Home

Data

Volunteer

Maps

Contact Us

Links

2004 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.

Date-->	5/22/2004	6/5/2004	6/19/2004	7/3/2004	7/17/2004	7/31/2004	8/14/2004	8/28/2004
Site	col/100 mL	col/100 mL	col/100 mL	col/100 mL	col/100 mL	col/100 mL	col/100 mL	col/100 mL	Max	Min	Geomean*
P200	4	5	35	12	6	11	24	3	35	3	8.92
P170	1	5	7	18	20	4	121	27	121	1	10.64
P160	5	101	10	6	15	10	nd	11	101	5	12.58
P150	2	7	5	2	7	9	248	3	248	2	7.11
P135	7	3	127	9	2	nd	1986	24	1986	2	21.73
P110	15	12	24	14	28	28	2419	33	2419	12	37.35
P089	10	13	50	17	24	26	>2419	20	>2419	10	36.76
P080	12	11	29	16	26	29	>2419	32	>2419	11	37.08
P065	10	16	46	32	29	51	>2419	19	>2419	10	44.72
P060	41	59	31	39	26	nd	nd	nd	59	26	37.69
P055	nd	nd	nd	nd	nd	41	>2419	43	>2419	41	162.17
P050	nd	nd	43	49	25	61	>2419	50	>2419	25	85.43
P030	43	35	54	64	66	99	>2419	37	>2419	35	86.18
P020	75	47	79	56	73	365	>2419	34	>2419	34	116.60
P010	24	38	nd	35	73	134	>2419	33	>2419	24	82.00
OB010	55	82	261	204	1553	649	548	172	1553	55	262.89
BB010	53	37	179	328	461	260	649	59	649	37	164.20
DB010	21	16	38	38	31	27	35	12	38	12	25.35
PL040	121	142	770	517	649	411	>2419	613	>2419	121	477.56
PL030	115	nd	345	308	291	219	>2419	>201	>2419	115	351.43
PL020	140	nd	161	248	225	250	>2419	>201	>2419	140	302.13
PL010	76	nd	152	11	40	228	>2419	74	>2419	11	110.99
BL010	6	15	11	46	24	62	1986	40	1986	6	39.03
CW020	49	172	186	201	186	nd	921	59	921	49	163.95
CW010	131	105	261	300	194	172	>2419	83	>2419	83	227.66
DG010	29	27	158	49	71	74	1046	27	1046	27	74.00
SA010	<1	13	980	145	nd	276	579	122	980	13	181.72
WE010	86	68	68	117	nd	236	649	112	649	68	134.55
NBL010	52	78	108	118	194	nd	1300	95	1300	52	143.26
L030	201	75	157	39	96	nd	2419	83	2419	39	150.87
L020	33	51	38	53	41	123	>2419	56	>2419	33	83.29
L010	31	51	45	68	26	80	>2419	92	>2419	26	82.94
IN010	236	413	411	219	138	127	2419	185	2419	127	301.79
M030	44	22	73	16	12	8	141	12	141	8	25.59
M010	28	80	190	365	285	284	1553	53	1553	28	178.59
PI020	99	63	nd	122	88	256	>2419	83	>2419	63	165.78
PI010	35	83	nd	90	261	148	>2419	260	>2419	35	180.95
TA040	17	91	77	38	179	122	nd	nd	179	17	68.00
TA010	59	52	137	50	488	102	649	52	649	50	117.08

* 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%.