Mercury in Baltic and North Sea waters

Improved determination methods for very low Hg concentrations in sea water using cold vapor AAS with pre-enrichment and purification on gold as well as a new sampling system (‘MERCOS’ PTFE water samplers) have been applied to extensive investigations for reactive and total Hg levels. The first research cruises concentrated on the southwestern Baltic Sea. Concentrations found in the surface water were around 2 ng L^?1 Since 1979, Hg has been regularly monitored in the German Bight of the North Sea as a part of German and international monitoring programs. Two investigations have been performed in the lower course of the river Elbe, from Hamburg to the sea. Results show that the Elbe is the predominant ‘point source’ for Hg in the German Bight. In a large multidisciplinary research project ‘ZISCH’, a closely spaced station network has been sampled twice, in 1986 and 1987, to survey the entire North Sea, i.a. for Hg. Over most of the area, the median of Hg values in the surface water was 0.5 ng L^?1; in a distinct field, however, extremely high levels were found, of more than 200 ng L^?1.     

Determination of Atmospheric Mercury During the North Sea Experiment

Total gaseous mercury (TGM) and rainwater were collected on board of two research vessels (F. S. ALKOR and R.V. BELGICA) positioned 200 km apart in the center of the North Sea Experiment, September 1991. On the F.S. ALKOR (up-wind ship) TGM concentrations ranged from 0.7 to 2.6 ng·m-3 with an average of 1.5 ng·m-3 and on the R. V. BELGICA (down-wind ship) TGM ranged from 0.7 to 1.9 ng·m-3 with an average of 1.2 ng·m-3. An average 20% decrease is observed from the up-wind to the downwind ship, which may largely be affected by entrainment into the free troposphere. An overall removal was 0.5 cm·s-1 for dry periods and varied between 1 to 5 cm·s-1 during rain events. Rainwater concentrations varied between 5 and 25 ng·l-1. Based on these data an annual wet deposition flux of 1.08 ng Hg cm-2 yr1- was estimated for the North Sea.     

Spatio-temporal associations between harbour porpoise Phocoena phocoena and specific fisheries in the German Bight

Interactions between cetaceans and fisheries are a major concern of cetacean conservation and fisheries management, as by-catch and resource competition occur as a result. To assess potential interaction between porpoises and fisheries in the German Bight, high-resolution spatial and temporal data were analysed in order to reveal association patterns between cetaceans and fisheries in the German Exclusive Economic Zone (EEZ) of the North Sea. To facilitate interpretation of resulting patterns, additionally, relationships of fish assemblages were analysed. Vessel monitoring system (VMS) data from 2006 and fisheries surveillance data from 2002 to 2006 were acquired to calculate fishing effort, aerial survey data from 2002 to 2006 to evaluate porpoise distribution, and trawl survey data from 2000 to 2007 to assess fish assemblage. Relationships were analysed in terms of seasonal association and overlap. Results showed that porpoise distribution was positively associated with sandeel fisheries in all seasons and with gillnet fisheries in summer. Overlaps for sandeel and gillnet fisheries were high in summer, while negligible in spring and autumn. In spring, high overlap was found for large beam trawlers targeting sole and plaice. In parallel, porpoise distribution was positively linked to fish assemblage components representing sandeel and poor cod in summer and flatfish in spring. Our results suggest that, especially in summer, resource competition between porpoises and industrial sandeel fisheries is likely and the risk of by-catch in gillnets is increased. In spring, interference with sole and plaice fisheries is to be expected.     

Mercury contamination in the Brazilian Amazon. Environmental and occupational aspects

Mercury (Hg) contamination of miners, riparian and Indian populations and fish in the Amazon region, due to gold extracting activities, has been studied. Samples of hair, urine, and blood of Indians and prospectors, and hair from riparian fish-eating population and fishes from Madeira river, respectively, were collected and analyzed by Cold Vapor, Atomic Absorption Spectrometry (CV-AAS) techniques. The results obtained showed that the aquatic food chains in the Amazonian ecosystems are contaminated by methylmercury (MeHg), exposing Indians, prospectors and riverines to thr risk of severe health hazard. The highest levels of contamination, based upon hair analysis, were found in riparian of the Madeira river, followed by Cuniã Lake population, Indians (Fresco river) and prospectors, in that order. Blood analysis showed 59% of the samples from Indians and 33% from prospectors with Hg contents above 10 ng mL^?1. Analysis of urine, on the other hand, showed 44% of Indians with Hg levels below the detection limit (d.l.), and 30% above 20 ng mL^?1, whereas 38% of the prospectors presented Hg concentrations over 20 ng mL^?1, and 20% below the d.l. These results prove that prospectors, who hardly ever eat fish but are badly exposed to inorganic Hg vapor, are ocupationally contaminated, while the rest of the populations under survey are exposed to environmental contamination by Hg, through polluted fish ingestion.     

Mercury and methylmercury in sediments and suspended particles from the river Elbe,North Germany

Total Hg and McHg concentrations have been determined in sediments and suspended particulate matter from one of the most Hg-polluted rivers of the world, the Elbe river in Northern Germany. Results of total Hg and McHg are presented. Total Hg concentrations in suspended particulate matter (SPM) are 30 mg kg^?1 in the average and up to 150 mg kg^?1 as the maximum value. Total Hg-fluxes ^?1 calculated from measurements of an automatically operating station upstream Hamburg as about 17 ta?1 in suspended particles. A new McHg determination by HPLC chromatography and photometric detection was developed and verified. Methylmercury concentrations were up to 10% of the total Hg, i. e. 2.7 mg kg^?1 (dw).     

Mercury in soils,sediments, and clams from a North Carolina peatland

Mercury concentrations were measured in samples of peat soils, sediments and clams (Rangia cuneata) from a peatland region of the Albemarle-Panlico Peninsula of North Carolina. Total Hg concentrations in peat cores ranged from 40 to 193 ng g^?1 (dw); no depth-related trends were noted. Mercury concentrations in surface sediments from canals draining the peatlands and from the Pungo River that receives this drainage ranged from 8 to 20 ng g^?1 (dw). Selective extractions of these peat and sediment samples revealed that the bulk of the Hg was associated with organic matter-associated fractions (particularly humic/fulvic acid bound and organic-sulfide bound fractions). No Hg was detected in the relatively mobile and bioavailable water-soluble or ion-exchangeable fractions. Total Hg concentrations in the soft tissues of clams from the Pungo River ranged from 25 to 32 ng g^?1 (ww). No concentrations of methyl Hg above the detection limit of a 25 ng g^?1 were measured in soils, sediments, or clams. These data indicate that Hg concentrations in this region are at the low end of the distribution of levels reported for uncontaminated systems and that mining of these peatlands is unlikely to significantly elevate Hg concentrations in the receiving estuarine system.     

Size Related Mercury Accumulations in Edible Marine Species from an Area of the Northern Tyrrhenian Sea

Mercury concentrations were studied in important edible species from an area of the northern Tyrrhenian Sea, near Mt. Amiata (Tuscany, Italy), affected by mercury contamination. The studied species were: Nephrops norvegicus (Norway lobster), Parapenaeus longirostris (pink shrimp), Merluccius merluccius(hake) and Eledone cirrhosa (horned octopus). From the results it was found that in N. norvegicus and M. merluccius the accumulation was exponential, while in the other two species it was linear. In females ofN. norvegicus, a sharper increase of Hg concentration beyond three centimetres of carapace length was observed and explained by the reduction in growth rate after sexual maturity. In M. merluccius, the metal concentration increased sharply after 40 cm of length, probably due to a reduction in growth rate over this size. In P. longirostris no statistically significant difference between the slope of the linear regressions of males and that of females was found. In Eledone cirrhosa nomercury accumulation difference between the two sexeswas found. The metal concentration was generally highin all the studied species, with a maximum of 4.2 μg g^-1 of fresh weight in N. norvegicus.     

Mercury content of soils in Western Britain with special reference to contamination from base metal mining

Mercury was determined in 51 soil samples from historic base metal mining areas of England and Wales, together with cadmium, copper, lead, zinc, pH and organic content. Background mercury was calculated as 0.093 ppm whence 51% of the samples were judged to be contaminated. A very strong statistical correlation between mercury and lead and weaker but significant correlations between mercury and copper and zinc were found. Highest levels of mercury (maximum, 1.78 ppm Hg) and other metals occurred in soils derived from the floodplain of a river which was at one time badly polluted by mine waste. In a profile pit near a lead mine in the west of England both mercury and lead were enriched in surface horizons. It is concluded that land contaminated by heavy metals, especially lead, in the historic metal mining areas of England and Wales is also likely to be contaminated by mercury.     

Biological and chemical characterization of harbour sediments from the Stockholm area

Purpose  

The main objective of the current study was to assess the impact of pleasure boat activities on harbour sediment quality in the Stockholm area. Sediment contamination is a growing ecological issue, and there is consequently a need to use sediment bioassays in combination with chemical analysis to determine the impact on the ecosystem. To generate sediment toxicity data relevant for the Baltic Sea, a secondary objective was to further develop and evaluate two well-established bioassays for saltwater, with the macroalga Ceramium tenuicorne and the crustacean Nitocra spinipes, to be useful also for toxicity testing of whole sediment. A major concern has been to minimize any manipulation of the sediments. A third objective was to assess whether a simple leaching procedure could be used to simulate sediment toxicity by comparing results from whole sediment and leachate tests.     

Investigation of methylmercury and total mercury contamination in mollusk samples collected from coastal sites along the Chinese Bohai Sea

This paper presents the investigation results of methylmercury and total mercury in gastropod and bivalve species collected from eight coastal sites along the Chinese Bohai Sea. The total mercury was directly determined by atomic fluorescence spectrometry (AFS), while the methylmercury was measured by a laboratory established high performance liquid chromatography-atomic fluorescence spectrometry system (HPLC-AFS). Certified reference material DORM-2 (Dogfish muscle) was used to validate the two methods and the obtained results proved to be in good agreement with the certified values. It was demonstrated that the mercury contamination was commonly existed in all selected mollusks, with methylmercury and total mercury concentration in the range of 4.8-168.4 and 6.7-453.0 ng Hg g(-)(1), respectively. Mollusks from HuLuDao were the most mercury contaminated, and those from PengLai took the second place. The species-dependent bioaccumulation capacity was observed in this study. Gastropods showed more capacity to bioaccumulate mercury than bivalves, and mercury contents in two kinds of gastropods (Rapana venosa and Neverita didyma) presented some uplifted trends with the dimensions increasing of the gastropods. Rapana venosa was found to be a potential biomarker to monitor mercury pollution in oceans. Evaluations were also made concerning about the ratio of methylmercury to total mercury.     

Distribution of Mercury and Other Heavy Metals in Core Sediments of the Northern Adriatic Sea

Seven sediment cores were collected along a transect about20 km off from the mouth of the Po River, in the northernAdriatic Sea (Italy). Cores were characterised by differentdepositional sequences associated with late Pleistocene-Holocene lowstand (LST), transgressive (TST) and highstand (HST) system tracts. Sediment samples were analysed for mercury, copper, nickel, chromium, manganese and iron, aswell as for total organic matter. Metal distributiongenerally showed vertical and spatial variability ascribed tograin size effects with no significant anthropogenicperturbation. Conversely, mercury showed vertical profilescharacterised by surface enrichment, with concentrations inthe upper layer (50–230 ng g^-1) exceeding 3–11 times the background value of 20 ng g^-1 determined in bottomcores. Surface maxima were attributed to anthropogenic mercurydelivered mainly by the Po River.     

Mercury contamination in hair of riverine populations of Apiacás Reserve in the Brazilian Amazon

Total and inorganic Hg in 55 samples of hair from riverines, mainly descended from Munduruku and Apiaká Indians, living along the rivers Teles Pires and Juruena have been determined. The sampled population represents 18% of the inhabitants of the region and they eat fish 6 or 7 days a week. Cold-vapor AAS and alkaline digestion with CdCl2/SnCl2 as reducing agent were employed to estimate total Hg in hair samples. A LDC Analytical, Mod. 1255, Mercury monitor was used for Hg determination. The mean value of total Hg was 34.2µg g-1, with an average of 87.2% of organic Hg Ninety-three per cent of the sampled population present levels of Hg above 10µg g-1, and 18% over 50µg g-1. A relationship between the mean value of Hg and age of the sampled population is presented. All women at child-bearing age present concentrations of Hg above 10µg g-1. Fifty-four per cent of them had levels over 30µg g-1, with a mean of 41.2µg g-1. For the children under ten years of age, 14% show Hg concentration above 50µg g-1. Comparison of these results with those obtained in 10 other Amazon surveys (n=1672) is shown. The results of the concentration of mercury in fish, mainly piscivorous (n=967) from Amazonian and Wetland (pantanal matogrossense) are also presented, with a mean of 726 ng mg-1. There appears to be a relationship between level of Hg in human and their food ingestion habits.     

Mercury contamination of fish in the Ojibwa diet: I. Walleye fillets and skin-on versus skin-off sampling

During the past two years, walleye (Stizostedion vitreum) have been collected and prepared into skin-off fillets and submitted for total mercury analysis. The survey included 105 fish from 18 lakes in 10 counties in northern Wisconsin and the upper peninsula of Michigan. Fourteen lakes yielded walleye fillets with greater than 0.5 ppm mercury, and six lakes yielded samples in excess of 1.0 ppm mercury. Fourteen fish were collected in the spring and prepared as fillets ground up as either skin-on or skin-off samples. The difference in Hg was significant (T₁₄=?3.26,p=0.006) with skin-on fillets, resulting in an approximately 10% decrease in mercury concentrations. Results of this study suggest that by leaving the skin on the sample, mercury concentrations will be reported 10% lower than if the skin is removed. Obviously, consumption advisories based on skin-off samples could provide more protection for Ojibwa people eating the spring harvest of walleye. In the fall, the difference in Hg samples between skin-on versus skin-off, was less and not statistically significant. However, removal of the skin would be expected to underestimate lipophilic organochlorine burdens and may not be appropriate for fish species where PCBs, DDT, and chlordanes are the major concern. Fall data for 67 fish from 26 lakes in 9 counties are also reported.     

中国北方典型地区农用地膜污染现状调查及其防治对策

通过对我国北方典型地区的调查,初步探索了该地区土壤农膜残留量和残膜特征.研究表明,河北省典型地区温室大棚、蔬菜田和作物田的农膜土壤残留量平均分别为5.629、7.369和2.822 kg·hm-2,黑龙江省典型地区温室大棚、蔬菜田和作物田残留量平均分别为4.169、3.682和2.430 kg·hm-2,各采样点之间存在着较大差异,但普遍较高,均明显高于未使用农膜的对照土壤.两地区之间除作物田的土壤农膜残留量没有明显差异外,河北地区其他两类土壤中的农膜残留量水平明显高于黑龙江地区,这种差异与各地区在农事活动及农膜使用上的差异具有一定的相关性.上述两地区土壤中残留农膜尺寸基本一致,主要集中在10～15 cm之间.该文针对我国目前农膜使用情况及其污染现状,提出了相应的防治对策.     

中国北方典型地区农用地膜污染现状调查及其防治对策

通过对我国北方典型地区的调查，初步探索了该地区土壤农膜残留量和残膜特征。研究表明，河北省典型地区温室大棚、蔬菜田和作物田的农膜土壤残留量平均分别为5.629、7.369和2.822 kg·hm^-2，黑龙江省典型地区温室大棚、蔬菜田和作物田残留量平均分别为4.169、3.682和2.430 kg·hm^-2，各采样点之间存在着较大差异，但普遍较高，均明显高于未使用农膜的对照土壤。两地区之间除作物田的土壤农膜残留量没有明显差异外，河北地区其他两类土壤中的农膜残留量水平明显高于黑龙江地区，这种差异与各地区在农事活动及农膜使用上的差异具有一定的相关性。上述两地区土壤中残留农膜尺寸基本一致，主要集中在10～15 cm之间。该文针对我国目前农膜使用情况及其污染现状，提出了相应的防治对策。     

Mercury contamination in the Carson River,Nevada: A preliminary study of the impact of mining wastes

From 1860 to 1890, approximately 7 100 metric tons of metallic mercury (Hg) were released into the Carson River-Lahontan Reservoir watershed as a by-product of Comstock Lode silver (Ag) and gold (Au) ore refining. Present-day Hg contamination is most severe in mine tailings, where total Hg concentrations can exceed several hundred µg/g. Hg-laden tailings were also dumped directly into the Carson River, and were subsequently transported downstream into the Lahontan Reservoir and the Stillwater Wildlife Management Area. The Hg, Ag and Au contents of sediments from the Carson River and the Lahontan Reservoir are well above local background levels, and both Ag and Au contents are positively correlated to Hg. Thus, tailings-derived Hg has been redistributed throughout the entire Carson-Lahontan watershed over the last century. Total Hg concentrations in water samples from the Carson River at seven localities show that: 1) elevated (e.g., >20 ng/L) Hg levels in Carson River waters first appear downstream from accumulations of mill tailings, 2) total Hg concentrations in unfiltered and filtered water from the Carson River increase downstream (i.e. away from the tailings piles), and 3) Hg concentrations in both the Carson River (downstream from the tailings piles) and the Lahontan Reservoir are among the highest known worldwide (100 to 1000 ng/L). Filtered water samples from the Carson-Lahontan system also have high Hg contents (up to 113 ng/L), and suggest that the >0.4 µm particle fraction constitutes over 60% of the total water-borne Hg.     

Methanogenesis in saltmarsh soils of the North Sea coast of Germany

Temperate saltmarshes are a potential source of atmospheric methane. We have measured the concentration and emission of methane in typical saltmarsh soils (Salic Fluvisols) and humus-rich saltmarsh soils (Thionic Fluvisols) from the German North Sea coast. We also measured the methane production rates of the latter. The methane content of typical saltmarsh soils reached 12.0 μmol 1^?1, although values of 1–4 μmol 1^?1 were usual. The sulphate concentrations of the pore-water were about 10 mm , which means sulphate reduction is not limited and methanogenesis would be suppressed. Methane concentrations were generally largest in summer. Independent of the redox potential and the degree of soil development, methane concentrations were smallest in those soils poorest in humus. Methane emission rates were almost zero. In the humus-rich saltmarsh soils, methane concentrations were roughly a thousand times larger than those in typical saltmarsh soils, reaching values of 23 mmol 1^?1 The sulphate concentrations of the pore-water were often less than 1 mM, indicating limited sulphate reduction. Methane production was up to 80 μg cm^?3 day^?1 and was not inhibited when we added sulphate. Methane emission rates reached up to 190 μg m^?2 day^?1 in summer, with values up to 20 μg m^?2 day^?1 at other times. The two kinds of saltmarsh soil behave quite differently: the typical saltmarsh soils act as a sink for methane; the humus-rich saltmarsh soils are a source.     

Mercury antagonists: protection of plants against vapor injury by thiamine and other compounds

Mercury vapor-induced abscission ofColeus cuttings was prevented by Thiamine, other organo-S (Se) compounds and selenite, but not by common sugar metabolites, amino acids, non-auxin growth regulators and selenate. Protection was also afforded to other plants including ferns and gymnosperms. Thus the compounds that protect plants against Hg intoxication correspond to the Hg antagonists known in animals including man.     

Mercury contamination of fish in the Ojibwa diet: II. Sensory evoked responses in rats fed walleye

The Ojibwa people of the upper Great Lakes in the United States have a long history of utilizing walleye caught by spear fishing as a major part of their diets. Walleye (Stizostedion vitreum) have been collected and prepared into fillets using traditional methods, submitted for total mercury (Hg) analysis, and fed to laboratory rats in standard neurotoxicity protocols to determine the human health risks associated with consuming these fish. Wisconsin officials recommend avoiding the consumption of fish containing more than 0.5 ppm Hg. Laboratory rodent neurotoxicity bioassays included blending composite fish samples of 0.8, 0.4, and 0.2 ppm total mercury and feeding it to 48 young adult female Long Evans rats for 90 days. Standard behavioral assessments included: clinical neurologic observations, motor activity, and accelerating rotarod. Twelve of the 48 rats were surgically implanted for electrodiagnostic evaluations using sensory evoked potentials with auditory and visual stimuli. Auditory (clicks) responses were relatively stable and unaffected by Hg laden diets. However, visual evoked responses at low flash intensities demonstrated a dose related slowing of brain visual processing activity. Methylmercury contamination is known to affect visual systems, and visual evoked brain potentials are apparently sensitive indicators of dietary Hg.     

Elemental composition of aircraft-sampled aerosols above the southern bight of the North Sea

During the period from September 1988 to October 1989, 23 flights were carried out over the Dutch Continental Shelf of the North Sea and a total of 108 aerosol filter samples were collected. The samples were analyzed for Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb using both particle-induced X-ray emission (PIXE) and energy-dispersive X-ray fluorescence (EDXRF). The results from PIXE exhibited better precision and lower detection limits than those from EDXRF. Therefore the further discussion and interpretation was based on the PIXE data only. It was observed that Si, S, V, Mn, Ni, Cu and Pb were enriched with respect to the earth's crust. It was seen that winds from the sector Southeast-South contributed most significantly to the total aerosol concentration. The vertical profiles of several elements indicated that their concentration increases with proximity to the sea. Principal factor analysis on the data matrix containing elemental concentrations, height and wind direction parameters allowed us to identify 6 possible aerosol sources, namely, a composite of CaSO₄ and metallurgical activities, refuse incineration, residual oil combustion, quartz, soil dust and sea-salt aerosol.