Baseline groundwater chemistry: the Pennine Coal Measures of the East Midlands and South Yorkshire

Mallin Martin, D.; Smedley, P.L.. 2021 Baseline groundwater chemistry: the Pennine Coal Measures of the East Midlands and South Yorkshire. Nottingham, UK, British Geological Survey, 73pp. (OR/21/023) (Unpublished)

Before downloading, please read NORA policies.

Preview

Text
OR21023.pdf
Download (8MB) | Preview

Abstract/Summary

This report details the hydrogeochemistry of a suite of inorganic and organic analytes in groundwater for the Pennine Coal Measures aquifer of the East Midlands and South Yorkshire region. The study aims to establish the groundwater baseline chemical compositions, particularly of those analytes that are and could be associated with onshore oil and gas (OOG) activities, in order to facilitate distinction between current compositions and any new industrial contamination from such activities. Analytes of special interest in this context include indicators of salinity, redox conditions, dissolved gases including carbon dioxide (CO2) and methane (CH4), and organic compounds including volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). The following assessment has been derived solely from Environment Agency Water Quality Archive (WIMS) data. The Pennine Coal Measures aquifer is a complex, multi-layered secondary aquifer, comprising sandstones interbedded with low-permeability mudstones and coal seams. Groundwater flow is influenced regionally both by natural structural features and a lasting legacy of coal-mining activities. Groundwater quality in the aquifer is characterised by a large range of pH values (4.9–9.3) and commonly high dissolved-solids contents (SEC up to 6030 μS/cm). Conditions in the aquifer appear reducing to strongly reducing, with typically elevated Fe and NH4, and in places high Mn, alongside low concentrations of NO3, U and V. Both dissolved Fe and SO4 are found in high concentrations in groundwater in a number of locations and are considered to be derived from the now-flooded mine workings and the dissolution of oxidised pyrite. Organic-carbon content in the groundwater has an upper baseline concentration of 5.22 mg/L for dissolved organic carbon (DOC), and 6.45 mg/L for total organic carbon (TOC). Sources for organic carbon within the aquifer may be partly anthropogenic (industry, urban, agricultural) in origin, but are in large part derived from the abundant coal seams present within the aquifer. No dissolved gas (CH4, CO2) analyses were available from the EA WIMS data, but previous studies have identified up to 9 mg/L of dissolved methane in groundwater from the area. Only a small number of PAH and VOC compounds were detected within the EA WIMS dataset, typically each of low concentrations (<1 μg/L), but with some evidence of localised pollution from anthropogenic sources.

Item Type:	Publication - Report
Funders/Sponsors:	British Geological Survey
Additional Information. Not used in RCUK Gateway to Research.:	This item has been internally reviewed, but not externally peer-reviewed.
Additional Keywords:	GroundwaterBGS, Groundwater
Date made live:	11 Jan 2022 10:51 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/531736

Item Type:

Publication - Report

Funders/Sponsors:

British Geological Survey

Additional Information. Not used in RCUK Gateway to Research.:

This item has been internally reviewed, but not externally peer-reviewed.

Additional Keywords:

GroundwaterBGS, Groundwater

Date made live:

11 Jan 2022 10:51 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/531736