Pesticides reaching the environment as a consequence of inappropriate agricultural practices in Argentina

ARIAS, A.H.; BUZZI, N.; PEREIRA, M.T.; MARCOVECCHIO, J.H.

Pesticides

INTECH, Vienna, Austria

Lugar: Vienna; Año: 2010; p. 313 - 332

&amp;amp;amp;amp;lt;!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&amp;amp;amp;amp;gt; The environmental occurrence of pesticides is a global rather than a regional problem, since these compounds used in tropical regions can be carried by long-range atmospheric transport and ultimately end-up in polar and environmentally pristine regions. As consequence, in 2001, the Stockholm Convention on Persistent Organic Pollutants has acknowledged some of them as a global problem. Pesticides have numerous effects in organisms, causing general stimulation of the nervous system, endocrine disruption and food chain biomagnifications. Consequently, apart from the global relevance, environmental problems associated with toxic pesticides in developing countries are of great concern. One of the main causes of these compounds reaching urban areas could be the transport of polluting agents from crop-growing areas to air, water and other natural resources, via different pathways. The applied pesticides can be carried through surface run-off, leaching and vapor phase and generally, estuarine and marine sediments are the temporary or long-term ultimate sinks for most of these compounds. Consequently, sediments and soil act later as secondary sources of these substances reaching the ocean and biota. As an agricultural country, Argentina was estimated from 26 to 30 million hm2 of farmland using pesticides in the period 2005-2008. It is stated that during pesticides application, up to 30-50% of the applied amount can be lost to the air. Assuming an average dose of a 4.3 kg.hm-1, the amount of pesticides used range between 112 to 129 million Kg with losses to the environment ranging from 33.6 to 64.5 million Kg per year (this means a minimum of about 1 Kg of pesticide in the environment per habitant). In addition, this estimate is not considering that the number of treatments has increased in the last decade, with 66% of the cropped area using two or more herbicide types, and 80% using two or more insecticides during treatment. One of the main reasons of the pesticides release to the environment appears to be the airborne drift and evaporation of effective pesticides. Then, these compounds enter in a cycle which includes degradation pathways (hydrolysis in water and soils, photolysis, reaction with OH radicals in the atmosphere and wind erosion) and subsequent deposition to the environment. Among the main variables affecting the airborne drift is the droplet size of the spray during application and environmental factors such as meteorological conditions. Although the Argentinean pesticide spraying systems do not use droplet size < 200 um -avoiding much of the airborne drifting-, pesticide application management usually relies on farmers personal decisions, with scarce regulatory control. The constant increase in biotech crops joint to inappropriate agricultural practices is leading to an increase in the pesticides release to the environment. This was documented during the last decade in several research papers focusing on pesticides traces in the soil, sediments and atmosphere. The present work gives an overview on the present agricultural practices, actual pesticides emissions and a bibliographic review of these compounds reaching the Argentinean environment.