Location: Water Quality and Ecology ResearchTitle: Contaminants of emerging concern in Zea mays: Uptake, translocation and distribution tissue patterns over the time and its relation with physicochemical properties and plant transpiration rate
|PEREZ, DEBORA - Instituto Nacional De Tecnologia Agropecuaria|
|DOUCETTE, WILLIAM - Utah State University|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2021
Publication Date: 10/7/2021
Citation: Perez, D.J., Doucette, W.J., Moore, M.T. 2021. Contaminants of emerging concern in Zea mays: Uptake, translocation and distribution tissue patterns over the time and its relation with physicochemical properties and plant transpiration rate. Chemosphere. https://doi.org/10.1016/j.chemosphere.2021.132480.
Interpretive Summary: Water is a precious commodity, especially in arid and semi-arid regions where agriculture must compete with other industries for limited resources. Reclaimed or reused water (water that has received at least secondary wastewater treatment and disinfection) is a potential source for irrigation in these agricultural regions. This raises questions about the possible movement of contaminants remaining in the reclaimed water entering the human food chain. Laboratory experiments used corn plants as test species and found two pharmaceutical drugs (the anti-convulsant carbamazepine and the antidepressant fluoxetine) as well as the herbicide atrazine were able to travel from the reclaimed water through the roots and into the shoots of the corn plants. This demonstrates the need for further examination of using reclaimed water for agricultural irrigation in order to determine potential risk to the human food supply.
Technical Abstract: Passive uptake of organic contaminants via plant roots is well documented. Uptake is often reported as concentration ratios between whole plants or specific plant compartments (e.g. roots, shoots, leaves, flower) and the exposure media (e.g. soil or water). Reported ratios are typically measured during the exposure period, and relatively few studies have investigated how changes in plant tissue concentrations over time are related to physico-chemical properties of the target compound and plant transpiration. Hydroponically grown corn ( Zea mays ) was exposed to four pharmaceutical and personal care products (PPCPs, carbamazepine -CBZ-, fluoxetine -FLX-, gemfibrozil -GBZ- and triclosan -TRI-) and the herbicide atrazine (ATZ) at environmentally relevant concentrations (20 µg/L each), and plant tissue concentrations of these compounds were determined several times over 21 days. Eighteen plants of uniform size were selected, with nine exposed to the target compounds and nine untreated. Whole plants were harvested at 7, 14 and 21 days and separated into roots, stem, leaf and male bud flower (only at 21days). Concentrations of PPCPs and ATZ in the exposure solution and various plant tissues were determined by LC-MS/MS. ATZ metabolites desisopropylatrazine (DIA) and desethylatrazine (DEA) were determined by LC-DAD. In shoot tissue, CBZ, FLX and ATZ were detected, while TRI and GBZ were detected mainly in roots. Uptake and translocation of the target compounds were described in relation with the lipophilicity (LogKow), ionization behavior (pKa), distribution coefficient (LogDow), and transpiration along the exposure time.