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2005 PRW E. coli Bacteria Data (in colonies per 100 mL of sample)

NOTE: These results are preliminary pending a quality control review of data transfer procedures.

Site ID	5/21/2005	6/4/2005	6/18/2005	7/2/2005	7/16/2005	7/30/2005	8/13/2005	8/27/2005	Max	Min	Geomean*
P200	1	0	2	114	9	3	7	3	114	0	2.45
P170	1	1733	435	29	41	16	11	11	1733	1	33.88
P160	1	32	111	8	10	4	18	4	111	1	9.75
P150	4	1203	57	13	10	17	25	16	1203	4	26.49
P135	3	2	35	28	22	37	17	6	37	2	12.19
P110	7	62	81	32	17	86	13	12	86	7	26.68
P089	9	10	86	117	36	73	63	16	117	9	35.28
P080	3	10	73	51	21	61	50	12	73	3	23.27
P065	9	19	91	69	62	68	51	17	91	9	37.52
P055	19	10	135	78	66	63	35	24	135	10	40.32
P050	-	-	-	-	64	46	56	39	64	39	50.36
P030	15	21	219	130	85	62	56	980	980	15	84.48
P020	16	9	261	115	38	59	78	38	261	9	48.11
P010	10	-	-	-	-	-	-	39	39	10	19.75
OB010	56	33	138	261	435	89	411	186	435	33	145.15
BB010	16	55	55	79	88	-	138	51	138	16	58.58
DB010	6	157	117	60	73	117	65	31	157	6	57.15
PL040	185	194	299	291	261	463	411	345	463	185	292.45
PL030	75	71	276	308	152	185	-	75	308	71	138.03
PL020	88	47	261	261	99	260	102	49	261	47	117.46
PL010	24	72	411	199	105	72	96	28	411	24	85.56
BL010	12	16	99	-	-	109	105	2419	2419	12	89.85
CW020	194	20	105	194	172	308	249	130	308	20	138.52
CW010	47	23	238	308	70	152	161	40	308	23	92.65
DG010	12	40	172	228	32	33	308	77	308	12	68.26
SA010	7	11	-	276	-	-	-	-	276	7	27.70
WE010	88	19	-	231	-	-	-	-	231	19	72.83
NBL010	-	-	-	-	-	-	-	-	-	-	-
L060	50	63	-	345	115	172	219	194	345	50	137.16
L050	49	27	145	276	108	88	172	70	276	27	93.93
L030	-	-	-	-	-	-	-	-	-	-	-
L020	24	131	151	357	126	112	166	31	357	24	102.63
L010	41	435	308	276	109	99	548	40	548	40	156.43
IN010	152	54	285	313	138	150	126	61	313	54	135.92
M030	6	19	57	30	9	9	6	3	57	3	11.39
M010	15	19	276	186	649	187	816	44	816	15	126.06
PI020	25	34	225	205	-	-	-	-	225	25	79.13
PI010	15	19	491	91	-	-	-	-	491	15	59.74
TA040	-	-	-	-	-	-	-	-	-	-	-
TA010	5	78	-	72	-	-	114	39	114	5	41.62

* Geomean = Geometric Mean

WHAT DO THESE RESULTS MEAN?

The State Legislature has established statutes that classify Maine surface waters on the basis of water quality standards and intended uses. The Maine Department of Environmental Protection is charged with ensuring that these standards are met for all surface waters in the State. The classification scheme and standards for E. coli are as follows:

· Class A: suitable for drinking (after disinfection), swimming and fishing
· Class B: suitable for drinking (after treatment), swimming and fishing
· Class C: suitable for drinking (after treatment), swimming and fishing

The main stem of the Presumpscot River is Class A from the Eel Weir Dam to its confluence with the Pleasant River (just below sample site P150); Class B from the Pleasant River to the Saccarappa Dam (just below sample site P060); and Class C from the Saccarappa Dam to the estuary in Falmouth (just below the former site of the Smelt Hill Dam).

E. coli Standards
· Class A: as naturally occurs
· Class B: between May 15th and September 30th, E. coli may not exceed a seasonal geometric mean of 64 colony forming units (cfu's) per 100 mL or an instantaneous level of 427 cfu's per 100 mL
· Class C: between May 15th and September 30th, E. coli may not exceed a seasonal geometric mean of 142 cfu's per 100 mL or an instantaneous level of 949 cfu's per 100 mL

Class B sample sites are considered to be in violation of the State's water quality standards if the E. coli results are greater than 64 cfu's / 100 mL on any given sampling event or greater than 427 cfu's / 100 mL for the seasonal geometric mean. For Class C sample sites, E. coli cannot exceed 142 cfu's / 100 mL on an instantaneous basis or 949 cfu's / 100 mL for the seasonal geometric mean.

E. coli bacteria indicate the presence of fecal contamination that can originate from a variety of sources. These include point sources such as wastewater treatment plant discharges and combined sewer overflows; and nonpoint sources such as livestock waste from agricultural runoff, failing septic systems, pets and wildlife. E. coli by itself is generally not a threat to human health, but its presence is associated with disease-causing organisms that do pose potential health risks.

Despite the importance of measuring fecal concentrations in surface waters, it is virtually impossible to distinguish between the sources of fecal contamination with conventional test methods like the one used by PRW. However, routine monitoring can identify problem areas where the implementation of best management practices (BMPs) for nonpoint source pollution may help reduce fecal contamination. Such BMPs might include maintaining vegetated buffers along river or stream corridors; implementing erosion or sediment control measures for new construction; installing fencing for livestock; and establishing stormwater management practices to reduce urban and agricultural runoff.

Key to PRW Abbreviations: P = Main stem of Presumpscot River, BB = Baker Brook, BL = Black Brook, CW = Colley Wright Brook, DG = Douglas Brook, DB = Ditch Brook, IN = Inkhorn Brook, L = Little River, M = Mill Brook, N = Nason Brook, OB = Otter Brook, PI = Piscataqua River (not the same as one at ME-NH border), PL = Pleasant River, TA = Tannery Brook.

The "% complete" column indicates the number of samples actually collected compared to the number of samples intended for collection. PRW has 8 sampling events per season, so if only 4 samples were collected for the season the completion rate would be 50%.