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Heavy metals are highly toxic at trace levels and their pollution has shown great threat to the environment and public health worldwide where current detection methods require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Herein, we report a low-cost, paper-based microfluidic analytical device (μPAD) for facile, portable, and disposable monitoring of mercury, lead, chromium, nickel, copper, and iron ions. Triple indicators or ligands that contain ions or molecules are preloaded on the μPADs and upon addition of a metal ion, the colorimetric indicators will elicit color changes observed by the naked eyes. The color features were quantitatively analyzed in a three-dimensional space of red, green, and blue or the RGB-space using digital imaging and color calibration techniques. The sensing platform offers higher accuracy for cross references, and is capable of simultaneous detection and discrimination of different metal ions in even real water samples. It demonstrates great potential for semiquantitative and even qualitative analysis with a sensitivity below the safe limit concentrations, and a controlled error range.

A novel miniaturized and sustainable platform exploiting two merged paper-based substrates has been applied for the programmable pre-concentration of analytes of interest and electrochemical detection of mercury traces in drinking water using printable sensor strips. This strategy represents a novel versatile possibility in merging humble materials maximizing their impacts on analytical and remediation challenges.

Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed.

Paper is one of the most commonly used food packaging materials. During the production of packaging paper, it is possible for trace amounts of heavy metals to be incorporated as contaminants. These could migrate into food when packaging paper (food contact paper) is used for cooking, storing and eating. The aim of this study was to determine the migration of lead (Pb) and arsenic (As) from food contact paper into a food simulant and then to assess human safety through the estimated daily intake (EDI) with consumption factor. Migration tests were conducted for 310 samples using 4% acetic acid as a food simulant at 25°C for 10 min and at 95°C for 30 min. Concentrations of Pb and As in a food simulant were quantified by inductively coupled plasma mass spectrometry. LODs for Pb and As were 0.002 and 0.005 µg L

Heavy metals are highly toxic at trace levels and their pollution has shown great threat to the environment and public health worldwide where current detection methods require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Herein, we report a low-cost, paper-based microfluidic analytical device (μPAD) for facile, portable, and disposable monitoring of mercury, lead, chromium, nickel, copper, and iron ions. Triple indicators or ligands that contain ions or molecules are preloaded on the μPADs and upon addition of a metal ion, the colorimetric indicators will elicit color changes observed by the naked eyes. The color features were quantitatively analyzed in a three-dimensional space of red, green, and blue or the RGB-space using digital imaging and color calibration techniques. The sensing platform offers higher accuracy for cross references, and is capable of simultaneous detection and discrimination of different metal ions in even real water samples. It demonstrates great potential for semiquantitative and even qualitative analysis with a sensitivity below the safe limit concentrations, and a controlled error range.

The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, (13)C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC) 14.43 cmol (+) kg(-1), N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs) and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the (13)C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2) groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application.

In this work, we report a simple and yet efficient stencil-printed electrochemical platform that can be integrated into the caps of sample containers and thus, allows in-field quantification of Cd(II) and Pb(II) in river water samples. The device exploits the low-cost features of carbon (as electrode material) and paper/polyester transparency sheets (as substrate). Electrochemical analysis of the working electrodes prepared on different substrates (polyester transparency sheets, chromatographic, tracing and office papers) with hexaammineruthenium(III) showed that their electroactive area and electron transfer kinetics are highly affected by the porosity of the material. Electrodes prepared on transparency substrates showed the best electroanalytical performance for the simultaneous determination of Cd(II) and Pb(II) by square-wave anodic stripping voltammetry. Interestingly, the temperature and time at which the carbon ink was cured had significant effect on the electrochemical response, especially the capacitive current. The amount of Cd and Pb on the electrode surface can be increased about 20% by in situ electrodeposition of bismuth. The electrochemical platform showed a linear range comprised between 1 and 200 mg/L for both metals, sensitivity of analysis of 0.22 and 0.087 mA/ppb and limits of detection of 0.2 and 0.3 mg/L for Cd(II) and Pb(II), respectively. The analysis of river water samples was done directly in the container where the sample was collected, which simplifies the procedure and approaches field analysis. The developed point-of-need detection system allowed simultaneous determination of Cd(II) and Pb(II) in those samples using the standard addition method with precise and accurate results, This work has been supported by the FC-15-GRUPIN-021 project from the Asturias Regional Government and the CTQ2014-58826-R project from the Spanish Ministry of Economy and Competitiveness (MINECO). Daniel Martín-Yerga thanks the MINECO for the award of a FPI grant (BES-2012-054408). Isabel Alvarez-Martos acknowledges the EU's support under H2020-MSCA-IF-2014 grant agreement 660339 (eADAM).

The mean concentrations of Zn, Cu, Cd, Cr and Fe in mosses around Webuye Pan Paper factory were found to be significantly higher than in controls taken from Kakamega, indicating atmospheric contribution from the anthropogenic activities within the factory, shown within a radius of 1 km around the factory. The mean concentrations (μg/g dry weight) in the mosses ranged from 60.9-124.5, 22.6-34.2, 13.3-14.7, 20.1-33.3 and 1,822.4-2,079.2, respectively. The mean concentrations of Pb in mosses sampled from the eastern and western side of the factory were also significantly higher than in controls. The mean concentrations of Zn, Cu, Cd, Cr, Pb and Fe in topsoil samples ranged from 7 (Pb)-2,310 (Fe) mg/kg dry wt, depending on sample means based on site direction, distance from the factory and season. There was no clear variation in metal concentrations in mosses and topsoils with direction from the factory which was consistent with the observed fluctuations in wind direction which changed from south-west in the mornings to north and south-west in the afternoons during sampling.

This study was undertaken to investigate the suitability of applying the conventional method of chemical deinking flotation of digital offset prints and ecological implications of the disposal of digital offset prints, with special emphasis on the content of heavy metal cations. The EDXRF method was used to determine the concentrations of Pb, Zr, Sr, As, Co, Zn, Cu, Ni, Fe, Mn, Cr, V, Ti, Ca, and K cations in handsheet ashes after flotation as well as in ashes of foams separated from cellulose suspension in the flotation phase. The same method was applied to determine the concentrations of Pb, Cr, Mn, Fe, Ni, Cu, Zn, and Co in process water filtrates obtained from the cellulose suspension after flotation and in foam filtrates. Centrifuging and coagulation previously treated flotation process water, while foam filtrates were centrifuged. Concentrations of Pb, As, Sr, Zr, K, Ca, Ti, V, Cr, Mn, Fe, Cu, and Zn were determined in the sediments obtained by centrifuging process water. The trials were done with unprinted substrates without deinking chemicals, with unprinted substrates in the presence of deinking chemicals and with printed substrates in the presence of deinking chemicals. Cation analysis revealed that deinking chemicals facilitate release of cations from the substrate and their transition into process water. Concentrations of most cations in the flotation process water, in foam water as well as in the sediment of the process water of printed substrate flotation deinking were lower than those obtained by flotation of unprinted substrate suspension. Polymer particles of ElectroInk incompletely separated from cellulose fibers prevent release of cations from cellulose fibers into process water. Deinking chemicals do not affect release of cations from ElectroInk particles, so the substrate is the main source of increased concentration of cations in the water of digital offset print deinking. The major part of cations in process water is bound to the colloid particles of the filler (CaCO3) released by substrate disintegration and to particles of fine fibers.

International audience; The literature on the presence of heavy metals in contaminated wastes is reviewed. Various categories of materials produced from domestic and industrial activities are included, but municipal solid waste, which is a more complex material, is excluded. This review considers among the most abundant the following materials - wood waste including demolition wood, phytoremediation scavengers and chromated copper arsenate (CCA) timber, sludges including de-inking sludge and sewage sludge, chicken litter and spent pot liner. The partitioning of the metals in the ashes after combustion or gasification follows conventional behaviour, with most metals retained, and higher concentrations in the finer sizes due to vaporisation and recondensation. The alkali metals have been shown to catalyse the biomass conversion, particularly lithium and potassium, although other metals are active to a lesser extent. The most prevalent in biomass is potassium, which is not only inherently active, but volatilises to become finely distributed throughout the char mass. Because the metals are predominantly found in the ash, the effectiveness of their removal depends on the efficiency of the collection of particulates. The potential for disposal into soil depends on the initial concentration in the feed material.

Industrial residue application to soil was investigated by integrating granulated blast furnace or converter steel slag with residues from the pulp and paper industry in various formulations. Specimen analysis included relevant physicochemical properties, total element concentrations (HCl+HNO3 digestion, USEPA 3051) and chemical speciation of chosen heavy metals (CH3COOH, NH2OH·HCl and H2O2+H2O2+CH3COONH4, the BCR method). Produced matrices showed liming effects comparable to commercial ground limestone and included significant quantities of soluble vital nutrients. The use of converter steel slag, however, led to significant increases in the total concentrations of Cr and V. Subsequently, total Cr was attested to occur as Cr(III) by Na2CO3+NaOH digestion followed by IC UV/VIS-PCR (USEPA 3060A). Additionally, 80.6% of the total concentration of Cr (370 mg kg(-1), d.w.) occurred in the residual fraction. However, 46.0% of the total concentration of V (2470 mg kg(-1), d.w.) occurred in the easily reduced fraction indicating potential bioavailability.

Article, WASTE MANAGEMENT. 29(3):1192-1197 (2009)

Spirotox is a short-term acute toxicity test with a large ciliated protozoan Spirostomum ambiguum. The test was created in the Department of Environmental Health Sciences, Medical University of Warsaw, Poland, during the early 1990s. It was presented for the first time during the 6th International Symposium on Toxicity Assessment, in Berlin in 1993. S. ambiguum was very resistant to a wide range of environmental conditions, especially to pH and dissolved oxygen. Over the last 10 years the sensitivity of S. ambiguum to many classes of toxicants was evaluated. Spirotox was found to be very sensitive to heavy metals, fungicides, and pharmaceuticals used to cure diseases of the human nervous system. On the other hand, it was generally less sensitive than standard bioassays to simple organics. Spirotox was also used for analysis of cyanobacterial blooms. Though it was moderately sensitive to hepatotoxins, the test seems to be a good tool for evaluation of the entire toxicity of blooms. The last but not the least of the applications of the Spirotox test was evaluation of the toxicity of extracts from medical devices. Protozoa, which are the simplest eukaryotes, seem to be good screening bioassays for monitoring the technology of medical device production.

The reuse and recycling of waste paper sludge is increasing rapidly as far as the economical and positive environmental benefits are realised. In this study, primary sludge coming from a large production plant, located in the centre of Italy, was collected and the environmental quality of the sludge was assessed through geotechnical, physical and chemical analysis and leaching tests, as required by the Italian regulation on solid waste recovery. The results suggest that primary sludge from paper industry do not represent a major threat for the environment in regard to the heavy metal content. The use of this sludge for in situ applications appears an interesting avenue for an integrated management of waste from the paper industry.

Several assays have been carried out in order to study in detail the cadmium mobility from water to virgin pulp as previous step of cadmium mobility description from paper into food. Virgin pulp has been immersed in different concentration aqueous solutions at several temperatures and during short and long time. The absorbed cadmium amounts have been measured by atomic absorption spectroscopy. For a long time, the temperature of storage is not an important factor except during the first 3 h. In general, percentage of migrated cadmium into pulp is between 30% and 90% of initial charge. Kinetic equation of cadmium mobility has been described employing statistics methods with a very good correlation. © 2002 Elsevier Science Ltd. All rights reserved.

Historical environment considerations are inevitable also for modern environmental analysis. They alone allow evaluation of anthropogenic impact into the environment. To receive information about the historical environment situation in inhabited regions, we approached this task by examining historical well dated and locatable products of the Homo faber. The work introduced here uses books as a source of environment historical data specially for the environmental compartment of water. The paper of historical books, dated by their printing and allocated by their watermark1 (Wasserzeichensammlung Piccard, Piccard online, Hauptstaatsarchiv Stuttgart, http://www.piccard-online.de) is a trap for traces of heavy metals contaminating their production water in historical times. Great amounts of water were brought into contact with the paper pulp in the historical paper mill process. The cellulose of the pulp acts as an ion exchange material for heavy metals, forming a dynamic equilibrium. A well defined pulp production process, starting with used clothes, allows estimation of the concentration of historical heavy metals (Cu2+, Pb2+, Zn2+, Cd2+) in the production water (river water). Ancient papers from well dated books are eluted without destruction of their paper and the resulting solution is analysed by ETAAS and inverse stripping voltammetry to determine the historical impact of metals. Afterwards in a flow system the eluted paper spot is equilibrated with different concentrations of heavy metals (Cu2+, Pb2+, Zn2+, Cd2+) to plot the adsorption isotherm of that very spot. Both data together allows a calculation of the heavy metal content of the historical river. For different waters of Germany and the Netherlands of the 16th–18th Century the heavy metal load could be estimated. The resulting concentrations were mostly similar to the level of modern surface waters, but in the case of the Dutch waters of the 17th Century, they were e.g. for Pb2+ significantly higher than modern values.

An approach based on the number of extractions performed over time was applied to study the time necessary to attain equilibrium conditions between the different chemical forms present in two natural soils laboratory-loaded with heavy metals (Cu(II), Pb(II), Zn(II)). The influence of some soil parameters, such as pH value, cation exchange capacity and organic matter content, on the equilibrium time was evidenced both by the different nature of the soils and by the treatment of soils with paper mill sludge. Equilibrium conditions were determined by studying the metal partitioning in the soil on a case by case basis. The behaviour of the three metals was not the same, and the conditions of equilibrium among the different chemical forms were the result of the amount of heavy metals added as well as of the nature of the soil.

The interest in the use of recycled products has been growing for the past many years. Thus, the dangerous chemicals once in use, now forbidden, may persist in the recycled products. This may pose a problem of bioaccumulation of poisonous chemicals as well as a threat to the philosophy of the use of recycled products. The non-carbon copying paper containing 2-6% polychlorinated biphenyls (PCB's) by weight has been commonly used in the nineteen sixties. Although the use of non-carbon copypaper has been forbidden for the past 15 years, it has been demonstrated that recycled papers contained small amounts of PCB's similar to those used for the production of non-carbon copypaper. Thus the old discarded archives may be one of the sources of PCB's in the recycled papers. Besides PCB's cadmium (Cd), mercury (Hg), lead (Pb) and other heavy metals from the print-inks (colors) may also be introduced to the recycled paper. The aim of the present study was to evaluate, on behalf of Danish Environmental Protection Agency, the levels of PCB's, Cd, Hg and Pb in the recycled paper for the household use. For this purpose the authors undertook a pilot study for the determination of the contents of PCB'smore » Cd, Hg and Pb in recycled papers that were available in the Danish market.« less