COMPARATIVE STUDY on THE EUTROPHICATION of LAKE SEBASTICOOK, MAINE 1965, 1971-1973 United States Environmental Protection Agency Region I JOHN F. KENNEDY FEDERAL BUILDING - GOVERNMENT CENTER - BOSTON, MASSACHUSETTS 02203 ------- COMPARATIVE STUDY on THE EUTRQPHICATION of LAKE SEBASTICOOK, MAINE 1965, 1971-1973 by P. M. Nolan A. F. Johnson U, S. ENVIRONMENTAL PROTECTION AGENCY REGION I BOSTON, MASSACHUSETTS APRIL 1975 ------- LAKE SEBASTICOOK, MAINE U. S. ENVIRONMENTAL PROTECTION AGENCY REGION I BOSTON, MASSACHUSETTS ------- TABLE OF CONTENTS Page SUMMARY 1 CONCLUSIONS 3 INTRODUCTION 4 History 4 Conduct of Study 5 Sampling Procedures 5 BIOLOGY 8 Benthic Invertebrates 8 Algae 10 Chlorophyll a_ 12 NUTRIENTS 13 Summary (Nitrogen and Phosphorus) 13 Sediments 18 Nitrogen/Phosphorus ratios 19 Discussion (Nutrients) 19 vertical Profiles,. Cha, pH, Temp., D.O. 24 RECOMMENDATIONS 25 BIBLIOGRAPHY 27, 28 TABLES - 29 - 40 APPENDIX 41, 42-A-l- 67 A-26 ------- LIST OF TABLES Table Title Page^ 1 Lake Sebasticook, Maine - Sampling 29 Stations 1965 - 1973 2 Benthic Organisms - Lake Sebasticook, 30, 31 Maine - May 31, 1972 3 Benthic Organisms - Lake Sebasticook, 32 Maine - May 30, 1973 4 Benthic Organisms - Lake Sebasticook, 33 and Lake Wassookeag, Maine July 31 - Aug. 1, 1973 5 Benthic Organisms - Lake Sebasticook, 34 Maine - Nov. 17, 1971 6 Midgeflies - Sludgeworms Average Per Sq. 35 Ft. Lake Sebasticook, Maine 1965 - 1973 7 Lake Sebasticook, Maine - Algae Count 36 (Average) Per Milliter - 1965 - 1973 8 East Branch Sebasticook River, Maine 37 Algae Count Per Milliter 1965, 1971 - 1973 (Comparable Stations) 9 Lake Sebasticook, Maine 38 Chlorophyll a_, Micrograms Per Liter 10 Lake Sebasticook, Maine 39 Sediments Nitrogen/Phosphorus Ratios 11 Lake Sebasticook, Maine 40 Sediments, Phosphorus and Nitrogen % Dry Weight 11 ------- LIST OF FIGURES Figure Title Page 1 Lake Sebasticook Sampling Station 6 Locations - 1965 and 1973 2 Lake Sebasticook Tributaries 7 Sampling Station Locations 1965 and 1973 3 Seasonal Averages - Lake Sebasticook, 15 Maine - Total Phosphorus, Total Kjeldahl Nitrogen 4 East Branch Sebasticook River - 16 Seasonal Average Total Phosphorus 5 East Branch Sebasticook River 17 Seasonal Average Total Kjeldahl Nitrogen 6 Lake Sebasticook - July 31, Aug. 1, 26 1973 Mean Chlorophyll a_ - pH - Temperature - Dissolved Oxygen Vs. Mean Water Depth 111 ------- SUMMARY A technical study was conducted from November 1971 to August 1973 to assess eutrophication of Lake Sebasticook at Newport, Maine and to measure progress versus work conducted in 1965. Selected biological and chemical parameters are compared on a seasonal and yearly basis. Average total phosphorus values are higher during the 1971-1973 survey than during 1965. Station EB-01 at the outlet of Corundel Lake (Station 3) is of special interest because of the higher total phos- phorus average of 0.15 mg/1 compared to 0.07 mg/1 average of 1965. This indicates the possibility of the discharge of additional municipal and/or industrial waste from the Dexter vicinity or a non point dis- charge since 1965. Total phosphorus concentration has increased in Lake Sebasticook to approximately 0.08 mg/1 in 1971-1972 and approxi- mately 0.10 for 1973, up from 0.05 mg/1 in 1965. This is considered hypereutrophic according to recent data from the National Eutrophication Survey. Less nitrogen is present in the inlet water of the East Branch of the Sebasticook River and in the water column and sediment of Lake Sebasticook now than in 1965. Denitrification of aquatic systems is known to occur when photosynthetic activity of algae causes high alkaline levels in warm eutrophic lakes, and sediments have low con- centrations of oxygen. However, denitrification is a complex process that is still inadequately understood and its explanation is not attempted in this report. -1- ------- Two kinds of pollution tolerant benthic fauna, tubificid worms and midgefly larvae, were dominant in 1972 and 1973 as in 1965. Further degradation of bottom sediments is indicated by the smaller number of pollution tolerant organisms present in 1972 (14 per sq. ft.) and in 1973 (3 per sq. ft.) compared to 1965 (35 per sq. ft.). Excessive algal growths similar to the 1965 eutrophic conditions for Lake Sebasticook are indicated when overall average chlorophyll a values and algal counts for 1971 to 1973 of 11.26 ug/1 and 11,715 cells/ml respectively are compared with 11.63 ug/1 chlorophyll a_ and 11,354 cells/ml for 1965. The extent of enrichment is apparent when Sebasticook is compared to the nonfertilized water of Lake Wassookeag with a 1973 chlorophyll -a value of 0.38 ug/1 and cell counts of 467/ml. -2- ------- Conclusions 1. Phosphorus input to Lake Sebasticook from the East Branch of the Sebasticook River is still too high to reverse Sebasticook from a eutrophic state to a non-eutrophic state. 2. Lake bed sediments and riverbed sludges are a significant source of phosphorus in Sebasticook. - 3. Nitrogen overall is lower within the immediate Sebasticook system and the data suggests a denitrification process within the lake. 4. Benthic animal populations are sparse and consist only of sludge worms and red midges. 5. Algae continues to be a problem, however, some seasonal improvements are noted. 6. All parameters taken collectively describe Lake Sebasticook as eutrophic. ------- INTRODUCTION History Lake Sebasticook at Newport, Maine was studied in 1965 by Mackenthun 1966 Get al) to determine the extent and cause of excessive fertilization of the lake. Eutrophication of the lake was confirmed by the volume of blue-green algae, noxious odors, low or absent dissolved oxygen in the deeper waters, high phosphorus and nitrogen concentrations and a lake bed associated animal population composed dominantly of midge larvae and sludgeworms. Fertilization of Lake Sebasticook was determined to be caused principally by nutrients contained in domestic and industrial wastes discharged to the East Branch of the Sebasticook River at Dexter and Corinna, Maine.<1} <2) Subsequent to the 1965 study one major source of phosphorus pollution, a potato processing plant, to Lake Sebasticook burned down. The town of Corinna constructed and now has in operation a secondary waste treatment plant (WWTP) with a designed level of treatment capable of 85-95% BOD and solids removal. Phosphorus removal up to 30% can be expected from a plant of this design. The WWTP is designed to receive a volume of 1.2 mgd which breaks down to 1 mgd from East- land Woolen Mills and 0.2 mgd from the town of Corinna. The town of Dexter upstream of Corinna on the East Branch of the Sebasticook River does not have a waste treatment facility and domestic and industrial wastes are discharged directly to the river. Being considered are two alternatives for waste water treatment for Dexter, either construction of a new WWTP or a tie-in with the plant in Corinna, after modification. ------- With the elimination of one major source of phosphorus pollution and the implementation and operation of waste treatment facilities, a technical study was undertaken by the Region I Division of Surveillance and Analysis, Biology Section to make an up-to-date assessment of Sebas- ticook to determine if the lake is demonstrating signs of recovery from the advanced eutrophic state reported in 1965. The program was initiated in November 1971 (autumn) and continued on a quarterly basis for the winter and spring quarters of 1972 and the spring and summer quarters of 1973. Conduct of Study Sample station locations Figure 1 and 2 are the sampling locations used for the 1971-1973 study. These stations on Lake Sebasticook and on the East Branch of the Sebasticook River are contiguous with stations designated in 1965 by Mackenthun. In the summer of 1973 Lake Wassookeag was sampled as a control and samples of substrate were obtained upstream of the mouth of the East Branch Sebasticook River to determine the nutrient potential in the river bottom. The 1965 reference stations are listed below those symbols used in 1971-1973, Figures 1 and 2. Table 1 indicates the approximate station locations in terms of longitude and latitude. Sampling Procedures Water samples were collected from boats, bridges or through drilled ice holes using a Kemmerer water sampler. The lake samples were collected at three depths and the tributary samples were collected from one depth. Benthic sediment samples for biological and chemical analysis were collected using a Petersen grab sampler. All samples were preserved and analyzed, according to standard procedures. C3»4>~5) -5- ------- MULLIGAN STREAM EAST BRANCH SEBASTICOOK RIVER STETSON STREAM. 1/2 MILES AREA: 4,288 ACRES 6 SAMPLE STATION 00 I DEPTH CONTOURS IN LAKE SEBASTICOOK SAMPLING STATION LOCATIONS 1965 AND 1973 ------- LWOI LAKE WASSOOKCAG LW03 LW02 \,\\co MOOS£HF. MILL POND LAKE SEBASTICOOK TRIBUTARIES SAMPLING STATION LOCATIONS 1965 AND 1973 -7- flOUftl * ------- BIOLOGY Benthic invertebrates Bottom muds were sampled in 1971, 1972 and 1973 (Table 1) (Figure 1) to make a comparison of benthic animals with the 1965 survey findings. Fine, soft, black mud at Stations LS01 through LS05 (Tables 2 and 3) had sparse populations of midgefly larvae (Chironomus riparius) and sludge- worms (Tubificidae). An average of 35 organisms per square foot, 57% midgefly larvae and 43% sludgeworms, were found during the May, 1965 survey. Similar benthic populations existed six years later (Nov. 1971) with an average of 44 organisms per square foot, 25% midgefly larvae and 72% sludgeworms, and May 1972 with an average of 14 organisms per square foot, 54% midgefly larvae and 46% sludgeworms (Table 6). Special charac- teristics of the blood of both animals facilitate extraction of dissolved oxygen from oxygen deficient environments. The midgefly, Chironomus rip- arius , has two pairs of finger-like anal gills for greater aid in the respiratory process. Three stations were selected in May, 1972 (LS06, LS07, LS08) near river and stream inlets' for benthic invertebrates analysis of shallow areas (average depth 6 feet compared to 40 feet for Stations LS01 through LS05). Soft mud at Station LS06 near the mouth of Mulligan Stream supported a variety of 6 kinds of life, pollution tolerant sludgeworms dominated the benthic life on this polluted substrate (Table 3). LS06 is in the general area of the inlet of the E.B. Sebasticook River. Water of apparent poor quality flows over the hard, gravel and sand substrate at Station LS07 near the mouth of the East Branch of the -8- ------- Sebasticook River as it supported a scant population of only 18 animals per square foot and was lacking the clean water mayflies and caddisflies. Living on the gravel and sand bottom of Station LS08 leading into Stetson Arm and Stetson Stream were a great variety of benthic fauna, 14 kinds, and greater numbers, 280 bottom organisms per square foot, including pollution sensitive forms such as caddisflies, mayflies, planarians, hydrozoans, ostracods and cladocerans. Organic nutrients have not accumulated on this hard substrate as flow from Pleasant Lake by route of Stetson Stream contributes water of good quality which enables a diverse population of benthic animals to survive. The bottom fauna on the natural substrate of Stetson Arm (Station LS08) contributes a food source that would support a sport fishery and is the only area of the lake where fishermen were observed during the May, 1972 survey. In contrast, environmental degradation of bottom sediments caused by excessive build-up of organic nutrients at Stations LS01-LS06 and the poor water quality at Station LS07 is indicated by the presence of pollution tolerant benthos and their paucity of numbers. The hard substrate of Station LS07 (50% gravel, 50% sand) with 7 feet of water is similar to the hard substrate of Station LS08 (50% gravel, 50% sand) with six feet of water. A slow water current flows over these stations. Benthos was sampled in 1973 (Stations LS01-LS05) with the average number of organisms for the month of May being 18 per sq. ft. and July being 3 per square foot. Two control stations in Lake Wassookeag -9- ------- (LW02 and LW03) in August 1973 yielded 137 organisms per square foot (Tables 4, 5 and 6). Strong hydrogen sulphide odors were detected in bottom sediments and a depleted oxygen level of 0.6 parts per million in the lower depths of Lake Sebasticook during the July-August 1973 survey which indicates active biological decomposition and an environment that is close to being saprobic thereby eliminating most aquatic animal life. A total of 17 pollution tolerant sludgeworms and midgefly larvae (Chironomus riparius) were collected in July from five stations in Lake Sebasticook (Stations LS01-LS05) which averaged 33 feet in depth, in comparison, one control station in oligotrophic Lake Wassookeag (LW03) supported 103 organisms consisting of sludgeworms and clean water midge- flies (Anatopynia sp.) in the profundal zone. Mayflies and an alderfly were found at a depth of approximately 30 feet. The soft mud substrate of control station LW02 (Aug. 1973) at a water depth of 7 feet supported a variety of 13 clean water forms of life. A comparable station in Lake Sebasticook (LS06) with a soft mud bottom at a water depth of 6 feet (May 1972) had 6 kinds of life dominated by pollution tolerant sludgeworms (Table 3 and 5). Algae Increased availability of phosphorus resulted in algal blooms causing the "green paint" covering the rock along the shoreline and the "pig-pen" odors reported in the 1966 report. Excessive algal growths have con- tinued into the 1971-1973 survey periods and the rock along the shoreline ------- were observed to have a dark green color; however, odors of decaying algae were not noticed. The seasonal averages for algal counts for all Lake Sebasticook stations at the five foot, 15-30 foot and 30-55 foot depths for three surveys in 1965 and for four surveys from February 1972 to July 1973 are listed in Table 7 for comparison purposes. Averages were determined at the five foot depth for all surveys rather than surface counts due to piling up of surface algae from wind and wave action. The effect of piling is considered significant but not representative of uniform lake conditions in this case. Climatological variation during the year, i.e., temperature, light intensity, cloud cover, and wind can cause variation in algae 'populations for different months at different vertical depths; however, when compared, algae counts for the spring and summer surveys at all depths in 1965 of 11,300 algae per milliter are similar to the spring and summer averages for 1973 of 11,700 algae per milliter. To contrast again, the Lake Wassookeag control has a sparse phyto- plankton population of 467 algae per milliter for the 1973 summer survey. This reflects upon the eutrophism of Lake Sebasticook which is attributed to the high phosphorus concentrations noted in the section on nutrients. High algal counts in the East Branch of the Sebasticook River are noted downstream of Dexter at Station EB01 (8,500 per milliter) and below Corinna at Station EB02 (20,600 per milliter). A substantially higher average was recorded in 1965 for Station EB02 (Station 5 in 1965) of -11- ------- 99,000 per milliter (Table 8). This massive algal growth could have resulted from the surface matting and subsequent shoreline decay of algae observed during the 1965 survey of Lake Sebasticook, but was not evidenced during the 1971-1973 surveys. Chlorophyll a_ In general, chlorophyll present in a lake increases as the lake becomes more eutrophic and supports greater algal populations. In Table 9, the averaged chlorophyll a^ values exhibit considerable variation at different depths, from season to season during a year, and from season to season for different years, due probably to thermal stratification, temperature, light intensity, availability of nutrients, etc.; but the seasonal and yearly averages for all depths and stations show a similar chlorophyll a. average value during 1965 as in the period from 1971 to 1973. The chlorophyll a_ averages, from the upper, middle and lower depths (0-5', 10-25', 30-55') from all stations for 1965 (summer and fall), of 11.63 ug/1 are similar to the summer (1973) and fall (1971) chlorophyll a_ average of 11.68 ug/1 in Lake Sebasticook. Overall, the average lake chlorophyll a concentration of 11.63 ug/1 is similar to the average Ch a_ concentration (11.26 ug/1) recorded for the 1971 to 1973 period. From this it is deduced that the relative amount of algal standing crop in Lake Sebasticook shows no change in the period since 1965. The unfertilized waters of Lake Wassookeag, Lake Sebasticook1s principle headwater source, has a summer 1973 chlorophyll a_ average value of 0.38 ug/1. -12- ------- NUTRIENTS Chemical parameters which are commonly associated with eutrophication were sampled for five seasons; November 1971, February 1972, May 1972, 1973 and July 1973. The results of the analysis for the samples are listed in the Appendix. Two parameters, total phosphorus (TP) and total Kjeldahl nitrogen (TKN) are discussed here as a means for comparison with data generated in 1965. Both Lake Sebasticook and the East Branch Sebasticook River are assessed in this manner to determine changes and make evaluations relative to eutrophication. The TKN values as reported for 1965 are the sum of the extrapolated organic nitrogen and ammonia (TKN=Org N+NH3). Summary (Nitrogen and Phosphorus) The histograms (Figures 3, 4, 5) summarize the data for TKN and TP for the fall, winter, spring and summer seasons. Total phosphorus in Lake Sebasticook for the fall of 1971 is approximately 2.5 times greater than the comparable season in 1965. In the winter of 1972 TP is 1.5 times greater than in 1965. For the spring of 1973 the total phosphorus is approximately 1.5 times greater than.those values reported for 1972 and 1965 with the 1972 and 1965 values being approximately equal. The 1973 summer values for total phosphorus again exceed those values for 1965 by approximately 1.5 times. Total phosphorus for the East Branch of the Sebasticook River (Figure 4) shows some variability from season to season and station to station. Station EB-01, (above Corinna) has higher phosphorus values -13- ------- recently (i. e., 1971-1973) than in 1965 with the summer of 1973 being the exception. Station EB02, below corinna, demonstrates higher values in 1965 than in 1971, 1972 or 1973 with the winter of 1972 being a major exception. EB03, at the outlet of Lake Sebasticook, exhibits total phosphorus concentrations which are higher overall for 1971-1973 than in 1965. This reflects the higher TP concentrations noted in Lake Sebasticook in Figure 3. Total Kjeldahl nitrogen, Figures 3 and 5, are compared in the same fashion as total phosphorus. For Lake Sebasticook for all seasons from 1971 to 1973 the TKN values range from approximately two to eighteen times less than in 1965. Similarly, for the East Branch of the Sebasticook TKN values are two to ten times less in 1971, 1972, 1973 than in 1965, the only exception being the winter 1972 value for Station EB01 where the TKN's are only slightly higher in 1965. Overall, the average total Kjeldahl nitrogen values for both Lake Sebasticook and the East Branch of the Sebasticook River are approximately five times less for the five seasons from 1971-1973 compared to 1965. Values for other parameters in the nitrogen series, ammonia (NH ), nitrate (N03) and nitrite (N02) appear in the Appendix. These nitrogen species are difficult to interpret because the concentrations contin- ually change due to the many factors regulating the complex nitrogen cycle in nature. For this reason, a comparative analysis has not been made, however, a general assessment of these parameters show a trend similar to that for TKN but it is not as marked. -14- ------- 4.6 1965 FALL WINTER SPRING * SUMMER FALL WINTER SPUING TOTAL PHOSPHORUS (mg/l) TOTAL KJELDAHL NITROGEN (mg/\) SEASONAL AVERAGES-LAKE SEBASTICOOK, MAINE ------- .34 co D it O X •1 n o a. .1? o 1965 EBOI EB02 EB03 FALL EBOI EB02 EB03 WINTER EBOI EBO2 SPRING EBOS EBOI EB02 EBOS SUIHIER EAST BRANCH SCBASTICOOK RIVER - SEASONAL AVERAGE TOTAL PHOSPHORUS ------- IO.8i 4.3 5.9. 2.8 1965 EBOI EB02 EB03 j EBOI EB02 EB03 FALL ' WINTER EBOI EB02 SPRING EB03 EBOI EB02 EB03 SUMMER EAST BRANCH SEBASTICOOK RIVER - SEASONAL A/ERAGE TOTAL KJELDAHL NITROGEN ------- Sediments Sediment samples were collected from five lake stations (Figure 1) for four seasons from November 1971 to July 1973. The sediments were analyzed for total Kjeldahl nitrogen and total phosphorus. The results of these analyses are presented as percent dry weight in Table 11. For comparative purposes the sediment data for the same parameters for May 1965 is also included. Total phosphorus (TP) values for the sediments show some variability from season to season. The data for May 1972 compares favorably with the data for May of 1965 in terms of lake average .100 vs. .106% dry weight respectively, however, when the data for May 1973 is compared to 1965 and 1972 the data shows approximately a 25% decrease. The data for November 1971 and July 1973 also represent 20-25% TP reductions when compared to May 1972 and 1965. These differences can be partially ex- plained by seasonal turnover during which time a recycling and restocking of nutrient deficient lake water normally occurs with resultant decreases in sediment concentrations. The reduction of TP in the sediments as shown in the data strongly suggests this phenomena to be a source of the increased total phosphorus concentrations noted for the overlying waters of Lake Sebasticook. Lake Sebasticook sediments data for nitrogen shows a marked decrease in concentration from November 1971 to July 1973 when compared to the 1965 data. Average values as shown in Table 11 represent approximately a decrease of five times overall. -18- ------- Nitrogen/Phosphorus Ratios Table 10 lists Nitrogen: Phosphorus ratios for November 1971, May 1972 and 1973 and for July 1973. Table 10 also lists the May 1965 values. The ratios show a substantial decrease for November 1971 - July 1973 when compared to May 1965. The literature does not offer a definitive explanation as to the significance of high or low N:P ratios. tfi 7 R 9) Data in the literaturel ' ' ' for which phosphorus and nitrogen sediment values are available show trends that suggest that low N:P ratios are more commonly found in eutrophic lake systems and higher ratios are more indicative of less fertile systems. It appears that the high TP concentrations found in eutrophic sediments are a factor in the low N:P ratios. The extremely low N:P ratios found for Lake Sebasticook in 1971 and 1972-1973 appear to be a result of the nitrogen values being lower by a factor of approximately five. TP in comparison is approxi- mately the same or slightly less than in 1965. Whether or not these ratios indicate that Sebasticook is more eutrophic now than in 1965 cannot be determined unless the lower nitrogen can be explained. Lake Wassookeag, a noneutrophic lake at the headwaters of the East Branch Sebasticook River has a N:P ratio of 7.5 for July 1973. Discussion (Nutrients) The report entitled "Fertilization and Algae in Lake Sebasticook, Maine," serves as baseline information which describes Lake Sebasticook as very eutrophic and which also describes the East Branch of the Sebasticook River as the principle source of nutrification to the lake. By use of this data and information generated in 1965 a comparison is made which correlates the condition of the 1960's with those conditions -19- ------- as of July and August 1973. Prior to the start of our studies in November 1971, the major source of phosphorus, a potato processing plant, to the river and thus to Lake Sebasticook burnt down. This quirk of fate together with the start of secondary treatment for the'Town of Corinna has not reflected any significant improvement in stream conditions or in the eutrophic lake conditions reported in 1966, particularly with respect to phosphorus. Above Corinna at Station EB01, the five season average for total phosphorus for 1971-1973 of 0.14 mg/1 is approximately 30% greater than the average value recorded in 1965 for a comparable time frame. The increase in phosphorus suggests greater and/or additional inputs to the river upstream, probably from industrial and municipal sources in the Dexter area or from a nonpoint discharge. Station EB02, at the mouth of the East Branch of the Sebasticook River, (the inlet to Lake Sebasticook) the average total phosphorus value for five seasons 1971-1973 is approximately the same as that for the four seasons average in 1965. EB02 is below the town of Corinna's municipal discharge and below the location of the former potato processing plant. Considering these averages compiled from seasonal data, the indication is that the new secondary treatment plant at Corinna and the total elimination of the major industrial source of phosphorus pollution (55% of all TP dis- charged to the East Branch Sebasticook River from the Corinna area in 1965) has not resulted in a decrease in TP being contributed to Lake Sebasticook. -20- ------- The fact that no significant change has occurred suggests other causes or sources of phosphorus. Among these other possibilities are inefficient waste treatment at Corinna, agricultural runoff and phosphorus in sludge deposits between Corinna and Lake Sebasticook which resuspend with gas bubbles from decomposition and which are scoured from the bottom during periods of high flow. Actual analysis of two sludge samples collected from the stretch of river during August 1973, approximately 2.0 miles upstream of the inlet to Sebasticook, Figure 2, yielded results of approxi- mately .07% TP dry weight. This is considered to be a relatively high concentration. The high TP coupled with the fact that sludge was seen floating to the surface with gas bubbles and carried with the current into Lake Sebasticook demonstrates that the stream bottom below Corinna is a discrete source of phosphorus pollution to the lake. Efficiency of the WWTP at Corinna should be evaluated and the role of agricultural runoff as a serious potential source of phosphorus to the system should also receive study to further determine exact phosphorus sources. In 1965, it was estimated that less than 2% of the TP in Lake Sebasticook came from agricultural drainage. Today, with the tendency to increase arable land and farm production phosphorus runoff could be substantially higher and therefore represent a significant non-point source. In the report entitled "Fertilization and Algae in Lake Sebasticook, Maine" 1966, a total phosphorus objective of .02 mg/1 for Lake Sebasticook was proposed. This objective is based on the phosphorus concentrations found for samples collected from Lake Wassookeag, a lake at the heart of the headwaters of the East Branch of the Sebasticook River. In 1965 the -21- ------- TP concentrations did not exceed 0.02 mg/1 and the lake did not demon- strate the problems associated with eutrophication which characterized Lake Sebasticook. Furthermore, to attain the .02 mg/1 objective it was suggested that an 80% reduction of TP would be required from all incoming wastes, which means essentially the East Branch of the Sebasticook River. It was estimated that ten years would be required to deplete the nutrient rich Lake Sebasticook water with inflowing nutrient poor river water. According to our data there are no gains in this direction. In the eight years elapsed since 1965, Lake Sebasticook demonstrates an overall average phosphorus increase in the range of 30%. For the East Branch of the Sebasticook River, the burning of the snowflake Canning Co., and the secondary treatment plant at Corinna should logically lower the amount of phosphorus contributed to the river and thus to Lake Sebasticook. This apparently is not the case, as stream phosphorus loads are approximately the same as in 1965 below Corinna at the inlet to Lake Sebasticook. It appears that .02 mg/1 TP for Lake Sebasticook may be an unrealistic objective. Preliminary results of the National Eutrophication Survey in- dicate that about one-third of the 242 lakes studied probably will have mean concentrations greater than .05 mg/1 phosphorus even- after advanced treatment for phosphorus removal (assuming that a 50% reduction in TP is accomplished). Our data to date suggests placement of Sebasticook into this category of lakes. Perhaps the only means of achieving the .02 mg/1 phosphorus objective may be similar to that method observed by Edmundson in his Lake Washington studies. He observed that when phosphorus concentrations were reduced by 72% from approximately .08 mg/1 to .02 mg/1, ------- the lake reverted from a eutrophic state to a noneutrophic state. This was accomplished by total diversion of the inflow of sewage treatment plant effluent. Although the measures were drastic, the results were positive. The lake bed of Sebasticook, taken alone, is a vast source of phosphorus for fertilization and algal growth. This is well demonstrated during the spring seasons of May 1965, 1972 and 1973. It can be seen that for May 1965 and 1972 the average water column TP values are both .06 mg/1 and similarly the TP in the sediments are .106% dry weight and .100% dry weight respectively. However, in May 1973 the average TP in the water column is .09 mg/1 or a 50% increase over the previous spring data. Corresponding to this, the average sediment value for May 1973 is .075% dry weight, or approximately a 25% decrease from that of the previous spring data. The sediment phosphorus reservoir as indicated appears to be a major supplement to the enriched condition in Lake Sebasticook and probably will be for many more years in the future. Contrary to the upward trend in total phosphorus in the Lake Sebasti- cook system, the nitrogen in the water and sediments show a decrease which is approximately five times less than in 1965. It is difficult to determine whether or not the nitrogen decrease in Lake Sebasticook is entirely due to decreased input as exemplified by the lower tributary load or whether a denitrification process is occurring within the lake. It could be a combination of these.factors. Denitrification, although not completely understood, is known to occur in eutrophic lakes in both sedi- ments and in the water column. ' The process is more likely to occur -23- ------- in anaerobic conditions such as found in sediments and overlying waters of the hypolimnion of a eutrophic lake during the summer stagnation. General warming trends and pH shifts to alkaline are factors contribu- tory to denitrification. Vertical Profiles - Ch a_, pH,, Temp., D.O. Figure 6 shows the curves for mean chlorophyll a_, pH, temperature and dissolved oxygen concentrations for mean lake depth. The vertical profile for temperature shows the lake to be stratified during late July 1973. The mean temperature differential between surface waters and hypo- limnial waters is approximately 10°C. Corresponding to the thermocline are distinct stratifications for Ch £, pH and D.O. Algal standing crop in Lake Sebasticook expressed as chlorophyll a. is highest in the lake epilimnion or euphotic zone. The mean Ch a con- centration of approximately 25 ug/1 in the upper water column decreases with depth to a mean of 3 ug/1 in the hypolimnial waters. In the euphotic zone of lakes, algae utilize (carbon dioxide) CO2 in photosynthesis and produce oxygen (C>2). Vigorous photosynthetic activity can produce supersaturated dissolved oxygen concentrations in the zone of activity in the epilimnion. The vertical profile for oxygen in Figure 6 shows supersaturated conditions approximately 180% of saturation in the upper water column; with depth the D.O. is reduced to almost O close to the bottom, creating nearly anaerobic conditions. As algae photosynthize in the water, free C0_ is used, calcium bicarbonate is reduced by precipitation of calcium carbonate, and the pH (14) rises. v The pH profile in Figure 6 dramatizes this quite well with a mean pH near 10 in the epilimnion and a neutral pH at the bottom. -24- ------- Taken collectively the profiles for dissolved oxygen, pH, temperature and chlorophyll ei show a distinct congruency towards describing Lake Sebasticook as eutrophic. Recommendations l: Evaluate treatment efficiency for the WWTP in Corinna and determine the total phosphorus contribution to the East Branch of the Sebasticook River from the Corinna area. 2. Determine significant point discharges of municipal and industrial wastes from the Dexter area which presently have a bearing on the phosphorus load in the East Branch Sebasticook River. 3. Closely evaluate the significance of non-point discharges such as agricultural runoff and other bank sources and the impact they have on Lake Sebasticook. 4. Enforcement of the State of Maine's water quality standards which require phosphorus removal on all point discharges, together with appropriate land management practices, are strongly urged in order to return Lake Sebasticook to a viable resource. 5. The State of Maine should monitor lake conditions at least once every year as a means of evaluating and assessing lake conditions relative to eutrophlcation. -25- ------- 10 15 20 25 30 35 10 15 20 35 10 10 20 30 40 Ch0 ug/l 15 20 25 TEMP. °C 30 8 12 pH 16 20 05 10 15 DO mg/l LAKE SEBASTICOOK JULY 31, AUG. I, 1973 MEAN CHLOROPHYLL o - pH - TEMPERATURE - DISSOLVED OXYGEN vs. MEAN WATER DEPTH -26- FIGURE 6 ------- Bibliography 1. Department of Health, Education, and Welfare, FWPCA, January, 1966, "Fertilization and Algae in Lake Sebasticook, Maine," Technical Advisory and Investigations Activities, Cincinnati, Ohio. 2. Mackenthun, K. M. , Kemp, L. E., Stewart, R. K., February 1968, Nutrients and Algae in Lake Sebasticook, Maine. Journal Water Pollution Control Federation, Vol. 40, No. 2, Part 2. 3. Environmental Protection Agency 1971, "Methods For Chemical Analysis of Water and Wastes," Water Quality Office, Analytical Quality Control Laboratory, Cincinnati, Ohio. 4. American Public Health Association 1971, Standard Methods, 13th Edition, AWWA, APHA, WPCF, New York, N. Y. 5. U. S. Environmental Protection Agency, 1973, "Biological Field and Laboratory Methods" EPA-670/4-73-001, Environmental Monitoring Series, Office of Research and Development, Cincinnati, Ohio. 6. Kemp, A., Gray, C., Mudrochova, A., Nutrients in Natural Waters, 1972, "Changes in C, N, P, and S in the Last 140 Years In Three Cores. From Lakes Ontario, Erie and Huron," John Wiley & Sons, N.Y., pgs. 251-279. 7. Gahler, A.R., Sanville, W.D., April 1971, "Lake Sediments - charac- terization of Lake Sediments and Evaluation of Sediment-Water Nutrient Interchange Mechanisms in the Upper Klamath Lake System," Pacific Northwest Water Laboratory, Water Quality Office, U.S. EPA, Corvallis, Oregon, pgs. 26-32. 8. Konrad, J.G., Keeney, D.R., Chesters, G., Chem., K.L. 1970, "Nitrogen and Carbon Distribution in Sediment Cores of Selected Wisconsin Lakes." J. Water Pollution Control Fed. 42,2096-7. 9. Williams, J., Syers, J., Harris, R., Armstrong, D., 1970, "Adsorption Desorption of Inorganic Phosphorus by Lake Sediments in a O.lm Na Cl System." Env. Sci. and Tech^ Vol 4, No. 6.519 10. U.S. Environmental Protection Agency, 1973, "Critique on Proposed Phosphorus Standards," Pacific Northwest Environmental Research Lab, Corvallis, Oregon pg. 3. 11. Edmondson W. T., 1970, "Phosphorus, Nitrogen and Algae in Lake Washington after Diversion of-Sewage," Science 14, 690-1. -27- ------- Bibliography 12. Brezonik, P. L., 1972 "Nitrogen: Sources and Transformations in Natural Waters" in Nutrients in. Natural Waters, John Wiley & Sons N. Y. Pg. 26-31. 13. Brezonik, P.L., Lee, F. G., "Denitrification as a Nitrogen Sink in Lake Mendota, Wis.", Env. Sci. & Tech. Vol 2, No. 2, Pg. 120-5. 14. Ruttner, F. 1963, Fundamentals of Limnology, Third Ed., Univ. of Toronto Press, Canada, Pg. 70. -28- ------- TABLE I Lake Sebasticook, Maine Sampling Stations 1965 - 1973 1971 1973 Stations LS-01 LS-02 LS-03 LS-04 LS-05 EB-01 EB-02 EB-03 LS-06 LS-07 LS-08 LS-09 LW-01 LW-02 LW-03 1965 Stations Longitude A 69° B 69° C 69° D 69° E 69° 3 69° 5 69° 8 69° 69° 69° 69° 69° 69° 69° 69° 15' 13' 14' 14' 14' 15' 15' 16' 16' 15' 13' 15' 18' 20' 19' 25" 28" 06" 32" 35" 41" 01" 31" 08" 23" 11" 54" 34" 18" 37" Latitude 44° 44° 44° 44° 44° 44° 44° 44° 44° 44° 44° 44° 45° 45° 45° 52' 53' 50' 51' 51' 55' 53' 50' 53' 52' 51' 52' 01' 01' 01' 12" 09 32 35 06 28 09 25 03 36 31 56 54 05 18 II II II II It 11 II II M II 11 » n -29- ------- TABLE 2 Benthic Organisms - Lake Sebasticook, Maine Organisms Oligochaeta (aquatic worms) Tubificidae (sludge worms) Diptera (midgeflies) Chironomus riparius (bloodworms) UJ o i Hirudinea (leech) Gastropoda (snails) Pelecypoda (clams) Copepoda (copepods) Cladocera (water fleas) Amphipoda (scuds) Ostracoda (seed shrimp) Hydracarina (water mites) Hydro zoa (hydra) Turbellaria (planarian) May 31, 1972 Per Sq. Ft. Stations LS 01 LS 02 LS 03 LS 04 LS 05 LS 06 LS 07 LS 08 4 64 16 17 134 46 1 15 7 21 3 8 11 1 12 1 80 9 1 36 1 4 38 5 29 1 3 1 3 1 5 ------- TABLE 2 (Con't) Benthic Organisms - Lake Sebasticook, Maine May 31, 1972 Per Sq. Ft. Stations i OJ Organisms Ephemeroptera (mayflies) Trichoptera (caddisf lies) LS 01 LS 02 LS 03 LS 04 LS 05 LS 06 LS 07 LS 08 1 3 Kinds 0 1 2 1 26 814 Total 0 7 37 3 25 203 18 280 ------- TABLE 3 Benthic Organisms - Lake Sebasticook/ Maine May 30, 1973 Per Sq. Ft. Stations Organisms LS 01 LS 02 LS 03 LS 04 LS 05 10 NJ I Oligochaeta (aquatic worms) Tubificidae (sludge worms) Diptera Chironomus riparius (bloodworms) Kinds Total 19 2 28 27 32 2 59 2 4 0 0 ------- TABLE 4 Benthic Organisms - Lake Sebasticook and Lake Wassookeag, Maine July 31 - Aug. 1, 1973 Per Sq. Ft. Organisms LS 01 LS 02 LS 03 LS 04 LS 05 LW 02 LW 03 U> LJ Oligochaeta (aquatic worms) Tubificidae (sludge worms) Diptera (midgeflies) Chironomus riparius Anatopynia sp. PolypedilumTophiodes Unidentified Ephemeroptera (mayflies) Hexagenia bilineata Tricory thidae Megaloptera (alderflies) Sialis sp. 5 3 29 47 11 19 1 56 38 Trichoptera (caddisflies) Psychomyia sp. Pelecypoda (clams) Cladocera (water fleas) Copepoda ( copepods ) Amphipoda ( s c uds ) Ostracoda (seed shrimp) Bryozoa (moss animalcules) Kinds 021 Total 087 8 13 19 8 1 11 1* 1 1 13 1 1 172 4 103 *Colonial Form ------- TABLE 5 Benthic Organisms - Lake Sebasticook, Maine Nov. 17, 1971 Per Sq. Ft. Stations Organisms LS 01 LS 02 LS 03 LS 04 LS 05 I OJ Oligochaeta (aquatic worms) Tubificidae (sludge worms) Diptera (midgeflies) 100 44 Chironomus Riparius Copepoda (copepod) (bloodworms) Kinds 1 Total 1 5 1 3 13 20 5 3 125 3 2 11 29 2 73 ------- TABLE 6 Midgeflies - Sludgeworms Average Per Sq. Ft. Year 1965* 1965* 1971 1972 1973 1973 Month May July Nov May May July Lake Sebasticook, 1965-1973 Average Per Sq. Ft. 35 57 44 14 18 3 Maine Midgefly Larvae % Scj. Ft. 57% 62% 25% 54% 45% 24% Sludgeworms % Sq. Ft. 43% 38% 72% 46% 55% 76% *Fertilization and Algae in Lake Sebasticook, Maine Technical Advisory and Investigations Activities, Robert A. Taft Sanitary Eng. Center, Cincinnati, Ohio January, 1966 -35- ------- TABLE 7 Lake Sebasticook, Maine Algae Count (Average) Per Milliter 1965 - 1973 Middle Lower Lake Sebasticook May 11-27, 1965* July 28-Aug. 1, 1965* Nov. 2, 1965* Feb. 15-16, 1972 May 31, 1972 May 31, 1973 July 31, 1973 Lake Wassookeag (Control) Aug. 1, 1973 5 ft. 17,875 27,684 4,090 4,852 6,940 16,527 14,969 283 15-30 ft. 10,416 4,467 11,727 9,576 6,554 15,817 2,863 723 Seasonal and yearly averages for comparable seasons Lake Sebasticook Spring - Summer 1965 22,780 Spring - Summer 1973 15,748 1965 11,354 per milliter 1973 11,715 per milliter Lake Wassookeag (Control) 1973 (Summer) 467 per milliter 7,441 9,340 30-55 ft. 6,959 725 3,850 13,369 7,778 16,594 3,520 396 3,842 10,057 *Fertilization and Algae in Lake Sebasticook, Maine Technical Advisory and Investigation Activities Robert A. Taft Sanitary Engineering Center, Cinn., Ohio January 1966 -36- ------- TABLE 8 East Branch Sebasticook River/ Maine Algae Count Per Milliter (Average) 1965, 1971-1973 (Comparable Stations) Station 3 58 May 11-27, 1965* 3,537 39,512 30,123 July 26-31, 1965* 610 - 224,150 7,275 Nov. 2, 1965* - 33,400 2,700 Average 2,073 99,020 13,366 Station EB01 EB02 EB03 Nov. 17, 1971 - 10,358 . - Feb. 15, 1972 6,000 28,979 5,830 May 31, 1972 7,075 6,395 9,735 May 31, 1973 16,987 39,620 26,205 July 31, 1973 . 4,245 17,716 4,641 Average 8,576 20,613 11,602 *Fertilization and Algae in Lake Sebasticook, Maine Technical Advisory and Investigation Activities Robert A. Taft Sanitary Engineering Center, Cinn. Ohio January 1966. -37- ------- TABLE 9 Lake Sebasticook, Maine Chlorophyll a_ Micrograms Per Liter (Average) Upper (0-5') Middle (10-25') Lower (30-55') July 28-Aug. 1, 1965* 21.97 3.67 2.99 Oct. 30-Nov. 2, 1965* 13.20 14.38 13.61 Nov. 17, 1971 8.67 7.40 8.90 Feb. 15, 1972 8.95 9.12 8.73 May 31, 1972 5.29 5.32 5.53 May 30, 1973 21.34 16.14 18.57 July 31, 1973 24.63 17.45 3.04 Aug. 1, 1973 (Lake Wassookeag) <0.10 0.94 <0.10 Seasonal and Yearly Averages for Entire Lake July 28-Aug. 1, 1965 <9.54 \ <11.63 Oct. 30-Nov. 2, 1965 Nov. 17, 1971 8.32) 11.68 July 31, 1973 May 30, 1973 18.68^ 16.86 July 31, 1973 Feb. 15, 1972 8.93^ 7.15 May 31, 1972 All surveys Nov. 17, 1971 - July 31, 1973 11.26 All surveys July 28, 1965 - July 31, 1973 11.37 Aug. 1, 1973 (Lake Wassookeag) <0.38 *Fertilization and Algae in Lake Sebasticook, Maine Technical Advisory and Investigation Activities Robert A. Taft Sanitary Engineering Center, Cinn., Ohio January 1966 -38- ------- TABLE 10 Lake Sebasticook, Maine Sediments Ni trogen/Phosphorous Ratios Station Reference Station May 65* LS 01 LS 02 LS 03 LS 04 LS 05 L. Wassookeag A B C D E 8.8 8.7 5.6 7.5 6.4 20.0 Nov. 71 2.7 1.8 1.5 1.2 2.1 May 72 1.1 1.8 1.7 1.2 1.5 May 73 1.9 2.1 , 1.3 1.3 2.1 July 73 1.8 2.3 1.5 1.7 1.8 8.9 *Seasonal Average 2 Values. -39- ------- TABLE Lake Sebasticook, Maine Sediments Phosphorus and Nitrogen % Dry Weight Phosphorus 1971 - 1973 1965 May 65 Nov. 71 May 72 May 73 July 7! Station Stations LS01 LS02 LS03 LS04 LS05 Average A B C D E Lake Wassookeag East Branch Sebasticook R. Lagoon Upstream of Inlet to Lake LS01 LS02 LS03 LS04 LS05 Average A B C D E Lake Wassookeag East Branch Sebasticook .095 .120 .070 .120 .125 .106 .05 .85 .90 • .40 .90 ,80 .77 1.0 .075 .074 .080 .101 .082 .082 Nitrogen .204 .130 .118 .120 .174 .149 . 114 ' .079 .083 .125 .101 .100 .133 .148 .147 .148 .157 .146 .090 .063 .062 .088 .074 .075 .173 .129 .083 .116 .154 .131 .084 .055 .077 .084 .078 .076 .027 .073 .152 .125 .114 .143 .141 .135 0.24 0.41 R. Lagoon Upstream of Inlet to Lake -40- ------- APPENDIX -41- ------- Lake Sebasticook, Maine Chlorophyll a_ Micrograms Per Liter Nov. 17, 1971 A-l Station LS01 LS02 LS03 LS04 LS05 Average Upper 8.18 6.75 6.04 5.74 8.67 Middle 9.22 8.34 5.27 6.75 7.47 7.40 Lower 14.54 6.75 12.95 9.61 10.65 8.90 EB01 EB02 EB03 4.45 40.81 4.46 -42- ------- A-2 Lake Sebasticook, Maine Chlorophyll £ Micrograms Per Liter Feb. 15-17, 1972 Station LS01 LS02 LS03 LS04 LS05 Average EB01 EB02 EB03 Upper 5' 7.08 15.18 6.92 10.25 5.34 8.95 10.61 8.21 4.61 Middle 10-25' 11.84 4.61 11.13 10.25 7.80 9.12 Lower 30-55' 4.62 5.85 26.11 2.32 4.77 8.73 -43- ------- A-3 Lake Sebasticook, Maine Chlorophyll a, Micrograms Per Liter May 31, 1972 Station LS01 LS02 LS03 LS04 LS05 LS06 LS07 LS08 Average EB01 EB02 EB03 Upper 5' 6.11 5.41 5.98 6.55 A. 26 6.11 5.53 2.41 5.29 3.12 10.13 8.07 Middle Lower 10-25' 30-55' 4.26 5.41 5.53 7.50 6.49 9.22 6.10 4.39 4.26 4.26 - 3.12 4.83 5.32 5.53 -44- ------- A-4 Lake Sebasticook, Maine Chlorophyll a_ Micrograms Per Liter of Water July 31, 1973 - August 1, 1973 Station Upper Middle 0-5' 10-25' LS LS LS LS LS LS 01 02 03 04 05 09 11 7 3 2 13 108 .91 2.55 .81 5.37 .86 19.33 .63 52.11 .37 7.88 .25 Lower 30-55' 0.39 0.01 11.69 2.65 0.47 - Average 24.63 17.45 3.04 EB 01 6.10 EB 02 36.54 EB 03 4.79 LS 01 (Lake Wassookeag) <0.10 0.94 < 0.10 -45- ------- A-5 Lake Sebasticook, Maine Chlorophyll a_ Micrograms Per Liter May 31, 1973 Station Upper Middle Lower LS01 29.07 15.31 17.39 LS02 22.34 22.95 16.92 LS03 19.32 16.92 25.52 LS04 17.31 18.24 18.21 LS05 18.70 7.31 14.65 Average 21.34 16.14 18.57 EB01 5.18 EB02 7.00 EB03 21.62 -46- ------- A-6 Lake Sebasticook, Maine Algae Count Nov. 17, 1971 Per Milliter Station Upper LS01 906 LS02 1,075 LS03 962 LS04 792 LS05 912 Average 929 EB01 EB02 10,358 EB03 -47- ------- Lake Sebasticook, Maine Algae Count Feb. 15-16, 1972 Per Milliter A-7 Station LS01 LS02 LS03 LS04 LS05 Upper 3,000 3,396 4,302 8,716 Middle 6,735 22,300 8,000 9,735 3,113 Lower 14,716 9,339 23,376 9,622 9,792 Average EB01 EB02 EB03 4,852 6,000 28,979 5,830 9,576 13,369 -48- ------- A-8 Station LS01 LS02 tS03 LS04 LS05 LS06 LS07 LS08 EB01 EB02 EB03 Average Lake Sebasticook, Maine Algae Count May 31,1972 Per Milliter Upper Middle 3,283 8,150 7,415 3,622 7,811 8,320 13,301 6,113 8,830 6,566 6,905 4,358 3,622 ge 6,940 6,554 7,075 6,395 9,735 Lower 6,622 6,452 8,547 13,641 8,999 - 6 , 169 4,019 7,778 -49- ------- A-9 Station LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 Lake Sebasticook, Maine Algae Count May 31,1973 Per Milliter Upper Middle 16,357 16,659 19,470 21,111 23,376 14,829 14,150 18,282 9,282 8,207 Average 16,527 15,817 16,987 39,620 26,205 Lower 11,829 22,017 25,696 13,018 10,414 16,594 -50- ------- A-10 Lake Sebasticook, Maine Algae Count Per Milliter July 31 and Aug. 1, 1973 Station LS01 LS02 LS03 LS04 LS05 LS09 Average EB01 EB02 EB03 Upper 2,264 1,585 1,302 2,660 2,207 79,800 14,969 4,245 17,716 4,641 Middle 283 2,038 3,339 4,471 4,188 - 2,863 Lower 1,698 1,868 4,641 2,434 6,962 - 3,520 LW01 (Lake Wassookeag) 283 723 396 -51- ------- A-ll Lake Sebasticook, Maine Total Kjeldahl Nitrogen as N Feb. 17, 1972 MG/L Station LS01 LS02 LS03 LS04 LS05 Average EB01 EB02 EB03 Upper 0.7 0.2 0.4 0.3 0.4 0.4 1.8 0.7 0.2 Middle 0.2 0.3 0.3 0.3 0.4 0.3 Lower 0.5 0.3 1.2 0.5 0.3 0.6 -52- ------- Lake Sebasticook, Maine Total Kjeldahl Nitrogen as N MG/L A-12 June 1, 1972 Station LS01 LS02 LS03 LS04 LS05 EB03 EB02 EB01 LS01 LS02 LS03 LS04 LS05 Average Average Upper 0.9 0.2 0.7 1.0 0.8 0.7 0.6 1.9 0.2 Nov. 17, 1971 0.8 0.4 0.3 0.4 0.4 0.5 Middle 0.6 0.8 0.7 0.8 0.6 0.7 0.8 0.4 0.3 0.3 0.6 0.5 Lower 0.8 0.9 0.7 0.7. 0.9 0.8 0.4 0.5 0.5 0.3 0.3 0.4 EB01 EB02 EB03 0.5 2.5 0.2 -53- ------- A-13 Lake Sebasticook, Maine Ammonia (NH_ - N) MG/L May 31, 1972 Station LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 Upper .01 .01 .01 .05 .01 Average 0.02 .01 .83 .05 .37 .22 .07 .11 .03 Average • 16 1.48 .75 .07 Middle Lower .01 .12 .04 .52 .19 -20 .04 .03 .19 0.09 0.22 Feb. 15, 1972 .10 5.36 .27 1.62 .37 .06 .03. -42 .03 .33 .16 1-56 -54- ------- A-14 Lake Sebasticook, Maine Total Phosphorus MG/L May 31, 1973 Station LS01 LS02 LS03 LS04 LS05 Average TOTAL PHOSPHORUS CONCENTRATION = 0.094 MG/L EB01 .23 EB02 .06 EB03 .05 Upper .21 .06 .06 .04 .05 .084 Middle .05 .04 .07 .04 .07 .054 Lower .28 .13 .08 .16 .07 .144 -55- ------- A-15 Station LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 Lake Sebasticook, Maine Nitrate - Nitrite MG/L May Upper .01 .01 .01 .02 .02 ige .01 .01 .04 .04 Feb .01 .03 .06 .02 .08 age . 04 31, 1972 Middle .01 .07 .06 .06 .03 .05 . 15-16, 1972 .06 .07 .02 .03 .03 .04 Lower .12 .07 .14 .02 .02 .07 .04 .02 .07 .15 .08 .07 .21 .26 1.45 -56- ------- Lake Sebasticook, Maine Nitrite, N02~N MGA May 31, 1973 A-16 Station LS01 LS02 LS03 LS04 LS05 Average Upper 0.01 0.01 0.01 0.01 0.01 0.01 Middle 0.01 0.01 0.01 0.01 0.01 0.01 Lower 0.01 0.01 0.01 0.01 0.01 0.01 AVERAGE NITRITE 0.01 EB01 EB02 EB03 0.01 0.01 0.01 -57- ------- Lake Sebasticook, Maine Nitrate NO..-N MG/L May 31, 1973 A-17 Station LS01 LS02 LS03 LS04 LS05 Average Upper 0.05 0.05 0.05 0.05 0.05 0.05 Middle 0.19 0.05 0.05 0.05 0.05 0.08 Lower 0.08 0.05 0.37 0.05 0.05 0.12 TOTAL NO -N CONCENTRATION =0.08 EB01 EB02 EB03 0.05 0.05 0.13 -58- ------- Lake Sebasticook, Maine Ammonia NH3-N* MG/L May 31, 1973 A-18 Station LS 01 LS 02 LS 03 LS 04 LS 05 Average Upper 0.20 0.20 0.20 0.20 0.20 0.20 Middle 0.20 0.20 0.20 0.20 0.20 0.20 Lower 0.20 0.20 0.20 0.20 0.20 0.20 Total NH.,-N Concentration = 0.20 EB 01 0.20 EB 02 0.20 EB 03 0.20 *A11 Values Less Than Recorded -59- ------- A-19 S tatioji LS 01 LS 02 LS 03 LS 04 LS 05 Lake Sebasticodk, Maine Total Kjeldahl Nitrogen MG/L Aug. 1, 1973 Upper 0.67 1.60 0.27 0.93 0.54 Average 0.80 Middle •0.67 0.70 0.61 0.21 0.26 0.49 Lower 0.40 0.34 0.44 0.42 0.54 0.43 Average TKN = 0.57 EB 01 EB 02 EB 03 0.35 0.85 0.38 -60- ------- A-20 Lake Sebasticook, Maine Algae Count Nov.17, 1971 Per Milliter Station Upper LS01 906 LS02 1,075 LS03 962 LS04 792 LS05 912 Average 929 EB01 EB02 10,358 EB03 -61- ------- A-21 Station LS01 LS02 LS03 LS04 LS05 LS06 LS07 LS08 EB01 EB02 EB03 Average Lake Sebasticook, Maine Algae Count May 31, 1972 Per Milliter Upper 3,283 7,415 7,811 13,301 8,830 6,905 4,358 3,622 6,940 7,075 6,395 9,735 Middle 8,150 3,622 8,320 6,113 6,566 - - _ 6,554 Lower 6,622 6,452 8,547 13,641 8,999 6,169 4,019 7,778 -62- ------- Lake Sebasticook, Maine Algae Count Feb. 15-16, 1972 Per Milliter A-22 Station LS01 LS02 LS03 LS04 LS05 Average EB01 EB02 EB03 Upper 3,000 3,396 4,302 8,716 4,852 6,000 28,979 5,830 Middle 6,735 22,300 8,000 9,735 3,113 9,576 Lower 14,716 9,339 23,376 9,622 9,792 13,369 -63- ------- Lake Sebasticook, Maine Algae Count May 31, 1973 Per Milliter A-23 Station LS01 LS02 LS03 LS04 LS05 Average EB01 EB02 EB03 Upper 16,357 19,470 23,376 14,150 9,282 16,527 16,987 39,620 26,205 Middle 16,659 21,111 14,829 18,282 8,207 15,817 Lower 11,829 22,017 25,696 13,018 10,414 16,594 -64- ------- A-24 Lake Sebasticook, Maine Algae Count Per Milliter July 31 and Aug. 1, 1973 Upper 2,264 1,585 1,302 2,660 2,207 79,800 14,969 4,245 17,716 4,641 Middle 283 2,038 3,339 4,471 4,188 _ 2,863 Lower 1,698 1,868 4,641 2,434 6,962 _ 3,520 S tation LS 01 LS 02 LS 03 LS 04 LS 05 LS 09 Average EB 01 EB 02 EB 03 LW 01 (Lake Wassookeag) 283 723 396 -65- ------- A-25 Lake Sebasticook, Mai,ne Nutrients 7/31, 8/1, 8/2, 1973 Station # LS01S LS01M LS01B LS09S LS02S LS02M LS02B LS03S LS03M LS03B LS04S LS04M LS04B LS05S LS05M LS05B EB01 EB02 EB03 Depth 2.0 18.0 35.0 2.0 2.0 21.0 42.0 2.0 11.0 22.0 2.0 18.0 32.0 2.0 17.0 32.0 2.0 2.0 2.0 TKN 0.2 0.2 1.4 0.3 0.5 2.0 0.3 0.2 1.2 0.4 0.2 1.5 0.4 0.3 0.8 0.3 2.1 0.3 NO^-N K.02 K.02 K.02 K.02 .04 K.02 K.02 0.05 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 N03-N K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 K.02 HH3^N 0.02 0.07 0.34 .06 .02 .04 1.4 .02 .06 .01 .01 .03 1.4 .02 0.02 0.78 0.10 1.5 .06 TP 0.06 0.08 0.05 K.05 K.05 0.41 K.05 K.05 .05 K.05 K.05 0.38 K.05 K.05 0.22 0.14 .05 .05 0.15 -66- ------- A-26 Lake Sebasticook, Maine Station LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 LS01 LS02 LS03 LS04 LS05 EB01 EB02 EB03 Average Average Average Total Phosphorus MG/L Nov. 17, 1971 Upper .10 .08 .06 .06 .20 .10 .14 .18 .06 Feb. 15-17, 1972 _ .04 .04 .06 .04 .04 .20 .50 .10 May 31, 1972 .04 .03 .03 .08 .02 .04 .11 .11 .57 Middle .10 .10 .06 .06 .06 .08 .16 .06 .05 .34 .06 .13 .02 .06 .04 .07 .09 .06 Lower -67- ------- |