Potential for microbial diuron mineralisation in a small wine‐growing watershed: from treated plots to lotic receiver hydrosystem

Abstract

This study provides strong suggestive evidence for high diuron biodegradation potential throughout its course, from the pollution source to the final receiving hydrosystem, and suggests that, after microbial adaptation, grass strips may represent an effective environmental tool for mineralisation and attenuation of intercepted pesticides.

Freshwater sediment pesticide biodegradation potential as an ecological indicator of microbial recovery following a decrease in chronic pesticide exposure: A case study with the herbicide diuron

“…In addition, and interestingly, the mineralization kinetics obtained with upstream sediments in this study (Fig. 3) were quite similar to those obtained, following the same protocol, with sediments collected in June 2007 (Pesce et al, 2009) and February 2008(Pesce et al, 2010b at the same sampling site. This temporal stability over seasons and years further strengthens the reproducibility of the observations reported here, and justifies the use of the upstream sediments as reference in the present study.…”

“…6D). In summer 2007, a similar gradual increase in diuron mineralization potential along the Morcille river was reported, with higher diuron-mineralizing ability observed in the downstream section of the river for both periphytic biofilm and sediment communities (Pesce et al, 2009). It is noteworthy that studies on the potential of natural freshwater sediments to degrade synthetic pesticides are scarce ( Kalsch et al, 1998, Larsen et al, 2000, Toräng et al, 2003and Trinh et al, 2012, but there is now convincing evidence that the capacity of microbial sediment communities to biodegrade these contaminants can increase after an in situ longterm pre-exposure to these compounds ( Toräng et al, 2003 andTrinh et al, 2012).…”

“…The ability of sediments to mineralize diuron was determined by radiorespirometry (Soulas, 1993) as described in Pesce et al (2009). Briefly, sediment samples (10 g dry weight equivalent) were immersed in 50 mL of mineral water (Volvic, Danone, France) and treated with uniformly [14C-U-ring] diuron (specific activity 567 MBq/mmol; radiochemical purity 99%; Sigma Aldrich) to reach a final diuron concentration of 10 µg L−1 in the water.…”

“…In lotic ecosystems, benthic microbial assemblages are now considered as useful potential indicators of ecological status because they integrate the effects of multiple anthropogenic disturbances and have strong capacities to adapt to novel environmental conditions (Burns andRyder, 2001 andSabater et al, 2007). Field studies have thus revealed that in situ diuron exposure can induce microbial adaptation leading to an increase in diuron tolerance in phototrophic biofilm communities (Dorigo et al, 2007, Pesce et al, 2010aand Roubeix et al, 2011 and an increase in diuron biodegradation potential of heterotrophic biofilm and sediment communities (Pesce et al, 2009). These studies clearly provide evidence that adaptation to biodegradation is strongly driven by exposure of microbial communities to diuron.…”

Herbicide Contamination of Freshwater Ecosystems: Impact on Microbial Communities

“…For example, Guash and Sabater (1998) showed that the differences in algal diversity linked to the light history of a biofilm can lead to differing responses to the presence of herbicides. Seasonal factors or spatial variability can also result in communities displaying differing diversity and differing susceptibilities to contaminants (Dorigo et al, 2009), including their ability to degrade pesticides (Pesce et al, 2009b). In a long-term laboratory experiment to test the effect of atrazine after grazing Muñoz et al (2001) demonstrated that grazers increased the toxic effect of atrazine on river biofilms.…”