Biometer flasks

In this study the soil samples were spiked with labelled and unlabelled benzo[<2]pyrene, or anthracene at 5 and 50pg/g soil. The samples were incubated in biometer flasks at 20°C for three and five months for anthracene and benzo[a]pyrene, respectively, allowing degradation to be monitored and the polyaromatic hydrocarbon to interact with the soil matrix. 

Following mineralization of 14C-phenanthrene, the contents of the biometer flasks were analyzed for residual 14C before disposal to ascertain that mass-balance constraints were satisfied. The soil-water mixture was combusted in a biological material oxidizer (R. J. Harvey Instrument Corp., Hillsdale, NJ). 14C02 from combustion was captured directly in a scintillation... 

Andrady and Song (1999) reported the design for a convenient self-contained biometer flask (see Fig. 6.14) for respirometry of polymers. The polymer is incubated in the biotic medium in the upper chamber and generates CO within that... 

FIGURE 6.14 A biometer flask respirometer for carrying out mineralization studies. A res-prrometry curve for cellophane (regenerated cellulose sheet) compared to that of oak leaves. Source Reprinted with permission from Andrady and Song (1999). 

The Biometer flask test procedure, partially modified for testing polymeric materials with low-to-moderate propensity to biodegradation was used. Biodegradation tests were carried out in glass vessels containing a multilayer substrate in which a mixture of mature compost with perlite, a chemically inert heat expanded aluminium-silicate rock, was sandwiched between two perlite layers (Figure 1). Test polymer samples were placed in the middle layer and the vessels were kept in the dark at 55 °C. The CO2 evolved from samples and blanks was trapped in beakers containing 40-50 ml of 0.05 N KOH solution placed inside the test vessels. Every few days, this solution was back titrated with 0.1 N HCl after addition of 4-5 ml of 0.25 N BaCb, and then replaced with fresh solution. 

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