In another study carried out in the UK, seven sediment samples from estuaries were evaluated with H4IIE-luc assay. These estuaries were selected because they contained varying degrees of industrial, agricultural and domestic inputs. Samples analyzed were intact sediments that underwent a cleanup procedure to remove labile compounds. The results of the H4IIE-luc screening of 35 samples ranged from 1.0 to 106 pg TEQ/g (Hurst et al., 2004).