Environment Report 2014

ENVIRONMENT REPORT 2014

The CEFAS OCNS data have been used in conjunction with the PON1 data to categorise the chemicals accidentally released offshore. Sufficient information was not recorded in the PON1 DECC data to categorise all chemicals, however, it was possible to categorise over 55 per cent of them. Figure 21 highlights that 34 per cent (257 tonnes) of all chemicals released in this period were hydraulic fluids that are used to actuate valves. Chemicals such as corrosion inhibitors and gas hydrate inhibitors, which are essential to maintain pipeline integrity, make up a smaller proportion of the chemicals released to the marine environment: three per cent (21 tonnes) and five per cent (38 tonnes), respectively. Cement products (three per cent) and weighting chemicals (three per cent) used during drilling are also small contributors to chemical releases.

Figure 21: Accidental Chemical Release Volumes by Chemical Function on the UK Continental Shelf from 2011 to 2013

Cement Product

Corrosion Inhibitor

Gas Hydrate Inhibitor Weighting Chemical

Hydraulic Fluid

Other*

Unattributable

3%

3% 3%

5%

44%

34%

8%

*Other includes chemicals such as scale inhibitors, biocides, water-based drilling fluids, brine and emulsifiers

Source: DECC April 2014

CEFAS uses the Chemical Hazard and Risk Management (CHARM) model to rank the hazard of offshore chemicals according to their calculated hazard quotients (the ratio of predicted environmental concentration (PEC) 18 to predicted no effect concentration (PNEC)) 19 . Inorganic chemicals and organic chemicals with functions for which the CHARM model has no algorithms are ranked using the CEFAS OCNS hazard groups. The CHARM chemicals are ranked based on hazard level using colour bands. From a higher to lower hazard level they are: purple, orange, blue, white, silver and gold. Non-CHARM chemicals are ranked from a higher to lower hazard level from A to E.

18 PEC is an indication of the expected concentration of a material in the environment. It considers the amount initially present in the environment, its distribution and rates of degradation and removal, either forced or natural. 19 PNEC represents the concentration below which exposure to a substance is not expected to cause adverse effects to species in the environment.

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