| dc.description.abstract | Large quantities of agrochemicals are regularly applied in co1ee farms to control pests and diseases and provide adequate
nutrients to boost yields. Agrochemicals have varied amounts of heavy metals and their prolonged use to attain maximum yields
contributes to the contamination of soil, surface, and groundwater. ,e study determined the levels of lead, cadmium, and copper
in soil and cassava tubers (Manihot esculenta) grown in single-cropped and intercropped farms in Kathiani Subcounty, Machakos
County, Kenya. Soil and cassava tuber samples were obtained in a zigzag of 8ve cores across the farms. Cadmium, copper, and lead
levels in the collected samples were determined using the atomic absorption spectrometer (AAS) Shimadzu AA-6200 model. Data
were presented using tables and 8gures. One-way ANOVA was used to examine the mean di1erences of heavy metals between
locations. Signi8cant treatment di1erence was tested at 2 � 0.05 using the Tukey test. ,e results revealed that soils from singlecropped
farms had a range of 0.09–0.59, 4.1–4.6, and 0.021–0.032 mg·kg−1 for cadmium, copper, and lead, respectively, while soils
from intercropped farms had a range of 0.25–0.83, 4.9–10.1, and 0.022–0.037 mg·kg−1 for cadmium, copper, and lead, respectively.
Considering cassava tubers in the single-cropped system, the mean values (mg·kg−1) of Cd, Cu, and Pb for the pith were 4.7, 6.8,
and 0.028, for the bark were 4.4, 4.3, and 0.02, and for the epidermis were 3.1, 4.0, and 0.02, while Besh had 2.6, 1.4, and 0.05,
respectively. Analysis of the tubers in the intercropped system indicated that the pith had a mean value of 7.8, 7.0, and 0.20 mg·kg−1
for Cd, Cu, and Pb, respectively. Similarly, the bark had 5.8, 4.6, and 0.16 mg·kg−1 for cadmium, copper, and lead. ,e epidermis
indicated a concentration of 5.1, 4.6, and 0.12 mg·kg−1 for cadmium, copper, and lead, while the Besh had 2.8, 1.5, and
0.06 mg·kg−1, respectively. ,e results revealed the presence of heavy metals in both single-cropped and intercropped farms. ,e
observed means for cadmium, copper, and lead in both sets of farms were within the WHO recommended levels for agricultural
soils. However, the study observed higher cadmium, copper, and lead levels in soils and cassava tissues from intercropped farms
compared to single-cropped farms. | en_US |
