Herbicide micropollutants in surface, ground and drinking waters within and near the area of Zagreb, Croatia

Abstract

The frequency and mass concentrations of 13 herbicide micropollutants (triazines, phenylureas, chloroacetanilides and trifluralin) were investigated during 2014 in surface, ground and drinking waters in the area of the city of Zagreb and its suburbs. Herbicide compounds were accumulated from water by solid-phase extraction using either octadecylsilica or styrene-divinylbenzene sorbent cartridges and analysed either by high-performance liquid chromatography with UV-diode array detector or gas chromatography with mass spectrometric detection. Atrazine was the most frequently detected herbicide in drinking (84 % of samples) and ground (61 % of samples) waters in mass concentrations of 5 to 68 ng L. It was followed by metolachlor and terbuthylazine, the former being detected in 54 % of drinking (up to 15 ng L) and 23 % of ground (up to 100 ng L) waters, and the latter in 45 % of drinking (up to 20 ng L) and 26 % of ground (up to 25 ng L) water samples. Acetochlor was the fourth most abundant herbicide in drinking waters, detected in 32 % of samples. Its mass concentrations of 107 to 117 ng L in three tap water samples were the highest of all herbicides measured in the drinking waters. The most frequently (62 % of samples) and highly (up to 887 ng L) detected herbicide in surface waters was metolachlor, followed by terbuthylazine detected in 49 % of samples in mass concentrations of up to 690 ng L, and atrazine detected in 30 % of samples in mass concentrations of up to 18 ng L. The seasonal variations in herbicide concentrations in surface waters were observed for terbuthylazine, metolachlor, acetochlor, chlortoluron and isoproturon with the highest concentrations measured from April to August.

Terbuthylazine and desethylterbuthylazine: Recent occurrence, mobility and removal techniques

“…TBA was among the most detected pesticides, posing a relevant risk for the environment, with 436 positive findings, 95 of which exceeded the 'predicted no effect concentration' (Tsaboula et al 2016). In Switzerland the highest levels of the herbicide were found in April during a 4-month monitoring study of the Sion-Riddes canal, which corresponded to the period of TBA application on crops (Schopfer et al 2014), while maximum TBA and DET contamination levels were observed from April to August in surface waters of Croatia, shortly after field application of TBA (Fingler et al 2017).…”

“…TBA and DET have frequently been detected in groundwaters around Zagreb in Croatia; during a monthly campaign conducted in 2014, TBA was detected in 26% of samples, up to 25 ng L -1 (Fingler et al 2017). The Vistrenque shallow alluvial aquifer (France) was tested between 2011 and 2013, where TBA was found in 59% of the 66 samples collected, up to 40 ng L -1 (Sassine et al 2017).…”

“…While binding to the dissolved organic matter increases mobility of organic pollutants through the soil column, their sorption in soil reduces transfer from the soil surface layers to the aquifer. When the persistence of herbicides in soil is high, their dissolution becomes a long-term source of groundwater pollution (Fingler et al 2017).…”

“…Treatment technologies commonly applied in the process of drinking water production have been shown to result in only partial removal of TBA (Ormad et al 2008). The herbicide and its metabolite DET have frequently been detected in tap water samples collected in France (Cotton et al 2016), Croatia (Fingler et al 2017) and other European countries (HerreroHernandez et al 2017). Recent occurrence, and mobility, of TBA and DET in European waters are summarised in this review.…”

Dissipation dynamics of terbuthylazine in soil during the maize growing season

“…If a herbicide is applied before crop emergence (as in this study), then only a very small portion will be absorbed by plant roots (13), while the bulk will remain in soil from where it can enter surrounding waters (10,(14)(15)(16). The mobility of a herbicide (leaching/runoff) or its retention in soil (adsorption) is highly affected by its characteristics (such as hydrophobicity), soil type (pH and humus/clay content), and soil moisture level and temperature (6,8,17).…”