『Abstract
An important component of monitoring pollution of urban road-deposited
sediment (RDS) is an understanding of the temporal variability
in its composition and physical characteristics. This study set
out to determine what the monthly variability in metal concentrations,
organic matter content, grain-size and grain-size fraction metal-loadings
are in inner city sites in Manchester, northwest England. The
results show that there is significant temporal variability in
metal (Pb, Zn, Fe, Mn) concentration in RDS from inner city Manchester.
There was no significant temporal variability in grain-size characteristics
or organic matter content, indicting that these metal variations
were the result of variation in sources and accumulation processes.
Pb and Zn displayed local variability, suggesting local controls
on variability, whereas Fe and Mn displayed consistent variability
across all sites, suggesting a common, larger-scale control on
variability. The finest grain-size fraction (＜63μm) contained
the highest Pb, Cu and Zn concentrations, but for the case of
Fe and Mn, the coarser fractions (＞300μm) commonly contained the
highest concentrations, again suggesting differing controls. For
all metals, due to the weight percent dominance of the coarser
fractions, the dominant loading of metals is in the coarser fractions.
This has implications on management strategies, via street sweeping
and the subsequent waste disposal, and on the modelling of the
input of RDS and associated metals into surface waterways. The
recognition of significant temporal variability of metal concentrations
in RDS, independent of grain-size changes, implies that the monitoring
of urban road sediment pollution will require not just consideration
of spatial variability, but the design of schemes that will capture
temporal variability also.
Keywords: Urban; Metals; Manchester; Sediment; Pollution; Temporal』
1. Introduction
2. Materials and methods
2.1. Study area and sample locations
2.2. Sampling strategy and sediment manipulation
2.3. Sample analysis
3. Results
3.1. Organic matter content
3.2. Grain-size characteristics
3.3. Metal concentrations
3.4. Grain-size specific metal concentrations and grain-size
loadings for metals
4. Discussion
4.1. Inter-site variability
4.2. Temporal variability
4.3. Grain-size relationships
5. Conclusions and implications
Acknowledgements
References