Multi-residue analysis of fifty pesticides in river waters and in wastewaters.

Three sampling campaigns were performed in the Lis River (Leiria, Portugal) in February of 2018, November of 2018, and May of 2019. River water and wastewater (influent and effluent) samples of two wastewater treatment plants were target of the study. A total of 25 samples were collected and 50 pesticides were monitored, including organochlorines, triazines, pyrethroids, and organophosphorus, among others. Most of the detected pesticides were insecticides and mainly organochlorines. Concentrations between 1.29 and 2134 ng/L were found. Aldrin, γ-HCH, and cypermethrin were detected in some samples in µg/L, being γ-HCH the pesticide most frequently detected with concentration in µg/L level. The pesticides with the highest detection frequency were (i) cypermethrin, HCB, methoxychlor, and ζ-HCH in river waters; (ii) isoproturon, cypermethrin, methoxychlor, pyrimethanil, γ-HCH, dieldrin, diuron, α-HCH, and α-endosulfan in effluents; and (iii) diuron and isoproturon in influents. The detection of the organochlorides and their degradation products is a consequence of their persistence in the environment, as their usage has long been prohibited in the European Union. Pesticides were grouped by their types in herbicides, insecticides, or fungicides and the detection and concentration for each type were discussed with the climatic conditions. Pesticide toxicity index was determined in the samples collected in the river.

Monitoring survey of caffeine in surface waters (Lis River) and wastewaters located at Leiria Town in Portugal.

Investigation during 11-month period was performed to study the presence of caffeine in the Lis River in Leiria Town in Portugal, and a monitoring during 9-month period was realized to check the contribution of the human pollution of two wastewater treatment plants (WWTPs) that discharge their effluents to the studied river. The samples were collected in five sampling points along the river and in two influents and two effluents of the studied WWTPs. Caffeine was detected in all ninety-one collected samples. The caffeine concentration ranged from 25.3 to 321 ng/L in the river samples, from 112 to 1927 ng/L in the WWTP effluents, and from 9478 to 83,901 ng/L in the WWTP influents. The highest concentration in the river was detected in the two sampling points located after the effluent discharge points and reached 315 and 321 ng/L. Risk assessment was performed for three trophic levels using the risk quotient calculation and revealed that caffeine do not cause toxic effect on Daphnia magna and on fish but could be possibly toxic to algae. The results proved that caffeine can be an effective indicator of human-born pollution.

Assessment of 83 pharmaceuticals in WWTP influent and effluent samples by UHPLC-MS/MS: Hourly variation.

The removal efficiency of pharmaceuticals in wastewater treatment plants (WWTPs) is variable and some of these compounds pass these plants almost intact and others presenting a removal efficiency close to 100%. Their incomplete removal results in a continuous discharge of pharmaceuticals into the environment. To assess the profile of contamination of influents and effluents over a day, a set of 83 pharmaceuticals were evaluated hourly in a WWTP in Leiria, Portugal. The composite samples of the influent and effluent were also collected. Concentrations varied from 1 in WWTP influents, and carbamazepine, fluoxetine, sertraline the pharmaceuticals with an RQ > 1 in WWTP effluents.

Presence of pharmaceuticals in the Lis river (Portugal): Sources, fate and seasonal variation.

The occurrence of 33 pharmaceuticals and metabolites was evaluated along the Lis river and in the influents and effluents of two wastewater treatment plants (WWTPs) located along the river. Results indicate that pharmaceuticals, such as ibuprofen, ketoprofen, carbamazepine and fluoxetine, and the metabolite salicylic acid are widespread along the Lis river, showing 100% of detection frequency, at levels up to 1.3µgL-1. The number of molecules detected increased along the river, with 11 molecules in the source, 15 upstream WWTP 1, 16 downstream WWTP 1 and upstream WWTP 2 and 19 downstream WWTP 2. The highest concentrations were often found downstream near the river mouth. Different possible sources of contamination of the Lis river were identified, namely WWTP effluents, untreated wastewaters and livestock production. Nevertheless, the discharge of WWTP effluents appeared to be the most pronounced, given that, in general, it was noticed an increase in the concentration of pharmaceuticals downstream of the WWTPs. WWTP effluents contributed with a total mass load of pharmaceuticals into the Lis river between 470 and 2317mg/d/1000 inhabitants. Non-steroidal anti-inflammatory drugs/analgesics were the therapeutic group with a high contribution to the total mass load of pharmaceuticals entering the Lis river, followed by psychiatric drugs and antibiotics. No seasonal variation was observed for the detected concentrations of pharmaceuticals. At the levels detected in the Lis river, sulfamethoxazole, clarithromycin, azithromycin and ibuprofen showed to have potential risk for aquatic organisms. These findings show that further studies embracing different environmental compartments (water, sediment and biota) are needed, in order to evaluate the partition/distribution of pharmaceuticals, their metabolites and transformation products in the environment as well as to predict their possible impact to non-target organisms and, in a last instance, to human health.