The advantages and disadvantages of the BMWP score
recorded in this study are similar to those associated
with use of the score in Europe. This indicates that
the score (and particularly the modified BMWPTHAI
version of it) may be equally appropriate for use in
Thailand as it is in Europe. As subtropical and tropical
macroinvertebrate faunas are similar at the family
level, this conclusion is likely to hold true on a wider
scale, in particular for countries in the neighbouring
S.E. Asian region.
The fact that the system may be more accurate
in identifying gross disturbance than more subtle
changes, is not a drawback restricted to this particular
index or to the situation in Thailand (see for example
Cao et al., 1996). Brinkhurst (1993) has stated that
“simplified indices, often based on an assumption that
groups (such as insect families) behave in a uniform
way, can only be applied to obvious, simple examples
of gross disturbance”. In Thailand, an index such as
the BMWPTHAI score, which could be used to rapidly
detect sites suffering from significant organic pollution,
and provide a degree of quantification of the
impact, would certainly still be of use to the authorities
responsible for water quality monitoring and control.
In view of the above, and the need for some
further testing of the BMWPTHAI score, it is recommended
that authorities with responsibility for water
quality monitoring in Thailand and potentially other
S.E. Asian countries, use the technique on a wider
trial basis. Trials should assess the effectiveness of
the system when used at new sites and should include
provision for training and assessing the performance
of practitioners in sample collection, sorting and
macroinvertebrate identification.
The development of a system operating on the
same principles as RIVPACS should be an important
longer-term goal for Thailand and other countries in
the region.