Enhanced photodegradation of diphenhydramine in aqueous solution containing natural sand particles

Co-Exposure of Nanopolystyrene and Other Environmental Contaminants-Their Toxic Effects on the Survival and Reproduction of Enchytraeus crypticus

Plastics in all shapes and sizes have become widespread across ecosystems due to intense anthropogenic use. As such, they can interact with other contaminants that accumulate in the terrestrial environment, such as pharmaceuticals, metals or nanomaterials (NMs). These interactions can potentiate combined toxic effects in the exposed soil organisms, with hazardous long-term consequences to the full ecosystem. In the present study, a terrestrial model species, Enchytraeus crypticus (oligochaeta), was exposed through contaminated soil with nanopolystyrene (representative of nanoplastics (NPls)), alone and in combination with diphenhydramine (DPH, representative of pharmaceuticals), silver nitrate (AgNO₃, representative of metals) and vanadium nanoparticles (VNPs, representative of NMs). AgNO₃ and VNPs decreased E. crypticus reproduction at 50 mg/kg, regardless of the presence of NPls. Moreover, at the same concentration, both single and combined VNP exposures decreased the E. crypticus survival. On the other hand, DPH and NPls individually caused no effect on organisms' survival and reproduction. However, the combination of DPH (10 and 50 mg/kg) with 300 mg NPls/kg induced a decrease in reproduction, showing a relevant interaction between the two contaminants (synergism). Our findings indicate that the NPls can play a role as vectors for other contaminants and can potentiate the effects of pharmaceuticals, such as DPH, even at low and sub-lethal concentrations, highlighting the negative impact of mixtures of contaminants (including NPls) on soil systems.

Evidence of low levels of trace organic contaminants in terminal lakes

Endorheic lakes (or terminal lakes, TLs) have no natural outlet other than evaporation and slow infiltration. Some TLs receive reclaimed wastewater which contains poorly removed trace organic contaminants (TrOCs). To determine if TLs accumulate TrOCs we conducted a preliminary assessment of the occurrence of ten TrOCs in three TLs receiving reclaimed wastewater and one TL which does not directly receive reclaimed wastewater. Five of ten TrOCs (carbamazepine, DEET, fluoxetine, primidone, and trimethoprim) were present in all four TLs' surface waters (~0.3-1109 ng/L), six (caffeine, carbamazepine, DEET, diphenhydramine, primidone, and trimethoprim) were present in sediment samples (0.1-77 ng/gDW) and in soil samples (0.1-137 ng/gDW). Concentrations of caffeine, carbamazepine, diphenhydramine, fluoxetine and meprobamate were significantly higher in TLs receiving wastewater from a secondary treatment plant compared to those TLs which received tertiary treated wastewater. Carbamazepine, fluoxetine, sulfamethoxazole, and trimethoprim were present at concentrations greater than is typical of other U.S. freshwater lakes, but other TrOC concentrations were present at lower concentrations than in other freshwater lakes. We conclude that some TrOCs may accumulate in TLs, but to a lesser extent than would be expected based on the accumulation of dissolved constituents alone, which indicates that there are other unidentified processes in TLs that contribute to TrOC losses. Other TLs across the globe may have similar levels of TrOCs due to anthropogenic influence and treated wastewater inputs.