Degradation of14c‐maneb in sediment from a Nicaraguan estuary

Abstract

Sediment samples were collected at 5 sites in the Nicaraguan estuary “El Naranjo” in July 94 and September 94. The samples were incubated with ¹⁴C‐maneb (0.08 μg.g^‐1 dw sediment), and evolved ¹⁴CO₂ and residual ¹⁴C‐ETU in soil were measured. Mineralization kinetics of ^I4C‐maneb was best described with kinetic models which include growth of microorganisms. The amounts of ¹⁴C‐maneb mineralized were highest at the sites closest to the mouth of the river. No significant differences in degradation between July and September were seen. After 67 days between 9.73 and 16.18% of added ¹⁴C had evolved as ¹⁴CO₂ in the July samples and after 150 days between 11.18 and 27.37% of added ¹⁴C had evolved as ¹⁴CO₂ from the September samples. When 4.61–8.20% of added ^I4C was found in the soil extract, 0.00–2.72% was ¹⁴C‐ETU.