LONG TERM MONITORING OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) IN BLUE MUSSELS (Mytilus edulis) FROM A REMOTE SCOTTISH LOCATION

Figures & data

FIGURE 1 Map showing the location of Loch Etive, where mussels have been collected on a monthly basis. Also the site of the Loch Leven aluminium smelter, which closed in 2000, is shown as is the location of the Braer oil spill which occurred in 1993.

FIGURE 2 Total PAH (2- to 6-ring parent and branched) concentrations in mussels collected from Loch Etive.

TABLE 1 Total PAH Concentrations (μg kg⁻¹ wet weight) in Farmed Mussels Collected from Loch Etive between 1999 and 2005. The Samples were Grouped into Two Time Periods: April to October and November to March. At Least 4 Samples were Collected from All but Two of the Time Periods. SD = standard deviation

Year	N	Range	Mean	Median	SD
1999/2000	April–October	4	17.0–67.6	37.3	32.4	21.4
	November–March	1	151.2
2000/2001	April–October	5	43.1– 74.3	51.7	43.4	13.5
	November–March	5	39.5–150.6	92.2	62.9	53.0
2001/2002	April–October	7	22.6–73.0	42.4	39.2	18.1
	November–March	5	54.2–90.1	71.1	73.6	15.9
2002/2003	April–October	6	14.8–73.1	38.1	30.2	22.4
	November–March	5	64.8–84.9	70.4	67.5	8.4
2003/2004	April–October	3	13.3–35.4	23.7	22.5	11.1
	November–March	5	38.8–78.8	51.1	44.9	15.9
2004/2005	April–October	5	12.5–33.4	21.7	21.3	7.8
	November–March	4	39.0–53.8	47.1	47.8	6.8

TABLE 2 Mean Concentrations for Selected PAHs in the Loch Etive Mussels for April–October and November–March, Compared to the OSPAR Background Concentrations (BCs) and Provisional Background Assessment Concentrations (BACs). BACs were Only Exceeded for November to March for Fluoranthene, Pyrene, Benz[a]anthracene and Benzo[a]pyrene. The Figures in Brackets are the 95% Upper Confidence Bound, Values in Bold are Above the OSPAR BACs

Geographical	Naphthalene	Phenanthrene	Anthracene	Fluoranthene	Pyrene	Benzo[a] anthracene	Chrysene	Benzo[a] pyrene	Benzoperylene	Indenolocation pyrene
BC	0.2	0.9	0.2	1.4	1.1	0.3	1.3	0.2	0.5	0.4
Provisional	1.1	4.9	0.4	2.5	1.8	1.1	3.4	0.7	2.7	1.6
BAC (μg kg^−1 wet weight)
April–October	0.30 (0.39)	1.11 (1.25)	0.07 (0.13)	1.28 (1.53)	1.20 (1.47)	0.50 (0.74)	1.07 (1.34)	0.32 (0.43)	0.93 (1.2)	0.42 (0.52)
November–March	0.31 (0.42)	1.31 (1.44)	0.06 (0.09)	2.52 (2.88)	2.20 (2.73)	1.04 (1.23)	2.88 (3.36)	0.96 (1.14)	1.52 (1.73)	1.05 (1.18)

FIGURE 3 Mean PAH composition in samples collected between April and October and samples collected between November and March, including error bars (standard deviations), of mussel samples collected from Loch Etive between 1999 and 2004. 128, naphthalenes (parent and C₁-C₄); 178, phenanthrene/anthracene (parent and C₁-C₃); DBT, dibenzothiophenes (parent and C₁-C₃); 202, fluoranthene/pyrene (parent and C₁-C₃); 228, benzanthracene/benzophenanthrenes/chrysene/triphenylenes (parent and C₁-C₂); 252, benzofluoranthene/benzopyrene/perylene and 276, indenopyrene/benzoperylene (parent and C₁-C₂).

FIGURE 4 (a) Loading plot and (b) score plot for the PCA of the parent (p) and alkylated (a) concentrations in each PAH group, expressed as proportions of the total PAH concentration. Samples collected between November and March are shown as open circles and samples collected between April and October as filled circles.