Mercury in precipitation at an urbanized coastal zone of the Baltic Sea (Poland)

Mercury dynamics at the base of the pelagic food web of the Gulf of Gdańsk, southern Baltic Sea

Planktonic organisms, which have direct contact with water, serve as the entry point for mercury (Hg), into the marine food web, impacting its levels in higher organisms, including fish, mammals, and humans who consume seafood. This study provides insights into the distribution and behavior of Hg within the Baltic Sea, specifically the Gulf of Gdańsk, focusing on pelagic primary producers and consumers. Phytoplankton Hg levels were primarily influenced by its concentrations in water, while Hg concentrations in zooplankton resulted from dietary exposure through suspended particulate matter and phytoplankton consumption. Hg uptake by planktonic organisms, particularly phytoplankton, was highly efficient, with Hg concentrations four orders of magnitude higher than those in the surrounding water. However, unlike biomagnification of Hg between SPM and zooplankton, biomagnification between zooplankton and phytoplankton was not apparent, likely due to the low trophic position and small size of primary consumers, high Hg elimination rates, and limited absorption.

Mercury in the Polish part of the Baltic Sea: A response to decreased atmospheric deposition and changing environment

Our review of the literature showed that since the beginning of the socio-economic transformation in Poland in the 1990s, the downward trend in Hg emissions and its deposition in the southern Baltic Sea was followed by a simultaneous decrease in Hg levels in water and marine plants and animals. Hg concentrations in the biota lowered to values that pose no or low risk to wildlife and seafood consumers. However, in the first decade of the current century, a divergence between these two trends became apparent and Hg concentrations in fish, herring and cod, began to rise. Therefore, increasing emission-independent anthropogenic pressures, which affect Hg uptake and trophodynamics, remobilization of land-based and marine legacy Hg deposits, as well as the structure of the food web, can undermine the chances of reducing both the Hg pool in the marine environment and human Hg exposure from fish.

Status and trends of mercury pollution of the atmosphere and terrestrial ecosystems in Poland

The goal of this paper is to assess the current status and trends of total mercury (THg) contamination of the atmosphere and terrestrial ecosystems in Poland. The study shows that the reduced domestic and worldwide atmospheric emission of Hg resulted in decreased THg level in the terrestrial biotope and biosphere. Considering that Poland is one of the main Hg emitters in Europe, the THg concentrations in its abiotic environment are still elevated. However, the THg level in terrestrial organisms is relatively low, which is because a large proportion of Hg deposited on land is accumulated in organic-rich soils. Regarding the THg concentration, consumption of wildlife and livestock from Poland is safe for humans. Nevertheless, the authors indicate the need for effective environmental monitoring, based on selected bioindicators, which is crucial considering the slowing reduction of Hg emission combined with the consequences of the changing climate.

Presence of mercury and methylmercury in Baltic Sea sediments, collected in ammunition dumpsites

Methylmercury (MeHg) is the most toxic and dangerous form of mercury occurring in the environment. MeHg is highly bioaccumulative in organisms and undergoes biomagnification via the food chain. In the Baltic Sea munition dumpsites, methylmercury can be formed from mercury fulminate contained in primary explosives, as environmental conditions there favour methylation. MeHg in analysed sediments ranged from 19 to 2362 pg g^-1d.w., the concentration of mercury (Hg_TOT) ranged from 4 to 294 ng g^-1 d.w., and the values of MeHg/Hg ratio ranged from 0.1 to 2.0%. The obtained results confirmed that munition dumpsites are a source of mercury. The concentration of MeHg is elevated in a wider area than immediately next to dumped munitions. Presented results suggest that physical processes responsible for sediment and near-bottom water movement are diffusing MeHg signal, making munition dumpsites rather a diffuse source of MeHg than a number of point sources associated with particular munitions.

Occurrence and risk assessment of total mercury and methylmercury in surface seawater and sediments from the Jiaozhou Bay, Yellow Sea

The Jiaozhou Bay is a semi-enclosed bay located in the middle of the Yellow Sea. Effluents from wastewater treatment plants have been carried into the bay, which has significantly increased the deposition of mercury. The spatial distributions of total mercury (THg) and methylmercury (MeHg) in dissolved state, in suspended matters of seawater and surface sediments at 26 locations inside the Jiaozhou Bay and five surrounding rivers in April 2018 were examined. The contents of THg and MeHg found along the eastern coast were higher than those found along the western coast, which indicated the impact of human activities (river input) on the Jiaozhou Bay. The partition coefficient (LogKd) was used to express the distribution relationships of THg and MeHg in suspended matters and dissolved state, and it was concluded that suspended matter was the main reservoir of mercury in Jiaozhou Bay seawater. The correlations between contents and physicochemical properties of seawater showed that THg and MeHg concentrations in seawater decreased with increasing salinity and pH. The effects of the mean grain diameter (MGD) and sediment organic matter (SOM) on the THg and MeHg in surface sediments were also discussed. Principal component analysis (PCA) was used to obtain the factors determining the methylation proportion in the surface sediments, indicating that the combination of human activities and natural processes affected the degree of methylation in the sediments. The spatial distribution of THg, MeHg and MeHg% was suggested to be disturbed by the interaction of natural processes and human activities (river input) by the correlation analysis of the corresponding pollutant concentrations among seawater and. Although the concentrations of THg and MeHg in seawater and sediments of the Jiaozhou Bay did not exceed the Chinese regulatory standards, the pollution levels of THg and MeHg were comparable to those in other bays in the world.

Impact of hydrotechnical works on outflow of mercury from the riparian zone to a river and input to the sea

The aim of this research was to assess the impact of hydrotechnical works within the riverbed and riparian zone on the mobility of mercury in soil and its outflow to the river and the sea. Deepening and reconstruction of the riverbed or the cutting of reeds, influenced the fate of mercury in the river system. However, only activitis that disturbed the riperian zone increased mobilization of Hg in soils. Hg transformations in these places were controled by inflow of fresh organic matter in soil and sediments as well as by oxidation-reduction potential. In areas where reducing conditions occurred, mercury released from the soil was incorporated into the sediment. However, in areas where oxidizing conditions prevailed in the sediment, mercury flowing out of the soil occurred mainly in dissolved form and most of it was transported downstream from where it could reach the sea.

Weir building: A potential cost-effective method for reducing mercury leaching from abandoned mining tailings

To mitigate mercury (Hg) pollution and reduce Hg downstream transportation, a weir was designed by a river system that had been inflicted by leachate from the slagheap of the Yanwuping Hg mine in Wanshan Hg mining area. A whole year monitoring of Hg species was conducted, and the efficiency of Hg reduction by the weir application was evaluated. The Hg concentrations in the river water were significantly higher in the wet season than in the dry season. Waterflow was confirmed to be the main driving factor for Hg mobilization and transportation, and an episode study revealed that most Hg was released in times of storms. Increased monitoring and preventive maintenance measures need to be taken on barriers in advance of storms. A large proportion of the total Hg (THg) and methylmercury (MeHg) is associated to particles. During the study period, approximately 412 g THg and 4.04 g total MeHg (TMeHg) were released from the YMM slagheap, of which 167 g THg and 1.15 g TMeHg were retained by the weir. Annually, 40.4% THg and 38.4% TMeHg was retained by the weir. Weir construction is considered as a potential cost-effective measure to mitigate Hg in river water and should be promoted and extended in the future after optimization.

The variability of Hg concentration and composition of marine phytoplankton

Mercury is a toxic element. It undergoes biomagnification in the marine trophic chain, which is why it is significant to identify the factors influencing its bioaccumulation on the first level of the trophic chain. At present, the input of heavy metals to the southern Baltic is being reduced. On the other hand, the parameters influencing mercury remobilisation in the environment are a subject to a long-time trend associated with climate changes. Examples include growing number of heavy rain events causing surges or floods, and increased frequency of storm winds leading to increased coastal erosion as well as overall temperature increase. The present studies were carried out in the coastal zone of the Gulf of Gdańsk (southern Baltic) for 18 months at two stations (Chałupy and Osłonino) located in the Puck Lagoon, and for 12 months in Gdynia. Climate changes influence the abundance and species composition of phytoplankton, which in consequence has an effect on Hg accumulation and magnification in the trophic chain, and in the human body as a result. Extreme phenomena such as land erosion or floods resulted in an additional inflow of nutrients, but also toxic substances, into the coastal zone. The bioconcentration factor (BCF) increased almost four times after abrasion of cliff. That was conducive to the growth of microflora, as well as increased Hg accumulation. The highest bioconcentration of Hg in phytoplankton was observed when the Mesodinium rubrum (spring and autumn) and Diatomophyceae (winter) prevailed in biomass. The BCF was then almost tenfold higher than during the rest of the year.

Mercury bonds with carbon (OC and EC) in small aerosols (PM1) in the urbanized coastal zone of the Gulf of Gdansk (southern Baltic)

PM1 aerosols were collected at the coastal station in Gdynia between 1st January and 31st December 2012. The main purpose of the study was to determine the variability in concentrations of mercury Hg(p), organic carbon (OC) and elemental carbon (EC) in PM1 aerosols under varying synoptic conditions in heating and non-heating periods. Additionally, sources of origin and bonds of mercury with carbon species were identified. The highest concentrations of Hg(p), OC and EC were found during the heating period. Then all analyzed PM1 components had a common, local origin related to the consumption of fossil fuels for heating purposes under conditions of lower air temperatures and poor dispersion of pollutants. Long periods without precipitation also led to the increase in concentration of all measured PM1 compounds. In heating period mercury correlated well with elemental carbon and primary and secondary organic carbon when air masses were transported from over the land. At that time, the role of transportation was of minor importance. In the non-heating period, the concentration of all analyzed compounds were lower than in the heating period, which could be associated with the reduced influence of combustion processes, higher precipitation and, in the case of mercury, also the evaporation of aerosols at higher air temperatures. However, when air masses were transported from over the sea or from the port/shipyard areas the mercury concentration increased significantly. In the first case higher air humidity, solar radiation and ozone concentration as well as the presence of marine aerosols could further facilitate the conversion of gaseous mercury into particulate mercury and its concentration increase. In the second case Hg(p) could be adsorbed on particles rich in elemental carbon and primary organic carbon emitted from ships.

Impact of intense rains and flooding on mercury riverine input to the coastal zone

The aim of the present research was to determine the impact of intense rains and flooding on mercury riverine input to the coastal zone. This study focused on four small rivers (Reda, Zagórska Struga, Płutnica, Gizdepka), typical of the Southern Baltic region, with no significant mercury sources. Samples were collected for 16months during average flow conditions and during selected meteorological events: floods, downpours, thaws and droughts. Results showed decreased retention of mercury during intense rainfalls, thus demonstrating mercury elution from the catchment. Floods and melting snow also have a tremendous impact on the outflow of mercury from the catchment. Development of urban infrastructure and farmlands increases the outflow of mercury from the catchment too, making such areas a significant source of mercury in the river. On the other hand, areas with natural character, predominated by forests, stimulate retention of mercury that reaches them through dry and wet atmospheric deposition.

Mercury in the Diatoms of Various Ecological Formations

Mercury is a neurotoxin, its main source in the human organism being fish and seafood. The first level in the marine food web is formed of planktonic and benthic photosynthetic microorganisms, which form a biofilm on the surface of the hard bottom (epilithon) or plants (epiphyton). They are carriers of nutritional as well as toxic substances and pass these on to subsequent levels of the trophic web. Their biomass is often dominated by diatoms. This was the basis for the presented study into Hg accumulation in epilithic, epiphytic and planktonic diatoms, which was carried out in 2012-2013 in the coastal zone of the Puck Lagoon and the Gulf of Gdańsk (southern Baltic). In this coastal area, both micro- and macroorganisms develop particularly intensively. The collected results indicate an increase in Hg concentration in the biofilm during the warm season which, with the lengthening of the vegetative period due to global warming in recent years, is of great significance. As a consequence, the annual mercury load entering the trophic web is larger in comparison with a year in which there is a long, cold winter. An important parameter influencing the accumulation of Hg was the function of those organisms from the biofilm-forming communities. In this case, the highest concentrations of Hg were measured in organisms forming high-profile guilds.

Transfer of mercury and phenol derivatives across the placenta of Baltic grey seals (Halichoerus grypus grypus)

The placenta is an intermediary organ between the female and the developing foetus. Some chemical substances, including the most harmful ones, exhibit the ability to accumulate in or penetrate through the placenta. The aim of the study was to determine the role of the placenta of the Baltic grey seal (Halichoerus grypus grypus) in the transfer of endocrine disrupting compounds (EDCs) - (bisphenol A, 4-tert- octylphenol, 4- nonylphenol), as well as total and organic mercury. 30 placentas were collected from grey seals pupping under human care at the Hel Marine Station in the years 2007-2016. The assays were conducted using the technique of high-preformance liquid chromatography (phenol derivatives) and atomic absorption spectrometry (mercury and selenium). A measurable level of EDCs was indicated in the placentas of grey seals. It was established that the inorganic Hg form was accumulated in the placenta, and that its concentrations were an order of magnitude higher than the concentrations of the organic form, which penetrated to the foetus. Similar observations were made for phenol derivatives - bisphenol A, 4-tert- octylphenol and 4-nonylphenol. For this compound group the placenta was a barrier, but the properties of phenol derivatives suggest the possibility of their penetration through this organ.

Coastal erosion as a source of mercury into the marine environment along the Polish Baltic shore

The climate changes in recent years in the southern Baltic have been resulting in an increased frequency of natural extreme phenomena (i.e. storms, floods) and intensification of abrasion processes, which leads to introduction of large amounts of sedimentary deposits into the marine environment. The aim of this study was to determine the mercury load introduced to the Baltic Sea with deposits crumbling off the cliffs-parts of the coast that are the most exposed to abrasion. The studies were carried out close to five cliffs located on the Polish coast in the years 2011-2014. The results show that coastal erosion could be an important Hg source into the marine environment. This process is the third most important route, after riverine and precipitation input, by which Hg may enter the Gulf of Gdańsk. In the Hg budget in the gulf, the load caused by erosion (14.3 kg a(-1)) accounted for 80 % of the wet deposition and was 50 % higher than the amount of mercury introduced with dry deposition. Although the Hg concentration in the cliff deposits was similar to the natural background, due to their large mass, this problem could be significant. In addition, the preliminary studies on the impact of coastal erosion on the Hg level in the marine ecosystem have shown that this process may be one of the Hg sources into the trophic chain.

The Influence of Weather Anomalies on Mercury Cycling in the Marine Coastal Zone of the Southern Baltic-Future Perspective

Despite the decreased emission loads of mercury, historical deposits of this metal in various compartments of the environment may become an additional diffuse source in the future. Global climate change manifests itself in the temperate zone in several ways: warmer winters, shorter icing periods, increased precipitation and heightened frequency of extreme events such as strong gales and floods, all of which cause disturbances in the rate and direction of mercury biogeochemical cycling. The present study was conducted at two sites, Oslonino and Gdynia Orlowo (both in the coastal zone of the Gulf of Gdansk), from which samples were collected once a month between January 2012 and December 2012. In the Southern Baltic region, climate changes can certainly enhance coast to basin fluxes of mercury and the transfer of bioavailable forms of this metal to the food web. They may also, in the future, contribute to uncontrollable increases of mercury in the seawater.

Factors influencing variability of mercury input to the southern Baltic Sea

The southern Baltic countries have been identified as significant sources of Hg into the sea. Are anthropogenic activities the sole source? How do meteorological parameters influence the deposition? Studies on input of Hg to the Baltic were conducted in 2008-2012 in the Polish coastal stations. The riverine load was found to depend directly or indirectly on the amount of precipitation and catchment type. Input of atmospheric Hg increased along with the number of precipitation episodes from remote maritime air masses, as well as with the number of days when continental air masses from regional (when domestic heating prevailed) and remote sources moved over the Baltic, during the heating season. During the non-heating season metal input was found to be proportional to episodes of rain from continental regional air masses and to the number of days under influence of continental and maritime air masses from regional sources.