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 lake's concentrations largely reflect external loading and lake flushing associated with surface inputs.     

The density of inflows to Onondaga Lake,U.S.A., 1980 and 1981

The temporal distributions of the densities of inflows to Onondaga Lake were calculated for the spring to fall period of 1980 and 1981, and compared to the attendant density stratification in ion enriched Onondaga Lake. The industrial utilization of the lake resulted in substantial density differences between the inflows and the lake. Inflows carrying substantial fractions of industrial ionic waste were more dense than the lake, and at times plunged to stratified layers. Water withdrawn from the lower layers of the lake for industrial cooling was displaced to the upper layers as a result of heating. Dilute fluvial inflows were substantially less dense than the lake. The density differences between the inflows and the lake were largely responsible for the rather unique features of density stratification documented for the lake in 1980, and are probably of further importance in nutrient loading to, and cycling in, Onondaga Lake.     

Modifications in phosphorus loading to Onondaga Lake,U.S.A., Associated with alkali Manufacturing

The effects of an alkali production facility on P loading to the epilimnion of Onondaga Lake are documented for the spring to fall interval of 1980 and 1981. The effects include additional load to the epilimnion from the hypolimnion and the outlet, and reduced loads from dense, ion-enriched inflows. Despite the compensating effects, the load received by the epilimnion from spring through fall is greater than previously estimated as a result of the manufacturing operations.     

Distribution of mercury in the sediments of Onondaga Lake,N.Y.

Sediment cores and surface grab samples were collected throughout Onondaga Lake, New York, to determine the concentrations and distribution of mercury (Hg) in the sediments. Horizontal distribution patterns show the effect of sediment focusing and localized sources, with generally low Hg concentrations in the littoral zone sediments, higher concentrations in the profundal sediments, and highest concentrations near known sources of Hg. Several cores were dated and reflect historical loading patterns, with low-level increases in Hg concentration starting in the early 1800s and a large increase in 1947 and decrease in 1970 related to the local chloralkali industry. These cores indicate that Hg has low mobility in profundal sediments and that the contaminated sediments are effectively being buried.     

Failure of spring turnover in Onondaga Lake,NY, U.S.A.

Onondaga Lake, N.Y., failed to turnover in the spring of 1986 because of the strong chemical stratification under the ice that developed as a result of ionic discharges from an alkali plant. This stratification had a negative impact on the O₂ resources of the lake, as the lower depleted layers of the lake were not replenished with O₂. Anoxia and anaerobiesis in the bottom water expanded following ‘ice-out’. Comparison of characteristics observed for the winter through spring interval of 1986 with historic data indicates Onandaga Lake has failed to experience spring turnover in a number of years (approximately 7 of the last 18 yr) because of the ionic discharges from the alkali plant.     

A chloride budget for Onondaga Lake,New York,U.S.A.

A Cl budget is presented for a 12 yr period (1970–1981) for Cl enriched (approximate volume-weighted average concentration of 1500 mg Cl L^?1) Onondaga Lake, New York. The budget utilizes continuous discharge and lake and stream water chemistry data, collected at an interval of approximately 2 weeks, over the 12 yr study period. Budget calculations are supplemented by high frequency water chemistry data from the lake and the tributary carrying the major portion of the loading. More than 85% of the external load of Cl (approximately 9 × 10⁸ kg yr^?1) to the lake originates from an alkali manufacturer. Export of Cl from the lake was highly correlated to outflow from the lake (R = 0.915, for a resolution of 1 mo). A good balance between estimated external loads and lake export was obtained (within 7%) for the 12 yr period, indicating that lake concentrations are consistent with external loading of this conservative substance. The results of this analysis contradict previous calculations that indicated 40 to 50% of the Cl in the lake originated from natural internal sources.     

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 lake's 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 lake's high rate of net sedimentation.     

Density stratification in ionically enriched Onondaga lake,U.S.A.

Denstity stratification was characterized in ionically enriched Onondaga Lake for a 7 mo period of 1980, based on paired profiles of temperature and cloride collected at 1 m depth intervals from a single deep water location on 54 different occasions. The lake was both thermally and chemically stratified. The chemical component represented 38.5% of the density stratification for the study period. It was most often the dominant component in establishing the depth of the upper mixed layer, which was unusually shallow in the lake. Further, the presense of the chemical component prolonged the stratification period. The chemical component of stratification decreased progressively through the study. The altered stratification characteristics of the lake may have negative effects on the level of biomass in the upper waters and the oxygen resources of the lower waters.     

Depletion of epilimnetic oxygen and accumulation of hydrogen sulfide in the hypolimnion of Onondaga Lake,NY, U.S.A.

The depletion of epilimnetic DO during fall, and the accumulation of H₂S in the hypolimnion during summer, are documented for polluted hypereutrophic Onondaga Lake, NY, U.S.A. The fall epilimnetic DO depletion is so severe that in many, if not all years, the New York State standard for minimum DO of 4 mg- L^?1 is violated for periods as long as 1 mo. The depletion is caused by the transport of O₂ demanding species, particularly H₂S, from the hypolimnion into the epilimnion. Hydrogen sulfide accumulates progressively through the summer, mostly via SO _inf4 ^sup2? reduction, to unusually high concentrations; a maximum of 1.65 mM has been observed. These conditions are apparently manifestations of hypereutrophy, and thus may be subject to remediation through P management efforts.     

Modeling Cl concentration in Cayuga Lake,U.S.A.

The annual average concentration of Cl in Cayuga Lake, NY, has decreased from a value of approximately 102 mg L^?1 in 1970, when the discharge of NaCl fines from an adjoining rock salt mine was discontinued, to a concentration of approximately 46 mg L^?1 in 1988. A complete-mixed model for Cl concentration accurately simulated this decrease in concentration, establishing that the decrease was the result of an abrupt reduction in loading. The time course of the decrease strongly supports the position that the high Cl concentrations that prevailed in the lake in the late 1960's were largely a result of the discharge from the mining facility, and not due to the input of enriched groundwater as previously hypothesized. The predicted steady-state Cl concentration associated with the complete flushing of the mining facility input, expected in about the year 2000, is approximately 32 mg L^?1. Further, the model analysis supports previous speculation that the major source of material loading to the lake, the Seneca River, ‘short-circuits’ to the outlet; i.e., this tributary should not be included in material budgets for the lake.     

Sediment Quality in Burlington Harbor,Lake Champlain,U.S.A.

Surface samples and cores were collected in 1993 fromthe Burlington Harbor region of Lake Champlain. Sediment samples were analyzed for trace metals(cadmium, copper, lead, nickel, silver and zinc),simultaneously extracted metal/acid volatile sulfide(SEM-AVS), grain size, nutrients (carbon and nitrogen)and organic contaminants (polycyclic aromatichydrocarbons (PAHs) and polychlorinated biphenyls(PCBs)). The concentrations of cadmium, copper,silver and zinc from the partial sediment digestion ofthe surface samples correlated well with each other(r ²>0.60) indicating that either a commonprocess, or group of processes determined the sedimentconcentrations of these metals. In an analysis of thespatial distribution of the trace metals and PAHs,high surficial concentrations were present in thesouthern portion of the Harbor. The trace metal trendwas strengthened when the concentrations werenormalized by grain size. A sewage treatment plantoutfall discharge was present in the southeasternportion of the Harbor at the time of this study and isthe major source of trace metal and PAH contamination. Evaluation of sediment cores provides a proxy recordof historical trace metal and organic inputs. Thepeak accumulation rate for copper, cadmium, lead, andzinc was in the late 1960s and the peak silveraccumulation rate was later. The greatestaccumulation of trace metals occurred in the late1960s after discharges from the STP began. Subsequentdeclines in trace metal concentrations may beattributed to increased water and air regulations. The potential toxicity of trace metals and organiccontaminants was predicted by comparing contaminantconcentrations to benchmark concentrations andpotential trace metal bioavailability was predictedwith SEM-AVS results. Surface sample results indicate lead,silver, ΣPAHs and ΣPCBs are potentially toxicand/or bioavailable. These predictions were supportedby studies of biota in the Burlington Harborwatershed. There is a clear trend of decreasing PAHand trace metal contaminant concentrations withdistance from the STP outfall.     

Responses of Nutrients to Experimental Acidification and Recovery in Little Rock Lake,U.S.A.

Nutrient concentrations and cycling processes were studied in Little Rock Lake, Wisconsin, U.S.A., during experimental acidification from pH 6.1 to target pH values of 5.6, 5.1 and 4.7 and during the first four years of recovery. Surface waterconcentrations of ammonium, nitrate, soluble reactive phosphate,and total phosphate were not affected, but total nitrogen was lower from year 2 at pH 5.6 until the end of recovery year 3 (pH 5.3). The decrease was attributed to lower dissolved organicN. Annual maximum concentrations of N and P forms at 9 m depth in the hypolimnion increased with decreasing pH, but most of theincrease resulted from a drought-induced decline in lake levelduring acidification that brought the 9 m sampling location closer to the sediment. In contrast to findings elsewhere, acidification of Little Rock Lake had no effect on rates of nitrification during winter ice-cover. Dissolved silica concentrations increased slightly at pH 4.7, probably because of a pH-induced decrease in the diatom population, but hydrologicfactors were more important in controlling silica levels than waspH. Most of the predictive hypotheses made about the effects ofacidification on nutrient forms and processes or their recoveryin the lake were qualitatively correct.     

Ionic composition and distribution in saline seeps of southwestern North Dakota,U.S.A.

Saline seeps, a common problem in the Northern Great Plains, were studied at four sites in southwestern North Dakota. Saturation extracts within seeps were dominated by sodium, magnesium, and sulfate. Where present, gypsum controlled calcium concentrations. Ionic distributions within and around seeps were influenced by precipitation and re-solution reactions, freeze-thaw phenomena, and ion pairing. Ion pairing reduced Ca²⁺ and Mg²⁺ activities to a greater extent than Na⁺, resulting in elevated SAR levels in seeps and surrounding soils. Dryland salinity resulted in a form of desertification around seep areas.     

Distribution of mercury in the aquatic food web of Onondaga Lake,New York

Historical discharges of mercury (Hg) to Onondaga Lake, New York, have resulted in elevated Hg concentrations in lake fishes. In 1990, a remedial investigation and feasibility study (RI/FS) was initiated to evaluate problems related to Hg and other hazardous substances in the lake. As part of the RI/FS, the distribution of Hg in the aquatic food web was determined to provide input to a site-specific model of Hg cycling and to evaluate potential ecological risks of Hg in the lake. Mercury concentrations were measured in surficial sediments, sediment interstitial water, lake water, phytoplankton, Zooplankton, benthic macroinvertebrates, and fishes (including planktivores, benthivores, and piscivores). The percentage of total Hg accounted for by methyl-Hg (CH₃Hg) generally increased with higher trophic levels, confirming that CH₃Hg is more efficiently transferred to higher trophic levels than is inorganic Hg. Concentrations of total Hg in amphipods and chironomids were closely related to concentrations of total Hg in sediments, suggesting that sediments are a likely source of Hg for benthic macroinvertebrates. Mercury concentrations in edible muscle tissue (fillets) of lake fishes have declined substantially from values found in the early 1970s, reflecting the large reductions in Hg discharges to the lake that have occurred since that time. The CH₃Hg concentrations in fillets and whole bodies of fishes generally were similar, indicating that concentrations in fillets often can provide estimates of concentrations in whole bodies. Methyl-Hg concentrations and bioaccumulation factors increased with higher trophic levels in both the pelagic and benthic components of the lake food web.     

Soil-geomorphology relations in mountains of Oregon,U.S.A.

The development and distribution of soils in the Coast Range and Klamath Mountains are related to geomorphic surfaces and slope gradients. Soils over basalt, studied in the Coast Range, were formed in transported materials and include examples of more than a half dozen great groups of the Alfisol, Inceptisol, Mollisol, and Ultisol orders. Distribution patterns of the soils can be related to active slopes, metastable slopes, pediments, ridge tops, flood plains, and alluvial fans. Variables among the factors of soil formation in the Coast Range are chiefly geomorphic surfaces and parent materials.Soils of a lithosequence of pyroclastics, granite and schist in the Klamath Mountains include examples of great groups in the Entisol, Inceptisol, and Mollisol orders. All soils from pyroclastics have argillic horizons, those from granite lack argillic horizons, and those from schist lack argillic horizons except on relatively stable surfaces. Average thicknesses of soils over saprolite range from 76 cm over granite and schist to 150 cm over pyroclastics.Lithologic discontinuities are common in both mountain areas. Field techniques for identification, described briefly, include stone lines, irregular distribution of rock fragments with depth, thicknesses of weathering rinds on rock fragments, and the lateral extensions of soil horizons.     

Sangamon paleosols of southwestern Indiana,U.S.A.

In southwestern Indiana, the Sangamon paleosol transgresses Illinoian glacial drift and weathered bedrock of Pennsylvanian and Mississippian ages in an unglaciated area. The paleosol is buried beneath Wisconsin age loess that thins from 3.2 to 0.5 m in a distance of 83 km eastward from the Wabash River Valley. The buried soil is redder, has more clay in the illuvial horizon, and also has a thicker solum than overlying ground soils formed in loess. Base saturation and pH states of the paleosol relate to secondary enrichment after burial. Free iron-oxide content relates to redder colors and is a genetic property of the buried soils. Greater depletion of illite and chlorite in the paleosol shows that it is more weathered than the overlying ground soil. Pedologic contrasts permit recognition of the Sangamon stage as an event of greater magnitude in the Quaternary than all postloess and Recent time in southwestern Indiana.The Sangamon paleosol has the redder colors and forest-soil profiles on well-aerated, upland, paleogeomorphic sites for a distance of 1000 km to the west. The Sangamon environment probably was uniformly warm, humid forest and woodland not unlike the climatic-vegetation pattern in southern United States today. The present ground soils have more diverse patterns ranging from forest soils in Indiana westward through grassland prairie soils to grassland chernozemic soils of the easternmost Great Plains and with related humid to dry subhumid climates.