Preliminary study of Lead (Pb) immobilization by meat and bone meal combustion residues (MBMCR) in soil: assessment of Pb toxicity (phytotoxicity and genotoxicity) using the tobacco model (Nicotiana tabacum var. xanthi Dulieu).

Lead (Pb) is a major chemical pollutant in the environment. The present investigation evaluates the possible use of Meat and Bone Meal Combustion Residues (MBMCR), to sequester Pb from the soil compartment using the heterozygous tobacco model (Nicotiana tabacum var. xanthi Dulieu) characterized by the a1+ /a1 a2+ /a2 system. The toxic potential of Pb-contaminations (50, 100, 1,000, 2,000 and 10,000 mg Pb kg(-1)) as Pb(NO3) in standard soil was investigated in lab conditions according to three endpoints: (i) acute toxicity of plants (mortality, height and surface area parameters), (ii) Pb-accumulation in roots, stems and leaves, and (iii) genetic effects as the expression of reversion in the leaf of plants. Moreover, chemical investigations of Pb interactions with soil were realized to complete the toxicity evaluation. The results demonstrated that: (i) MBMCR were not acutely toxic or genotoxic to tobacco plants, (ii) Pb is acutely toxic to tobacco plants at 10,000 mg Pb kg(-1) of soil, (ii) but is not genotoxic, and (iii) Pb-bioaccumulation is significant in leaves, stems and roots (from 1,000, 2,000, and 50 mg Pb kg(-1) of soil, respectively). In contrast, in the presence of MBMCR, the toxic impacts of Pb were inhibited and Pb-accumulation in tobacco plants was reduced. In complement, chemical analyses highlighted the high capacity of the standard soil to immobilize Pb. The results suggest that even if Pb is bioavailable from soils to plants, complex mechanisms could occur in plants protecting them from the toxic impact of Pb.

Assessment of lead ecotoxicity in water using the amphibian larvae (Xenopus laevis) and preliminary study of its immobilization in meat and bone meal combustion residues.

Lead (Pb) is a major chemical pollutant of the environment. It has been associated with human activities for the last 6000 years. Quite rightly, it remains a public health concern today. The present investigation evaluates the toxic potential of Pb in larvae of the toad Xenopus laevis after 12 days exposure in lab conditions. Acute toxicity, genotoxicity and Pb bioaccumulation were analyzed. The genotoxic effects were analyzed in the circulating blood from the levels of micronucleus induction according to the French standard micronucleus assay (AFNOR 2000 Association française de normalization. Norme NFT 90-325. Qualité de l'Eau. Evaluation de la génotoxicité au moyen de larves d'amphibien (Xenopus laevis, Pleurodeles waltl)). Lead bioaccumulation was analyzed in the liver of larvae at the end of exposure. Moreover, the toxic potential of lead, in aquatic media, was investigated in the presence of meat and bone meal combustion residues (MBMCR) known to be rich in phosphates and a potential immobiliser of lead. Previously, acute toxicity and genotoxicity of MBMCR alone were evaluated using Xenopus larvae. The results obtained in the present study demonstrated: (i) that lead is acutely toxic and genotoxic to amphibian larvae from 1 mg Pb/l and its bioaccumulation is significant in the liver of larvae from the lowest concentration of exposure (1 microg Pb/l), (ii) MBMCR were not acutely toxic nor genotoxic in Xenopus larvae, (iii) lead in presence of MBMCR induced inhibition or reduction of the toxic and genotoxic potential of lead in water at concentrations that do not exceed the capacity of MBMCR of Pb-binding (iv) Pb accumulation in larvae exposed to lead with MBMCR in water was lower than Pb-accumulation in larvae exposed to lead alone except at the concentration of 0.01 mg Pb/l suggesting complex mechanisms of MBMCR interaction in organisms. The results confirm the high toxicity and genotoxicity of lead in the aquatic compartment and suggest the potential utility of MBMCR for use in remediation.

Work status after workers' compensation claims for upper limb musculoskeletal disorders.

AIM: To provide information on employment status after workers' compensation (WC) claims for musculoskeletal disorders of the limbs (MSDs). METHODS: Two-year follow up of the workers who filed a WC claim for MSDs in 1996 in the Pays de la Loire region. Of the 701 eligible workers, 514 workers (70%) participated. Information was requested by means of a mailed questionnaire about the characteristics of the MSDs and job status at the time of the WC claim and two years later. RESULTS: Two years after the WC claim, 65% of the claimants had returned to work in the same company, often without any ergonomic improvement, 12% had retired or had left employment voluntarily, and 18% had been dismissed. The risk of dismissal was associated with three factors: being older than 45 years, having two or more MSDs at claim, and working in the cleaning services sector.