IWA Publishing

Table 3

Colony-forming units of bacteria in recreational water samples not in compliance with Greek Regulation^a (northern Greece, 2011–2016)

Bacteriological indicator		2011	2012	2013	2014	2015	2016
Total heterotrophic bacteria	n	7	7	15	12	3	2
	Median^b	250	300	250	242	250	257
	Range	220–270	260–300	210–300	200–260	250–278	254–260
Total coliforms	n	2	5	9	2	6	4
	Median	20	40	23	24	28.5	22
	Range	16–24	17–54	15–60	20–28	20–40	15–58
E. coli	n	–	5	7	3	–	2
	Median	–	10	3	12	–	7.5
	Range	–	1–22	1–20	4–16	–	4–11
Pseudomonas aeruginosa	n	122	119	56	57	39	40
	Median	6	6	10	14	18	18
	Range	1–80	1–70	1–61	2–54	4–62	1–48

Bacteriological indicator		2011	2012	2013	2014	2015	2016
Total heterotrophic bacteria	n	7	7	15	12	3	2
	Median^b	250	300	250	242	250	257
	Range	220–270	260–300	210–300	200–260	250–278	254–260
Total coliforms	n	2	5	9	2	6	4
	Median	20	40	23	24	28.5	22
	Range	16–24	17–54	15–60	20–28	20–40	15–58
E. coli	n	–	5	7	3	–	2
	Median	–	10	3	12	–	7.5
	Range	–	1–22	1–20	4–16	–	4–11
Pseudomonas aeruginosa	n	122	119	56	57	39	40
	Median	6	6	10	14	18	18
	Range	1–80	1–70	1–61	2–54	4–62	1–48

n = no. of samples analysed.

^aGreek hygiene regulations (limit values): total heterotrophic bacteria < 200/mL, total coliforms < 15/100 mL, E. coli 0/100 mL.

^bMedian of CFUs is shown due to the statistically abnormal distribution of the samples.