This research article published by Elsevier B.V, 2021
The dramatic increase in world population underpins current escalating food demand, which
requires increased productivity in the available arable land through agricultural intensification.
Agricultural intensification involves increased agrochemicals use to increase land productivity.
Increased uses of agrochemicals pose environmental and ecological risks such as contamination
and water eutrophication. Consequently, toxic metals accumulate in plant products, thus entering
the food chain leading to health concerns. To achieve this study, secondary data from peerreviewed
papers,
universities,
and
government
authorities
were
collected
from
a
public
database
using
Tanzania as a case study. Data from Science Direct, Web of Science, and other internet
sources were gathered using specific keywords such as nutrient saturation and losses, water
eutrophication, potentially toxic metal (PTEs), and impact of toxic metals on soils, water, and food
safety. The reported toxic metal concentrations in agro-ecosystem worldwide are linked to
agricultural intensification, mining, and urbanization. Statistical analysis of secondary data
collected from East African agro-ecosystem had wide range of toxic metals concentration such as;
mercury (0.001–11.0 mg Hg/kg), copper (0.14–312 mg Cu/kg), cadmium (0.02–13.8 mg Cd/kg),
zinc (0.27–19.30 mg Zn/kg), lead (0.75–51.7 mg Pb/kg) and chromium (19.14–34.9 mg Cr/kg). In
some cases, metal concentrations were above the FAO/WHO maximum permissible limits for soil
health. To achieve high agricultural productivity and environmental safety, key research-informed
policy needs are proposed: (i) development of regulatory guidelines for agrochemicals uses, (ii)
establishment of agro-environmental quality indicators for soils and water assessment to monitor
agro-ecosystem quality changes, and (iii) adoption of best farming practices such as split
fertilization, cover cropping, reduced tillage, drip irrigation to ensure crop productivity and agroecosystem
sustainability. Therefore, robust and representative evaluation of current soil
contamination status, sources, and processes leading to pollution are paramount. To achieve safe
and sustainable food production, management of potential toxic metal in agro-ecosystems is vital.