The antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are considered new classes of water contaminants due to their potential adverse effects on aquatic ecosystems and human health. This paper describes the susceptibility evaluation of Escherichia coli, isolated from the influent and effluent of the biological reactors in two wastewater treatment plants (WWTP1 and WWTP2), and the evaluation of the disinfection efficiency of the UV radiation system in WWTP2. The exposure to different families of antibiotics was evaluated, namely, macrolides (erythromycin, azithromycin, clarithromycin), quinolones (ofloxacin, ciprofloxacin), nitroimidazoles (metronidazole), sulfanilamides (sulfamethoxazole) and trimethoprim, the latter is used in combination with sulfamethoxazole due to its synergistic effect. The results of the antimicrobial susceptibility tests, using disc diffusion (Kirby–Bauer) method, showed the occurrence of E. coli strains resistance. The analysis performed indicated an overall resistance (considering both influents and effluents) in WWTP1 and WWTP2, of respectively: 33.3% and 37.5% to erythromycin; 0.0% and 4.0% to azithromycin; 25.0% and 29.2% to clarithromycin; 12.5% and 4.2% to ofloxacin; 16.7% and 4.2% to ciprofloxacin; 29.2% and 12.5% to trimethoprim; 41.7% and 12.5% to sulfamethoxazole. A variability of resistance was observed along the studied period, from WWTP1 and WWTP2, and from influent to effluent. Disinfection by UV demonstrated good performance, achieving in some samples 100% removal of E. coli that has growth in TBX agar. However, a proper supervision is needed in order to achieve the allowed limits concerning the number of bacteria. The results from this work contribute to a better awareness of ARB dissemination from wastewater treatment plants to the aquatic environment.

The climate of a place has a decisive role in human adaptations. Man’s health, adaptability, behavioural patterns, food, shelter, and clothing are mainly influenced by the temperatures of the area. Hence, a study is undertaken to analyse the spatial distribution, frequency, and trend in the heat waves over the country. The statistical characteristics of heat waves over India are addressed in this study. Gridded daily temperature data sets for the period 1951–2019 were used to compute the arithmetic mean (AM), standard deviation (SD), coefficient of variation (CV), and trends of monthly maximum temperature. The number of heat wave days were identified using the criteria given by India Meteorological Department (IMD) i.e., a heat wave is recognized when the daily normal maximum temperature of a station is less than or equal to (greater than) 40 °C than it will be considered as a heat wave if the daily maximum temperature exceeds the daily normal maximum temperature by 5 °C (4 °C). The analysis was confined to the two summer months of April and May only. The spatial distribution of the AM shows higher values during May, and the core hot region with temperatures exceeding 40 °C lies over central India extending towards the northwest. The SD distribution shows higher values over the northeast of central India decreasing towards the southwest. The CV distribution shows higher values over the north decreasing toward the south. Higher numbers of heat waves are observed during May and the number is higher over Andhra Pradesh and south Telangana regions of southeast India. This study concludes that a moderate hot region experiences a higher number of heat wave days over India.

A large number of studies indicated the presence of volatile organic compounds (VOCs) of various chemical classes in indoor environments (public buildings, homes). VOCs affect the air quality indoors having an impact on human health and wellbeing. They are the result of infiltration of polluted outdoor air and emissions from various indoor sources, including building materials, consumer products (fragrances, air fresheners), activities of the occupants (cleaning) and smoking. On average, people spend a great part of their time (85 to 90%) in confined spaces (homes, office buildings and schools) exposed to a complex mixture of air contaminants at concentration levels that are often several times higher than outdoors. For many chemicals present in indoor air (and their mixtures) the risk for human health and comfort is almost unknown and difficult to predict because of the lack of toxicological data and information on the dose-response characteristics in humans or animal models. Saving of energy for homes and public buildings becomes an additional and essential criterion for the overall quality of the built environment. The need to construct airtight buildings may lead to the accumulation of air contaminants indoors and thus changing the prevailing philosophy for a healthy indoor environmental quality. The necessity emerged, in particular, for low emitting construction and building materials along with the adaptation of appropriate ventilation regimes to ensure wellbeing and comfort for building occupants. The paper provides an overview of indoor/outdoor air concentrations of volatile organic compounds in buildings. It discusses the methodological approaches and procedures applied so far to assess VOC's presence indoors and outdoors, notably benzene and formaldehyde as model compounds for indoor air quality emphasizing the needs for future research and action plans to ensure a healthy and occupant friendly indoor environment.

Drought is one of the most natural hazards that cause damage to ecosystems, agricultural production, and water resources. This study has analyzed seasonal and annual rainfall trends using monthly data series of 33 years (1983–2015) in Addis Ababa city over three stations namely; Sendafa, Bole, and Observation. Here, we examined the occurrence of historical drought trends in the study jurisdiction. The Reconnaissance Drought Index (RDI) and the Standardized Precipitation Index (SPI) were employed to find long-term drought trends as well as to examine the occurrence of drought history at a longer duration. The analysis indicated that severe drought conditions were observed for SPI and RDI indices in the year 2013 for Bole station, while medium droughts were recorded for the years 1991 and 2002 for all stations. Similarly, the RDI indices for 1996 was recorded as severe drought for the Observatory station. On the other hand, higher variability (coefficient of variation) of rainfall during winter seasons were 95.8%, 95.9%, and 77.9% for Sendafa, Bole, and Observatory stations respectively. However, the lower coefficient of variation during annual rainfall was 15.59% for Sendafa, 14.38% for Bole, and 13.98% for the Observatory station. Furthermore, the drought severity classification for the long-term drought analysis of annual precipitation shows that 3% of severe drought, 12% of moderate drought, and 85% of the normal condition were recorded in Bole station. The severe and moderate drought indices due to the reduction of rainfall, temperature change, and other factors can cause a shortage of urban water supply. Thus, the results of this study will help the water sector professionals in forecasting weather variations and for better management of urban water resources.

The carcinogenic and endocrine-disrupting PAHs were investigated in surface water of the north-western creeks of India. The concentrations of ΣPAHs were found to vary in the range of 114.32–347.04 μg L⁻¹, (mean 224.78 ± 8.85 μg L⁻¹), out of which 49.12% contribution is due to ΣC-PAHs. The assessment of toxicity and biological risk arising due to individual C-PAHs was made by calculating their toxic equivalent quantity. The level of individual C-PAHs was reported exceeding the final chronic values, Canadian water quality guideline values and Netherlands maximum permissible concentration values set for the protection of aquatic life. The mean BaP concentration (10.32 ± 2.75 μg L⁻¹) was above the European Directive 2008/105/EC Environmental Quality Standards (EQS) value; while the sum of BkF + BbF (26.76 μg L⁻¹) and BghiP + InP (19.59 μg L⁻¹) were significantly higher than that set by the EQS. The results of the present study will help in understanding the global distribution and fate of PAHs which is required for implementing the necessary steps towards mitigation of the ecotoxicological risk arising due to the existence of such contaminants in the aquatic environment across the world.