Due to intensive agricultural activities to meet the growing needs for food, large volumes of water are consumed and an increasing amount of agrochemicals are released into the environment threatening the aquatic ecosystem. In order to ensure a sustainable agricultural management, it is crucial to develop an integrated water assessment plan that includes not only water quantity and quality but also toxicological assessments. The Pergamino River basin (province of Buenos Aires, Argentina) was selected as a representative case of study to monitor and assess the impact of both the long-term intensification of soybean production and fast-growing urban development on surface and groundwater sources. Physicochemical analyses and a Water Quality Index were determined and showed that water quality falls into the marginal category, compromising the irrigation purposes and threatening aquatic life. Glyphosate and aminomethylphosphonic acid were detected at least once in all sites. Caenorhabditis elegans toxic bioassays were performed and a toxicological ranking was developed. This analysis proved to be useful to detect toxicity even when water parameters met regulatory requirements and water quality seemed to be satisfactory. This research constitutes a valuable model to be replicated in other river basins that have been impacted by intensive agriculture and growing urban development in order to assess water quality conditions and ensure sound water resources management.

Reduced graphene oxide (RGO) and titanium dioxide (TiO₂) nanoparticles were immobilized on cotton textile substrates to produce self-cleaning textiles. Varying number of layers of RGO and TiO₂ nanoparticles were coated by a facile method, and their photocatalytic potential was evaluated by measuring the degradation rate of rhodamine B (Rh-B) in an aqueous solution in a photoreactor under simulated solar irradiation. X-ray diffraction (XRD) and zeta potential measurements of starting materials were studied as they are crucial for innovative methods of functionalization. The study confirms that it is possible to ensure a good adhesion of nanoparticles on textile samples without the use of a resin. The application of varying number of RGO and TiO₂ coatings has influence on photocatalytic properties of functionalized cotton textile substrates. The energy band gap of the samples reduces from 3.25 to −3.20 eV with the number of RGO coatings. All five de-ethylated intermediates of Rh-B during the photocatalytic degradation were identified using a high-performance liquid chromatography–mass spectrometry method. The experimental results show that, in general, the higher the number of RGO coatings is, the higher the photocatalytic efficiency (η) of the functionalized substrate is (η=87% for three RGO coatings on TiO₂).

With an annual production of about 10 Gt concrete is by far the most used solid man-made material. In order to adjust the workability of fresh concrete most often so-called superplasticisers, essentially water-soluble organic polymers, are utilised. As concrete is commonly in direct contact with soil or water, the leaching of organic and inorganic compounds and their environmental impact need to be assessed. The present study contributes to this purpose by investigating leachates from hardened cement pastes gained using the horizontal dynamic surface leaching test. Pastes were prepared with and without superplasticiser. The root growths as well as the germination behaviour of cress (Lepidium sativum) and white mustard (Sinapis alba) were examined with respect to phytotoxicity. Different proportions (100, 50, 25 and 12.5%) of the leachates were considered in the test scheme. The results indicate a positive effect of most of the leachates on seed germination and root growth, although statistical significance was only found in some cases. Both test species showed no or only slight harmful effects as relative root growth exceeded always 66% for S. alba and 74% for L. sativum. Seed germination was not negatively influenced by the leachates. Slight beneficial effects on both test species could be observed for leachates containing superplasticiser compared to samples in absence of superplasticiser.

The aim of this study was to determine if benthic diatoms can be used as effective and reliable indicators of ionic composition and conductivity in different stream order categories. Samples were collected on two occasions from 22 sampling sites within the Bloukrans River system, Eastern Cape Province, South Africa. The data collected were subjected to multivariate statistical technique, i.e. CCA, to determine environmental gradients along which the diatom species were distributed as well as to elucidate hypothesised differences in community structure per stream order. Significant differences between the two sampling periods were observed in dissolved oxygen, temperature, Na, B, Ca, Zn, Cu, Cr, K, Fe, phosphate, conductivity, salinity and nitrate, while significant stream order variation was observed for conductivity, salinity, Mg, Ca and sediment nitrates. Study sites were grouped into two broad categories (stream order 1 and 2/3 sites) based on CCA. As pollution increased, low to moderate pollution-tolerant species such as Fragilaria tenera, Cyclostephanos dubius and Gyrosigma acuminatum were replaced by high pollution-tolerant species such as Nitzschia palea, Gomphonema parvulum, Tryblionella apiculata, Diploneis vulgaris and Staurosira elliptica. This shows that diatom assemblages are appropriate indicators of ionic composition/conductivity and hydromorphological characteristics (e.g. stream size) of running waters. The results highlight the importance of creating regional calibration datasets which will make it possible to develop procedures to determine conductivity and ion concentration effects on biota.

A quantitative microbial risk assessment method can be used to evaluate infections probabilities for microorganisms in a specific place. The methodology provides suitable information to generate strategies focusing on health problems. Giardia cysts (GC) and Cryptosporidium oocysts (CO) are considered emerging pathogens that can infect human and animals by ingesting contaminated food or water, where food and water are transport vehicles for these parasites. Studies for GC and CO have reported occurrences for these parasites in water up to 100%, and some of these studies documented a number of cases, about 403,000 people, infected worldwide. This review is focused on compiling the most relevant works assessing the risk for GC and CO and their presence in different water samples that are susceptible for direct and indirect human consumption. The annual risk infection probability for these parasites has been reported from different water sources, with a range between 1 × 10⁻⁶ and 1, while the world standard regulation is 1 × 10⁻⁴. The infection probability depends not only on water quality but also on water treatment implementations.

Elevated radium (Ra) concentrations have been observed in aquifers with high naturally occurring salinity. The flux of radon (Rn) gas from the decay of Ra out of saline aquifers can be enhanced owing to salting-out effects. This raises the issue as to whether increased salinization of groundwater from road deicing practices can enhance Ra and Rn mobility to the extent that they become a human health concern. Continued use of salt (NaCl) as a road deicing agent has resulted in a gradual salinization of groundwater systems in snow-affected regions. This study presents groundwater data from a monitoring well field installed around a permeable pavement parking lot at the University of Connecticut, Storrs campus. The data suggest a connection between road salting and (a) the mobilization of dissolved Ra as well as (b) enhanced Rn gas flux from the water table. A positive correlation (R ² = 0.92) was identified between dissolved Na⁺ and isotopes of Ra; a negative relationship was observed between specific conductance and dissolved Rn. In two monitoring locations, concentrations of Ra were detected that exceeded the EPA MCL of 5 pCi/L. Concentrations of Rn in the groundwater were found to be at a level that theoretically could generate gas concentrations in the vadose zone that exceed the indoor Rn standard by orders of magnitude. Given these findings, it appears that salt contamination of groundwater could increase the potential for human exposure to these radioactive and carcinogenic elements. Graphical Abstract Photo of the study area taken 1/14/16

In this study, cassava starch wastewater was subjected to coagulation/flocculation (C/F) combined with microfiltration (MF) to improve the final quality of treated water. In the C/F tests of the effluent, the best concentration of the natural coagulant (Tanfloc POP) was determined from a statistical analysis of color removal and turbidity data. The supernatant produced in the C/F step was subjected to MF while varying the transmembrane pressure to evaluate the permeate fluxes, fouling mechanism, and permeate quality. The mathematical model that best represented the filtration process was the fouling mechanism of partial membrane pore blockage. The best experimental conditions for coagulant dosage, settling time, and MF pressure in the combined C/F-MF process were 320 mg L⁻¹, 15 min, and 1.4 bar, respectively. The highest overall removal efficiency rates achieved were 99% color, 91% cyanide, 75% total organic carbon, and 100% turbidity, demonstrating the promising potential of the combined C/F-MF process in the treatment of cassava starch wastewater.

Research was conducted on the most polluted river system in Poland, impacted by active and historical mining. Bottom sediment, suspended particulate matter and river water were collected in 2014 from Przemsza river and its tributaries. Sampling points remained the same as those chosen in a 1995 study. This allowed the comparison of heavy metal accumulation in bottom sediment over a span of almost two decades. It was concluded that Przemsza river water and its tributaries are heavily contaminated with the following (in μg/dm³): Pb (0.99–145.7), Zn (48–5020), and Cd 0.12–12.72). Concentrations of metals in bottom sediment exceeded the background values by a factor of several hundred (100 times for Zn, 150 times for Pb, and 240 times for Cd). The arithmetic mean for metal concentration in fractions <63 μm sampled in 2014 has remained comparable to the level found in 1995 (in mg/kg): Zn 16,918 and 13,505, Pb 4177 and 4758, and Cd 92 and 134. It was determined that 20–50% more metals have accumulated in suspended matter, rather than in bottom sediment (in mg/kg): 20,498 Zn, Pb 5170, and 164 Cd. This exceeds the limits of the most polluted LAWA Class IV classification. Since the concentrations of Zn, Pb, and Cd increase drastically after the outlet of the Przemsza into the Vistula, it was concluded that river Przemsza is the cause of significant degradation of Vistula’s bottom sediment and suspended matter. A two-decade legacy of extremely high contamination of the Przemsza river sediments has persisted despite decreasing mining and smelting activity in the vicinity.

The current study aims to tackle one of the main obstacles in the application of anaerobic ammonium oxidation (Anammox) technology, i.e., the extreme slow growth of the Anammox bacteria. Three conventional sludge has been tested in sequencing batch reactor for Anammox enrichment, including conventional aerobic sludge, denitrification sludge, and anaerobic sludge. With a high selection stress and insufficient oxygen control, the reactor seeded with aerobic sludge reached 50–60% total nitrogen removal after 240 days whereas that seeded with anaerobic sludge failed to establish Anammox activity. Anammox process was successfully established in the reactor seeded with denitrification sludge with a total nitrogen removal of approximately 80% after 150 days under strict oxygen control (DO <0.2 mg/L) and low selection stress. Under the same operational condition, the reactor seeded with anaerobic sludge reached only 20–30% total nitrogen removal. All the reactors experienced fluctuating performances during the enrichment process, which was believed to be the consequence of inhibitory factors such as dissolved oxygen, nitrite and free ammonia as well as undesirable coexisting bacteria which compete for the same substrate. The denaturing gradient gel electrophoresis (DGGE) band from the amplified DNA samples extracted from different enrichment stage showed a clear evolution of the microbial composition as reflected by the change in the band locations and their intensity.

Organic matter and nutrient in pig manure were treated using an integrated filter system. The influent flowed into an anaerobic filter (AF), and the AF effluent was polished in a biological aerated filter (BAF). The filter system was operated with recirculation ratios of 1–3. The filter system was operated with two recirculation methods. When a filter system was operated under bottom recirculation conditions, the nitrated effluent from the BAF was mingled with the influent in the AF. For upper recirculation conditions, the nitrated effluent from the BAF was injected into a height of 36% from the bottom in the AF. Removal of organic matter and nitrogen under upper recirculation conditions was greater than those under bottom recirculation conditions. The average chemical oxygen demand and solids removals were over 99 and over 97% under upper recirculation conditions. Total nitrogen and total phosphorus removals were over 77 and over 69% at recirculation 3 under upper recirculation conditions.