Carol M. Brooks

Domestic Waste Inputs of Nitrogen and Phosphorus to Onondaga Lake, and Water Quality Implications

ABSTRACT The recent history of loading of total phosphorus (TP) and nitrogen (N) species to Onondaga Lake, NY, from an adjoining domestic waste treatment facility (METRO), and related impacts on die lake, are documented. The discharge from METRO represents an extraordinary contribution to the inflow of the lake; e.g., in most years it is the largest source of water during the month of August. Approximately a 20-fold reduction in effluent TP concentration has been achieved by METRO over die 1970–1993 period, in response to a detergent ban and increased levels of treatment. The TP loading from the facility decreased about 5-fold over the 1977–1992 interval. A significant level of nitrification has been achieved during die warmer mondis since the late 1980s, but this has been attended by increased effluent concentrations of nitrite (NO− 2). METRO presently contributes approximately 60, 90, and 80% of the total external loads of TP, ammonia, and total N, respectively. The extremely high prevailing external to...

The oxygen resources of the hypolimnion of ionically enriched onondaga lake, NY, U.S.A.

The depletion of hypolimnetic DO and the upper depth boundary of anoxia for four different years (1978, 1979, 1980 and 1981), and the accumulation of sulfide for a single year (1981), are documented for ionically enriched hypereutrophic Onondaga Lake, NY, USA. The depletion rate, represented as the areal hypolimnetic oxygen deficit (AHOD, g m−2 day−1), was extremely high (1.2–2.7 g m−2 day−1), The large differences in the rate within individual years and from year to year were largely a result of differences in attendant vertical mixing (parameterized as the hypolimnetic heating rate). The entire hypolimnion (depth interval from 11 to 20 m) was without O2 by late June of all 4 yr; anoxia was observed above the hypolimnion on some occasions when secondary stratification occurred. Sulfide accumulated progressively in the hypolimnion in 1981 following the onset of anoxia to a volume weighted concentration of I1 mg L−1. The ionic discharge from an adjoining alkali manufacturer exacerbated the problem of limited O2 resources of the hypolimnion by: (1) decreasing vertical mixing, (2) prolonging the duration of stratification, (3) causing abbreviated turnovers, and (4) encouraging increased rates of phytoplankton settling.

Pollutant loadings from solvay waste beds to lower Ninemile Creek, New York

Concentrations of Cl, total ammonia (TNH3), NO3 plus NO2, total P (TP), and soluble reactive P (SRP) were measured at two sites, located 5 km apart, on Ninemile Creek, New York, for a period of more than 8 mo. The sites bound the most recently formed Solvay waste beds, associated with the production of soda ash, that adjoin the creek. Concentrations of Cl and T-NH3 increased on average by factors of 16.1 and 7.6, respectively, over the monitored stream reach. The estimated average loadings of these materials to the stream over this reach were 2.3 × 105 and 1.2 × 102 kg d−1, respectively. These inputs are attributable to the Solvay waste beds. The loading of Cl from this source has not changed significantly over a 4 yr period since the closure of the soda ash manufacturing facility. This is the single largest source of Cl, and the second largest source of T-NH3, to polluted Onondaga Lake. Profiles of Cl in the lake indicated that at times the creek inflow plunges to subsurface layers as a result of its elevated density. This is at least in part a result of the creeks ionic enrichment. The concentration of SRP decreased by a factor of 2.0 on average over the study reach, probably due to adsorption to the CaCO3 deposits that cover the stream bed in this area. However, the TP load from the creek to the lake is not significantly affected by this phenomenon.

The distribution of nitrogen species in polluted Onondaga Lake, N.Y., U.S.A.

The temporal and vertical distributions of four N species, N03−, NO2−, total ammonia (T-NH3), and free ammonia (NH3), are documented for Onondaga Lake, an urban, polluted, hypereutrophic, dimictic, lake that receives a very high load of T-NH3. Nitrate and NO2− were lost rapidly from the hypolimnion, and T-NH3 accumulated to high concentrations (maximum > 10 mgN L−1), after the onset of anoxia, consistent with the lakes high level of productivity. The concentrations of T-NH3, NH3 and N03− that were maintained in the epilimnion (average concentrations at a depth of 1 m of 2.81, 0.16 and 0.91 mgN L−1, respectively), and concentrations of N02− that developed in the epilimnion (maximum of 0.48 mgN L−1), were high in comparison to levels reported in the literature. These elevated concentrations are largely a result of the extremely high loads of T-NH3, and its precursors, received by the lake. Water quality problems in the lake related to the prevailing high concentrations of N species include potential toxicity effects and severe lake-wide oxygen depletion during fall turnover.

Turbidity and Particle Signatures Imparted by Runoff Events in Ashokan Reservoir, NY

ABSTRACT The occurrence, temporal and spatial patterns, and origins of turbidity events, and their linkage to runoff events, are documented for a water supply impoundment with two separated basins, Ashokan Reservoir, NY. The analysis is supported by a comprehensive 6-week study of the major inflow and the reservoir during the summer of 1996, that captured the effects of a single runoff event, and turbidity (Tn) measurements made in the reservoir and the water supply intakes for the entire year. Measurements supporting the short-term study include: temperature, specific conductance, beam attenuation coefficient, electronic particle counts, Secchi disc transparency, Tn, up- and downwelling cosine irradiance, chlorophyll, microscopy-based individual particle size and chemistry, and total suspended solids (TSS) on sediment trap collections. The external load of mostly quartz and clay particles delivered by die principal tributary, as an interflow, during the summer runoff event imparted distinct signatures in...

The Effect of Terrigenous Inputs on Spatial Patterns of Water Quality Indicators in South Lake, Lake Champlain

Spatial patterns of measures of trophic state, optical properties and particle composition are documented for Lake Champlain, with particular emphasis on the southernmost shallow section (< 10 m deep, ∼ 55 km in length) known as South Lake, to depict the impacts of terrigenous inputs. The analysis is supported by two surveys conducted in 1998 for South Lake (thirteen sites) following typical and unusually high runoff intervals, and for selected deep-water sites (thirteen) for the typical runoff interval. Terrigenous inputs, particularly as clays, cause light penetration to be lower, turbidity (Tn) and phosphorus (P) concentrations to be higher by a wide margin, and particle composition to differ greatly in South Lake relative to deeper portions of the lake. Generally progressive gradients are documented within South Lake for Secchi disc transparency (SD), the light attenuation coefficient, (Tn), particulate organic carbon, total P, and particulate P, that demonstrate diminishing impacts of the terrigenous inputs with the approach to the deeper portions of the lake. Increased loadings associated with high runoff impart greater, and a wider array of, impacts in South Lake, that appear to be relatively shortlived (less than 1 month). The high levels of inanimate particles (tripton) that prevail in South Lake systematically compromise total P concentration and SD as measures of trophic state. Despite lower levels, this terrigenous material also influences these measures in deep-water areas. Management strategies that focus on reductions in P loading will not result in substantive increases in SD in South Lake, as phytoplankton biomass is unimportant in regulating the prevailing clarity conditions. Erosion control may be a more promising alternative to pursue improved clarity in this portion of the lake.

Gradients and Dynamics in Downward Flux and Settling Velocity in Cannonsville Reservoir

ABSTRACT Seasonal and longitudinal patterns in downward fluxes and settling velocities of selected particulate constituents, including suspended solids (TSS), organic carbon (C), nitrogen (N), phosphorus (P) and chlorophyll (Cr), are documented for eutrophic Cannonsville Reservoir, NY, for the stratification period of 1995, based on analyses of particulate concentrations in the epilimnion and sediment collected in cylindrical traps deployed below the epilimnion at six different sites. Strong longitudinal gradients in downward flux were observed for all the constituents; the highest rates prevailed in the upstream/riverine zone, the lowest in the downstream/lacustrine zone. These gradients in deposition were driven by gradients of the same form in both the concentrations of the particulate constituents in the epilimnion and the settling velocities of these materials. Substantial temporal variability was observed in particulate species concentrations, and the downward fluxes and settling velocities of these...

Dry Weight Deposition in Polluted Onondaga Lake, New York, U.S.A.

Short and long-term trends in dry weight deposition rates are documented for polluted Onondaga Lake, NY, based on analyses of sediment trap collections made below the epilimnion at a single deep-water location in ten years over the 1980–1992 period using cylindrical traps. Additionally, comparisons of dry weight rates obtained with two different diameter (4.0 and 7.6 cm) traps of the same aspect ratio (6), at four different depths below the epilimnion, and from the lakes two basins, in 1993, are presented to establish the representativeness of the long-term data. The near equivalence of fluxes determined with the different size traps and cumulative deposition rates measured over the range of deployment depths, and the minor differences in flux observed for the two basins, supports the representativeness of long-term data in quantifying deposition rates for the pelagic zone of the lake. Short-term variations in downward flux have been common in the lake over the period of monitoring. The summer-average dry weight deposition rate decreased systematically (by about 45%) following the closure (in 1986) of a soda ash facility that caused enhanced rates of calcium carbonate deposition; from an average of 23.2 to 12.8 g m-2 d-1. These dry weight deposition rates are high compared to values reported in the literature for other lakes, and are responsible for the lakes high rate of net sedimentation.

Chloride in the pore water and water column of Onondaga Lake, N.Y., U.S.A.

The vertical distributions of Cl in the pore waters of the sediments and in the water column of Onondaga Lake, New York, are documented and used to estimate the diffusion flux of Cl across the sediment-water interface, and establish the reduction in lake concentrations that has occurred as a result of the closure of an industrial source of Cl. Despite the industrial enrichment of the water column with Cl over the last 100 yr, gradients within the upper sediments toward the overlying water of 6.9 to 8.5 × 10−2 mg cm−3 cm−1 exist in the deep basins of the lake. These upwards gradients are apparently a manifestation of the salt deposits that underlie the region. The estimated diffusion flux from the sediments to the water column, 3.2 × 106 kg yr−1, represents a small percentage of the external load during the operation of the industry (0.4%) and after its closure (1.6%). The Cl concentration has decreased approximately 70% in response to an approximately equal percent reduction in external loading, as a result of closure of the industry. This supports the position that the lakes concentrations largely reflect external loading and lake flushing associated with surface inputs.