terça-feira, 11 de março de 2008

Água contaminada nos EUA

Nos EUA as pessoas ficaram chocadas ao descobrir que bebem água cheia de resíduos de remédios. Isto porque nem tudo o que a gente usa fica na gente. Uma boa parte sai sem nem ter sido metabolizada, outra sai como metabólitos da substância original. Mas sai. E vai parar na água, no solo, no ambiente. Resumindo, a gente acaba bebendo de novo o que não foi removido pelo sistema de filtragem.
Ah, precisa também lembrar que água não pára na fronteira e poluição não precisa de passaporte.
Vale também recordar que a notícia não é tão nova assim. Já em 2002 a coisa rolava solta:

Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance.
Kolpin DW, Furlong ET, Meyer MT, Thurman EM, Zaugg SD, Barber LB, Buxton HT.
US Geological Survey, Iowa City, Iowa 52244, USA. dwkolpin@usgs.gov
To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during 1999 and 2000. The selection of sampling sites was biased toward streams susceptible to contamination (i.e. downstream of intense urbanization and livestock production). OWCs were prevalent during this study, being found in 80% of the streams sampled. The compounds detected represent a wide range of residential, industrial, and agricultural origins and uses with 82 of the 95 OWCs being found during this study. The most frequently detected compounds were coprostanol (fecal steroid), cholesterol (plant and animal steroid), N,N-diethyltoluamide (insect repellant), caffeine (stimulant), triclosan (antimicrobial disinfectant), tri(2-chloroethyl)phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite). Measured concentrations for this study were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria. Many compounds, however, do not have such guidelines established. The detection of multiple OWCs was common for this study, with a median of seven and as many as 38 OWCs being found in a given water sample. Little is known about the potential interactive effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of OWCs in the environment. In addition, results of this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of OWCs in the hydrologic system but also their ultimate overall effect on human health and the environment.

Nenhum comentário: