ATMOSPHERIC INPUT 



Atmospheric deposition of ma- 

 terials in the form of wet fall and 

 dry fall has been identified as a 

 significant source of metals and cer- 

 tain organic compounds to the Great 

 Lakes. In order to determine the 

 importance of atmospheric inputs to 

 the Chesapeake Bay, a network of ten 

 sampling stations fringing the bay 

 has been established. At each sta- 

 tion, both wet fall and dry fall will 

 be continuously collected using Aero- 

 chem Metric model 301 samplers. Ex- 

 tensive chemical analysis will be 

 performed on all of the samples for 

 inorganic constituents, and on se- 

 lected samples for organic compounds 

 to provide an assessment of the types 

 and amounts of materials contributed 

 to the estuary from the atmosphere. 



partition coefficients, as a measure 

 of bioaccumulation potential. The 

 toxic screening protocol is being 

 developed for the states of Maryland 

 and Virginia under contract with the 

 Monsanto Research Corporation. 



The toxic chemical identifica- 

 tion involves the use of gas chroma- 

 tograph/mass spectrometer procedures 

 which are compatible with those of 

 Dr. Robert Huggett of the Virginia 

 Institute of Marine Science who is 

 measuring toxic organic chemicals in 

 sediments and benthic biota from the 

 bay. Both procedures utilize compu- 

 ter capability to identify specific 

 compounds and to store the data base 

 and "finger-prints" of unknown chem- 

 icals for future reference. 



BASELINE SEDIMENT STUDIES 



POINT SOURCE ASSESSMENT 



Two approaches are being used to 

 obtain data on toxic chemical load- 

 ings from point sources to the bay. 

 The first approach utilizes informa- 

 tion available from the National 

 Pollution Discharge Elimination Sys- 

 tem permits. From these permits es- 

 timates can be made on the volume of 

 industrial discharges to the bay. 

 Knowledge of industrial chemical 

 processes will give information on 

 the expected kinds of chemicals and a 

 first order estimate of their 

 effluent concentration. The second 

 approach is also qualitative. It 

 involves the identification of a wide 

 range of toxic organic chemicals as 

 part of a toxic screening protocol. 

 Approximately 30 effluents will be 

 examined from plants discharging 

 effluents into the bay and its tidal 

 tributaries. The work includes chem- 

 ical analysis of the effluents, the 

 development of a set of bioassays 

 and the application of octanal/water 



The Chesapeake Bay Program is 

 conducting an intensive survey of the 

 physical, chemical and biological 

 characteristics of the sediments of 

 the Chesapeake Bay estuary. Surface 

 sediment is being sampled on a kilo- 

 meter grid in the Maryland portion of 

 the bay and on a 1.4 kilometer grid 

 in the Virginia portion of the bay. 

 The surface sediment samples are be- 

 ing analyzed for particle size dis- 

 tribution, and the content of water, 

 carbon and total sulphur. Maps por- 

 traying these parameters are in prep- 

 aration. In addition, maps showing 

 the areas of sediment accumulation 

 and erosion on the bay bottom have 

 been compiled. Rates of sedimenta- 

 tion have been determined independ- 

 ently using Pb geochronology and 

 pollen biostratigraphy . 



A set of surface sediment 

 samples and cores (1-meter depth) 

 from selected transects across the 

 bay has been analysed for a suite of 

 trace metals. Interstitial water 

 chemistry has been investigated in 



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