A review of the science behind drinking water standards for copper

Comparing Conventional and Advanced Approaches for Heavy Metal Removal in Wastewater Treatment: An In-Depth Review Emphasizing Filter-Based Strategies

Various industrial activities release heavy metal ions into the environment, which represent one of the major toxic pollutants owing to their severe effects on the environment, humans, and all living species. Despite several technological advances and breakthroughs, wastewater treatment remains a critical global issue. Traditional techniques are dedicated to extracting heavy metal ions from diverse wastewater origins, encompassing coagulation/flocculation, precipitation, flotation, and ion exchange. Their cost, side toxicity, or ineffectiveness often limit their large-scale use. Due to their adaptable design, simple operation, and reasonable cost, membrane filtration and adsorption have proven their efficiency in removing metals from wastewater. Recently, adsorption-based filters have appeared promising in treating water. Within this range, filters incorporating natural, synthetic, or hybrid adsorbents present an appealing alternative to conventional approaches. This review aims to list and describe the conventional and advanced wastewater treatment methods by comparing their efficiency, cost, and environmental impact. Adsorption-based filters were highlighted due to the significant advantages they can provide.

Physicochemical Properties and Application of Silica-Doped Biochar Composites as Efficient Sorbents of Copper from Tap Water

This article concerns research on new sorption materials based on silica-doped activated carbon. A two-stage synthesis involved pyrolysis of plant material impregnated in a water glass solution, followed by hydrothermal activation of the pyrolysate in KOH solution. The resulting composite can be used as a sorbent in drinking water filters. The proposed method of synthesis enables the design of materials with a surface area of approximately 150 m²·g^-1, whose chemical composition and structure were confirmed by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA) and Fourier-transform infrared spectroscopy (FTIR). The sorption properties of the obtained materials were determined relative to copper ions using the batch experiment method. The optimal operating parameters of the obtained materials relative to copper ions are T = 313.15 K, pH = 5, S:L ratio = 4 g·dm^-3 and t = 120 min. The research shows that the sorption kinetics of copper ions can be described by a pseudo-second-order model. The plotted copper(II) sorption isotherm clearly indicates the Langmuir model. Under optimal conditions, the maximum sorption of copper ions was 37.74 mg·g^-1, which is a satisfactory result and confirms the possibility of using the obtained material in drinking water filters.

Solid-phase extraction and preconcentration of copper in mineral waters with 4-(2-pyridyl-azo) resorcinol-loaded amberlite XAD-7 and flame atomic absorption spectrometry

A simple, sensitive, accurate, and selective method for determination of ultratrace levels of copper is modified. The method is based on preconcentration of copper on the 4-(2-pyridyl-azo) resorcinol-loaded amberlite XAD-7 (non-ionic copoly[styrene-acrylic compound]) at pH 5.0 to 6.5 for contact time as low as 45 minutes. The adsorbed copper was eluted with concentrated nitric acid and measured by flame atomic absorption spectrometry. Recoveries of up to 90% were achieved. The optimized preconcentration method was applied to copper determination in various water samples. The detection limit was found to be 0.09 ng mL(-1). The relative standard deviation was found to be 9% using 300 mL of 5.0 ng mL(-1) for 10 replicate preconcentration procedures. Copper concentrations in the studied water samples were found to be in the ranges of 0.4 to 18.0 ng mL(-1).

Heavy metals in drinking waters from Mount Amiata (Tuscany, Italy). Possible risks from arsenic for public health in the Province of Siena

Concentrations of As, Al and some heavy metals (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were measured in drinking waters from Siena and Grosseto districts, South Tuscany, Italy. The analysis, performed mostly by electrothermal activated atomic absorption spectroscopy equipped with graphite furnace, and in some cases high-resolution inductively coupled plasma mass spectrometry, indicated that concentrations of the elements were generally far below the maximum allowed concentration (MAC). However, the concentration of As in some of the waters at sources or at the terminals of the water webs was relatively high (largest value, 14.4(2) microg/l) when compared to the MAC(As) value (10 microg/l, December 25, 2003; Italian Law). Relatively high concentrations of some metals had been detected in a few samples from the ends of the distribution webs, when compared to values at sources. These effects are probably due to leaching from metal pipes. A general 'metal index' (MI) for drinking water, which takes into account possible additive effects of N heavy metals on the human health that helps to quickly evaluate the overall quality of drinking waters, is introduced in this paper as MI=?(i=1,N)[C(i)/(MAC)(i)]. Samples from Ermicciolo spring and Siena water web had MI values of 1.1 and 1.3, respectively, showing that the quality of drinking water in town is somewhat worse than that at one of the main sources, at least regarding the 12 elements taken into account.

Biosensor-controlled perfusion culture to estimate the viability of cells

A perfusion cell culture is characterised by the continuous addition of fresh nutrient medium and the withdrawal of an equal volume of used medium, allowing the realisation of cell cultivation conditions that are approximated as closely as possible to the in vivo situation. The combination of a perfusion cell culture with an enzyme glucose biosensor allows the glucose consumption of the cell culture to be monitored continuously. The resulting biosensor-controlled perfusion cell culture is a complex biomonitoring system that is useful for checking the metabolic state of a perfusion cell culture continuously and non-invasively over several days. With this experimental setup, it has been possible to test detrimental external effects on living systems at early stages, in vitro, but under in vivo-like conditions.

Survival of Escherichia coli O157:H7 in private drinking water wells: influences of protozoan grazing and elevated copper concentrations

The survival characteristics of Escherichia coli O157:H7 in private drinking water wells were investigated to assess the potential for human exposure. A non-toxigenic, chromosomally lux-marked strain of E. coli O157:H7 was inoculated into well water from four different sites in the North East of Scotland. These waters differed significantly in their heavy metal contents as well as nutrient and bacterial grazer concentrations. Grazing and other biological factors were studied using filtered (3 and 0.2 microm) and autoclaved water. The survival of E. coli O157:H7 was primarily decreased by elevated copper concentrations. This hypothesis was supported by acute toxicity assay data. In addition, significant protozoan predation effects were observed in untreated water when compared with survival rates in filtered water. The combination of these two factors in particular determines the survival time of the pathogen in a private water well. It therefore appears that wells with higher water quality as assessed using the European Union Drinking Water Directive standards will also allow survival of E. coli O157:H7 for much longer periods.