The Equilibrium Distribution of Semivolatile Organochloro Compounds between Atmosphere and Surface Water in the Atlantic Ocean

Abstract

The South Atlantic Ocean is of global importance as sink and source for anthropogenic pollutants. Here the distribution of polychlorinated cyclic hydrocarbons between surface water and the atmosphere in this region is shown to fit a classical thermodynamic model of a temperature‐dependent equilibrium—a new example of the concept of a global environmental chemistry.

Air-Water Equilibrium of Hexachlorocyclohexanes and Chloromethoxybenzenes in the North and South Atlantic

“…Concentrations and patterns of polychlorinated biphenyls as well as of hexachlorobenzene, dieldrin, and endosulfan were also analyzed in the air samples discussed here. These results are reported in separate papers (10,32,33).…”

“…In the case of < 10-2 (dimensionless), equivalent to a Henry's law constant H < 25 Pa m3/mol, changes in the concentration in air within 1 order of magnitude caused by the temperature dependence of Kgw affect the concentration in water, cw, on a local basis in a hardly measurable way. In this case, cw is practically constant, and the concentration in air can be expressed by (33) In cg…”

Evidence for Dynamic Air−Water Coupling and Cycling of Persistent Organic Pollutants over the Open Atlantic Ocean

“…If PCBs in air and water are in or near equilibrium, the changes in gaseous PCB concentrations as a function of temperature can be used to deduce their enthalpy of waterair exchange, ∆Hgw. This approach was used by Schreitmu ¨ller and Ballschmiter to demonstrate the close coupling of HCHs in air and water of the South Atlantic (32). When aqueous concentrations are constant, the natural logarithm of gaseous concentration is linearly proportional to 1/T, with a slope equal to ∆Hgw/R.…”

Halomethoxybenzenes in air of the Nordic region

“…Halomethoxybenzenes (HMBs: anisoles, veratroles, and related compounds), a group of compounds with natural and anthropogenic origins [ 1 , 2 ], are found in the air worldwide from the southern and northern hemispheres, over oceans and in polar regions [ [1] , [2] , [3] , [4] , [5] , [6] , [8] , [9] , [10] , [11] , [12] , [13] ]. Typical HMBs in the atmosphere are chloro-, bromo- and mixed chlorobromo-anisoles, and halogenated dimethoxy compounds [ 1 , 2 , 10 ].…”

“…Chloroanisoles (CAs) are thought to be mainly anthropogenic [ 2 ], although structurally related “chlorinated anisyl metabolites” and other chlorinated organic compounds are synthesized by terrestrial fungi [ [20] , [21] , [22] ]. Pentachloroanisole (PeCA) is a metabolite of the wood preservative pentachlorophenol (PeCP) [ 23 ] and is common in the air [ [1] , [2] , [3] , [4] , [8] , [9] , [10] , [11] , [12] , 24 , 25 ]; however, continent-wide spatial patterns of PeCA and PeCP in pine needles suggest separate origins [ 26 ]. CAs and BAs are “taste and odor” compounds arising from the disinfection of drinking water containing halogens [ 27 ], infamous for causing “cork taint” in wines [ 28 , 29 ], and mustiness in packaged food [ 30 ] and water [ 31 ].…”