Environment Report 2019

ENVIRONMENT REPORT 2019

Figure 16: Dispersed Oil Discharged with Produced Water to Sea

Dispersed Oil Discharged with Produced Water Dispersed Oil in Water Concentration Limit Average Dispersed Oil Concentration with GC-FID Method

3,500

35

3,000

30

2,500

25

2,000

20

1,500

15

1,000

10

Dispersed Oil in Water Concentration (mg/l)

500

5

Dispersed Oil Discharged with Produced Water (Tonnes)

0

0

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Source: EEMS, May 2019

Naturally Occurring Radioactive Materials (NORM) In Produced Water Radium and many other radionuclides occur naturally in seawater and have done so for millions of years. The UKCS rock strata contains radionuclides of the uranium and thorium decay series, some of which dissolve into the water in the reservoir. These materials do not have a significant impact on the marine environment or human health. Discharges of NORM are controlled through authorisations issued under the Radioactive Substances Act (RSA) 1993. A condition of these authorisations is to notify the relevant environment agency if the concentration of Ra-226 is greater than 0.1 becquerel per millilitre (Bq/ml). There has been a 14 per cent decrease in the total NORM activity (Pb-210, Ra-228, Ra-226) discharged to sea compared with 2017. The amount of NORM discharged is dependent on the reservoir conditions and the volume of produced water discharged. The average Ra-226 concentration and the average total NORM concentration remain consistently and significantly below the 0.1 Bq/ml limit by two orders of magnitude.

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