190 
6.4.2 Trichloropyridinol (TCPy) 
6.4.2.1 Water 
The analytical method which has been developed for the determination of 
trichloropyridinol is characterised by a moderate sensitivity, making it suitable for first 
screening in sea water. An LOD of 0.1 ng/L and LOQ is 0.4 ng/L has been achieved. A 
full validation of the method was not performed because no positive findings were 
obtained with the screened samples. 
Trichlorpyridinol was analysed in sea water samples from the North Sea which were 
taken during 3 cruises in 2003 to 2004. TCPy was below 0.1 ng/L (LOD) in all samples. 
6.4.2.2 Discussion 
TCPy is the principal metabolite of chlorpyrifos, but it also is a metabolite of the 
herbicide triclopyr (Petty et al., 2001). 
The half-lives of TCPy in water range from 4 to 8.8 days, in sediments from 3.8 to 13.3 
days (Petty et al., 2001). According to a US EPA review (1989), it adsorbs weakly to 
soil particles and appears to be moderately mobile and persistent in soils. 
Considering the low concentrations of chlorpyrifos observed and the moderate 
environmental persistence reported for TCPy, it is no surprise that no TCPy was found 
in the sea water samples analysed. In view of these findings, it was decided that no 
project priority should be given to a further improvement of the method and lowering of 
the LOQ to detect ultra-trace levels of TCPy or to the development of a sensitive 
analytical procedure for sediment and biota samples. 
6.4.3 Endosulfan 
The analytical method which has been developed and validated (3.3) is characterised by 
its high sensitivity, which is necessary for the determination of pollutants in marine 
matrices. Table 79 summarises the LODs and LOQs achieved in the different matrices.