Assessment of the toxic potential of rainwater precipitation: First evidence from a case study in three Greek cities

Hydrochemical and isotopic characteristics on the southern and northern slopes of the Himalayas: spatio-temporal controls and source apportionment

Water-soluble ions, inorganic nitrogen, and stable isotopes in precipitation were assessed from the southern (Koshi Tappu and Khandbari) and northern slopes (Lhasa and SET) of the Himalayas to understand the sources, chemistry of regional precipitation, and climatic processes. Water soluble ions showed distinct seasonal variation, with higher concentrations in the non-monsoon. The concentration of ionic species was highest in Koshi Tappu, followed by Lhasa, SET, and Khandbari. The sources were from the terrigenous (Ca2+, HCO3-), marine (Na+ and Cl-), anthropogenic (SO42-, NO3-, and NH4+), terrigenous and marine (Mg2+), and biomass-burning (K+). The southern slope, relative to the northern, was more prone to anthropogenic emissions with higher deposition. Among all sites, inorganic nitrogen deposition at Koshi Tappu was higher than the threshold value (10 kg ha-1 y-1). The isotopic composition during the study period was higher in non-monsoon, started declining from June, and depleted in July and August compared to other months, i.e., the monsoon mature phase, along the south-to-north transect. The diminished value of stable isotopes in precipitation with increasing altitude underlines the evidence of the orographic effect in isotopic composition. Our study delineated that the higher/lower d-excess value increased with altitude on the southern/northern slope of the Himalayas. The backward trajectory analysis and the National Centers for Environmental Prediction's Final (NCEP FNL) datasets identified that most of the trajectories arrived from warm and humid low-latitude regions during monsoon and westerlies in non-monsoon. Thus, the chemical characteristics and stable isotopic composition of precipitation differed on the southern and northern slopes of the Himalayas by orographic effect and various sources. This study provides new insights into the atmospheric environment and climatic control of stable isotopes in the Himalayan Tibetan Plateau and facilitates monitoring of transboundary air pollution.

Distribution and temporal variability of uranium and toxic metal(loid)s in snow and rainwater from an oil industry and urban area in Thessaloniki-Greece

The concentrations of uranium and nine elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in snow and rainwater samples were determined. Samples were collected in Thessaloniki-northern Greece in three sites, one in the industrial area close to an oil production power plant and two in the centre of the city. Snow samples were collected during January-February 2019 and 2021 whereas in the case of rainwater, a two-year survey has been performed during 2019 and 2020. The activity concentrations of the uranium radioisotopes were measured by alpha spectrometry whereas the metal(loid)s concentrations were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The elevated concentrations of uranium (U) and the deviation of the isotopic ratio of U-234/U-238 from the equilibrium value indicated intensive dissolution of uranium. The results were analyzed using statistical analysis (Shapiro-Wilk, Friedman and Kruskal-Wallis tests). The obtained data and the calculated enrichment factors (Efs) denote variation of the concentration values between industrial and urban area and different elemental distribution influenced from anthropogenic contributions, meteorological conditions and the COVID-19 pandemic.

Study on the mechanism of the black crust formation on the ancient marble sculptures and the effect of pollution in Beijing area

In Beijing area, the precious stone objects often suffer from the black crusts on the specific parts of the objects, in order to understand the forming mechanism of the black crusts, samples from the stone sculptures in Beijing Stone Carving Art Museum, ZHIHUA Temple and Museum of Western Zhou Yandu Relics were taken and studied. Nondestructive measurement was carried out firstly to acquire main elements of the samples by portable X-ray spectrum (pXRF). Morphology and microstructure of typical black crust samples were examined by ultra-depth of field microscope (UDFM) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Compositions of black crusts and body rocks were evaluated with X-ray diffraction (XRD), Raman spectra and mapping. Inductively coupled plasma optical emission spectrometry (ICP-OES) and pyrolysis-gas chromatography/mass spectrometry (Py-GCMS) were used to identify the major pollution sources leading to the black crusts.

Through this study, the composition of the black crusts was revealed. Different gypsum crystals and carbonaceous species were found. Pollutant elements analysis and pyrolysis products provide indicators of the pollution sources. As consequence of strong photochemical oxidation processes and the high temperature from June to September in Beijing, more acid rain precursors can be formed. Frequent sulphation process occurs on the CaCO₃/CaMg(CO₃)₂ surface. Combining morphology results and atmospheric data, the formation of black crusts in Beijing can be deduced.

Chemical and biological tracking in decentralized sanitation systems: The case of artificial constructed wetlands

Given that the social and economic sustainability of rural areas is highly based on the protection of natural resources, biodiversity and human health, simple-operated and cost-effective wastewater treatment systems, like artificial constructed wetlands (CWs), are widely proposed for minimizing the environmental and human impact of both water and soil pollution. Considering that the optimization of wastewater treatment processes is vital for the reduction of effluents toxic potential, there is imperative need to establish appropriate management strategies for ensuring CW performance and operational efficiency. To this end, the present study aimed to assess the operational efficiency of a horizontal free water surface CW (HFWS-CW) located in a world heritage area of Western Greece, via a twelve-month duration Toxicity Identification Evaluation (TIE)-like approach, including both chemical and biological tracking tools. Conventional chemical tracking, by means of pH, conductivity, total COD, and nitrogen-derived components, like nitrates and ammonia-nitrogen, were monthly recorded in both influents and effluents to monitor whether water quality standards are maintained, and to assess potent CW operational deficiencies occurring over time. In parallel, Whole Effluent Toxicity (WET) bioassays were thoroughly applied, using freshwater algae and higher plant species (producers), crustaceans and rotifers (consumers), as well as human lymphocytes (in terms of Cytokinesis Block Micronucleus assay) to evaluate the acute and short-term toxic and hazardous potential of both influents and effluents. The integrated analysis of abiotic (physicochemical parameters) and biotic (toxic endpoints) parameters, as well as the existence of "cause-effect" interrelations among them, revealed that CW operational deficiencies, mainly based on poorly removal rates, could undermine the risk posed by treated sewage. Those findings reinforce the usage of WET testing, thus giving rise to the importance of applying appropriate water management strategies and optimization actions, like oxygen enrichment of surface and bottom of HFWS-CW basins, expansion of the available land, the enhancement of bed depth and seasonal harvesting of plants, for ensuring sewage quality, in favor of water resources protection and sustainable growth in rural areas.

The Potential Risk of Electronic Waste Disposal into Aquatic Media: The Case of Personal Computer Motherboards

Considering that electronic wastes (e-wastes) have been recently recognized as a potent environmental and human threat, the present study aimed to assess the potential risk of personal computer motherboards (PCMBs) leaching into aquatic media, following a real-life scenario. Specifically, PCMBs were submerged for 30 days in both distilled water (DW) and artificial seawater (ASW). Afterwards, PCMBs leachates were chemically characterized (i.e., total organic carbon, ions, and trace elements) and finally used (a) for culturing freshwater (Chlorococcum sp. and Scenedesmus rubescens) and saltwater (Dunaliella tertiolecta and Tisochrysis lutea) microalgae for 10 days (240 h), (b) as the exposure medium for mussel Mytilus galloprovincialis (96 h exposure), and (c) for performing the Cytokinesis Block Micronucleus (CBMN) assay in human lymphocytes cultures. According to the results, PCMBs could mediate both fresh- and marine algae growth rates over time, thus enhancing the cytotoxic, oxidative, and genotoxic effects in the hemocytes of mussels (in terms of lysosomal membrane impairment, lipid peroxidation, and NO content and micronuclei formation, respectively), as well as human lymphocytes (in terms of MN formation and CBPI values, respectively). The current findings clearly revealed that PCMBs leaching into the aquatic media could pose detrimental effects on both aquatic organisms and human cells.

Producing and storing self-sustaining drinking water from rainwater for emergency response on isolated island

Drinking water on isolated islands includes treated rainwater, water shipped from the mainland, and desalinated seawater. However, marine transportation and desalination plants are vulnerable to emergencies, such as extreme weather, making self-sustaining stand-by water for emergency response essential. Rainwater is ideal for producing the stand-by water, and rainwater harvesting is sustainable and clean, and prolonged biostability can be ensured by managing biological and chemical parameters. The present study applied a stand-by drinking water purification system (primarily including nanofiltration and low-dose chlorination) to explore the feasibility of producing and storing cleaner drinking water from rainwater and the following conclusions were drawn. First, treatment of rainwaters ensures biosafety for seven days, which is longer than that for untreated rainwater; the proportion of opportunistic pathogens decreased from 23.40-7.77% after nanofiltration, and it was proposed that the microbial community converges after advanced water treatment. Second, chemical qualities were improved. Local resource coral sand prevents pH in rainwater from decreasing below 6.5, and treated rainwater had lower disinfection by-product potential and higher disinfection efficiency, allowing periodical rainwater recycling. Third, harvesting rainwater was extremely cost-effective, with an operation cost of 1.5-2.5 RMB/m³. From biosafety, chemical safety, and economic cost perspectives, self-sustaining water from rainwater can contributes to the development of sustainable and cost-effective water supply systems on isolated islands. Mixing treated rainwater and desalinated seawater reasonably guarantees sufficiency and safety.

On-site rainwater harvesting and treatment for drinking water supply: assessment of cost and technical issues

This study assessed the performance of rainwater-harvesting systems installed for selected public utilities in the northern provinces of Vietnam where rainwater was collected, stored in stainless steel tanks, and treated with a complex filtration unit and Ultraviolet (UV) disinfection system (full system). Results from an operation of over 5 years show that the untreated rainwater could not be used directly for drinking purposes as it was contaminated with bacteria (total coliforms TC = 200-300 CFU/100 ml, Pseudomonas aeruginosa PA = 40-160 CFU/100 ml), and turbidity = 2-4 NTU. Most of the heavy metals detected were found below the standard limits. Phenol and its derivatives were detected occasionally as higher than the standard value (1 μg/L). After treatment, all parameters met the drinking water standards. The capital costs of the rainwater systems were approximately US$200/m³ and US$180/m³ for a full system and simplified system (without complex filtration unit), respectively, while the operation and maintenance (O&M) costs were 3 cents/L and 0.8 cents/L on average for a full system and simplified one, correspondingly.

Evidence of Natural and Anthropogenic Impacts on Rainwater Trace Metal Geochemistry in Central Mexico: A Statistical Approach

Trace metals Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, and As were determined on a monthly basis in a total of 52 rain samples collected from six different locations in the central region of Mexico during March 2016–April 2017. The average concentrations of trace metals (mg/L) in the rainwater samples showed an order of Zn (0.873) > Fe (0.395) > Mn (0.083) > Cr (0.041) ≥ Cu (0.041) > Pb (0.031) > Ni (0.020) > Co (0.013) > As (0.0003) > Cd (0.002). The differences observed in metal concentrations are related to variations in the influence of continental air masses, local transport, regional advection, and the solubility of trace metals. High concentrations of metals were observed in the months of March to May at all sites, probably due to the less extensive removal of air/air pollutants. The values obtained from the enrichment factor (EF) per metal showed relatively high values for Cd, Zn, Cu, Pb, Co, Ni, and Cr, suggesting anthropogenic origin. Pearson’s correlation matrix validated the distribution of trace metal sources and their relationships with local/regional meteorological characteristics. This paper presents relevant basic information for the evaluation of the toxic potential of rainwater and the possible health risks when using this source of water for human consumption.