Effects of urban particulate deposition on microbial communities living in bryophytes: an experimental study.

Our previous in situ study showed that bryophyte-microorganism complexes were affected by particulate atmospheric pollution. Here, the effect of urban particulate wet deposits on microbial communities living in bryophytes was studied under controlled conditions. An urban particulate solution was prepared with particles extracted from analyzer' filters and nebulized on bryophytes in treatments differing in frequency and quantity. The bryophytes did not accumulate metallic trace elements, which were present in very weak concentrations. However, in treated microcosms the total microbial biomass and the biomasses of cyanobacteria, active testate amoebae and fungi significantly decreased in response to the deposition of particles. These results confirm that microbial communities living in terrestrial bryophytes could be more sensitive indicators of atmospheric pollution than bryophytes. Moreover, they suggest that unicellular predators--such as testate amoebae--could be especially useful microbial indicators, since they seem to be both directly and indirectly affected by pollution.

Transfer and effects of cadmium in an experimental food chain involving the snail Helix aspersa and the predatory carabid beetle Chrysocarabus splendens.

The transfer and the toxic effects of Cd were studied in an experimental food chain involving the snail Helix aspersa as prey organism and one of its natural predators, the carabid beetle Chrysocarabus splendens. Juvenile snails were fed plant-based food enriched with 0, 10, 50 and 100 microg g(-1) of Cd, then were offered as prey to beetle larvae from egg hatching to pupation stage. Cd concentrations in snail tissues increased with increasing Cd concentration in food and with duration of exposure. Bioaccumulation factors ranged from 1.87 to 3.39, showing that H. aspersa snails, even in their early life stages, belong to macroconcentrator species for Cd. No significant reduction of snail consumption by beetles was found in exposed groups. Cd concentrations in beetle larvae remained very low (lower than 1 microg g(-1) for all groups), demonstrating a very effective regulation capacity in beetle larvae. However, Cd concentrations in highest exposed groups were higher than those found in control groups. Cd contents in adult beetles were lower than in larvae, showing a loss of Cd during metamorphosis. Despite the low Cd concentrations found in beetles, their exposure to Cd contaminated snails led to 31% of mortality, which occurred only during pupation and for the highest exposure level. No clear sublethal effects were found. These results showed that snails inhabiting heavily polluted areas may represent a risk of secondary poisoning for predatory invertebrates and provided quantitative data on the transfer of Cd between two compartments of a terrestrial food chain.

The mass media and the prevention of child behavior problems: the evaluation of a television series to promote positive outcomes for parents and their children.

This paper examines the impact of a 12-episode television series, "Families", on disruptive child behavior and family adjustment. This media intervention comprises the first of a five-level early intervention parenting and family support strategy, known as Triple P (Positive Parenting Program). Fifty-six parents of children aged between 2 and 8 years were randomly assigned to either watching the television series or to a waitlist control group. Compared to the control group, parents in the television viewing (TV) condition reported significantly lower levels of disruptive child behavior and higher levels of perceived parenting competence, immediately following intervention. Prior to intervention approximately 42.9% of the children in the TV condition were in the clinically elevated range for disruptive child behavioral problems. This had reduced to 14.3 % following intervention. In addition, a high level of consumer acceptability was reported by parents in the TV condition. All post-intervention effects were maintained at 6-month follow-up. Implications for public health approaches to family mental health are discussed.