MARINL CONTAMINANTS 



Figure X-15 — COMPARISON OF CAUCASIAN DUST FALL 

 AND THE SOVIET ECONOMY 



240 



160 



E 



80 



DUST FALL IN CAUCASUS 



AMOUNT IN CAPITAL STOCK 



III 



250 



1930 



1940 



1950 



1960 



The diagram shows a close correspondence between (a) measurements of fallout 

 of atmospheric dust in milligram per liter, as measured in glaciers of the Caucasus 

 mountains, and (b) the amount of capital stock (equivalent inventories, building and 

 livestock) in the Soviet economy expressed in billions of 1937 rubles. 



environment may be seen in the find- 

 ing of talc as a common constituent 

 of atmospheric dusts. This mineral 

 is rare in land soils, but appeared 

 ubiquitous in solids collected from 

 air masses, as well as in glacial snows 

 deposited before 1946. This talc 

 arises from its use as a carrier and 

 diluent for pesticides in surface and 

 aerial spraying of agricultural crops. 



Direct measurements of chlorinated 

 hydrocarbon pesticides and their resi- 

 dues have followed the discovery of 

 talc in these domains. Comparisons 

 of the contributions of river-borne 

 and atmospherically transported pes- 

 ticides to the marine environment 

 have been made and both appear to 

 be of the same order of magnitude. 

 The atmospheric estimates based on 



particle collection are clearly under- 

 estimates, inasmuch as some of the 

 pesticides are carried to the marine 

 environment in the vapor phase. 

 Nonetheless, these mechanisms for 

 conveying pesticides to areas of the 

 oceans where river influxes appear 

 to be slight do explain the increasing 

 levels of chlorinated hydrocarbons 

 appearing in birds and fish. 



Interactions of Contaminants and 

 the Atmosphere-Ocean System 



The interactions of airborne con- 

 taminants with the marine biosphere 

 are more speculated upon than estab- 

 lished. The scientific literature is re- 

 plete with tales of woe concerning 

 the possible effects of pesticides on 



the photosynthetic activities of marine 

 algae and a consequential loss of oxy- 

 gen from our atmosphere. Recent 

 investigations do indicate that photo- 

 synthesis and growth of some species 

 of marine phytoplankton can be ad- 

 versely affected by exposure to chlori- 

 nated hydrocarbons; others show a 

 complete insensitivity. But to ex- 

 trapolate such findings to a possible 

 elimination of all photosynthetic ac- 

 tivity in the oceans appears un- 

 warranted, inasmuch as the factors 

 governing the gross production of 

 organic matter in marine plants are 

 still incompletely determined. 



On the other hand, present-day 

 experimental and monitoring data do 

 suggest that there is a significant 

 decrease in the productivity of estua- 

 rine fish and shellfish as a result of 

 the ingestion of DDT and its residues, 

 some of which is airborne from the 

 continents. Further, it appears that 

 the resistant surviving animals are 

 able to concentrate and transmit toxic 

 quantities of these residues in the 

 food chain. The reproductive suc- 

 cesses of seabirds has decreased due 

 to interferences with their normal cal- 

 cium metabolism by the high body 

 burdens of these halogenated hydro- 

 carbons. These birds, feeding on 

 marine fish, are at the upper levels 

 in the food chain. The marine fish are 

 building up levels of these pesticides 

 that equal, and sometimes exceed, 

 those of their freshwater counter- 

 parts. The ocean waters act as a 

 reservoir for these river- and wind- 

 transported materials, while the re- 

 birth of rivers every year often results 

 in lower concentrations even though 

 the rivers are closer to their points 

 of origin. 



These studies with DDT and its 

 residues are providing a most impor- 

 tant pattern to study the polycholori- 

 nated biphenyls (PCBs) — another 

 industrial chemical group, most prob- 

 ably dispersed through the atmos- 

 phere, that is appearing in marine 

 fish and birds. Manufactured since 

 1929, PCBs are used as plasticizers, 

 transformer fillings, solvents for 



359 



