scholarly journals Mercury dynamics in macroinvertebrates in relation to environmental factors in a highly impacted tropical estuary: Buenaventura Bay, Colombian Pacific

2019 ◽  
Vol 27 (4) ◽  
pp. 4044-4057 ◽  
Author(s):  
Diego Esteban Gamboa-García ◽  
Guillermo Duque ◽  
Pilar Cogua ◽  
José Luis Marrugo-Negrete
Keyword(s):  
Food Consumption ◽  
Blue Crab ◽  
Local Population ◽  
Dry Weight ◽  
Local Economy ◽  
Trophic Levels ◽  
Small Scale ◽  
Accumulation Factor ◽  
Tropical Estuary ◽  
Mantis Shrimp

AbstractThe environmental health of Buenaventura Bay, a highly impacted tropical estuary, is influenced by numerous human activities, including mining upstream. Large- and small-scale fishing plays an important role in the local economy, so we investigated the dynamic processes of bioaccumulation of mercury at basal trophic levels. Four samples were taken at each of the four locations in Buenaventura Bay during each of the four seasons of 2015. We measured the total mercury content (T-Hg, dry weight) in sediments and in muscle tissue across 17 macroinvertebrate species. The most abundant were the blue crab (C. arcuatus) and the mantis shrimp (S. aculeata aculeata). Blue crab showed an average muscle T-Hg value ​​exceeding the limit of 0.2 g·g-1, which is the maximum T-Hg level suggested for food consumption by vulnerable humans and populations: pregnant women, children, and the community that feeds from this source of protein on a daily basis. It was found that, 6.22% of individuals exceeded the 0.5 g·g-1 level, which is the maximum T-Hg level suggested for food consumption by the general population: the population that consumes it sporadically. Significantly high values ​​of T-Hg in blue crab and mantis shrimp occurred during low salinity conditions in the estuary, suggesting that Hg mainly originates from river runoff during the rainy season. Nevertheless, the biota-sediment accumulation factor (BSAF) was favored in high salinity, which could mean greater availability of Hg for higher levels of the estuarine food web in the dry season and in marine waters. In general, the T-Hg levels in some samples exceeded 0.2 g·g−1. Therefore this pollutant must be monitored due to its biomagnification potential and as a threat to human health, especially that for the local population of fishermen and their families.

scholarly journals Mercury Bioaccumulation in Benthic Invertebrates: From Riverine Sediments to Higher Trophic Levels

Toxics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 197
Author(s):  
Laura Marziali ◽  
Claudio Roscioli ◽  
Lucia Valsecchi
Keyword(s):  
Benthic Invertebrates ◽  
Sediment Accumulation ◽  
Dry Weight ◽  
Quality Standard ◽  
Trophic Levels ◽  
Accumulation Factor ◽  
Trophic Chain ◽  
Top Predators ◽  
Riverine Sediments ◽  
Wet Weight

Riverine sediments are important sites of mercury methylation and benthic invertebrates may be indicators of Hg exposure to higher organisms. From 2014 to 2018, sediments and invertebrates were collected along a mercury gradient in the Toce River (Northern Italy) and analyzed for THg and MeHg. Concentrations in invertebrates, separated according to taxon and to Functional Feeding Group, ranged from 20 to 253 µg kg−1 dry weight (d.w.) for THg, increasing from grazers (Leuctra, Baetis, Serratella) to predators (Perla). MeHg ranged from 3 to 88 µg kg−1 d.w. in biota, representing 6–53% of THg, while in sediments it was mostly below LOD (0.7 µg kg−1), accounting for ≤3.8% of THg. The Biota-Sediment Accumulation Factor (BSAF, ranging 0.2–4.6) showed an inverse relation to exposure concentrations (THg in sediments, ranging 0.014–0.403 µg kg−1 d.w.) and to organic carbon. THg in invertebrates (up to 73 µg kg−1 wet weight), i.e., at the basal levels of the aquatic trophic chain, exceeded the European Environmental Quality Standard for biota (20 µg kg−1 w.w.), posing potential risks for top predators. Concentrations in adult insects were close to those in aquatic stages, proving active mercury transfer even to terrestrial food chains.

scholarly journals Assessment of Mercury Accumulation and Magnification in a Freshwater Food Chain: Sediment, Benthos and Benthivorous Fish

2018 ◽  
Vol 12 (5) ◽  
pp. 17-22
Author(s):  
Mehdi Khoshnamvand ◽  
◽  
Almasieh Almasieh ◽  
Shahram Kaboodvandpour ◽  
◽  
...  
Keyword(s):  
Common Carp ◽  
Muscle Tissue ◽  
Trophic Level ◽  
Sediment Accumulation ◽  
Dry Weight ◽  
Trophic Levels ◽  
Accumulation Factor ◽  
Benthivorous Fish ◽  
The Common ◽  
Study Sites

Background: Present study was conducted to measure the level of total mercury (tHg) in sediments, benthos and benthivorous fish (i.e., common carp) for determining Biota (Benthos)-Sediment Accumulation Factor (BSAF), as well as Biomagnification Factor (BMF) of tHg between two trophic levels of benthos and benthivorous fish caught from Sanandaj Gheshlagh Reservoir (SGR) in the west of Iran. Methods: Samples of sediments and benthos biomasses were collected from three sampling stations. Common carps were captured around the selected stations during July to December 2010. Results: Means accumulated tHg (±SE) in sediments, benthos masses and muscle tissue of common carp were 117.66±9.72, 94.3±5.02 and 233.21±20.67 ng g-1 dry weight, respectively. Means accumulated tHg in benthos masses and muscle tissue of the common carp during the studying months showed no significant differences (P>0.05), while it was significantly differed in sediment samples (P<0.05). Results showed that there were statistically significant differences between accumulated tHg between sediment and benthos mass samples collected from the study sites (P<0.05). Conclusion: During the study, all calculated BSAF measurements were less than one, indicating transmission of mercury from sediment to benthos was not considerable. However, mercury BMFs was higher than one, denoting mercury biomagnification occurred from the benthos trophic level to the higher trophic level (i.e., common carp) in study site. Hence, the health considerations have to be taken in to the account for consumption of fishery products of SGR.

Cereal Consumption, Production, and Prices in West Pakistan (Notes & Comments)

1968 ◽  
Vol 8 (2) ◽  
pp. 288-306 ◽  
Author(s):  
G. C. Hufbauer
Keyword(s):  
Food Consumption ◽  
Ad Hoc ◽  
Dry Weight ◽  
Small Sample ◽  
Tax Rates ◽  
Active Population ◽  
Early Settlement ◽  
Consumption Rates ◽  
Late Nineteenth ◽  
Better Than

In the late nineteenth and early twentieth centuries, several Punjab Settlement Officers attempted to estimate food consumption rates. These estimates, based on direct observation and ad hoc guesses, were made partly out of academic curiosity, but more urgently, as an aid in establishing the land revenue (i.e., tax) rates. The pre-1926 estimates are summarized in Table I, expressed in pounds of wheat and other foodgrain consumption per person per year1. Broadly speaking, the later, more systemtic observers (e.g., Sir Ganga Ram and C. B. Barry), found lower consumption levels than the earlier observers. It was generally accepted that the rural populace ate better than urban dwellers. Despite the ingenuity of the early Settlement Officers, their compiled estimates suffer from all the difficulties of haphazard small sample observation. Given the revenue purpose of the estimates, they may be biased towards the able-bodied, economically active, population. Further, the very early estimates may have confused dry weight with cooked weight, including water.

Local Communities as a Tool for the Development of Municipal Democracy: German Experience and Lessons for Russia

2020 ◽  
Vol 29 (5) ◽  
pp. 74-88
Author(s):  
Aleksandr Larichev ◽  
Emil Markwart
Keyword(s):  
Local Government ◽  
Urban Areas ◽  
Local Population ◽  
Local Communities ◽  
The State ◽  
Household Waste ◽  
Small Scale ◽  
Issue Management ◽  
State Management ◽  
Municipal Level

Local government as a political, legal and social institution finds itself in a very difficult period of development in Russia. The long-established tendency of its subordination to the state has intensified today in connection with the newly adopted constitutional amendments. At the same time, it seems obvious that further “embedding” of local government into the state management vertical, in the absence of any positive effect in terms of solving socio-economic and infrastructural problems, will inevitably lead to other hard to reverse, negative results both for local government institutions and the system of public authority as a whole. The normal functioning of local government requires, however, not only the presence of its sufficient institutional and functional autonomy from the state, but also an adequate territorial and social base for its implementation. To ensure the formation of viable territorial collectives, especially in urban areas, it seems appropriate to promote the development of self-government based on local groups at the intra-municipal level. Such local groups can independently manage issues of local importance on a small scale (landscaping, social volunteering, and neighborly mutual assistance), and provide, within the boundaries of a local territory, due civil control over the maintenance by municipal authorities of more complex and large-scale local issues (repair and development of infrastructure, removal of solid household waste and more). At the same time, the development of local communities can by no means be a self-sufficient and substitutional mechanism, whose introduction would end the need for democracy in the full scope of municipal structures overall. In this regard, the experience of local communities’ development in Germany, a state with legal traditions similar to Russian ones, with a centuries-old history of the development of territorial communities and a difficult path to building democracy and forming civil society, seems to be very interesting. Here, the progressive development of local forms of democracy and the participation of residents in local issue management are combined with stable mechanisms of municipal government, and the interaction of municipalities with the state does not torpedo the existing citizen forms of self-government. At the same time, the experience of Germany shows that the decentralization of public issue management which involves the local population can only be effective in a situation where, in addition to maintaining a full-fledged self-government mechanism at the general municipal level, relevant local communities are endowed with real competence and resources to influence local issue decision-making. The role of formalized local communities in urban areas, as the German experience shows, can not only facilitate the decentralization of solving public problems, but can also help in timely elimination of triggers for mobilizing citywide supercollectives with negative agendas. This experience seems useful and applicable in the Russian context.

scholarly journals Soft bodies make estimation hard: correlations among body dimensions and weights of multiple species of sea cucumbers

2015 ◽  
Vol 66 (10) ◽  
pp. 857 ◽  
Author(s):  
James Prescott ◽  
Shijie Zhou ◽  
Andhika P. Prasetyo
Keyword(s):  
Power Function ◽  
Body Length ◽  
Sea Cucumber ◽  
Dry Weight ◽  
Basic Knowledge ◽  
Small Scale ◽  
Body Width ◽  
Sea Cucumbers ◽  
Body Dimensions ◽  
Wet Weight

Tropical sea cucumbers are commonly exploited by small-scale, poorly managed fisheries. A fundamental problem in managing sea cucumber fisheries is the lack of basic knowledge of important life history characteristics for most species. As a result of plastic body dimensions, biological research on this group of animals becomes exceptionally challenging. To improve our understanding of essential biological parameters, we conducted a study to investigate correlations among various body measurements. We analysed a total of 18 sea cucumber species and more than 6600 individuals collected at Scott Reef in the Timor Sea, north-west Australia. We used hierarchical Bayesian errors-in-variables models to specifically take into account measurement errors that are obviously unavoidable. The measures included three types of weights (wet weight, gutted weight and dry weight) and two body dimensions (length and width). The modelling reveals that using both body length and width as independent variables, wet weight increases approximately linearly with body length, but is a power function (~1.6) of body width, although variability exists among species. Dry weight tends to increase more slowly with body length, but has a similar power function of body width. Linear relationships are established between the three types of weights. On average, ~11% of a live specimen and ~16% of a gutted specimen is processed to the commercially traded dry body wall. Our results can be applied to sea cucumbers in other areas and can be useful for data standardisation and size-based fisheries management.

scholarly journals Uptake and trophic changes in polybrominated diphenyl ethers in the benthic marine food chain in southwestern British Columbia, Canada

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 20-51
Author(s):  
Brenda Burd ◽  
Chris Lowe ◽  
Carmen Morales-„Caselles ◽  
Marie Noel ◽  
Peter Ross ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Polybrominated Diphenyl Ethers ◽  
Dry Weight ◽  
Trophic Levels ◽  
Marine Food Chain ◽  
Deposit Feeders ◽  
Diphenyl Ethers ◽  
Bottom Fish ◽  
Harbour Sediment ◽  
Marine Food

We examined the physical and geochemical effects of sediment on the uptake of polybrominated diphenyl ethers (PBDEs) into marine sediment feeders and their transfer to higher trophic fauna. Sediment PBDEs increased with % total organic carbon (%TOC), organic carbon (OC) flux and grain size (%fines). Tissue PBDE variance was best explained ( R2 = 0.70) by sediment acid volatile sulfides (AVS), PBDEs, and organic lability and input, with the highest values near wastewater outfalls. Dry weight tissue/sediment PBDEs declined with increasing sediment PBDEs, resulting in tissue dilution (ratio <1) at >10 000 pg/g in harbours. Ratios also decreased with increasing %fines, resulting in regional differences. These patterns imply that high levels of fines and high sediment concentrations make PBDEs less bioavailable. Dry weight PBDEs increased >100× between background deposit feeders and predators (polychaetes, crabs, bottom fish, seal), but lipid normalized PBDEs barely increased (<1.3%), suggesting remarkably high uptake in low-lipid sediment feeders, and that PBDEs don’t accumulate at higher trophic levels, but lipid content does. Filter feeders had lower lipid-normalized PBDEs than deposit feeders, highlighting the importance of food resources in higher trophic fauna for bioaccumulation. The most profound congener change occurred with sediment uptake, with nona/deca-BDEs declining and tetra-hexa-BDEs increasing. Harbour sediment feeders had more deca-BDEs than other samples, suggesting PBDEs mostly pass unmodifed through them. Deca-BDEs persist patchily in all tissues, reflecting variable dependence on sediment/pelagic food.

scholarly journals A new approach to assess marine opportunity costs and monetary values for spatial planning and conservation; the case study of Gulf of Naples, Mediterranean Sea, Italy

2018 ◽  
Author(s):  
Luca Appolloni
Keyword(s):  
Local Population ◽  
Small Scale ◽  
Conservation Priorities ◽  
Opportunity Costs ◽  
Tyrrhenian Sea ◽  
Economic Activities ◽  
Fishing Activity ◽  
Flexible Approach ◽  
Gulf Of Naples ◽  
Total Turnover

Conservation actions (as Marine Protected Areas) are key tools to maintain coastal ecosystems. However, many reserves are characterized by several problems related to inadequate zonings that preclude important areas from economic activities, determining a strong hostility by local populations. Thus, estimations of marine economic values-in-use are needed for protection of marine ecosystem in order to find the best compromise between conservation priorities and local population needs. Algorithms to estimate monetary values of the main human activities in marine territories (large scale and small scale fishings, aquaculture, beach resorts, yachting, diving and commercial shipping) are here implemented using Gulf of Naples (centre Tyrrhenian sea, Italy) as study area example. These algorithms are based on different sources data (questionnaires, monitoring activities, official local authority reports, web and scientific literature). They can also be compared with each other being their outputs all expressed in the same measure unit. During the models development process a new flexible approach, called “Systematic Costs Assessment” (SCA), to assess opportunity costs in systematic conservation planning process was developed and applied. Results show that the total turnover in the Gulf of Naples is 3,950,753,487 € per year and 747,647,887 € per year excluding small scale fishing estimation, and one hectare of marine territory is worth 40,672 € and 7,696 € per year excluding small scale fishing activity. In particular, excluding small scale fishing activity, beach resort and yachting show the highest values referred to one hectare of marine territories. In conclusion, SCA is a flexible approach where no long and costly sampling campaigns are always needed, provided that two assumptions have to be taken into account, in order to estimate credible values-in-use costs: i) do not use economic activities data and ecosystem services data in the same assessment layer, since it could lead to costs overestimation and ii) SCA method are efficient when used by operators with strong knowledge of the study area, since they are able to recognize parameters affecting economic activities of local population.

scholarly journals Geographical and logistical factors of sustainable development of rural tourism in the context of regional economy

2016 ◽  
pp. 9-14
Author(s):  
I. Smyrnov
Keyword(s):  
Sustainable Development ◽  
Large Scale ◽  
Regional Economy ◽  
Local Economy ◽  
Rural Tourism ◽  
Small Scale ◽  
Resource Base ◽  
Tourist Flows ◽  
Definition Of ◽  
The Impact

Rural tourism is now seen as an important direction of development of the regional economy. From the perspective of sustainable development rural tourism affects the economic, social and environmental aspects of the regional and local economy. Rural tourism is closely linked with agrotourism, eco-tourism, natural tourism and so on. Sustainable rural tourism can be realized by applying logistic, geographic and marketing approaches as components of sustainable development strategies. Logistics approach is determined by logistic potential of resource base of rural tourism and appropriate tourist flows regulation. In this context in the article the concept of tourism capacity or capacity of the resource base of rural tourism is used. The problem of the definition of tourism pressure on the resource base of rural tourism, particularly in natural landscapes is disclosed. Unlike environmental and recrealogical sciences, which stop at the capacity definition of the resource base of tourism, tourism logistics compares this figure with the existing tourist flows and accordingly determines the safe way of tourism management to ensure its sustainable nature. It was shown that these strategies boil down to two basic types – the further development of tourism in a particular area or limit such activities to conserve the resource base of tourism. Recreational (travel) load is the indicator that reflects the impact of tourism on the resource base of tourism (especially landscape complex), expressed by the number of tourists or tourists-days per area unit or per tourist site for the certain period of time (day, month, season year). There are actual, allowable (the maximum) and destructive (dangerous) types of travel load. The latter can lead recreational area or resource base of rural tourism to destruction. Thus, depending on the intensity of tourism resource base using in rural tourism it may change – according to tourist consumption. Large number of tourists affects the entire range of recreational destinations and their individual components. The most vulnerable part of the environment in this sense is vegetation, except that significant changes may occur with soil, water bodies, air and so on. The geographic dimension of the problem of rural tourism sustainable development includes the concept of zoning, ie the division of the territory, offering to develop rural tourism in several zones with different modes of travel usage – from a total ban (in protected areas) for complete freedom with transitional stages, involving various limit degrees in the development of rural tourism. Marketing approach reflects the application of the curve R. Butler to the stages of development of rural tourism destinations with the release of such steps as: research, involvement, development, consolidation, stagnation (also called “saturation”), revival or decline. Shown the models that link the stage of resource base tourist development (under “Curve Butler”), strength of tourism consumption the magnitude of such effects (eg weak (disperse) impact in large scale, strong (concentrated) impact in large scale, strong (concentrated) impact in small scale, weak (disperse) impact in small scale), dynamics of tourism development at the territory.

scholarly journals THE EFFECT OF SELENIUM ON MERCURY TRANSPORT ALONG THE FOOD CHAIN

AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Primož ZIDAR ◽  
Špela KRŽIŠNIK ◽  
Marta DEBELJAK ◽  
Suzana ŽIŽEK ◽  
Katarina VOGEL MIKUŠ
Keyword(s):  
Food Chain ◽  
Contaminated Soil ◽  
Local Population ◽  
Trophic Levels ◽  
Food Chains ◽  
Chemical Transformations ◽  
Soil Concentration ◽  
Preliminary Results ◽  
Mercury Transport ◽  
Hg Accumulation

More than 500 years of mercury (Hg) production in Idrija (Slovenia) resulted in aconsiderable pollution of Idrija region with Hg. Although the mine is closed formore than 20 years, the total soil concentration of Hg may still reach up to severalhundred mgkg-1dry weightin local gardens and more that thousand inother urbanregions. Hg in soil undergoesdifferent chemical transformations and in someformsit may enterplants and higher trophic levelsin food chains, also withbiomagnification pattern.The local population is, besides air and dust, thus exposedto mercury also via consumption of locally produced food.Several studies showedthat the increased level of selenium in soil may reduce the uptake of mercury inplants but very few include other trophic levels in a food chain as well.In our pilotstudy we followed an impact of Seon Hg transport from soil to plants(Lactucasativa) and further to soil dwelling animals (Porcellioscaber). Lettuce wasplanted in a contaminated soil from Idrija and in soil with added HgCl2. The leavesof half of the plants weresprayed with Sesolution (5μg L-1)threeand five weeksafter planting.After six weeks plants were analyzed for Hg and Se and offered asfood to terrestrial isopods for two weeks. Our preliminary results revealed thatfoliar treatment of plants with Se may affect Hg accumulation in plants andtherefore further transport of Hg across the food chain.

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