The effect of PFOs on the uptake and translocation of emerging contaminants by crops cultivated under soil and soilless conditions.

The Mediterranean is a region of substantial agriculture production that faces concurrent environmental stresses and freshwater pollution given the occurrence of emerging contaminants (ECs). Among these pollutants, the surface-active substances have been suggested to enhance the bioavailability of other ECs. This research evaluates a comparative uptake and translocation assessment of irrigation exposure to atenolol (ATN, 60 µg/L), carbamazepine (CBZ, 60 µg/L) and triclosan (TCS, 30 µg/L) alone vs. these combined with perfluorooctanesulfonic acid (PFOS, 10 µg/L) under semifield (i.e., soil experimental set) vs. hydroponics (i.e., soilless experimental set) growing conditions with lettuce, radish and tomato plants. Both experimental sets revealed efficient root uptake and translocation for the three ECs regardless of their co-existence with PFOS. The overall results of the uptake and translocation of the ECs in the lettuce and tomato plants suggested a simultaneous treatment-plant organ interaction, which was not affected by PFOS being present in both experimental sets. PFOS in irrigation water did not increase cellular perviousness to the other three ECs. These observations support the hypothesis of factors other than PFOS being responsible for the differential bioaccumulation and translocation potentials seen in both experimental sets. However, the radish plants co-irrigated with PFOS brought about increased movement of ECs from roots to aerial parts, more specifically ATN and CBZ in the soil experimental set, and ATN and TCS in the soilless set. These results support the notion that factors inherent to the physiological characteristics of this root vegetable contributed to ECs' increased tendency to move from roots to aerial parts. Despite the three ECs efficiently accumulating, the risk to humans from eating the edible parts of these plants grown under soil or soilless conditions was low.

Uptake of atenolol, carbamazepine and triclosan by crops irrigated with reclaimed water in a Mediterranean scenario.

Water scarcity is a natural condition in the Mediterranean rim countries. In this region, reuse of reclaimed water (RW) from wastewater treatment plants (WWTPs) is becoming a potential source for highly water-demanding activities such as agriculture. However, the removal capacity of contaminants in regular WWTPs has been found to be limited. Considering a Mediterranean scenario, this research investigated the plant uptake and translocation of three representative pharmaceuticals and personal care products (PPCPs) typically present in RW samples from a WWTP located in an urban area in Spain, and assessed the potential risk to humans from plant consumption. The RW samples were collected and analyzed for three representative PPCPs (atenolol -ATN-, carbamazepine -CBZ- and triclosan -TCS-). The target contaminants were also spiked at two levels in the RW samples to consider two worst-case scenarios. Three plant models (lettuce, maize and radish) were grown outdoors and irrigated with four treatments: tap water; RW samples, and the two spiked RW samples. Generally speaking, results revealed an efficient root uptake for the three PPCPs regardless of plant species and fortification level, and suggested an interaction effect of treatment and plant organ. Different bioaccumulation and translocation potentials of the three PPCPs were seen into the aerial organs of the plants. Overall, these observations support the idea that factors including the physico-chemical properties of the PPCPs and physiological plant variables, could be responsible for the differential accumulation and translocation potentials observed. These variables could be critical for crops irrigated with RW in regions with extended dry seasons, high solar incidence and low annual rainfall such as those in the Mediterranean rim where plants are subjected to high transpiration rates. However, the results obtained from this experimental approach suggested a negligible risk to humans from consumption of edible plants irrigated with RW samples with presence of PPCPs, despite the fact that the three representative PPCPs under study accumulated efficiently in the plants.

Uptake of perfluoroalkyl substances and halogenated flame retardants by crop plants grown in biosolids-amended soils.

The bioaccumulation behavior of perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) was examined in three horticultural crops and earthworms. Two species, spinach (Spinacia oleracea) and tomato (Solanum lycopersicum L.), were grown in field soil amended with a single application of biosolids (at agronomic rate for nitrogen), to represent the scenario using commercial biosolids as fertilizer, and the third crop, corn (Zea mays) was grown in spiked soil (~50mg PFOS/kg soil, ~5mg Deca-BDE/kg soil and a mixture of both, ~50mg PFOS and ~5mg Deca-BDE/kg soil) to represent a worst-case scenario. To examine the bioaccumulation in soil invertebrates, earthworms (Eisenia andrei) were exposed to the spiked soil where corn had been grown. PFASs and HFRs were detected in the three crops and earthworms. To evaluate the distribution of the compounds in the different plant tissues, transfer factors (TFs) were calculated, with TF values higher for PFASs than PBDEs in all crop plants: from 2 to 9-fold in spinach, 2 to 34-fold in tomato and 11 to 309-fold in corn. Bioaccumulation factor (BAF) values in earthworms were also higher for PFASs (4.06±2.23) than PBDEs (0.02±0.02).

Semifield assessment of the runoff potential and environmental risk of the parasiticide drug ivermectin under Mediterranean conditions.

INTRODUCTION: The antiparasitic ivermectin is of particular concern to regulatory agencies. Ivermectin can reach the environment through the direct emission of dung from livestock on pasture and via manure application on agricultural lands. METHODS: A semifield study was conducted for assessing the ivermectin dynamic in runoff and drainage waters from dung-treated soils placed on experimental trays. The experiment was conducted under natural Mediterranean conditions. Realistic pasture and arable land applications were assessed using dung of treated animals and compared with a positive control (spraying the ivermective solution without dung). RESULTS: Similar concentrations were obtained in all three treatments for drainage waters, with values ranging from <5-10 to about 20 ng/l. However, strong treatment-related variation was observed in runoff waters, with the highest concentrations found in the spray treatment (9-188 ng/l), followed by the arable land (<5-88 ng/l) scenario, and concentrations not exceeding 6 ng/l in the pasture scenario. Ivermectin levels in runoff particles were up to 1,660 and 5,890 ng/kg dry weight for the pasture (I1) and arable land (I2) scenarios, respectively. Ivermectin was only detected in the drainage and runoff waters collected in the first rainfall events after treatment. CONCLUSIONS: The measured concentrations in water (0.006-0.118 ng/ml) and runoff particles (0.052-5.89 ng/mg dry suspended matter) are orders of magnitude higher than those provoking effects on aquatic and benthonic communities under experimental and mesocosm conditions, suggesting a clear risk for aquatic systems in the vicinity of pasture areas of treated animals or arable soil fertilized with its manure.