Distribution, contamination status and source of trace elements in the soil around brick kilns

This study reports the distribution, contamination level, and possible sources of 54 metal (oid)s in the soils found around brick kilns in south-western Bangladesh. In total, 40 soil samples were collected from the vicinity of five brick kilns in four directions at 250 m intervals. This study reveals that the mean respective concentrations of caesium (Cs), beryllium (Be), lead (Pb), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), dysprosium (Dy), holmium (Ho), terbium (Tb), erbium (Er), thulium (Tm), ytterbium (Yb), thorium (Th), germanium (Ge), yttrium (Y), zirconium (Zr), niobium (Nb), silver (Ag), hafnium (Hf), tantalum (Ta), and tungsten (W), were 7.83, 3.19, 22.93, 85.93, 9.61, 36.86, 7.30, 1.23, 5.76, 1.13, 0.99, 3.14, 0.45, 2.91, 17.72, 3.04, 30.07, 185.13, 13.99, 0.30, 5.34, 1.26, and 2.61 μg g^-1. Furthermore, those amounts exceeded their respective shale values. The pollution evaluation indices indicated a moderate level of contamination by Cs, Pb, Th, Ag, Hf, Ta, W, and lanthanides but excluding lanthanum (La) and lutetium (Lu). The pollution load index revealed pollution at two brickfields. Multivariate statistics reported that coal combustion in the brick kilns is the primary source of lanthanides, actinides, Y, Zr, and Hf in the soil, while other elements derived mostly from natural sources. A portion originated from coal combustion in brick kilns and agricultural activities. Changes in metal (oid)s concentrations were non-linear with the distance between the kilns and sampling points. Consequently, further studies are required and should consider meteorological factors and severity of human impact in the study area.