Mercury in rivers in NW England: from rural headwaters to the heartlands of the historic industrial base

Total mercury (T-Hg) concentrations in rivers are described across a rural to urban/industrial and agricultural landscape gradient in NW England. T-Hg ranges between 0.2 and 230 ng L −1 . The regional median was 3.6 ng L −1 with individual river medians ranging between 1.9 and 8.3 ng L −1 . Median T...

Full description

Saved in:
Bibliographic Details
Published in:Journal of environmental monitoring 2010-12, Vol.12 (12), p.2299-236
Main Authors: Rowland, A. P, Neal, C, Scholefield, P, Halford, A. P, Vincent, C. D, Hockenhull, K
Format: Article
Language:English
Subjects:
Agriculture
England
Industry
Mercury - analysis
Regression Analysis
Rivers
Water Pollutants - analysis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Total mercury (T-Hg) concentrations in rivers are described across a rural to urban/industrial and agricultural landscape gradient in NW England. T-Hg ranges between 0.2 and 230 ng L −1 . The regional median was 3.6 ng L −1 with individual river medians ranging between 1.9 and 8.3 ng L −1 . Median T-Hg concentrations were sometimes moderately higher for the lowland areas and at higher flows. Our estimates suggest that the Ribble estuary receives 9.2 kg y −1 and the Wyre estuary 0.7 kg y −1 . In order to examine regional inputs from urban/industrial components, regression analysis was undertaken by comparing three types of hydrochemical signature: suspended sediments (SS), which provide a measure of the particulate component, dissolved organic carbon (DOC) that provides an indication of humic/fulvic acids that are part of the organic colloids and strong chelating agents, and boron a marker of sewage effluents and population density. The results show high positive relationships of T-Hg with both SS and DOC, but no relationship with the urban/industrial signal. The regression analysis with T-Hg indicated on average a gradient of 0.33 ng mg −1 for DOC and 0.2 ng mg −1 for SS. They indicate the primary importance of a diffuse source of T-Hg. For the upland areas and cleaner river systems, the linkages between T-Hg and DOC were particularly strong, while for the lowland areas, the linkage with SS proved stronger. Analysis of a latter subset of data that partition the SS into organic and inorganic fractions indicated that the T-Hg was primarily linked with the organic fraction. Indeed, multiple regression of T-Hg with DOC and POM reveals gradients similar to other parts of the World. It is estimated that approximately 9 kg of mercury (particulate + dissolved) are discharged into the Ribble estuary each year.
ISSN:1464-0325
1464-0333
DOI:10.1039/c0em00398k