Atrazine groundwater contamination

Deladedova, P., Sesana, G., Bersani, M., Riparbelli, C., Maroni, M., 1996 Atrazine groundwater contamination in an intensive agricultural area west of Milan - Italy., Period 1986-1994. Proceedings of the X Symposium Pesticide chemistry, Piacenza, 669-73. 

Groundwater contamination by agrochemicals from non-point sources has been well documented in a number of countries [26-28, 30-32], The pesticides that have been detected in regional council groundwater surveys include 2,4-D, Amitrole, Picloram, Simazine and Atrazine [20]. 

Guideline values proposed by the World Health Organization based on a toxicological approach for each substance are 2 /rg/l for simazine and atrazine, and 20 /rg/l for alachlor. Directive 91/414/CE harmonizes at the European scale the principle of authorization delivery of active substances. For example, a herbicide can be introduced in the positive list of the directive Annex 1 if only the scenario takes into account toxicity, ecotoxicity, and study on presence and fate in the environment, in order to exclude aU risks of groundwater contamination at levels higher than... 

Among the triazine herbicides, atrazine has been classified as a restricted use pesticide (RUP) because of its potential for groundwater contamination. Only the certified applicators may purchase and use this compound. 

An interesting example on the question of by-products is provided by the surface and groundwater contamination by pesticides. Triazines are among the most abvmdant pesticides and since 1997, atrazine has been found in more than 50% of samples of both surface water and groundwater, while its degradation product, desethylatrazine, is the most frequently found (about half of all analyses). Other frequently found herbicides include diuron and isoproturon (urea substitute... 

Cobalt and nickel porphyrins have also been used for catalyzing the chemical dechlorination with a reductant, namely titanium(III) citrate or nanoscale Zero Valent Iron (nZVI), of e.g. atrazine, (2-chloro-4-(ethylamine)-6-(isopropylamine)-s-triazine), a widely used herbicide which is a persistent groundwater contaminant [38]. Nickel 5,10,15,20-tetrakis(l -methyl-4-pyridinium)porphyrintetra(p-toluene-sulfonate) (TMPyP) was activated by nZVI, while cobalt porphyrins (TMPyP,5,10,15,20-tetrakis(4-hydroxyphenyl)-21 H,23H-porphine-(TP(OH)P) and 4,4, 4",4 -(porphine-5,10,15,20-tetrayl)tetrakis (benzenesulfonic acid)-(TBSP)) were activated by titanium(lll) citrate as the electron donor. All these processes probably could be more efficient using electrochemical methods. 

In several AT studies, pesticide levels in the Ebro were found to be high. Hildebrandt et al. [50] found a homogeneous contamination pattern from atrazine (and also from simazine from May 2000) in intensive Rioja cultivation areas throughout the Ebro. Nearer to the delta, Barata et al. [72] found high levels of bentazone, methyl-4-chlorophenoxyacetic acid, propanil, molinate and fenitrothion in water, while Kuster et al. [71] found low concentration levels of atrazine and simazine at the delta, but high levels of other pesticides used in rice cultivation. Importantly, Hildebrandt et al. [50] found that levels of pesticides in groundwater... 

Outside Spain, the profile of pesticide contamination is fairly similar. For instance, Kolpin et al. [28] analysed pesticides in groundwater samples from the United States and found, in samples taken in 2001, triazine concentrations between 50 and 620 ng/L. In groundwater samples collected in Portugal between 2005 and 2008, atrazine and terbuthylazine were also detected [16]. 

Groundwater. Atrazine dominated the world herbicide market in the 1980s, and contamination of groundwater has been reported in several locations in the U.S., Europe, and South Africa. Successful biodegradation has been achieved with indigenous organisms in laboratory mesocosms after a lag phase, and once activity was found, it remained, It is clear that intrinsic remediation is likely to lead to the disappearance of atrazine from groundwaters. 

Jayachandran, K., T.R. Steinheimer, L. Somasundaram, T.B. Moorman, R.S. Kanwar, and J.R. Coats (1994). Occurrence of atrazine and degradates as contaminants of subsurface drainage and shallow groundwater. J. Environ. Qual., 23 311-319. 

Pionke, H.B. and D.W. Glotfelty (1990). Contamination of groundwater by atrazine and selected metabolites. Chemosphere, 6 813-822. 

It is hypothesized that the DAR may be an indicator of point-source versus nonpoint-source contamination of groundwater by atrazine (Adams and Thurman, 1991). The DAR hypothesis is predicated on the assumption that atrazine degrades slowly in an aquifer because of low organic carbon concentrations, small microbial populations, and anaerobic conditions. This is substantiated by Wehtje et al. (1983) who determined that, under aquifer conditions, atrazine did not undergo deethylation or deisopropylation, and only slowly underwent abiotic degradation to... 

Herbicides are sometimes also used in urban areas for control of weeds on railway lines and roadside verges, and around areas of hard standing. Some of the herbicides used are sufficiently persistent to be able to be washed into drains or soil, and possibly percolate into groundwater. One of the most common of these herbicides is atrazine, which has been found in the groundwater of many countries. Awareness of the potential for contaminating groundwater and careful selection of herbicides, where they are required, has significantly decreased contamination in many of the areas where it was common. 

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