Metals (lead, cadmium and mercury) - HELCOM Indicators/HELCOM-CoreIndicator-Metals.pdf · Mercury and cadmium are included in the HELCOM Baltic Sea Action Plan. All the three metals
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HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Current status in the Baltic Sea ........................................................................................................................................... 5
Lead ................................................................................................................................................................................. 5
General Information ........................................................................................................................................................... 6
General properties .......................................................................................................................................................... 6
Main impacts on the environment and human health ................................................................................................... 6
Status of the indicator on international priority lists and other policy relevance .......................................................... 6
Status of restrictions, bans or use ................................................................................................................................... 6
Concentrations and time series of metals in the Baltic Sea ................................................................................................ 7
Concentrations of metals ................................................................................................................................................ 7
Lead ........................................................................................................................................................................... 10
Lead ........................................................................................................................................................................... 13
Data source ................................................................................................................................................................... 19
Description of data ........................................................................................................................................................ 19
Lead ........................................................................................................................................................................... 20
Current monitoring network ..................................................................................................................................... 21
Geographical relevance in the monitoring of metals ................................................................................................ 22
Methodology and frequency of data collection ............................................................................................................ 22
Methodology of data analyses ...................................................................................................................................... 22
Shellfish or sediment for local surveys. ......................................................................................................................... 22
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Fish muscle (Hg) and liver (Cd, Pb) for regional surveys. .............................................................................................. 22
Determination of GES boundary ................................................................................................................................... 22
Thresholds in the time series .................................................................................................................................... 24
Strengths and weaknesses of data ................................................................................................................................ 24
Further work required ................................................................................................................................................... 24
Metals in different parts of fish, ................................................................................................................................... 27
The 6-year averages of cadmium concentrations in Baltic fish and blue mussels (2005–2010) are spatially varying. In
general, elevated concentrations are found from all parts of the Baltic Sea, but particularly the Gulf of Bothnia has
poorer status than other sub-basins of the region (Figure 1). The status of cadmium does not seem to depend on
species, but concentrations measured from perch and blue mussels represent more local conditions and hence show
higher variability.
Mercury
The 6-year averages of mercury concentrations show elevated status in several sites in the Baltic Sea (Figure 2). The
blue mussel and flounder data from the Danish Straits and Kattegat indicate several locations of sub-GES status and
the perch data from the Estonian coast indicates even more clearly the same. The herring and cod data from Gulf of
Bothnia and the Baltic Proper indicates GES. It seems that the status classes depend on sampled species; for example,
perch has accumulated generally higher concentrations of mercury than the fattier herring.
Lead
The 6-year averages of lead concentrations in Baltic fish and bivalves show a variation from bad status in the Gulf of
Finland and Baltic Proper to a moderate or good environmental status in the Danish Straits and Kattegat (Figure 3). In
the Gulf of Bothnia, the status is most likely better than elsewhere, but the high detection limit of the herring liver
Figure 2. Status of mercury in relation to the mercury GES boundary in different fish species and the blue mussel in 2005–2010. Herring and perch concentrations were converted to whole fish concentrations. For explanations, see Fig 1.
Figure 3. Status of lead in relation to the lead GES
boundary in different fish species and the blue mussel in
2005–2010. Herring and perch concentrations were
converted to whole fish concentrations. For explanations,
see Fig 1.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Concentrations and time series of metals in the Baltic Sea
Concentrations of metals
Cadmium
Cadmium concentrations in the herring liver range between 0.35–3.6 mg kg-1
dw (Figure 4a). The highest
concentrations are found from the Bothnian Sea.
TISS - 12.09.19 11:20, CDmedICES2012arit
Figure 4a. Spatial variation in arithmetic mean concentration (2008–2010 in µg/g dry weight) of cadmium in herring
liver. The highest concentration (around 3.6 mg/kg ) was found in the northern Bothnian Sea (Gaviksfjärden), the
lowest (around 0.35 mg/kg) in Kattegat (Fladen). The Swedish data originates from the Swedish national monitoring
programme and are analysed at the Department of Applied Environmental Science, Stockholm University. Additional
data is obtained from ICES database.
Figure 4b. Spatial variation in arithmetic mean concentration (2005–2011 in µg/kg wet weight) of cadmium in herring whole body. Sites closer than 50 km are fused together to an arithmetic mean concentration.The highest bar represents a concentration of 94 µg/kg. Red columns represent concentrations above 26 µg/kg.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Figure 4c. Spatial variation in arithmetic mean concentration (2005–2011 in µg/kg wet weight) of cadmium in
perch whole body. Sites closer than 50 km are fused together to an arithmetic mean concentration.The highest
bar represents a concentration of 32 µg/kg. Red columns represent concentrations above 26 µg/kg.
Figure 4d. Spatial variation in arithmetic mean concentration (2005–2011 in µg/kg dry weight) of cadmium in blue mussel. The highest bar represents a value of 4 100 µg/kg dw. Red columns represent concentrations above 960 µg/kg.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
The mercury concentrations in perch are clearly higher than in herring and somewhat higher than in blue mussels
(Figures 5–7). The concentrations are high almost everywhere in the Baltic Sea, but lower concentrations may exist in
the eastern Bothnian Sea and the Archipelago Sea. Similar result was also shown in the HELCOM Thematic Assessment
(HELCOM 2010) and by Bignert et al. (2011). The high mercury concentrations in the Bothnian Bay and eastern Gulf of
Finland are also seen in the sediment data (HELCOM 2010).
Figure 4e. Spatial variation in arithmetic mean concentration (2005–2011 in µg/kg dry weight) of cadmium in sediment. The highest bar represents a value of 2 480 µg/kg dw. Red columns represent concentrations above 960 µg/kg.
Figure 5. Concentrations of mercury (µg/kg ww) in herring muscle, converted to whole fish concentrations (see
Annex 1 of this indicator report). The green part of the bars represent a concentration of 35 µg/kg ww, which is
the EQS for fish. Sites closer than 50 km are fused together to an arithmetic mean concentration.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
The temporal trends for metals in biota are inconclusive, as there are both areas with increasing trends of mercury
and cadmium, and areas with decreasing trends (Figures 9–16; see also HELCOM 2010 and Jensen 2012).
Cadmium
Cadmium concentrations in herring are generally showing significant increasing trends followed by decreasing trends (Figure 9). Cadmium concentration in liver tissue from various species show coherent trends of similar magnitudes from various regions. Cadmium concentrations in cod liver samples (adjusted for varying fat content) from south east of Gotland and Fladen, however, show significant decreasing trends (Figure 10).
In general, the recent levels are not significantly lower compared to the concentrations measured at the beginning of the 80s, despite measures taken to reduce discharges of cadmium to the environment.
Mercury
There is no common general trend for mercury in herring muscle for the investigated time series. The concentration in
herring from the northern Baltic Proper seems to increase during the investigated time period until the mid-90s but
with a decreasing trend the last 15 years (Figure 11). The annual mean concentrations in herring muscle during the
investigated time period are all below 100 µg/kg except for a few years at Ängskärsklubb. The concentrations in the
eggs of Common Guillemot have decreased since 1970s (Figure 12).
The time series for autumn-caught herring from Ängskärsklubb in the Bothnian Sea shows a very large between-year
variation. Although the sampling site at Ängskärsklubb is located rather far off the coast, the mercury concentration in
the herring samples could be influenced by local discharges. Ängskärsklubb may thus not be representative of the
Bothnian Sea.
Mercury was monitored in spring-caught herring from Ängskärsklubb and Karlskrona for four years in the beginning of
the seventies, and these series were taken up again in 1996. The Ängskärsklubb time series shows significantly lower
concentrations during the recent time period compared to the concentrations in the early seventies and this decrease
is about 60%.
Lead
Lead is showing significant declining trends in almost all investigated biotic matrices of sufficient length, obviously as a
result of measures taken to reduce discharges of lead to the environment (Figures 13–16). The investigated time
Figure 8e. Spatial variation in arithmetic mean concentration (2005–2011 in µg/gg dry weight) of lead in
Macoma balthica. The highest bar represents a concentration of 1514 µg/kg. The green part of the bars
represent a concentration of 1300 µg/kg ww.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
series in herring liver show significant decreasing trends at Harufjärden (-5.9 %), Ängskärsklubb (autumn, -4.5 %),
Landsort (-5.7 %), and Utlängan (autumn, -2.8 %). Lead concentrations in cod liver (after adjusting for varying fat
content) showed decreasing trends from SE Gotland (-5.3 %) and Fladen (about –2.8 %). Perch liver from the coastal
sites Holmöarna (Bothnian Sea) and Kvädöfjärden (Baltic Proper) show decreasing concentrations of lead at an annual
rate of -8.9 % and -7.1 % respectively.
Figure 9. Temporal development of cadmium concentrations (µg kg-1
ww) in herring liver in Bothnian Bay (Harufjärden), Bothnian Sea (Ängskärsklubb), Northern Baltic Proper (Landsort) and Bornholm Basin (Utlängan). The green line denotes the GES boundary.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Figure 11. Temporal development of mercury concentrations (µg kg-1
ww) in herring liver in Bothnian Bay (Harufjärden), Bothnian Sea (Ängskärsklubb), Northern Baltic Proper (Landsort) and Bornholm Basin (Utlängan). The green line denotes the GES boundary.
Figure 12. Temporal development of mercury concentrations (µg kg-1
dw) in eggs of Common Guillemot
in Stora Karlsö, Gotland.
HELCOM Core Indicator of Hazardous Substances Metals (lead, cadmium and mercury)
Annex 1. Cadmium, mercury and lead in national monitoring programmes in sediment and biota. Number of stations and frequency of monitoring (interval in years) is shown for each sub-basin. Species key: her=herring, per=perch, flo=flounder, eelp=eelpout, sal=salmon, mus=mussel
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