Environmental effects of therapeutic agents used in veterinarian medicine.

YOSHIDA, N.; MOSCUZZA, C.H.; DU MORTIER, C.; CASTRO. M; FERNÁNDEZ CIRELLI, A.

Buenos Aires, Argentina

Congreso; Environmental change and rational water use; 2005

Union Geográfica Internacional (UGI)

The evolution of animal raising systems to meet the needs of a growing population is evidenced by a consistent trend toward the replacement of extensive breeding with animal feeding practices that maximize the number of livestock confined in a certain area. Veterinary medicines or drugs have become a critical component of the food-animal production system providing benefits related to animal health and growth efficiency. Animal feeding operations have begun using feedstocks fortified with these compounds for enhancing growth and feed efficiency. For a long time, the environmental effect of pesticides, detergents and other pollutants have been studied but the effect of compounds that act as therapeuthic agents and growth promoters used in veterinarian medicine has been neglected even when the amount of pharmaceutical products used in some countries per year is in the same order than the pesticide amount. This group of compounds could be interfering with biological processes in soil, development and quality of the crops, and affecting the rest of the trophic chain. A significant proportion of these compounds or their metabolites are excreted. Large quantities of biosolids and cattle excretes are used as manure for land in agriculture. Drugs and their breakdown products, once assumed to be broken down in sewage treatment plants, are showing up in streams, lakes and coastal waters. Moreover, drugs (and their breakdown products) eliminated by animals usually do not go through the same kinds of treatment processes typical for human waste before reaching streams or groundwater. Among the therapeutic agents most widely used in intensive production systems we can found antibiotics, antiparasites and growth promotors. They may be excreted intact, partial or totally metabolized, or in both forms in urine and/or feces. So, animal excretes are a source of xenobiotic compounds which transport and final fate are related with environmental conditions (precipitations, runoff, slope, characteristics of soil) of the site of emplacement of animals breeding establishments. Our aim is to study which of these componds would have influence on the environment in our country depending on their use (amount and frequency) their way of excretion, their physical and chemical properties, their amount of sorption to the soil, their biodegradability, their biological function and the biological function of their potential metabolites.