Dimethyl soil emission

Forest systems also act as sources of CO2 when controlled or uncontrolled burning and decay of litter occur. In addition, release of ethylene occurs during the flowering of various species. One additional form of emission to the atmosphere is the release of pollen grains. Pollen is essential to the reproductive cycle of most forest systems but becomes a human health hazard for individuals susceptible to hay fever. The contribution of sulfur from forests in the form of dimethyl sulfide is considered to be about 10-25% of the total amount released by soils and vegetation (12). 

A U. S. national biogenic sulfur emissions inventory with county spatial and monthly temporal scales has been developed using temperature dependent emission algorithms and available biomass, land use and climatic data. Emissions of dimethyl sulfide (DMS), carbonyl sulfide (COS), hydrogen sulfide (H2S), carbon disulfide (CS2), and dimethyl disulfide (DMDS) were estimated for natural sources which include water and soil surfaces, deciduous and coniferous leaf biomass, and agricultural crops. The best estimate of 16100 MT of sulfur per year was predicted with emission algorithms developed from emission rate data reported by Lamb et al. (1) and is a factor of 22 lower than an upper bound estimate based on data reported by Adams et al. 

Dimethyl sulfide is emitted mainly from the ocean where it is released from phytoplankton. Estimates of emission rates range from 30 to 68 Tg yr . Soils and vegetation contribute comparatively little to the global emission rate. The rate of DMS emissions evidently exceeds that of all other reduced sulfur compounds. Although this makes DMS the most important reduced sulfur compound globally, its impact is essentially confined to the marine atmosphere. The removal of DMS occurs primarily by reaction with OH radicals. 

The main sources of soil contamination are industrial and municipal waste, agrochemicals and emissions. In the soil, phthalates tend to adsorb to organic matter, where they accumulate. The soil adsorption coefficient Kqq increases with the relative molecular weight of phthalates and their decreasing solubility in water, so that bis(2-ethylhexyl) phthalate is strongly sorbed and essentially immobile, while dimethyl phthalate is very mobile. Dimethyl and diethyl phthalates can easily leach into groundwater from soils and may be partially evaporated. 

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