Abstract The role of light, temperature, and pH was evaluated on the accumulation of phenol by the green alga, Selenastrum capricornutum. All three environmental variables had a significant effect on the accumulation of phenol. Differences in phenol accumulation were observed in algae that were cultured under light or dark conditions. In the light tests, the accumulation of phenol over a temperature range of 12–28°C was unimodal while in the dark test accumulation exhibited a monotonic relationship with temperature. Differences in accumulation were not simply a function of algal growth or biomass. A unimodal relationship was also observed in the pH experiments with the maximal phenol accumulation in algae occurring at pH 6 and the least at pH 10. Temperature also influenced the accumulation of phenol by algae in the pH tests. As was determined in the light tests, biomass or cell growth was not a significant factor in determining the extent of accumulation in these studies. The results from this study demonstrate that accumulation of organics by algae is not simply a partitioning process but one that can be influenced by the interaction of biotic and abiotic variables.