Heavy Metals Pollution of Soil and Plant Shoots Nearby the Municipal Solid Waste Dumpsite in Al-Suli, Riyadh, Kingdom of Saudi Arabia

Document Type: Original Article

Author

Center of Excellence for Wildlife Research- Life Sciences & Environment Research Institute

Abstract

A study was conducted to determine the impact of the distance from the municipal solid waste dumpsite, at
which E-waste was disposed, on heavy metals [Iron (Fe), Cadmium (Cd), Lead (Pb) and Zinc (Zn)]
contamination of plants and soils. To achieve this objective a systematic sampling approach was used to
collect composite soil samples from plots located at distances of (0,100,200,300 and 400 m) from Al-Suli
municipal waste dumpsite. A soil auger was used for soil sampling at each plot at the depth of 0-25 cm. In
addition, the aerial parts of three selected plants species (Rhazyastricta Dence, Artemisia Monosperman
Delile and Panicum Turgidum Forssk) naturally growing in Al- Suli area were sampled from within each
sampling site. The concentration of heavy metals in both soil and plant samples were determined. The
results showed that the soil was polluted with the studied heavy metals (Fe, Pb, Cd and Zn). The highest
concentration of heavy metals in the soil was within the dumpsite and then decreased as the distance
increased. The obtained data indicated very high pollution with both Cd and Fe in the dumpsite (zero meter),
while their concentration in the second site (100 m away from the dumpsite) was lower. Cd concentration
in the dumpsite soil was 75.6-± 0.49 mg kg - ᶦ, a level that affects human health. Cd concentration at a
distance of 100 m was 57.1-± 0.37b mg kg - ᶦ, which means that the soil is significantly contaminated with
Cd. The soil within the dumpsite and at a distance of 100 m was also contaminated with both Pb and Zn to
levels that could be considered harmful to human health (47.9 ± 0.24 and 38.3 ±0.20 as well as 0.79 ± 0.09
and 0.75 ±0.06 mg kg - ᶦ for Pb and Zn, respectively).

The results of the present study showed a decrease in the accumulation of heavy metals (Cd, Pb, Fe, Zn)
in plants shoot tissues with distance from the dumpsite. The highest concentrations of heavy metals in the
soil and plant aerial parts within and near to the dumpsite (between 0 and 100m) recorded higher heavy
metals concentrations. The concentration of heavy metals in plants shoots within the dumpsite was in the
order: Fe>Pb>Cd>Zn, while in all other tested sites was in the order Fe>Cd>Pb>Zn.
Plant growth in the soil adjacent to the E-waste dumping area soil should be encouraged to contribute to
heavy metals uptake and reduce environmental pollution. Plants could also be used as indicators of
environmental pollution with heavy metals (Fe, Pb, Zn, and Cd). In conclusion, the obtained data of this
study indicated the urgent need for more efforts in order to reduce heavy metals concentrations in municipal
waste dumpsite at Al-Suli. In addition, there is an urgent need for determining heavy metals concentrations
in the blood of the community members living in the neighborhood of Al-Suli dumpsite.



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