Introduction
Materials and methods
Study species
Sampling sites, number of samples, and sampling frequency
N in map | Lake | Latitude | Longitude | Species | Years analyzed for PCBs |
---|---|---|---|---|---|
1 | Abiskojaure | 68.31° | 18.65° | Arctic char | 81a, 86–98a, 00a, 07a, 08b, 09–10c, 11–12d
|
2 | Tjulträsk | 65.96° | 16.07° | Arctic char | 86–87a, 95a, 06b, 08–10c, 11–12d
|
3 | Storvindeln | 65.70° | 17.13° | Pike | 85–00a, 05a, 06b, 07a, 08b, 09c, 10b, 11–12d
|
4 | Brännträsket | 65.53° | 21.42° | Perch | 07b
|
5 | Remmarsjön | 63.86° | 18.27° | Perch | 00a, 05a, 07b
|
6 | Degervattnet | 63.87° | 16.23° | Perch | 05a, 07b
|
7 | Stor-Björsjön | 63.61° | 12.23° | Arctic char | 07b
|
8 | Stor-Backsjön | 62.68° | 14.51° | Perch | 07b
|
9 | Stensjön | 61.64° | 16.58° | Perch | 97–00a, 05
a
, 06b, 07a, 08b, 09c, 10b, 11–12d
|
10 | Gipsjön | 60.65° | 13.63° | Perch | 07b
|
11 | Spjutsjön | 60.64° | 15.45° | Perch | 07b
|
12 | Övre Skärsjön | 59.84° | 15.55° | Perch | 05a, 07b
|
13 | Limmingsjön | 59.59° | 14.51° | Perch | 07b
|
14 | Fysingen | 59.57° | 17.92° | Perch | 07b, 10b, 11–12e
|
15 | Tärnan | 59.56° | 18.37° | Perch | 05a, 07b
|
16 | Bysjön | 59.30° | 12.34° | Perch | 05a, 07b
|
17 | Stora Envättern | 59.11° | 17.35° | Perch | 00a, 05a, 07b
|
18 | Älgsjön | 59.09° | 16.37° | Perch | 07b
|
19 | Svartsjön | 58.76° | 14.22° | Perch | 07b, 11–12d
|
20 | Fräcksjön | 58.15° | 12.18° | Perch | 07b
|
21 | Bästeträsk | 57.92° | 18.94° | Perch | 07b
|
22 | Allgjuttern | 57.95° | 16.10° | Perch | 07b
|
23 | Horsan | 57.87° | 18.84° | Perch | 07a, 08b, 09c, 10b, 11–12d
|
24 | Skärgölen | 57.78° | 15.58° | Perch | 99a, 06
b
, 08b, 09–10c, 11–12d
|
25 | Lilla Öresjön | 57.56° | 12.34° | Perch | 07b
|
26 | Fiolen | 57.09° | 14.53° | Perch | 07b
|
27 | Hjärtsjön | 57.05° | 15.26° | Perch | 00a, 05a, 07b
|
28 | Bolmen | 56.97° | 13.77° | Pike | 88–00a, 05a, 06b, 07a, 08b, 09–10c, 11–12d
|
29 | Stora Skärsjön | 56.67° | 13.07° | Perch | 97–98a, 07b
|
30 | Sännen | 56.33° | 15.36° | Perch | 07b
|
31 | Krankesjön | 55.70° | 13.47° | Perch | 07a, 08b, 09c, 10b, 11–12d
|
32 | Krageholmsjön | 55.50° | 13.75° | Perch | 07b
|
Sample preparation and registered variables
Chemical analysis
Statistical analysis and maps
Environmental assessment criteria
Results
Biological variables
Lake | Species | Age (years) 95 % CI | Length (cm) 95 % CI | Weight (g) 95 % CI | Fat content (%) 95 % CI |
---|---|---|---|---|---|
Allgjuttern | Perch | 4.6 (4.4–4.9) | 18.0 (17.6–18.4) | 56.6 (51.7–61.4) | 0.54 (0.39–0.70) |
Abiskojaure | Arctic char | 5.1 (5.0–5.3) | 26.9 (26.4–27.4) | 216 (203–230) | 1.7 (1.5–1.8) |
Bolmen | Pike | 5.2 (5.0–5.3) | 54.1 (53.3–54.9) | 1080 (1040–1120) | 0.55 (0.54–0.57) |
Brännträsket | Perch | 7.6 (7.2–8.1) | 18.7 (18.3–19.1) | 68.1 (63.3–72.8) | 0.62 (0.28–0.96) |
Bysjön | Perch | 5.4 (5.1–5.7) | 17.3 (17.0–17.6) | 52.9 (49.8–56.0) | 0.68 (0.36–0.99) |
Bästeträsk | Perch | 3.9 (3.7–4.1) | 17.5 (17.3–17.8) | 53.4 (51.2–55.6) | 0.70 (0.37–1.0) |
Degervattnet | Perch | 5.5 (5.2–5.8) | 18.3 (18.0–18.6) | 63.8 (60.6–67.0) | 0.48 (0.31–0.65) |
Fiolen | Perch | 4.4 (4.2–4.7) | 18.0 (17.6–18.3) | 61.5 (57.5–65.5) | 0.60 (0.43–0.76) |
Fräcksjön | Perch | 5.3 (5.0–5.5) | 17.1 (16.8–17.4) | 51.9 (48.3–55.5) | 0.58 (0.43–0.76) |
Fysingen | Perch | 4.7 (4.4–4.9) | 17.1 (16.8–17.4) | 53.4 (50.0–56.8) | 0.54 (0.46–0.62) |
Gipsjön | Perch | 6.4 (6.2–6.6) | 17.3 (17.0–17.7) | 56.1 (52.7–59.5) | 0.52 (0.41–0.62) |
Hjärtsjön | Perch | 3.6 (3.4–3.7) | 18.7 (18.3–19.0) | 68.7 (64.9–72.6) | 0.76 (0.44–1.1) |
Horsan | Perch | 5.3 (5.1–5.6) | 19.0 (17.6–20.4) | 58.4 (55.6–61.3) | 0.68 (0.62–0.74) |
Krageholmsjön | Perch | 2.5 (2.3–2.7) | 17.5 (16.9–18.1) | 70.6 (61.0–80.2) | 0.63 (0.49–0.77) |
Krankesjön | Perch | 3.1 (3.0–3.3) | 19.5 (16.5–22.5) | 59.6 (56.6–62.6) | 0.50 (0.45–0.56) |
Lilla Öresjön | Perch | 5.6 (5.3–5.9) | 18.3 (18.0–18.7) | 63.5 (59.2–67.8) | 0.70 (0.37–1.02) |
Limmingsjön | Perch | 4.9 (4.7–5.2) | 17.5 (17.2–17.9) | 55.8 (52.7–58.9) | 0.65 (0.54–0.76) |
Remmarsjön | Perch | 6.8 (6.5–7.2) | 18.9 (18.4–19.4) | 72.7 (67.3–78.0) | 0.66 (0.53–0.78) |
Skärgölen | Perch | 4.7 (4.5–5.0) | 17.8 (16.9–18.7) | 59.0 (54.8–63.1) | 0.68 (0.64–0.72) |
Spjutsjön | Perch | 3.9 (3.7–4.1) | 18.2 (17.9–18.4) | 62.0 (59.1–64.9) | 0.72 (0.52–0.92) |
Stora Envättern | Perch | 5.3 (5.1–5.6) | 16.8 (16.5–17.2) | 47.8 (44.2–51.4) | 0.62 (0.30–0.93) |
Stensjön | Perch | 7.4 (7.0–7.7) | 19.0 (18.3–19.7) | 63.3 (61.1–65.6) | 0.60 (0.54–0.65) |
Stora Skärsjön | Perch | 6.3 (6.1–6.6) | 16.4 (16.2–16.6) | 46.3 (44.4–48.2) | 0.56 (0.45–0.68) |
Stor–Backsjön | Perch | 6.5 (6.2–6.7) | 18.4 (18.1–18.6) | 63.8 (61.1–66.5) | 0.65 (0.47–0.82) |
Stor–Björsjön | Arctic char | 5.6 (4.5–6.7) | 26.3 (25.6–27.1) | 160 (146–175) | 1.0 (0.46–1.6) |
Storvindeln | Pike | 5.8 (5.6–5.9) | 61.3 (60.7–62.0) | 1630 (1570–1680) | 0.58 (0.57–0.60) |
Svartsjön | Perch | 7.3 (6.5–8.1) | 15.6 (14.7–16.5) | 39.1 (31.0–47.1) | 0.70 (0.59–0.80) |
Sännen | Perch | 5.7 (5.5–6.0) | 17.0 (16.7–17.3) | 47.5 (44.1–51.0) | 0.59 (0.39–0.79) |
Tjulträsk | Arctic char | 5.2 (5.1–5.3) | 26.9 (26.3–27.6) | 209 (193–225) | 1.5 (1.3–1.6) |
Tärnan | Perch | 5.9 (5.6–6.2) | 17.7 (17.3–18.1) | 58.1 (53.1–63.0) | 0.60 (0.50–0.69) |
Älgsjön | Perch | 5.8 (5.4–6.1) | 16.7 (16.3–17.0) | 46.1 (43.4–48.8) | 0.69 (0.47–0.90) |
Övre Skärsjön | Perch | 6.4 (6.1–6.7) | 18.5 (18.2–18.8) | 64.6 (61.1–68.1) | 0.63 (0.58–0.67) |
Temporal trends
Lake | Species | Contaminant | Annual % change (95 % CI) |
r
2
|
p value | Lowest detectable change (%) | CV (%) |
N years required to detect a trend of 10 % |
---|---|---|---|---|---|---|---|---|
Abiskojaure | Arctic char | CB-118 | ||||||
1981–2012 | −5.8 (−7.8, −3.9) | 0.67 | <0.001 | 14 | 40 | 13 | ||
2003–2012 | −10 (−22, 2.2) | 0.57 | 0.084 | 6.7 | 19 | 9 | ||
Tjulträsk | Arctic char | CB-118 | ||||||
1986–2012 | −7.8 (−11, −4.7) | 0.83 | <0.001 | 15 | 40 | 13 | ||
2003–2012 | −5.0 (−12, 1.5) | 0.54 | 0.098 | 4 | 11 | 7 | ||
Bolmen | Pike | CB-118 | ||||||
1988–2012 | −4.2 (−6.0, −2.4) | 0.55 | <0.001 | 12 | 32 | 11 | ||
2003–2012 | −4.3 (−18, 9.5) | 0.08 | 0.48 | 14 | 38 | 12 | ||
Storvindeln | Pike | CB-118 | ||||||
1985–012 | −4.9 (−6.0, −3.9) | 0.83 | <0.001 | 6.9 | 19 | 9 | ||
2003–2012 | −4.4 (−12, 2.7) | 0.28 | 0.18 | 6.9 | 19 | 9 | ||
Skärgölen | Perch | CB-118 | ||||||
1999–2012 | −3.6 (−9.1, 2.0) | 0.35 | 0.16 | 8.4 | 24 | 10 | ||
2003–2012 | −2.0 (−17, 13) | 0.03 | 0.72 | 9.4 | 26 | 10 | ||
Stensjön | Perch | CB-118 | ||||||
1997–2012 | −2.1 (−7.8, 3.6) | 0.06 | 0.44 | 17 | 48 | 14 | ||
2003–2012 | 6.7 (−11, 24) | 0.13 | 0.39 | 18 | 49 | 14 | ||
Abiskojaure | Arctic char | CB-153 | ||||||
1981–2012 | −4.4 (−5.9, −2.9) | 0.64 | <0.001 | 11 | 31 | 11 | ||
2003–2012 | −8.7 (−13, −4.8) | 0.87 | <0.01 | 3.2 | 9.0 | 6 | ||
Tjulträsk | Arctic char | CB-153 | ||||||
1986–2012 | −7.2 (−10, −4.5) | 0.85 | <0.001 | 13 | 36 | 12 | ||
2003–2012 | −2.5 (−9.4, 4.6) | 0.20 | 0.38 | 4.4 | 13 | 7 | ||
Bolmen | Pike | CB-153 | ||||||
1988–2012 | −1.2 (−3.2, 0.74) | 0.08 | 0.33 | 12 | 34 | 12 | ||
2003–2012 | −0.1 (−14, 14) | 0.00 | 0.95 | 14 | 39 | 13 | ||
Storvindeln | Pike | CB-153 | ||||||
1985–012 | −3.6 (−4.6, −2.6) | 0.73 | <0.001 | 6.9 | 19 | 9 | ||
2003–2012 | −4.7 (−9.5, 0.18) | 0.48 | 0.055 | 4.6 | 13 | 7 | ||
Skärgölen | Perch | CB-153 | ||||||
1999–2012 | −1.6 (−5.2, 2.0) | 0.21 | 0.30 | 5.4 | 15 | 8 | ||
2003–2012 | −2.6 (−12, 6.9) | 0.13 | 0.49 | 5.9 | 17 | 8 | ||
Stensjön | Perch | CB-153 | ||||||
1997–2012 | 0.57 (−5.9, 7.0) | 0.00 | 0.83 | 19 | 55 | 15 | ||
2003–2012 | 12 (−6.3, 31) | 0.30 | 0.16 | 19 | 52 | 25 | ||
Abiskojaure | Arctic char | CB-101/CB-153 | ||||||
1981–2012 | −2.4 (−3.4, −1.5) | 0.59 | <0.001 | 6.7 | 19 | 9 | ||
2003–2012 | 2.6 (−4.6, 9.8) | 0.15 | 0.40 | 6.0 | 17 | 8 | ||
Tjulträsk | Arctic char | CB-101/CB-153 | ||||||
1986–2012 | −0.98 (−2.0, 0.052) | 0.42 | 0.058 | 4.6 | 13 | 7 | ||
2003–2012 | 0.37 (−5.9, 6.7) | 0.00 | 0.85 | 3.9 | 11 | 7 | ||
Bolmen | Pike | CB-101/CB-153 | ||||||
1988–2012 | −2.5 (−3.2, −1.7) | 0.71 | <0.001 | 4.6 | 13 | 7 | ||
2003–2012 | −2.7 (−8.4, −2.9) | 0.19 | 0.28 | 5.4 | 15 | 8 | ||
Storvindeln | Pike | CB-101/CB-153 | ||||||
1985–012 | −2.0 (−2.7, 1.3) | 0.63 | <0.001 | 4.8 | 13 | 7 | ||
2003–2012 | −0.41 (−2.2, 1.4) | 0.04 | 0.61 | 1.7 | 4.9 | 5 | ||
Skärgölen | Perch | CB-101/CB-153 | ||||||
1999–2012 | −1.9 (−5.4, 1.5) | 0.29 | 0.21 | 5.1 | 14 | 7 | ||
2003–2012 | 0.60 (−7.8, 9.0) | 0.01 | 0.83 | 5.2 | 15 | 8 | ||
Stensjön | Perch | CB-101/CB-153 | ||||||
1997–2012 | −2.5 (−4.1, −0.97) | 0.57 | <0.01 | 4.4 | 12 | 7 | ||
2003–2012 | −4.9 (−9.4, −0.34) | 0.54 | <0.05 | 4.3 | 12 | 7 |
Spatial patterns
Target levels
Discussion
-
Examination of individual congeners rather than only looking at the summed concentrations of a substance.
-
The importance of annual monitoring.
-
The choice of monitoring species, organ and selection of samples concerning e.g., age, sex, size, and sampling season.
-
The importance of using the same laboratory for contaminant monitoring for temporal trend studies.