Effect of compost and manure amendments on zinc soil speciation, plant content, and translocation in an artificially contaminated soil

The addition of organic matter in soil can modify the bioavailability of heavy metals. A greenhouse pot experiment was carried out using an edible plant species Eruca vesicaria L. Cavalieri grown on an artificially contaminated soil with Zn (665 mg?kg^?1). In this study, the effect of compost at 20 t?ha^?1 (C20) and at 60 t?ha^?1 (C60), manure at 10 t?ha^?1 (M10) and at 30 t?ha^?1 (M30), and chemical fertilizers (NPK) on Zn fate in a soil–plant system was evaluated. At the end of the experiment, the main growth parameters and Zn content in plants were determined. In addition, Zn speciation in the soil was assessed using the original Community Bureau of Reference sequential extraction and diethylene triamine pentaacetic acid extraction. Zinc, though an essential element for plant growth, caused toxicity effects in plants grown on control and manure treatments, while in the compost treatments, plants showed no visual toxicity symptoms. The concentrations of Zn in roots were similar for all treatments, while significant differences were observed for shoots. In fact, in the compost treatments, plants showed the lowest Zn concentration in shoots. Zinc speciation seems not to be affected by the applied treatments. Indeed, Zn plant content and translocation to shoots seems to be affected. Compost amendments significantly reduced Zn content and translocation in comparison to other treatments.     

Genotoxicity biomarkers in the amphipod Gammarus elvirae exposed in vivo to mercury and lead,and basal levels of DNA damage in two cell types

The present work deals with the application of genotoxicity biomarkers by means of the Comet assay in haemocytes and spermatozoa of the crustacean Gammarus elvirae exposed in vivo to heavy metals. Furthermore, a basal levels (BLs) study of DNA damage in the two cell types considered for two different gammarids species, G. elvirae and Echinogammarus veneris, was carried out. It is important to identify factors that influence the outcome of the assay in order to obtain reliable and reproducible results usable for risk assessment purposes. Our results highlight that the Italian legal limits for Hg and Pb, respectively, 0.5 and 50?µg/L, are inadequate for establishing safety thresholds in the aquatic environment. Furthermore, the freshwater invertebrate G. elvirae, used for the first time to measure the effect of genotoxicants, is a good candidate for evaluating the genotoxicity damage induced by heavy metals. Our results concerning spermatozoa show excessively variable responses and high BLs.     

The protection of wildlife from mortality: hypothesis and results for risk assessment

Wildlife deaths associated with cyanide-bearing tailings dams are a significant environmental issue that has affected the gold mining industries for many years and still characterized by little knowledge about how to measure, monitoring, reduce or eliminate those deaths. The purpose of this paper is statistically to determine: the potential for establishing causal relations between exposure to cyanide (in its most common species relevant to tailings) and response (measured by death counts), to develop a protocol of data analysis, the understanding of the significance of data gaps, and the effect of likely risk management interventions to achieve the goals of the International Cyanide Management Code (ICMC); [ICMC The International Cyanide Management Institute. International cyanide management code, the international cyanide management institute 2005, www.cyanidecode.org.]. However, operator's certification under the ICMC is difficult because of the limited data and potentially serious under-estimation of the death counts. This is due to observational skill and monitoring frequency, the small size of the carcasses, large extent of tailings facilities, carcasses loss by; entombment in tailings, sink, or taken by scavenging wildlife. This (1st order or bounding) assessment results focus on bird-deaths, which appear to be most frequent at sites where elevated cyanide concentrations are found. Those results indicate that the empirical causal associations we generate support the hypotheses that: This paper also develops the basis for a complete risk assessment study to be based on additional data gathering activities and detailed statistical analyses. These two activities, combined with a risk management plan also being developed, will provide a tool for compliance with the ICMC.     

Removal of hydrocarbons from wastewater using treated bark

This paper explores the possibility of removing hydrocarbons (HCs) and trace elements from synthetic and industrial effluents using treated bark as biosorbent. Coniferous bark was treated either chemically (Tc) or biologically (Tb) to eliminate soluble organic compounds of bark. The removal efficiency (RE) of the HCs from a synthetic oil-water mixture containing spent diesel motor oil exceeds 95% using 2 g/L of treated bark mixed with a synthetic oil-water mixture containing 2 g/L of spent oil. Under these conditions, the retention capacity (RC) was approximately 1 g HC/g dry substrate. The sorption reaction seems to be quasi-instantaneous, and the retention capacity of spent oil on treated bark increases as the temperature augments. This implies that the retention mechanism is related to the capillary action. Results of Fourier transform infrared (FTIR) spectroscopy indicate that spent oil is mainly composed of alkanes. They also suggest that no chemical bonds between Tc and spent oil were established. Measurement of the surface tension of spent oil and the wetting index of the bark suggests that only spent oil will be retained by the substrate. Treatment of an industrial effluent containing 14.4 g/L of total HCs was performed using Tc. It was possible to remove 97% of HCs and retain some trace elements such as Al, Ca, Fe, Mg, S, and so on.     

Commercialization of Dredged-Material Decontamination Technologies

This article describe a unique federal project aimed at the commercialization of different technologies for the decontamination of dredged material. The project is organized so that commercialization is achieved in a seamless way, starting with validation at the bench- and pilot-scale levels, and ending with the actual construction of operational facilities. This is the first integrated sediment decontamination program in which a step-wise bench-scale validation process of innovative/emerging technologies will scale-up to a production-scale facility capable of processing up to 375,000 m³ of dredged material per year. The need to develop public-private partnerships for the facility construction is emphasized as a way of obtaining adequate finding for capital and operating costs during the startup time of the commercialization process. It is expected that the end result of the project work will be the creation of economically-viable, self-sustaining decontamination technology companies.     

Use of treated bark for the removal of lipids from water

Raw, biologically treated bark and bark impregnated with transition metal ions were used to retain the lipids from synthetic emulsions. Several experimental parameters affecting the lipid removal efficiency (RE) were studied (initial concentration of lipids, temperature, time, pH, carboxylic acid chain length, etc.). Saturated bark was characterized using Fourier transform infrared (FTIR) spectroscopy and light microscopy, and the treated bark wetting index was determined. Results show that lipid removal can exceed 95% of the initial concentration at a pH lower than 7. The uptake of lipids by these sorbents varied from 0.2 to 2.5 g/g of dry bark. Trials for regenerating the sorbent saturated by lipids allowed the recovery of approximately 95% of lipids. The calorific value of the saturated bark was approximately 79% that of domestic fuel and can be considered as an energy source, thus avoiding its waste disposal. These results may upgrade the treatment of wastewater generated by several industrial sectors, such as the food industry, surface treatment, and so on.     

Challenges to reducing post-consumer plastic rejects from the MSW selective collection at two MRFs in São Paulo city,Brazil

Journal of Material Cycles and Waste Management - ​The present study is concerned with an overview of the main aspects of the selective collection from the municipal solid waste in São...     

Exposure to polychlorinated biphenyls in residents near a chemical factory in Italy: the food chain as main source of contamination

High levels of PCBs were recently found in soil, food and some farmers living close to a chemical factory which until the 1980s had produced polychlorinated biphenyls (PCBs) in Brescia, North Italy. We performed a survey on a random sample of subjects aged 20-79 years living in various areas of the town with different levels of soil pollution to investigate factors associated with increased levels of PCB in serum (24 congeners were tested). Total PCB values were closely related to age (Spearman r=0.68; p<0.0001). The 166 consumers of locally produced food had higher PCB levels than non-consumers (median=1143 versus 719; 95th centile=9301 versus 2635ng/g lipid) with the highest levels among consumers of food produced in the most contaminated area close to the factory (median=2551; 95th centile=33464ng/g lipid). A dose-effect relationship between consumption of food produced in this area and PCB blood levels was observed (Spearman r=0.52, p=0.0014). Consumers of only plant food produced in this area had higher levels of PCB than non-consumers (median=1100; 95th centile=10,800ng/g lipid). Three subjects who had worked at the factory in the past showed high PCB levels. Distribution of PCB congeners did not differ between consumers of locally produced food and non-consumers, apart from PCB 209 which was found at high levels in former factory workers and was more common among consumers of food produced in the polluted area. In conclusion, we found high serum PCB levels in humans living in a highly polluted area in an industrialized town in Italy, due mainly to consumption of food produced in polluted areas.