Environmental and Health Concerns Associated With Compost Products in Iran

In this research, health, safety, and environmental risks were studied
for the final compost products in Iran. Municipal solid waste
(MSW) is the major feedstock for composting plants and the main
users are farmers. According to the objective of this research
program three factors including heavy metal concentrations, foreign
matter content, and maturity degree were identified as important
parameters. The values were measured in the ready-for-sale compost
produced in the active Iranian composing plants.
This results showed that the amount of foreign matters and the stone
of all compost samples were less than the standard values and the
samples were either practically free from the above mentioned
matters or had a very little amount. In all compost samples the
maturity grade, which is very important with respect to the
pathogens removal, was in comply with EPA-503 standard, except
for Saleh Abad with the maturity grade of III, which needs further
fermentation. But the major problem for Iranian compost goes with
the heavy metal concentrations in the final product which makes it
unsuited to the agricultural applications. The concentrations of
copper, cadmium, and zine had the highest differences with the
standard values, respectively. For example, copper concentrations
had a difference about 4.5 to 8 times by comparing the compost
samples with a German standard (which is 100 mglkg). For other
heavy metals (Cr, Ni, Pb), except for a few cases, the concentrations
at the compost exceeded the standard levels e.g., chromium values,
except for one of compost plants, were at least 2 to 2.5 times greater
than the standard values.