Does Long-Term Irrigation with Untreated Wastewater Accelerate the Dissipation of Pharmaceuticals in Soil?

Abstract

Long-term irrigation with untreated wastewater may increase soil microbial adaptation to pollution load and lead to enhanced natural attenuation. We hypothesized that long-term wastewater irrigation accelerates the dissipation of pharmaceuticals. To test our hypothesis we performed an incubation experiment with soils from the Mezquital Valley, Mexico that were irrigated for 0, 14, or 100 years. The results showed that the dissipation half-lives (DT50) of diclofenac (<0.1-1.4 days), bezafibrate (<0.1-4.8 days), sulfamethoxazole (2-33 days), naproxen (6-19 days), carbamazepine (355-1,624 days), and ciprofloxacin were not affected by wastewater irrigation. Trimethoprim dissipation was even slower in soils irrigated for 100 years (DT50: 45-72 days) than in nonirrigated soils (DT50: 12-16 days), was negatively correlated with soil organic matter content and soil-water distribution coefficients, and was inhibited in sterilized soils. Applying a kinetic fate model indicated that long-term irrigation enhanced sequestration of cationic or uncharged trimethoprim and uncharged carbamazepine, but did not affect sequestration of fast-dissipating zwitterions or negatively charged pharmaceuticals. We conclude that microbial adaptation processes play a minor role for pharmaceutical dissipation in wastewater-irrigated soils, while organic matter accumulation in these soils can retard trimethoprim and carbamazepine dissipation.

Assessing the ecological long-term impact of wastewater irrigation on soil and water based on bioassays and chemical analyses

“…Also for trimethoprim and diclofenac, detection in wastewater irrigated soils has been reported from field studies (Dalkmann et al, 2014;Grossberger et al, 2014), while metoprolol has been detected in crops irrigated with treated wastewater (Prosser and Sibley, 2015). The agreement of our findings (Fig.…”

“…Soil accumulation and persistence potential is known for carbamazepine from soils irrigated with treated wastewater (Dalkmann et al, 2014;Grossberger et al, 2014) and can be assumed for benzotriazole due to high effluent concentrations and low biodegradability (Reemtsma et al, 2010). Also for trimethoprim and diclofenac, detection in wastewater irrigated soils has been reported from field studies (Dalkmann et al, 2014;Grossberger et al, 2014), while metoprolol has been detected in crops irrigated with treated wastewater (Prosser and Sibley, 2015).…”

Pharmaceuticals in soils of lower income countries: Physico-chemical fate and risks from wastewater irrigation

“…Nevertheless, other factors, such as soil aeration, moisture content, temperature and patterns of API use, form emitted and mode of emission (episodic or continuous) will also play a role (Dalkmann et al, 2014;Jjemba, 2006). For APIs, of which N80% are ionisable at environmental pH (5-9), predicting how changes in the soil environment influence the ionisation of the molecule and its resulting lipophilicity and hence its behaviour and fate (accumulation, abiotic and biotic degradation, leaching), is an area of ongoing research with respect to exposure and environmental risk assessment (Boxall et al, 2012;ECETOC, 2013a).…”

From consumption to harvest: Environmental fate prediction of excreted ionizable trace organic chemicals

“…Accumulation of pharmaceuticals was shown in soils irrigated partially or entirely with treated wastewater (Kinney et al, 2006;Calder onPreciado et al, 2011). Long-term exposure to untreated wastewater was additionally found not to enhance the biological removal of pharmaceuticals in soils (Dalkmann et al, 2014). Data on the effects of irrigation with wastewater on plant uptake of pharmaceuticals are still scarce in the literature.…”