Accumulation of some heavy metals in plants and soils adjacent to Cairo – Alexandria agricultural highway

Abstract

A UTOMOBILE exhausts are considered the main source of air pollution with heavy metals. Airborne pollutants are precipitated on soils surrounding highways causing serious ecological hazards. The current study aimed at evaluating levels of Pb, Ni, Co and Cd in surface (015-cm) and subsurface (1540-cm) soils nearby Cairo-Alexandria agricultural highway, and their accumulation in plants grown thereon. Seven locations were sampled at interval distances 50 meters on both sides of the highway road near Toukh city (Qualubya Governorate). Cabbage and citrus plants were also sampled and separated into its parts. Results revealed that the investigated soils are contaminated with Pb, Ni and Cd. These contaminants were brought to the subsurface layers of the soil at relatively high concentrations. Total and DTPA-extractable contents of Pb and Ni in the top surface soil decreased with increasing the distance from the high way on both sides of the road. Moreover, concentrations of these metals in the cabbage parts were significantly correlated with their total and DTPA-extractable contents. However, Co and Cd in soils seemed to be not affected by the exhausts of the cars on the highway. Heavy metals decreased in cabbage parts as follows: root > stem > outer leaves > inner leaves > core. Calculated BAF values for Pb, Ni and Co were very low indicating that cabbage might be an excluder for these metals whereas, their transfer from roots to shoots (transfer factor, Ts) were high. Heavy metal concentrations in citrus decreased as leaves > flavedo > albedo > segments. Generally, concentrations of heavy metals in plants particularly Pb exceeded the permissible limits. 19

Implications of long term irrigation with wastewater on the contents and retention kinetics of potentially toxic elements in Typic Torripsamment soils

“…02, 11.13, 31.52, 16.40, 10.39, 44.50 fold higher than those of the control one of PTEs in deeper soil layers also increased with ageing, but with a relatively lower trend. The successive irrigations and the different agricultural practices might account for the transfer of pollutants to deeper soil layers (Hashim et al, 2017). Also, SOM can chelate PTEs forming relatively soluble organometallic complexes (Kalbitz and Wennrich, 1998;Almås, 2000;Ren et al, 2015) and these complexes increase the mobility of heavy metals in soil (Ashworth and Alloway, 2008;Rikta et al, 2018).…”

Indirect impacts of irrigation with low quality water on the environmental safety

“…On the other hand, pepper plants grown on the Nile irrigated soil of New Salhia accumulated the highest concentrations of PTEs within their fruits. This indicates high potentiality of the contaminants to enter the food chain through ingestion (Abdelhafez et al, 2015;Hashim et al, 2017;Thatai et al, 2019). According to the JOINT FAO/WHO Food Standards (2011), the maximum acceptable levels for contaminants and toxins in foods should not exceed 0.2 mg Pbkg -1 and 0.2 mg Cd kg -1 .…”

Potential of rice straw biochar, sulfur and ryegrass (Lolium perenne L.) in remediating soil contaminated with nickel through irrigation with untreated wastewater

“…Nickel (Ni 2+ ) is one of the common heavy metals used on a large scale in producing metal alloys, stainless steel, ceramic, glass, electronic products and batteries (Rathor, Chopra & Adhikari, 2014). This heavy metal is released in the environment through mining, vehicles exhausts, industrial wastes and applications of fertilizers (Hashim et al, 2017;Kabata-Pendias & Mukherjee, 2007). In order to decontaminate the polluted soils by this heavy metal, chemicals such as acids, chelators, and immobilizers are used which are called in situ Chemo-remediation agents (Abdel-Salam et al, 2015).…”

“…An estimated 6.24% or 137,000 km 2 of European agricultural lands are destroyed by heavy metals and need urgent remediation (Tóth et al, 2016). A number of previous studies have shown that the Ni 2+ contamination of Egyptian soils due to anthropogenic and natural sources endangers the agroecosystem (El-Gammal, Ali & Samra, 2014;Hashim et al, 2017;Nour et al, 2019).…”