Diclofenac biotransformation in the enhanced biological phosphorus removal process.

Diclofenac is a pharmaceutical active compound frequently detected in wastewater and water bodies, and often reported to be persistent and difficult to biodegrade. While many previous studies have focussed on assessing diclofenac biodegradation in nitrification and denitrification processes, this study focusses on diclofenac biodegradation in the enhanced biological phosphorus removal (EBPR) process, where the efficiency of this process for diclofenac biodegradation as well as the metabolites generated are not well understood. An enrichment of Accumulibacter polyphosphate accumulating organisms (PAOs) was operated in an SBR for over 300 d, and acclimatized to 20 µg/L of diclofenac, which is in a similar range to that observed in domestic wastewater influents. The diclofenac biotransformation was monitored in four periods of stable operation and linked to the microbial community and metabolic behaviour in each period. Nitrification was observed in two of the four periods despite the addition of a nitrification inhibitor, and these periods were positively correlated with increased diclofenac biodegradation. Interestingly, in two periods with excellent phosphorus removal (>99%) and no nitrification, different levels of diclofenac biotransformation were observed. Period 2, enriched in Accumulibacter Type II achieved more significant diclofenac biotransformation (3.4 µg/gX), while period 4, enriched in Accumulibacter Type I achieved lower diclofenac biotransformation (0.4 µg/gX). In total, 23 transformation products were identified, with lower toxicity than the parent compound, enabling the elucidation of multiple metabolic pathways for diclofenac biotransformation. This study showed that PAOs can contribute to diclofenac biotransformation, yielding less toxic transformation products, and can complement the biodegradation carried out by other organisms in activated sludge, particularly nitrifiers.

Long-term exposure to ambient air pollution and road traffic noise and asthma incidence in adults: The Danish Nurse cohort.

BACKGROUND: Ambient air pollution is likely a risk factor for asthma, and recent evidence suggests the possible relevance of road traffic noise. OBJECTIVES: We examined the associations of long-term exposure to air pollution and road traffic noise with adult-asthma incidence. METHODS: We followed 28,731 female nurses (age > 44 years) from the Danish Nurse Cohort, recruited in 1993 and 1999, for first hospital contact for asthma from 1977 until 2015. We estimated residential annual mean concentrations of particulate matter with diameter < 2.5 µm (PM2.5) since 1990 and nitrogen dioxide (NO2) since 1970 with the Danish DEHM/UBM/AirGIS modeling system, and road traffic noise (Lden) since 1970 with the Nord2000 model. Time-varying Cox regression models were used to associate air pollution and road traffic noise exposure with asthma incidence. RESULTS: During 18.6 years' mean follow-up, 528 out of 23,093 participants had hospital contact for asthma. The hazard ratios (HR) and 95% confidence intervals for asthma incidence associated with 3-year moving average exposures were 1.29 (1.03, 1.61) per 6.3 µg/m3 for PM2.5, 1.16 (1.07, 1.27) per 8.2 µg/m3 for NO2, and 1.12 (1.00, 1.25) per 10 dB for Lden. The HR for NO2 remained unchanged after adjustment for either PM2.5 or Lden, while the HRs for PM2.5 and Lden attenuated to unity after adjustment for NO2. CONCLUSIONS: Long-term exposure to air pollution was associated with adult-asthma incidence independently of road traffic noise, with NO2 most relevant. Road traffic noise was not independently associated with adult-asthma incidence.

Occurrence of antibiotics as emerging contaminant substances in aquatic environment.

The occurrence of pharmaceutical residues in the environment has become a subject of growing concern. Due to the constant input of the emerging contaminants in the surface water via wastewater which leads to the long-term adverse effects on the aquatic and terrestrial organisms, special attention is being paid to their presence in the aquatic environment. Most of the emerging substances, especially pharmaceuticals, could not be completely removed using the wastewater treatment. Pharmaceuticals are usually water soluble and poorly degradable. They can pass through all natural filtrations and then reach the groundwater and, finally, the drinking water. The trace levels of antibiotics could have a negative impact on the environment and public health because of their inherent bioactivity. This article is an overview of the presence of the antibiotic residual concentrations, methods and levels of detection and possible risks to both health and environment.

Gas-particle partitioning of persistent organic pollutants in the Western Balkan countries affected by war conflicts.

BACKGROUND, AIM, AND SCOPE: Bombing and destruction of the industrial and military targets accompanied by complete or incomplete combustion during the war conflict and NATO operation in former Yugoslavia caused the emission of persistent organic pollutants into the atmosphere, water, and soil. A total of 129 ambient air samples from 24 background, urban, and industrial sites, including hot spots, were collected to assess a gas-particle partitioning behavior of various persistent organic pollutants. MATERIALS AND METHODS: High volume sampling technique was applied with quartz filters that collect the atmospheric particles and polyurethane foam filters (PUF) that retain the gaseous compounds. Three to ten samples were taken at each site. GFs and PUFs were analyzed separately for their content of polychlorinated biphenyls, organochlorine pesticides, and polyaromatic hydrocarbons. RESULTS: Gas phase and particle phase concentrations of selected persistent organic pollutants (POPs) in all samples were converted into the particle-bound fractions Phi. These fractions were found to be highly variable, but generally highest in Bosnia and Herzegovina due to the elevated levels of total suspended material in ambient air. DISCUSSION: Experimental values of particle-associated fraction were compared to the Junge-Pankow model. Interestingly, a model for urban/industrial environments provided a better prediction of partitioning behavior than a model for background and rural background sites. That is probably because the total amount of atmospheric particles is higher in the Balkan region than found in the previously published studies. CONCLUSIONS: Even though it has been stated in previous studies that less than 5% of polychlorinated biphenyls (PCBs) are bound to the particles, up to 67% of PCBs were particle associated at several sampling sites in this study. PCB-contaminated soils are probably still one of the strong sources of particles to the atmosphere. RECOMMENDATIONS AND PERSPECTIVES: Information on the particle-bound fractions of POPs is important not only for prediction of their fate but also for an estimation of risks they can pose to the environment as well as to humans. When assessing such hazards, it has to be considered that modeled values of the particle-bound fractions can be seriously underestimated at sites with elevated levels of suspended atmospheric matter or at sites with heavily contaminated soils.