Biomonitoring of antimony in environmental matrices from terrestrial and limnic ecosystems

Elder and poplar leaves from various sampling sites were studied with respect to their antimony content. Moreover, a retrospective determination of Sb was performed in representative limnic and terrestrial samples of the Federal Environmental Specimen Bank of Germany which have been collected over 14 years. The analytical procedure is based on an open vessel acid digestion of freeze-dried biological samples and the subsequent quantification of Sb in the digests by flow injection hydride generation atomic absorption spectrometry. Strict quality control schemes were applied to the entire procedure to guarantee accurate and precise results. No long-term changes of the Sb concentrations were found in spruce shoots or poplar leaves from different sampling sites. However, spruce shoots from a semi-natural region showed concentrations of Sb (~22 ng g−1; range: 17-29 ng g−1) that were approximately four times lower than in corresponding samples from an urban-industrialized area. The analysis of virgin and washed elder leaves revealed that approximately 20-30% of the Sb is present on the leaf surface. Sb levels in elder leaves ranged from 5.2±0.3 ng g−1 in samples from Argentina to 589±30 ng g−1 in leaves collected directly beside a motorway in Germany. Similarly, poplar leaves from Argentina and Chile showed about 4 ng Sb g−1, whereas 150 ng Sb g−1 was found in poplar leaves from Germany. The lowest concentrations of Sb were determined in digests of pigeon eggs (~2 ng g−1), bream liver (~4 ng g−1) and deer liver (~6 ng g−1). A similar pattern of Sb concentrations in spruce shoots, leaves or liver samples from an industrialized area and an agrarian ecosystem in Germany was established. Concentrations of Sb in elder leaves were closely associated with car traffic, giving maximum concentrations of 589 ng g−1 directly beside a motorway, 207 ng g−1 50 m from the motorway and 153 ng g−1 in a close residential area. The concentrations of Sb in many biological samples are i

Methyl mercury in terrestrial compartments: the present state of the art

On the basis of the analytical methodology available at present the state of the art for the determination of total mercury and of various organometallic compounds of mercury in air, precipitation, limnic systems, soils, plants and biota is reviewed. This is followed by the presentation and discussion of examples for the data obtainedhitherto for trace and ultratrace levels of total mercury and mainly methyl mercury in terrestrial and limnic environments as well as in biota. The data discussed stem predominantly from the past decade in which, due to significant methodological progress, many new aspects were elucidated. They include- themost important results in this area achieved by the Research Centre (KFA) Juelich within the project "Origin and Fate of Methyl Mercury (contracts EV4V-0138-D and STEP-CT90-0057) supported by the Commision of the European Communities, Brussels

Antibiotic Resistance in Escherichia coli from Broiler Chickens After Amoxicillin Treatment in an Experimental Environment

Groupwise antibiotic treatments are common in broiler chicken production. They induce selection for antibiotic resistance in commensalEscherichia coli.This study aimed to investigate antibiotic resistance after individual (I, drenching) or groupwise treatment (G, by water) with amoxicillin, and after contact with I or G (KI or KG), compared with untreated broilers without contact with treated broilers (C), and pretreatment values. Finally, we compared antibiotic resistance from broilers (G) after a second treatment, with a treatment in the contact animals (KG), and a first treatment in the control animals (C). Resistance to ampicillin and other antibiotics was significantly increased in groups G and I within 2 days, suggesting (co-)selection of resistance. The increase was lower in groups KI, KG, and C during the first treatment (days 1-5). The increased resistance in group C was interpreted as a change in the microbiota after initial moving and first feeding. After treatment, resistance rates decreased to initial or lower values in all groups. During the second treatment period (days 34-38), all three groups' (G, KG, and C) resistance levels increased to equally high levels. Cephalosporin resistance was low, and did not change over the experimental period. On days 3 and 38, resistance rates ofE. colifrom duodenum, jejunum, and cecum did not differ between segments and treatment routes. Overall, the baseline levels of antibiotic resistance inE. coliwere high. Amoxicillin triggered an increase in resistance levels, irrespective of the mode of treatment. Substantial resistance dynamics in untreated controls warrant further investigation