Distribution of Mercury in the Sediments and Fishes of the Lagoon of Aveiro, Portugal

1986 ◽  
Vol 18 (4-5) ◽  
pp. 141-148 ◽  
Author(s):  
M. F. Lucas ◽  
M. T. Caldeira ◽  
A. Hall ◽  
A. C. Duarte ◽  
C. Lima
Keyword(s):  
Coastal Waters ◽  
Total Mercury ◽  
Feeding Habits ◽  
Sediment Concentration ◽  
Point Sources ◽  
The Other ◽  
Ecological Niches ◽  
Ongoing Work ◽  
Superficial Sediments ◽  
Significant Point

Dry and wet sieving were compared on their suitability for the size fractionation of bottom sediment samples, collected from a brackish water, coastal lagoon, prior to flameless atomic absorption analysis of the sediment concentration of total mercury. The work aimed at identifying the most important point sources of mercury to the lagoon waters and at assessing the distribution, throughout the ecosystem, of the mercury discharged. The results reported in this paper refer to the lagoon sediments and fishes. Ongoing work is extending the survey to the other inland ecological niches and to the coastal waters and sediments. A chlor-alkali plant proved to be the most important source of mercury but its contribution has not yet been disentangled from those originating at a pyrite roasting facility and a PVC factory operating in the same industrial park. Sewage discharges from the bankside communities are the other significant point sources of Hg. Concentrations of Hg in the superficial sediments ranged from 850 mgkg−1, near the chlor-alkali sewer outlet, to 0.05 mgkg−1 in the intertidal sands of the coastal beaches. Sewage-affected sediments have concentrations of Hg in the range of 1 to 2 mgkg−1. The concentrations observed in the water samples and superficial sediments suggest that some of the Hg historically discharged into the lagoon may have been exported to the Atlantic Ocean coastal waters. Bioaccumulation of Hg in fish tissues shows the usual dependence on species, territoriality, feeding habits and size. Concentrations as high as 25 mgkg−1 fresh weight have been observed but the average values do not exceed the EEC quality objective of 0.3 mgkg−1 (EEC, 1982).

scholarly journals Pollution Characteristics, Distribution and Ecological Risk of Potentially Toxic Elements in Soils from an Abandoned Coal Mine Area in Southwestern China

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 330
Author(s):  
Libo Pan ◽  
Xiao Guan ◽  
Bo Liu ◽  
Yanjun Chen ◽  
Ying Pei ◽  
...  
Keyword(s):  
Ecological Risk ◽  
Toxic Elements ◽  
Low Ph ◽  
Potentially Toxic Elements ◽  
Point Sources ◽  
The Other ◽  
Guizhou Province ◽  
Pollution Level ◽  
Agricultural Activity ◽  
Background Values

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn), and mercury (Hg) concentrations were measured in 27 surface soil samples from areas in which coal-mining activities ceased nine years previously in Youyu Catchment, Guizhou Province, China. The soil was acidic, with a mean pH of 5.28. Cadmium was the only element with a mean concentration higher than the national soil quality standard. As, Cd, Cu, Ni, Zn, Mn, Cr, and Fe concentrations were all higher than the background values in Guizhou Province. This was especially true for the Cd, Cu, and Fe concentrations, which were 1.69, 1.95, and 12.18 times their respective background values. The geoaccumulation index of Cd and Fe was present at unpolluted to moderately polluted and heavily polluted levels, respectively, indicating higher pollution levels than for the other elements in the study area. Spatially, significantly high Fe and S concentrations, as well as extremely low pH values, were found in the soils of the AMD sites; however, sites where tributaries merged with the Youyu River (TM) had the highest Cd pollution level. Iron originated mainly from non-point sources (e.g., AMD and coal gangues), while AMD and agricultural activity were the predominant sources of Cd. The results of an eco-risk assessment indicated that Cd levels presented a moderate potential ecological risk, while the other elements all posed a low risk. For the TM sites, the highest eco-risk was for Cd, with levels that could be harmful for aquatic organisms in the wet season, and may endanger human health via the food chain.

scholarly journals SEQUENTIAL PHOTOGRAPHY OF COASTAL WATER

1972 ◽  
Vol 1 (13) ◽  
pp. 37
Author(s):  
Maynard M. Nichols
Keyword(s):  
Coastal Waters ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Control Points ◽  
Dynamic Features ◽  
Density Control ◽  
Causal Processes ◽  
Tonal Patterns ◽  
Quantitative Analyses ◽  
Digital Or

Sequential photographs from aircraft and satellites provide a source of data for studying dynamic features of coastal waters. Procedures for detecting features in sequential photos follow two approaches; (1) application of sequential signatures, (2) simple comparative analysis. For quantitative analyses images of two or more frames must have proper registration and comparable tones, i.e. tones free of photographic variance from film processing, varying exposure and solar illumination. After a normalization correction for variance is determined through use of density control points, density of successive frames is measured with a microdensitometer, the correction is a.pplied and tonal differences determined. Such differences relate to the time character of a feature and to causal processes. Application of correction values and numerical differencing is best accomplished in a digital or computerized densitometer. However, corrections and differencing can also be accomplished graphically from line traces or plots of an objective densitometer. Application of the procedures is demonstrated by analyses of tonal patterns of suspended sediment concentration in an estuary.

scholarly journals Feeding Habits of Sebastes thompsoni in the Coastal Waters off Busan, Korea

2008 ◽  
Vol 41 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Sung-Hoi Huh ◽  
Ki-Mun Nam ◽  
Hyun-Gi Choo ◽  
Gun-Wook Baeck
Keyword(s):  
Coastal Waters ◽  
Feeding Habits

scholarly journals Feeding Habits of Juvenile and Young Yellow Tail Seriola quinqueradiata in Coastal Waters of the South Sea, Korea

2016 ◽  
Vol 49 (5) ◽  
pp. 635-641
Author(s):  
Jae-Mook Jeong ◽  
Kang-Seok Hwang ◽  
Se-hyun Song ◽  
Hee-yong Kim ◽  
Jeong-Ho Park ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Feeding Habits ◽  
The South ◽  
Seriola Quinqueradiata ◽  
South Sea

Measuring the Other Half: New Measures of Intangible Investment from the ONS

2019 ◽  
Vol 249 ◽  
pp. R17-R29
Author(s):  
Josh Martin
Keyword(s):  
Intangible Assets ◽  
Physical Capital ◽  
Evidence Base ◽  
The Other ◽  
National Accounts ◽  
Ongoing Work ◽  
Alternative Approaches ◽  
The Uk ◽  
Intangible Investment ◽  
Made In

Only half of investment by firms is in physical capital, such as buildings and machinery. The other half is in intangible assets, such as branding, software and training. This has been true for the past two decades or more in the UK, but only if you step beyond the measures in the National Accounts, which include only some of the recognised intangible assets. This paper surveys ongoing work at the Office for National Statistics to develop measures of investment in intangible assets, using new insights and innovative approaches. In particular, this paper reviews developments in three areas: in-house branding investments, employer-funded training investments, and in-house investments in organisational capital. We reconsider some of the key assumptions made in the literature and propose alternative approaches to measurement. The paper concludes by considering implications of this work, and identifies some of the remaining gaps in the evidence base for measuring intangible assets.

Harp seal (Phoca groenlandica) invasions in Norwegian coastal waters: age composition and feeding habits

1991 ◽  
Vol 48 (3) ◽  
pp. 363-371 ◽  
Author(s):  
T. Haug ◽  
A. B. Kroyer ◽  
K. T. Nilssen ◽  
K. I. Ugland ◽  
P. E. Aspholm
Keyword(s):  
Coastal Waters ◽  
Feeding Habits ◽  
Harp Seal ◽  
Age Composition ◽  
Phoca Groenlandica

scholarly journals The life histories and population dynamics of monogenean gill parasites of Trachurus trachurus (L.)

1962 ◽  
Vol 42 (3) ◽  
pp. 587-600 ◽  
Author(s):  
J. Llewellyn
Keyword(s):  
Coastal Waters ◽  
Life Histories ◽  
Feeding Habits ◽  
Limiting Factor ◽  
Trachurus Trachurus ◽  
Free Living ◽  
Sea Bottom ◽  
Second Year ◽  
Post Spawning ◽  
Gill Parasites

Gastrocotyle trachuri and Pseudaxine trachuri infect young Trachurus trachurus at Plymouth as soon as the 3- or 4-month-old adolescent fishes descend to the sea bottom in October. The parasites normally mature in 3 or 4 months, but, exceptionally, in about 1 month, and the life-span is normally no longer than 1 year. Trachurus specimens at the beginning of their second year pick up a largely new infection of parasites.G. trachuri and P. trachuri are much less frequent on 2- and 3-year-old specimens of Trachurus and probably occur only very rarely on still older fishes, the limiting factor being not an age-immunity but a post-spawning migration of the host from the concentration of free-living infective stages of the parasites in coastal waters.The parasites have adapted themselves to a seasonal change in the feeding habits of Trachurus by ceasing to produce larvae in anticipation of the summer disappearance of scad from the sea bottom in pursuit of pelagic food-organisms.

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