Non-antibiotics matter: Evidence from a one-year investigation of livestock wastewater from six farms in East China

Pharmaceuticals, hazard and ecotoxicity in surface and wastewater in a tropical dairy production area in Latin America

Pharmaceuticals comprise a complex group of emerging pollutants. Despite the significant number of pharmaceuticals used in veterinary medicine, the input of these compounds into the environment due to livestock activities has been scarcely described. This work assays for the first time in Central America the occurrence of pharmaceuticals in farm wastewater in an area devoted to dairy production, and in the surrounding surface waters. Among 69 monitored pharmaceuticals, a total of eight compounds were detected in wastewater samples collected from seven dairy farms after three sampling campaigns. Six pharmaceuticals were considered either of high (albendazole, lovastatin and caffeine) or intermediate estimated hazard (ciprofloxacin, acetaminophen and ketoprofen) based on the HQ approach, while 26% of the samples were considered of high estimated hazard according to the cumulative ∑HQ approach. Similarly, when ecotoxicological tests were applied, all the samples showed some level of toxicity towards Daphnia magna, and most samples towards Vibrio fischeri and Lactuca sativa. Fourteen pharmaceuticals were detected in surface water samples collected in the surroundings of the dairy production farms, including rural and urban areas. Seven out of these compounds showed high estimated risk (risperidone, diphenhydramine, trimethoprim, fluoxetine, ofloxacin, caffeine and ibuprofen), while three (gemfibrozil, ciprofloxacin and cephalexin) exhibited intermediate estimated risk. In a similar worrisome way, 27% of these samples were estimated to pose high environmental risk according to the pharmaceutical content. Despite being nontoxic for D. magna or V. fischeri, frequent inhibition (>20%) of GI in L. sativa was determined in 34% of surface water samples; such findings raise concern on the apparent inceptive environmental pollution and risk within the area. According to the pharmaceutical content patterns in both kinds of studied matrices, no clear evidence of significant contamination in surface water due to livestock activities could be retrieved, suggesting a main role of urban influence.

On-farm Occurrence of Pharmaceuticals and Their Environmental Hazard: Case Study of a Tropical Dairy farm

Animal husbandry wastewaters represent an important source of pharmaceuticals into the environment. This work aimed to evaluate the occurrence of pharmaceuticals and their hazard in wastewater from a model dairy farm from Costa Rica. Among the seven pharmaceuticals detected (acetaminophen, caffeine, carbamazepine, ibuprofen, ketoprofen, risperidone, sulfamethazine), caffeine, ibuprofen and acetaminophen showed the highest concentrations, while caffeine, carbamazepine and risperidone were the most frequently detected compounds. High (HQ ≥ 1) or medium (0.1 ≤ HQ < 1) hazard were estimated for three (caffeine, ibuprofen, risperidone) and two (acetaminophen, ketoprofen) pharmaceuticals, respectively; similarly, high overall hazard (∑HQ) and significant ecotoxicity were determined in samples from all sampling points. According to our results, the release of these aqueous matrices is a matter of environmental concern, as the treated wastewater is used for farm irrigation or directly released into nearby water streams. This work contributes to the knowledge on the scarcely described occurrence and risk of pharmaceuticals in Latin American regions.

Photocatalytic degradation of sulfamethoxazole using TiO2-based materials - Perspectives for the development of a sustainable water treatment technology

Heterogeneous photocatalysis using titanium dioxide-based materials is considered a promising and innovative solution to the water pollution problem. However, due to the limitations concerning the use of the developed materials and the applied photodegradation conditions, the research on photoremediation using TiO₂ often stays behind the lab door. The challenge is to convert the basic research into a successful innovation, leading to the implementation of this process into wastewater treatment. For this purpose, the most active materials and optimal photodegradation conditions must be chosen. This article collects and compares the studies on photocatalytic degradation of an emerging pollutant - sulfamethoxazole, an antibacterial drug - and attempts to find the best approaches to be successfully applied on an industrial scale. Various types of TiO₂-based photocatalysts are compared, including different nanoforms, doped or polymer-based composites, composites with graphene, activated carbon, dyes or natural compounds, as well as possible supporting materials for TiO₂. The paper covers the impact of the irradiation source (natural sunlight, LED, mercury or xenon lamps) and water matrix on the photodegradation process, considering the ecological and economic sustainability of the process. Emphasis is put on the stability, ease of separation and reuse of the photocatalyst, power and safety of the irradiation source, identification of photodegradation intermediates and toxicity assays. The main approaches are critically discussed, main challenges and perspectives for an effective photocatalytic water treatment technology are pointed out.

Enhanced Adsorption of Sulfonamides by Attapulgite-Doped Biochar Prepared with Calcination

The extensive use of sulfonamides seriously threatens the safety and stability of the ecological environment. Developing green inexpensive and effective adsorbents is critically needed for the elimination of sulfonamides from wastewater. The non-modified biochar exhibited limited adsorption capacity for sulfonamides. In this study, the attapulgite-doped biochar adsorbent (ATP/BC) was produced from attapulgite and rice straw by calcination. Compared with non-modified biochar, the specific surface area of ATP/BC increased by 73.53−131.26%, and the average pore width of ATP/BC decreased 1.77−3.60 nm. The removal rates of sulfadiazine and sulfamethazine by ATP/BC were 98.63% and 98.24%, respectively, at the mass ratio of ATP to rice straw = 1:10, time = 4 h, dosage = 2 g∙L−1, pH = 5, initial concentration = 1 mg∙L−1, and temperature = 20 °C. A pseudo-second-order kinetic model (R2 = 0.99) and the Freundlich isothermal model (R2 = 0.99) well described the process of sulfonamide adsorption on ATP/BC. Thermodynamic calculations showed that the adsorption behavior of sulfonamides on the ATP/BC was an endothermic (ΔH > 0), random (ΔS > 0), spontaneous reaction (ΔG < 0) that was dominated by chemisorption (−20 kJ∙mol−1 > ΔG). The potential adsorption mechanisms include electrostatic interaction, hydrogen bonding, π−π interaction, and Lewis acid−base interactions. This study provides an optional material to treat sulfonamides in wastewater and groundwater.