and sectioned soils layers (Cao et al, 2008;Liu et al, 2005;Rodríguez Martín et al, 2015;Shrivastav et al, 1998;Zhang et al, 2005). However, these approaches are only applicable to estuarine and coastal areas or at geologic timescales.…”

Section: Introductionmentioning

confidence: 99%

Mass balance-based regression modeling of Cd and Zn accumulation in urban soils of Beijing

Peng

Wang

Chen

et al. 2017

Journal of Environmental Sciences

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Accumulation of heavy metals in urban soil can pose adverse impacts on public health and terrestrial ecosystems. We developed a mass balance-based regression model to simulate the heavy metal accumulation in urban soils as a function of time and to explore connections between metal concentration and urbanization processes. Concentrations of Cd and Zn in 68 residential soil samples in the urban area of Beijing were used. The background concentrations, the loss rates and the input fluxes of Cd and Zn in urban soils of Beijing during the last three decades were estimated using a regression of the time series of accumulations of the metals. Based on the regression estimates, we simulated the general trends of Cd and Zn accumulation in the soils from 1978 to 2078. The concentrations of Cd and Zn in urban soil generally increased with the population growth, vehicle use and coal consumption. The mean concentrations of Cd and Zn in urban soil of Beijing would increase by 3 fold over the next 70years for the current development scenario. The mass balance-based regression approach, which is able to reconstruct the history data of urban soil pollution, provides fundamental information for urban planning and environmental management.

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“…In a study in the city of Agra, India, it was possible to trace the pollution by analyzing bricks of different ages that contained the original metals plus those added to the soil by industrial activities (Shrivastav et al, 1998). Similarly, the pre-industrial revolution pollution was defined relative to present day contamination by analyzing 800-year-old slag heaps produced by medieval metallurgical activities (Baron et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Earth walls as repositories of background levels of soil metal contaminants

2013

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Data about the background concentration of potentially toxic elements in soils is indispensable for establishing legislative limits, risk thresholds and, in general, assess the intensity of the pollution. Crude earth buildings are diffuse in the Mediterranean area and may be used as archives for original concentration of various metals. The building technique uses local soil which is mixed with water, let dry in formworks and covered with plaster. This has protected the soil material from external additions. The aim of this work was to evaluate the crude earth walls as repositories of the original concentration of some metals. Six crude earth walls were investigated in a location in north-western Italy. Their concentration in Cd, Cu, Cr, Ni, Pb and Zn were measured and compared with those of 2 surrounding soil profiles. Also, the results were compared with those of the Province.Organic carbon and pH seem to confirm the different evolution of the soils in the field with respect to that in the wall while iron oxides were not useful in discriminating the samples.Cadmium and Pb appeared to be the most reliable for the evaluation of the accumulated contamination evaluated while Cr and Ni are influenced by the lithogenic substratum.

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Bricks reveal recent history of heavy metal pollution in soil around a north Indian city

Cited by 5 publications

References 17 publications

Weathering traces in ancient bricks from historic buildings

Weathering traces in ancient bricks from historic buildings

Mass balance-based regression modeling of Cd and Zn accumulation in urban soils of Beijing

Earth walls as repositories of background levels of soil metal contaminants

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