Surfactant Effects on Environmental Behavior of Pesticides - Reviews of Environmental Contamination and Toxicology - page 71

Pesticide formulation

Spray drift

Air

Volatilization

Penetration

Crop

Photolysis

Biota

Metabolism

Accumulation

Ecotoxicity

Soil

Run-off

Surface water

Hydrolysis

Adsorption/
desorption

Adsorption Desorption

Leaching

Metabolism

Sediment

Ground water

Fig. 1 Distribution and transformation of pesticide and adjuvants after application in the environment

in crops and soil. To know the environmental behavior of surfactants, each process
in Fig. 1 has been extensively studied and monitored by many researchers together
with their ecotoxicological impacts. In addition to spray drift, runoff events would
facilitate their distribution especially in water. Pedersen et al. (2003) have identified
by gas chromatography-mass spectrometry (GC-MS) many petroleum distillates
and degradates of nonionic surfactants originating from pesticide formulations. The
occurrence of many surfactants and their degradates originating from agricultural,
laundry, and cosmetic uses has also been reported for sewage effluents, treated
sludges, natural water, and associated sediments (Eichhorn 2003; Knepper et al.
2003; Krogh et al. 2003; Sanderson et al. 2006; Ying 2006). The biodegradable
surfactants used in pesticide formulations together with their metabolites have been
scarcely detected at the total residual level exceeding around 10 ppb in most natural
surface waters and associated sediments, but more residues were detected for linear
alkylbenzene sulfonates. Thus, the high concentration of surfactants in the area of
pesticide application is generally reduced to a trace level through distribution to
other areas such as a body of water via dilution and degradation processes.