Evaluation of Levels, Sources and Health Hazards of Road-Dust Associated Toxic Metals in Jalalabad and Kabul Cities, Afghanistan

Abstract

This study was designed to investigate selected road-dust associated heavy metals, their relations with natural and anthropogenic sources, and potential human and environmental health risks. For this purpose, 42 and 36 road-dusts samples were collected from Jalalabad and Kabul cities (Afghanistan), respectively. The following elements were found in descending concentrations: Mn, Zn, Pb, Ni, Cu, Cr, Co, and Cd in Jalalabad; and Mn, Zn, Ni, Cu, Cr, Pb, Co, and Cd in Kabul. Except for Ni, all the elemental contents were less than the Canadian permissible limits in residential/parkland soils. Principle Component Analysis and enrichment of Cd, Cu, Ni, Pb, and Zn pointed to anthropogenic sources, whereas Co, Cr, and Mn indicated crustal inputs. Broadly, Cd monomial risk index ([Formula: see text]) was considerable; however, one site each in both cities showed high risk ([Formula: see text] ≥ 350). The potential ecological risk (RI) is mostly low; however, at some sites, the risk was considerable. Ingestion appeared to be the main exposure route (99%) for heavy metals and contributed > 90% to noncancerous (all residents), as well as 92% (children) and 75-89% (adults) cancerous risks. The noncancerous risks of all metals and their integrated risks for all residents were within acceptable levels. Moreover, potential cancer risks in children from Ni and Cr were slightly higher than the US-EPA safe levels but were within acceptable levels for adults. This study found higher risks to children and therefore recommends proper management and ways to control metals pollution load in these areas to decrease human health and RIs.

Geochemical approach for heavy metals in suburban agricultural soils of Sialkot, Pakistan

“…These agricultural soils were moderately to significantly enriched with Cr and Co, and moderately enriched with Ni and Zn. The EF value fluctuates between 0.5 and 1.5 if the metal is of crustal origin or a result of natural weathering of rocks in a given area [4,39]. However, in this investigation except Cu the ranges of EFs for metals exceeded the limit of 1.5 suggesting that significant proportions of these elements were of anthropogenic origin [4,39].…”

“…Thus, the presence of these metals in the study area may be influenced by human activities such as emissions from traffic, industry (especially tanneries), pesticide/ fertilizer application, and automobile repair workshops [2,4,8]. All of these activities have been observed to contribute toxic metals in Sialkot district [2,3].…”

“…Unplanned urban and industrial expansion is causing an accumulation of heavy metals in suburban agricultural soils, which is a serious and growing concern in recent decades in Pakistan [1][2][3]. Such upsurges of metal concentrations are mainly caused by anthropogenic activities such as traffic emissions, use of agrochemicals, industrial/ municipal wastes and atmospheric deposition [2,4]. The soil contamination with heavy metals is of special concern due to metal's ability to damage the soil environment, which can compromise soil ecological functions.…”

“…Moreover, the long-term input of heavy metals could result in decreased buffering capacity of soil, further aggravating the threats to the ecological environment [5]. These metals can also be detrimental for living organisms through bioaccumulation and inclusion in the food chain, and inevitably compromise human health via ingestion [4,6]. Long-term consumption of contaminated food (with elements viz., Cr, Cd, Pb, and Ni) obtained from crops, which are grown in heavy metal contaminated soil, can cause accumulation of these metals in the human liver and kidneys, which can lead to organ malfunction [6].…”

“…These indexes of potential contamination are calculated by the normalization of one metal concentration in the topsoil respect to the concentration of a reference element (Iron was chosen as reference element in this study). Similarly, the pollution load index (PLI) was applied for detecting pollution which permits a comparison of pollution levels between sites and at different times [4,15]. The PLI was obtained as a concentration factor of each heavy metal with respect to the background value in the soil.…”