Biodegradation of [C-14]-4-nitrophenol in a sediment-water simulation test

A laboratory simulation test with natural water and sediments to study biod egradability of low concentrated chemicals in surface waters was evaluated by measuring the mineralisation and fate of 0.37 mu g kg(-1) [C-14]-4-nitro phenol. The effects of the sediment type, the time of sediment collection, temperature, illumination and the method of aeration on the feasibility of the test, the mineralisation of 4-nitrophenol, the distribution of radioact ivity between the different compartments and the physicochemical and biolog ical state of the sediment-water systems were studied. During 35 days of in cubation, non-reducing conditions prevailed in the test reactors and the ov erall microbial activity did not vary substantially. The aeration method, t he sediment and water origin and temperature significantly influenced miner alisation, whereas illumination only slightly affected mineralisation and t he addition of organic nutrients had almost no effect on the test systems. These results, together with those of experiments with lindane were used to propose a test guideline for standardised testing. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.