Risk assessment of herbicides and booster biocides along estuarine continuums in the Bay of Vilaine area (Brittany, France)

Abstract

A 2-year study was implemented to characterize the contamination of estuarine continuums in the Bay of Vilaine area (NW Atlantic Coast, Southern Brittany, France) by 30 pesticide and biocide active substances and metabolites. Among these, 11 triazines (ametryn, atrazine, desethylatrazine, desethylterbuthylazine, desisopropyl atrazine, Irgarol 1051, prometryn, propazine, simazine, terbuthylazine, and terbutryn), 10 phenylureas (chlortoluron, diuron, 1-(3,4-dichlorophenyl)-3-methylurea, fenuron, isoproturon, 1-(4-isopropylphenyl)-3-methylurea, 1-(4-isopropylphenyl)-urea, linuron, metoxuron, and monuron), and 4 chloroacetanilides (acetochlor, alachlor, metolachlor, and metazachlor) were detected at least once. The objectives were to assess the corresponding risk for aquatic primary producers and to provide exposure information for connected studies on the responses of biological parameters in invertebrate sentinel species. The risk associated with contaminants was assessed using risk quotients based on the comparison of measured concentrations with original species sensitivity distribution-derived hazardous concentration values. For EU Water Framework Directive priority substances, results of monitoring were also compared with regulatory Environmental Quality Standards. The highest residue concentrations and risks for primary producers were recorded for diuron and Irgarol 1051 in Arzal reservoir, close to a marina. Diuron was present during almost the all survey periods, whereas Irgarol 1051 exhibited a clear seasonal pattern, with highest concentrations recorded in June and July. These results suggest that the use of antifouling biocides is responsible for a major part of the contamination of the lower part of the Vilaine River course for Irgarol 1051. For diuron, agricultural sources may also be involved. The presence of isoproturon and chloroacetanilide herbicides on some dates indicated a significant contribution of the use of plant protection products in agriculture to the contamination of Vilaine River. Concentration levels and associated risk were always lower in estuarine sites than in the reservoir, suggesting that Arzal dam reduces downstream transfer of contaminants and favors their degradation in the freshwater part of the estuary. Results of the additional monitoring of two tidal streams located downstream of Arzal dam suggested that, although some compounds may be transferred to the estuary, their impact was probably very low. Dilution by marine water associated with tidal current was also a major factor of concentration reduction. It is concluded that the highest risks associated to herbicides and booster biocides concerned the freshwater part of the estuary and that its brackish/saltwater part was exposed to a moderate risk, although some substances may sometimes exhibit high concentration but mainly at low tide and on an irregular basis.

Microalgal sensitivity varies between a diuron-resistant strain and two wild strains when exposed to diuron and irgarol, alone and in mixtures

“…In Singaporean coastal waters, irgarol concentrations in the range of 3e4 mg L À1 have been reported (Basheer et al, 2002). As for diuron, concentrations from 11 to 33 ng L À1 were reported in Mediterranean coastal waters (Munaron et al, 2012), and 0.268 mg L À1 in Vilaine Bay (Caquet et al, 2013). The highest concentrations reported in European rivers and ground waters have been 0.279 mg L À1 and 0.864 mg L À1 , respectively (Loos et al, 2009(Loos et al, , 2010.…”

“…Along the French coasts, average irgarol concentrations from 10 to 40 ng L À1 were found in Arcachon Bay, while concentrations up to 0.1 mg L À1 were reported in Arcachon port (Auby and Maurer, 2004). More recently, irgarol concentrations up to 0.186 mg L À1 were reported in Vilaine Bay (Caquet et al, 2013). In Singaporean coastal waters, irgarol concentrations in the range of 3e4 mg L À1 have been reported (Basheer et al, 2002).…”

Atrazine, triketone herbicides, and their degradation products in sediment, soil and surface water samples in Poland

“…According to our best knowledge, there is a scarce current data concerning the monitoring of ATR in European environment (Price et al 2006; Caquet et al 2013; Farlin et al 2013, Ouyang et al 2016a). The main attention is paid to degradation and transformation of ATR during water treatment processes (Baranda et al 2012; Lekkerkerker-Teunissen et al 2012; Yixin et al 2014; Cheng et al 2016), its toxicity (Roustan et al 2014) or sorption behaviour in soil (Prado et al 2014; Nachimuthu et al 2016; Ouyang et al 2016b).…”

Toxicity of environmental Gesagard to goldfish may be connected with induction of low intensity oxidative stress in concentration- and tissue-related manners

“…For example, prometryn concentrations of 0.078-4.40 g L −1 were measured in surface water in Greece (Vryzas et al, 2011) whereas, in surface waters of Western France, prometryn was detected at concentrations from 0.1 to 0.44 g L −1 (Caquet et al, 2013). The highest environmental concentration of prometryn (0.51 g L −1 ) was detected in Czech rivers (Stará et al, 2014).…”