Ecotoxicological assessment of leachates from MSWI bottom ashes.

In this paper, chemical and ecotoxicological data of leachates from bottom ashes collected in different Municipal Solid Waste Incinerators (MSWI) are shown. The bottom ashes were collected in Belgium (three incinerators--samples B1 to B3), France, Germany, Italy and United Kingdom (one incinerator in each country--samples F1, D1, I1 and UK1, respectively). Both chemical and ecotoxicological characterizations of leachates were done on the framework of the European Directive 91/689/EEC and the European Council Decision 94/904/EC. This work was carried out under the European project called Valomat, which was supported by the European Commission through Brite-Euram III program. Twenty-one inorganic parameters were analyzed. The ecotoxicological assays were done under standard laboratory conditions, using the bacterium Photobacterium phosphoreum, the freshwater alga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the vegetable Lactuca sativa. Chemical data varied from sample to sample. Similar results were obtained in biological assays. The samples can be classified as ecotoxic/hazardous according to the French proposal for a Criterion and Evaluation Methods of Waste Ecotoxicity (CEMWE) and the German regulation on Hazardous Waste Classification (HWC). However, samples B1, B2, B3 and D1 comply the maximum limits for direct valorization category defined in the French Classification of Bottom Ashes based on their Polluting Potential (CBAPP). Sample B1 presented the lowest level of ecotoxicity, being considered as the most interesting to be used in the development of new materials for civil engineering works.

An ecotoxic risk assessment of residue materials produced by the plasma pyrolysis/vitrification (PP/V) process.

Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experience has amply demonstrated that solids exposed to the oxygen-deficient plasma flame are converted to liquid, and liquid exposed to the same flame is converted to gas. A low amount of vitrified solid residue material usually remains at the end of this process. Plasma pyrolysis/vitrification (PP/V) has been demonstrated as a safe, efficient, cost-effective technology for the treatment of wastes, including hazardous wastes. Besides the low amounts of gaseous byproducts that PP/V produces, the solid vitrified residue presents a low leachability of pollutants. Studies have been performed in many countries in order to assess the leachability of chemical substances. But from the results of identified studies, none has reported results on the ecotoxicological properties of the leachates. The aim of this study was to contribute to the assessment of ecotoxic risk of four different vitrified materials. Vitrified samples of contaminated soils, municipal solid wastes, and incinerator bottom ashes were submitted to the European leaching pre-standard test number prEN 12457-2. The leachates were analyzed for 22 chemical parameters. The biological characterization comprised the assessment of bioluminescence inhibition of Photobacterium phosphoreum bacterium, growth inhibition of Pseudokirchneriella subcapitata algae and the germination inhibition of Lactuca sativa vegetable. The chemical and ecotoxicological results were analyzed according to the French proposal of Criteria on the Evaluation Methods of Waste Toxicity (CEMWT) and a Toxicity Classification System (TCS). The chemical and ecotoxicological results indicated a low leachability of pollutants and a low toxicity level of leachates. All samples studied were as below the TCS class 1 level (no significant toxicity observed) and as non-ecotoxic for CEMWT. Therefore, the environmental ecotoxic risk of the analyzed vitrified samples was determined to be very low.

Effect of exogenous lysine on the expression of early cephamycin C biosynthetic genes and antibiotic production in Nocardia lactamdurans MA4213.

In beta-lactam producing microorganisms, the first step in the biosynthesis of the beta-lactam ring is the condensation of three amino acid precursors: alpha-aminoadipate, L-cysteine and D-valine. In Nocardia lactamdurans and other cephamycin-producing actinomycetes, alpha-aminoadipate is generated from L-lysine by two sequential enzymatic steps. The first step involves a lysine-6-aminotransferase activity (LAT), considered to be one of the rate-limiting steps for antibiotic biosynthesis. Here, we report the effect of exogenous lysine on antibiotic production by N. lactamdurans MA4213. Lysine-supplemented cultures showed higher titers of cephamycin C, an effect that was more significant at early fermentation times. The increase in cephamycin C production was not quantitatively correlated with specific LAT activity in lysine-supplemented cultures. Observation of a positive effect of lysine on cephamycin C production by N. lactamdurans was dependent on carbon source availability in the culture media. Supplementation of the culture media with exogenous lysine did not affect the mRNA levels of the early biosynthetic genes controlled by the bidirectional promoter. These results indicate that L-lysine is required not only for antibiotic biosynthesis, but particularly as carbon or nitrogen source.

Comparative evaluation of European methods for sampling and sample preparation of soils--the Portuguese contribution.

The main purpose of this work was to prepare a Portuguese sampling strategy, according to the existing Portuguese recommendations, for the soil sampling exercise at Dornach in the framework of the CEEM soil project of the SMT Programme of the EU. Within this project, the results obtained from the Dornach study were compared with the results obtained by other European participants and also with the reference sampling. The objective of this comparison was to validate the method used and to evaluate possible factors of uncertainty that may arise from the application of our national guideline as well as possible advantages. Another objective, also important, was to provide information regarding the need for a harmonised procedure within the European Union related to soil sampling and sample preparation of soils. The results obtained were consistent with the results obtained by other participants, however, in the Portuguese recommendations there is a general lack of specific information that may complicate its application to polluted scenarios. In fact, those guidelines are valuable to detect the average contamination of the soil, but they are not useful to identify hot spots or the edge influence in a contaminated land. As a conclusion, the results obtained by the CEEM soil project helped to evaluate the Portuguese sampling plan. This may provide a basis for further standardisation of soil sampling for specific purposes, e.g. contaminated land, and to establish a technical support for criteria used in the accreditation of laboratories for soil sampling.