Assessment of water quality in standing water using dominant phytoplankton (AARL-PP Score)

The Applied Algal Research Laboratory (AARL), Department of Biology, Faculty of Science, Chiang Mai University [Thailand] has done 35 research topics on the quality of water and phytoplankton diversity in the past 15 years. The new knowledge, which has simplified standing water quality studies using phytoplankton, is suitable for high school students and beginning researchers. Besides, these methods are economical and do not require chemical reagents. They are also environment-friendly and could be used to indicate the water quality not only on the day of examination but also part of the history of the sample. This methods of biomonitoring water quality is called 'AARL-PP Score'. It is composed of a two-part scoring system. The first part is the standard score of water quality based on status trophic level. The water quality was categorized into 7 statuses using a 1-10 score. Each status was divided into intervals, including experiences in the past research, i.e. clean (oligotrophic status), clean to moderate (oligotrophic-mesotrophic status), moderate (mesotrophic status), moderate to polluted (mesotrophic-eutrophic status), polluted (eutrophic status), polluted to very polluted (eutrophic-hypereutrophic status) and very polluted (hypereutrophic status). In the second part, the dominant genus of phytoplankton from different water quality resource was given 1-10 score. The lower score indicated clean water, whereas the higher score indicated polluted water. During the assessment of water quality, the phytoplankton were collected and identified to the genus level and the quantity of each genus was determined. Three to five dominant genera of the phytoplankton were selected in accordance with their respective amounts. The score of each genus following the water quality in the second part decided, averaged and compared with the standard score of water quality in the first part. The AARL-PP Score has been tested in 50 water resources around Thailand, with more than 90% showing positive results.