Removal of cytostatic platinum compounds and recovery of precious metal from aqueous wastestream

Over the last decades, a strong antropogenic increase in platinum concentrations in the environment is observed. While catalytic converters used in cars and industry contribute to elevated levels in vegetation and soils, hospitals intensely discard platinum from their effluents to surface waters. Since the discovery of its cytostatic properties by Rosenberg, cisplatin and other platinum coordinating compounds such as carboplatin and more recently oxaliplatin are extensively used in chemotherapy for cancer treatment. After ingestion and interaction with DNA, the drugs are biodegraded and excreted by patients through urine – either in hospital or at home - to remain mostly untreated. Biomaterials are ubiquitous distributed over the world and ready available with equal performance. They show a promising potential as sorbent for pollutants from wastewaters. The precious metal containing material can be separated from solution as a solid and be processed and valorised afterwards. In a screening step, several natural wood-based materials and dried microalgal biological flocs have been tested for their sorption efficiency towards cytostatic platinum compounds

Speciation-analysis for recycling of critical elements in aqueous waste streams

Limited availability of inorganic commodities is one of the largest challenges for a future sustainable material use as set by European Commission. Growing life standards, demand for mobility and electronic devices require more and more specialty materials. Combining this economic importance and their supply risk, a class of critical materials is defined. PGM’s include Pt, Rh, Pd, Ir, Ru and Os. They possess unique properties, making them indispensable in autocatalysts, jewelry, electrical and electronical applications and industrial catalysts. PGM prices, with Pt being the far most important, have seriously risen in the last years. REE’s comprehend 17 elements with a large chemical similarity, essential in i.a. permanent magnets and related ‘clean energy’ applications such as wind turbines, rechargeable batteries and electric vehicles. Tight export quota set by the world’s largest exporting country of REE’s, China, hardly meet this rising demand

Fate of silver nanoparticles in constructed wetlands : a microcosm study

Nano-enabled materials are produced at growing volumes which increases the likelihood of nanoparticles being released into the environment. Constructed wetlands (CWs) are likely to receive wastewater containing nanoparticles leaching from products during usage. Therefore, we investigate the retention of silver nanoparticles (Ag-NPs) in microcosms simulating CWs treating domestic wastewater. The effects of aeration and organic matter content on the Ag-NP removal efficiencies are studied in particular. CWs remove most of the Ag (80-90%) and the largest fraction of Ag is found in/on the biofilm. Detailed electron microscopy analyses suggest that Ag-NPs are transformed into Ag2S in all microcosm experiments. The good correlation between total suspended solids (TSS) and the Ag concentration measured in the effluent indicates that Ag-NPs are bound to the solids in the effluent. Aeration of the microcosms does not affect the release of Ag-NPs from the systems but increasing organic matter leads to increased amounts of Ag passing the CWs, correlating with the increased release of TSS from the CWs. These results suggest that Ag-NPs are retained with the (suspended) solids in CWs and that the removal efficiency of TSS is an important factor determining the discharge of Ag-NPs from CWs

Fate of metallic engineered nanomaterials in constructed wetlands : prospection and future research perspectives

Metallic engineered nanomaterials (ENMs) undergo various transformations in the environment which affect their fate, toxicity and bioavailability. Although constructed wetlands (CWs) are applied as treatment systems for waste streams potentially containing metallic ENMs, little is known about the fate and effects of ENMs in CWs. Hence, literature data from related fields such as activated sludge wastewater treatment and natural wetlands is used to predict the fate and effects of ENMs in CWs and to analyze the risk of nanomaterials being released from CWs into surface waters. The ENMs are likely to reach the CW (partly) transformed and the transformations will continue in the CW. The main transformation processes depend on the type of ENM and the ambient environmental conditions in the CW. In general, ENMs are expected to undergo sorption onto (suspended) organic matter and plant roots. Although the risk of ENMs being released at high concentrations from CWs is estimated low, caution is warranted because of the estimated rise in the production of these materials. As discharge of (transformed) ENMs from CWs during normal operation is predicted to be low, future research should rather focus on the effects of system malfunctions (e.g. short-circuiting). Efficient retention in the CW and increasing production volumes in the future entail increasing concentrations within the CW substrate and further research needs to address possible adverse effects caused

Gap analysis of nickel bioaccessibility and bioavailability in different food matrices and its impact on the nickel exposure assessment

The metal nickel is well known to cause nickel allergy in sensitive humans by prolonged dermal contact to materials releasing (high) amounts of nickel. Oral nickel exposure via water and food intake is of potential concern. Nickel is essential to plants and animals and can be naturally found in food products or contamination may occur across the agro-food chain. This gap analysis is an evaluation of nickel as a potential food safety hazard causing a risk for human health. In the first step, the available data regarding the occurrence of nickel and its contamination in food and drinks have been collected through literature review. Subsequently, a discussion is held on the potential risks associated with this contamination. Elevated nickel concentrations were mostly found in plant-based foods, e.g. legumes and nuts in which nickel of natural origin is expected. However, it was observed that dedicated and systematic screening of foodstuffs for the presence of nickel is currently still lacking. In a next step, published studies on exposure of humans to nickel via foods and drinks were critically evaluated. Not including bioaccessibility and/or bioavailability of the metal may lead to an overestimation of the exposure of the body to nickel via food and drinks. This overestimation may be problematic when the measured nickel level in foods is high and bioaccessibility and/or bioavailability of nickel in these products is low. Therefore, this paper analyzes the outcomes of the existing dietary intake and bioaccessibility/bioavailability studies conducted for nickel. Besides, the available gaps in nickel bioaccessibility and/or bioavailability studies have been clarified in this paper. The reported bioaccessibility and bioavailability percentages for different food and drinks were found to vary between < LOD and 83% and between 0 and 30% respectively. This indicates that of the total nickel contained in the foodstuffs only a fraction can be absorbed by the intestinal epithelium cells. This paper provides a unique critical overview on nickel in the human diet starting from factors affecting its occurrence in food until its absorption by the body

DNA fingerprinting of spore-forming bacterial isolates, using Bacillus cereus repetitive polymerase chain reaction analysis (Bc-Rep-PCR)

Bc-repetitive extragenic palindromic polymerase chain reaction (Bc-Rep PCR) analysis was conducted on seven Bacillus thuringiensis isolates accessed from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) culture collection and on five local isolates of entomopathogenic spore-forming bacteria. The five isolates were three strains of B. thuringiensis, one strain of B. cereus and one strain of Brevibacillus laterosporus. All five isolates were distinguished from each other using Bc-Rep PCR analysis. The three B. thuringiensis isolates were closely related. The isolate of B. laterosporus was not related to any of the B. cereus group isolates. Serotyping was also conducted on the five local isolates. However, only one of these isolates could be identified with serotyping and was identified as B. thuringiensis subsp. kenyae.Keywords: Bc-repetitive extragenic palindromic polymerase chain reaction, Bacillus sp., serotypingAfrican Journal of Biotechnology Vol. 12(14), pp. 1598-160

Seasonal Variation of Yields and Nutrient Uptakes of IR-64 Grown in Terraced Paddy Field System

In the past, most rice study was carried out in irrigated lowland rice and less or no attention was paid to the terraced paddy field system. Study on seasonal rice biomass production and nutrient uptake variation of IR-64 variety cultivated in terraced paddy field system was carried out in Keji Village, Ungaran Sub district during the wet season 2003-04 and dry season 2004. The aim of the study was to evaluate the seasonal variation of rice biomass productions, nutrient concentrations and nutrient uptakes of IR-64. Data were taken from four treatments, namely conventional farmer practice, conventional farmer practices + rice straw, improved technology and improved technology + rice straw. For the conventional farmer practice, only 50 kg of urea ha-1 season-1 was applied. Meanwhile, about 100 kg each of urea, triple super phosphate, and potassium cloride ha-1 season-1 were applied in the improved technology treatments. About 33% of rice straw produced from the previous season was recycled in the treatments of conventional farmer practices + rice straw and improved technology + rice straw. Each treatment was replicated three times and arranged in a Randomised Completely Block Design. Plants were sampled five times, at 45, 60, 75, 90 and 105 days after transplanting. The results indicated that overall production of the improved technology + rice straw treatment was significantly higher than the other treatments both in the wet season 2003-04 and the dry season 2004. Rice grains and rice residues in the dry season were higher than in the wet season, except for the rice straw. However, statistically, there were no significant variations of rice biomass production between the wet season 2003-04 and the dry season 2004. When the rice straw addition was considered, only rice grain production of the dry season was consistently greater than the rice grain production of the wet season. Concentrations of N, P, and K in shoots and roots significantly decreased during rice growth. In contrast to the concentrations, the nutrient uptake increased by the time of rice growth. The highest nutrient concentrations both in the wet and dry season were observed at 45 days after. Contrary to the nutrient concentrations, the highest N, P, and K uptakes were taken place at harvest.  Seasonally, nutrient uptakes at harvest in the dry season were higher than in the wet season, but statistical evidences were not consistent. As only rice residues were left in the field, the nutrient amounts taken up by rice straw and rice grains reflect the nutrients removal from the field through harvest. The total nutrients removal ranged between 114 and 119 kg N, 10 and 12 kg P, 133 and 148 kg K ha-1 season-1

Arsenic in drinking water wells on the Bolivian high plain: field monitoring and effect of salinity on removal efficiency of iron-oxides-containing filters

In the rural areas around Oruro (Bolivia), untreated groundwater is used directly as drinking water. This research aimed to evaluate the general drinking water quality, with focus on arsenic (As) concentrations, based on analysis of 67 samples from about 16 communities of the Oruro district. Subsequently a filter using Iron Oxide Coated Sand (IOCS) and a filter using a Composite Iron Matrix (CIM) were tested for their arsenic removal capacity using synthetic water mimicking real groundwater. Heavy metal concentrations in the sampled drinking water barely exceeded WHO guidelines. Arsenic concentrations reached values up to 964 mu g L-1 and exceeded the current WHO provisional guideline value of 10 mu g L-1 in more than 50% of the sampled wells. The WHO guideline of 250 mg L-1 for chloride and sulphate was also exceeded in more than a third of the samples, indicating high salinity in the drinking waters. Synthetic drinking water could be treated effectively by the IOCS- and CIM-based filters reducing As to concentrations lower than 10 mu g L-1. High levels of chloride and sulphate did not influence As removal efficiency. However, phosphate concentrations in the range from 4 to 24 mg L-1 drastically decreased removal efficiency of the IOCS-based filter but had no effects on removal efficiency of the CIM-based filter. Results of this study can be used as a base for further testing and practical implementation of drinking water purification in the Oruro region

Biomarkers of selenium status in dogs

Background: Inadequate dietary selenium (Se) intake in humans and animals can lead to long term health problems, such as cancer. In view of the owner's desire for healthy longevity of companion animals, the impact of dietary Se provision on long term health effects warrants investigation. Little is currently known regards biomarkers, and rate of change of such biomarkers in relation to dietary selenium intake in dogs. In this study, selected biomarkers were assessed for their suitability to detect changes in dietary Se in adult dogs within eight weeks. Results: Twenty-four dogs were fed a semi-purified diet with an adequate amount of Se (46.1 mu g/MJ) over an 8 week period. They were then divided into two groups. The first group remained on the adequate Se diet, the second were offered a semi-purified diet with a low Se concentration (6.5 mu g/MJ; 31 % of the FEDIAF minimum) for 8 weeks. Weekly urine and blood was collected and hair growth measurements were performed. The urinary Se to creatinine ratio and serum Se concentration were significantly lower in dogs consuming the low Se diet from week 1 onwards, by 84 % (adequate 25.3, low 4.1) and 7 % (adequate 257 mu g/L, low 238 mu g/L) respectively. Serum and whole blood glutathione peroxidase were also significantly lower in dogs consuming the low Se diet from weeks 6 and 8 respectively. None of the other biomarkers (mRNA expression and serum copper, creatine kinase, triiodothyronine: thyroxine ratio and hair growth) responded significantly to the low Se diet over the 8 week period. Conclusions: This study demonstrated that urinary Se to creatinine ratio, serum Se and serum and whole blood glutathione peroxidase can be used as biomarkers of selenium status in dogs. Urinary Se to creatinine ratio and serum Se concentrations responded faster to decreased dietary Se than the other parameters. This makes these biomarkers candidates for early screening of long term effects of dietary Se provision on canine health