Heavy metals pollution in the soils of suburban areas in big cities: a case study

Abstract

Soil pollution in agricultural areas surrounding big cities is a major environmental problem. Tabriz is the largest city in the northwest of Iran and the fourth largest city in the country. Soil samples were taken from 46 sites in the suburbs of the Tabriz city, and separate samples were taken from control site and analyzed. The results indicated that the mean pH value of the soil samples was 9.29, while the mean EC value was 354.33 ls/cm and the amount of TOC and TOM was 0.99 and 1.7 %, respectively. The mean concentrations of Cd, Pb, Cu, Cr, Ni, and Zn in the soil were determined to be 1. 61, 10.56, 101.25, 87.40, 38.73, and 98.27 mg/kg, respectively (dry weight). The concentrations of heavy metals (Cd, Pb, Cu, Cr, and Zn), with the exception of Ni, were higher than the concentrations of the same heavy metals at the control site. Despite these elevated concentrations, the concentrations of heavy metals were lower than the toxicity threshold limit of agricultural soils. The values of the pollution index revealed that the metal pollution level was Pb [ Cr [ Cu [ Zn [ Cd [ Ni, and the mean value of the integrated pollution index was determined to be 1.81, indicating moderate pollution. Nevertheless, there were some sites that were severely polluted by Cr (maximum values of 1,364 mg/kg). It was concluded that city probably has affected the surrounding agricultural area. Application of wastewater (municipal and industrial) as irrigation water, using of sludge as soil fertilizer, and atmospheric perceptions have been considered as main reasons of increased heavy metals concentrations found in the studied area.

Determination of Heavy Metal in Agricultural Soils near and Far From the Cement Factory in Tehran, Iran

“…Anthropogenic sources of Cd in soils are related to application of manure, or phosphate fertilizers can lead increasing cadmium in the soil [1-4, 14, 15]. The mean Zn concentration in this study compared with some citiesis similar; in this study is: 98.8, in the Iran (Tabriz and Isfahan) is 98.27 and 111.5 respectively, in the China is 94.9 (mg\kg) [1,3,15]. The Zn concentration was lower than CCEM [16].…”

“…Industrial and agricultural development has been largely responsible for pollution of the environment with heavy metals (HMs).The mobilization of metals from industrial regions by transport with seepage waters or by windblown dust may also be an important source of soil contamination [1][2][3].Cement industry is one of the sources for environmental pollution. Cement dust contains HMs pollutants hazardous to the biotic environment with impact for vegetation, human health, animal health and ecosystem [4][5][6].…”

Grey water characterisation and pollutant loads in an urban slum

“…In particular, sodium tripolyphosphate is an ingredient of many detergents whose use has been associated with eutrophication (Köhler 2006). Furthermore, accumulation of heavy metals and micropollutants in the environment may cause toxicity through the food chain, distort the ecological balance (Schwarzenbach et al 2006;Ternes and Joss 2006;Escher and Fenner 2011;Taghipour et al 2013) and negatively affect humans and animals after long exposure time or after bioaccumulation and biomagnification (Snyder et al 2003;Arjoon et al 2013;González-Naranjo and Boltes 2013). Also pathogenic microorganisms in grey water may cause diseases that result in either morbidity or mortality depending on the severity and duration of the exposure (Eriksson et al 2002;Ottoson and Stenström 2003;Birks and Hills 2007).…”

Heavy metals concentration in soils under rainfed agro-ecosystems and their relationship with soil properties and management practices

“…Alfisols, Vertisols, Aridisols and Inceptisols are major soil orders, which occur predominantly in rainfed regions of India. Soil pollution in agricultural areas surrounding big cities is a major environmental problem (Taghipour et al 2013). The urban and dense cities of India with significant industrial waste generation have been found to have heavy metal contaminated soils.…”