TITLE:
Growth of the Earthworm Millsonia omodeoi and Its Capacity to Accumulate Five Heavy Metals (HM) in Soils along a Toll Highway in Côte d’Ivoire
AUTHORS:
Mamadou Toure, Kpan Kouakou Gains Kpan, N’guetta Moïse Ehouman, Seydou Tiho
KEYWORDS:
M. omodeoi, Bioaccumulation, Heavy Metals, “Autoroute du Nord”, Côte d’Ivoire
JOURNAL NAME:
Open Journal of Soil Science,
Vol.14 No.1,
January
29,
2024
ABSTRACT: The
roads in correlation with the traffic linked to their existences are at the
origin of the emission of numerous polluting substances likely to induce
disturbances of the growth and the behavioral changes in the organisms living
in their vicinities. The purpose of this study is to analyze the growth and
capacity accumulation of a common earthworm species (Millsonia omodeoi) in Cu, Cr, Ni, Pb and Zn in soils along a main
road called “Autoroute du Nord” in C?te d’Ivoire. Thus, the earthworms were
harvested in soils from a distance of 0 m (just after the sidewalk) to a
distance of 200 m from the toll highway and in a control soil sampled in Lamto
reserve (C?te d’Ivoire). The study was carried out in the soil laboratory at
the ecological station of Lamto reserve. The Ford-Walford technique was used to
determine the model and parameters most appropriated for describing the growth
of earthworms. A pairwise comparison of the growth parameters was carried out
using the Kruskal-Wallis test with the STATISTICA 7.1 software. The heavy
metals contained in the cultivated soils and earthworms were detected and
quantified using a Scanning Electron Micro-scope (MEB FEG Supra 40 VP Zeiss)
and an Atomic Absorption Spectrometer SPECTRA 110 (VARIAN). The capacity
accumulation of heavy metals in earthworm was determined by the bioaccumulation
factor (BAF) calculation. The results of this study showed that Gompertz is the
most appropriated model to describe the growth of M. omodeoi. The life
cycle of M. omodeoi shows that this
earthworm adopts a K type demographic strategy. Cu is the most accumulated
heavy metals in M. omodeoi, when Cr
is the least accumulated. Concerning heavy metal content in the earthworms, it
decreases while moving away from the pavement. These results highlight a
possibility of choice of M. omodeoi as 1) indicators of heavy metals pollution and 2) target of biological organisms for environmental
impact studies.