The health effects of particulate air pollution - a Christchurch perspective

Air quality in Christchurch has been debated widely over the last 30 years and at present there is a Draft Plan from the Canterbury Regional Council which has the main aim of improving air quality in the region. It has been shown in an inventory of emissions, that the main source of particulate pollution in the city is the use of solid fuel domestic heating appliances such as open fires and wood burners. Pollution from road traffic is considered a significant contributor to other contaminants but is less that 10% for particulate. There is local evidence that during the winter months, when atmospheric inversion conditions occur, levels of PM₁₀ (particulate matter less than 10 µm in diameter) exceed local guidelines (50 mcg m^-3 -24 hr average) approximately 30 times each year. Research performed in Christchurch suggests that these levels of air pollution account for both premature mortality and an increase in symptoms and medication requirements in susceptible sub-groups such as those with chronic obstructive airways disease. Ongoing research is planned in Christchurch and a collaborative approach between public health physicians, biostatisticians, toxicologists and clinical researchers is likely to yield further useful information which will inform the decision-making process by the Canterbury Regional Council.     

Temporal variations of metallothionein and metal concentrations in the digestive gland of oysters (Crassostrea gigas) from a clean and a metal-rich site

The concentrations of metallothionein (MT) in bivalves, a potential biomarker of metal pollution, are variable according to specific organs, the highest concentrations being encountered in the digestive glands of oysters. Thus, the present study has been focussed on this organ with a view to validate the use of MT as a biomarker in the field, the temporal changes of metal and metallothionein concentrations have been examined from March to October 1997 in the digestive gland of resident oysters from a clean site (Bay of Bourgneuf, France) and a metal-rich site, the Gironde estuary which has been shown as the most Cd-contaminated marine area in France but is also enriched with Cu and Zn. Moreover, oysters from the clean site have been translocated to the Gironde estuary over the same period. Taking into account all the samples collected over the 7 months of the study, MT concentrations in the digestive gland were positively correlated with weight whereas metal levels were negatively correlated with weight. However, considering monthly samples including specimens from both sites (resident or translocated oysters), a positive correlation was shown between MT and metal concentrations in autumn (September and October) but not in spring and summer. These findings limit the interest of using the digestive gland of oysters as the preferred tissue for the determination of MT concentration as a biomarker.The alternative use of gills should be considered.