scholarly journals The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution

2021 ◽  
Vol 22 (9) ◽  
Author(s):  
Indriyani Nur ◽  
ERICK ARJUNA ARIS ◽  
YUSNAINI YUSNAINI ◽  
SARA BEAVIS
Keyword(s):  
Bioconcentration Factor ◽  
River Sediments ◽  
Gill Tissue ◽  
Mercury Pollution ◽  
Mercury Contamination ◽  
Small Scale ◽  
The Mean ◽  
Potential Use ◽  
Host Tissues ◽  
Mud Crabs

Abstract. Nur I, Aris EA, Yusnaini Y, Beavis S. 2021. The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution. Biodiversitas 22: 3764-3772. Artisanal small-scale gold mining and the use of mercury is widespread across Indonesia, often characterized by relatively short-lived gold rushes. In the late and post-mining phases, mercury stored in mine tailings and river beds was transported down catchment, posing risks to ecosystems and human health over much longer time scales. These risks can be under-rated when mercury concentrations in water, sediments, and aquatic species are low enough to meet relevant guideline thresholds. In this study in Southeast Sulawesi, Indonesia, we have investigated the Costraca barnacle, Octolasmis, as a bioindicator of mercury contamination. The presence of Octolasmis parasites in mud crabs, Scylla spp., and the accumulation of mercury (Hg) in the hosts, parasites, and the ambient environment, were analyzed across both dry and wet seasons. Severe infestation of Octolasmis was assessed using prevalence, abundance, and intensity. Hg concentrations were significantly higher in the Octolasmis parasites than in the host tissues, water and sediments. The mean bioconcentration factor (BCF) of Hg equaled 7938.21 from water to parasites, and 28.91 from the host’s gill tissue to the parasites. The results suggest that Octolasmis spp. can be used effectively as a bioindicator in coastal catchments impacted by mercury contamination, even when concentrations of mercury are low in water and river sediments. The study provides the first report of Octolasmis spp. parasitized to mud crabs as a reliable bioindicator of Hg contamination and pollution.

scholarly journals Mercury Contamination from Dental Amalgam

2019 ◽  
Vol 9 (22) ◽  
Author(s):  
Anita Vazquez Tibau ◽  
Blanche D. Grube
Keyword(s):  
Sewage Sludge ◽  
Gold Mining ◽  
Negative Impact ◽  
Developed Countries ◽  
The United States ◽  
Dental Amalgam ◽  
Mercury Pollution ◽  
Mercury Contamination ◽  
Small Scale ◽  
The European Union

Background. Mercury in dental amalgam is a hidden source of global mercury pollution, resulting from the illegal diversion of dental mercury into the artisanal and small-scale gold mining sector, to crematoria emissions from the deceased and sewage sludge that is sold to farmers. These significant mercury sources result in air, water, and food contamination that consequently have a negative impact on human health. Objectives. The aim of the present study was to investigate and report on all of the various pathways mercury in dental amalgam can enter the environment. Methods. The present study searched the electronic data bases of PubMed and Google Scholar. Peer reviewed journals and references of studies included for full-text review were examined for potentially relevant studies. Articles published between 2000 to 2018 were searched and specifically screened for articles that referenced “Dental Amalgam,” and the following key words in various combinations: “Minamata Convention on Mercury Treaty,” “Sewage Sludge,” “Cremation,” and “Artisanal and Small-Scale Gold Mining.” Data were included on the most populous countries of China, India, the United States, Brazil, and the European Union collectively. We also included data on cremation statistics and current global trends, looking at populations where cremation is a common practice, such as Japan and India. Discussion. Dental amalgam represents a significant, but understudied area of global mercury pollution that includes cremation, sewage sludge, burial, and small-scale gold mining. Conclusions. Mercury used in products and processes, including dental amalgams, is a global pollutant. Even after the last mercury dental amalgam is placed, its toxic legacy will continue for decades, because of its pervasive bioaccumulation in the environment. Government regulatory agencies should make it mandatory to utilize available technologies, not only in developing countries, but also in developed countries, to reduce mercury contamination. Competing Interests. The authors declare no competing financial interests.

scholarly journals Characterization of potential mercury contamination in the ASGM area of Mandailing Natal, North Sumatera

2021 ◽  
Vol 882 (1) ◽  
pp. 012062
Author(s):  
H Astika ◽  
S Handayani ◽  
R Damayanti ◽  
W Surono ◽  
Maryono ◽  
...  
Keyword(s):  
River Sediments ◽  
Ecological Impacts ◽  
Mercury Contamination ◽  
Small Scale ◽  
Gold Extraction ◽  
Grab Sampling ◽  
The North ◽  
Soils And Sediments ◽  
Area Sampling

Abstract A large amount of Hg is used for gold extraction through the amalgamation process in the Mandailing Natal derived from artisanal and small-scale gold mining (ASGM) area located in the North Sumatera Province, Indonesia. The objective of this work was to characterize the potential contamination of total Hg in water, sediments, and soil in this ASGM area. Sampling was done in two locations in West Panyabungan and Huta Bargot Districts using grab sampling method. Results showed that accumulation of Hg in the studied soils and sediments was the highest, but Hg in aquatic solution was below the detection limit of the analytical method of the studied community wells and rivers. The highest concentration of Hg was found in the river sediments of the Saba Padang irrigation (1,63 mg/kg), and in the soil of the plantation area of Huta Bargot (1,62 mg/kg) respectively. These concentrations may pose a serious problem for aquatic and land life, related ecosystems, and human health. For further study, there is a need to study Hg availability in riverine biota to better understand the cycling of Hg in this ASGM area. Understanding the ecological impacts can assist in the prioritizing of impact mitigation efforts.

scholarly journals Mercury toxicity potential from artisanal and small scale gold mines in Lebong Regency, Bengkulu Province

2018 ◽  
Vol 73 ◽  
pp. 06002
Author(s):  
Munawar Ali ◽  
Suhartoyo Hery ◽  
Suci Asriani Putri
Keyword(s):  
Total Mercury ◽  
River Sediments ◽  
Aquatic Organisms ◽  
Analysis Data ◽  
Mercury Contamination ◽  
Small Scale ◽  
Gold Mines ◽  
Mercury Analysis ◽  
Toxicity Potential ◽  
Streambed Sediments

Artisanal and small scale gold mining (ASGM) is considered as the largest source of mercury pollution worldwide. The ASGM has been practiced for years in the area of Lebong Regency of Bengkulu Province. To extract gold from the ores, miners use a simple technique called Gelondong. This practice involves amalgamation process which forms amalgam, a mixure composed of mercury and gold. These amalgamation generates liquid and solid wastes (tailings) which still contain significant amount of mercury. Consequently, ASGM activities can potentially create mercury contamination of the environment, especially aquatic ecosystems. This study was aimed to investigate the concentration and distribution of total mercury in rivers to which wastes from ASGM communities in three villages of North Lebong District were dumped. Water and streambed sediments along the rivers were collected and brought to the laboratory for total mercury analysis. Data showed that total mercury was not detected in the river water but high in the river sediments with high variations among lactions from 0.11 to 110.37 mg kg-1. Apparently, total mercury tended to decrease with the distance from it source. High amounts of mercury in the river sediments could potentially spread to wider area and cause bioaccumulation in aquatic organisms, especially fish which can be dangerous to consume.

Quantification of small-scale heterogeneity in aquatic aminopeptidase activity

2020 ◽  
Vol 84 ◽  
pp. 127-140
Author(s):  
BM Gaas ◽  
JW Ammerman
Keyword(s):  
Chlorophyll Fluorescence ◽  
Leucine Aminopeptidase ◽  
Hudson River ◽  
Aminopeptidase Activity ◽  
Small Scale ◽  
Analysis Instrument ◽  
Sequential Samples ◽  
Degree Of Confidence ◽  
The Mean ◽  
Hydrolysis Of

Leucine aminopeptidase (LAP) is one of the enzymes involved in the hydrolysis of peptides, and is sometimes used to indicate potential nitrogen limitation in microbes. Small-scale variability has the potential to confound interpretation of underlying patterns in LAP activity in time or space. An automated flow-injection analysis instrument was used to address the small-scale variability of LAP activity within contiguous regions of the Hudson River plume (New Jersey, USA). LAP activity had a coefficient of variation (CV) of ca. 0.5 with occasional values above 1.0. The mean CVs for other biological parameters—chlorophyll fluorescence and nitrate concentration—were similar, and were much lower for salinity. LAP activity changed by an average of 35 nmol l-1 h-1 at different salinities, and variations in LAP activity were higher crossing region boundaries than within a region. Differences in LAP activity were ±100 nmol l-1 h-1 between sequential samples spaced <10 m apart. Variogram analysis indicated an inherent spatial variability of 52 nmol l-1 h-1 throughout the study area. Large changes in LAP activity were often associated with small changes in salinity and chlorophyll fluorescence, and were sensitive to the sampling frequency. This study concludes that LAP measurements in a sample could realistically be expected to range from zero to twice the average, and changes between areas or times should be at least 2-fold to have some degree of confidence that apparent patterns (or lack thereof) in activity are real.

scholarly journals Quantification of Measurement and Model Effects in Monopile Foundation Scour Protection Experiments

2021 ◽  
Vol 9 (6) ◽  
pp. 585
Author(s):  
Minghao Wu ◽  
Leen De Vos ◽  
Carlos Emilio Arboleda Chavez ◽  
Vasiliki Stratigaki ◽  
Maximilian Streicher ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Flow Field ◽  
Three Dimensional ◽  
Small Scale ◽  
Maximum Wave Height ◽  
Chaotic Flow ◽  
The Mean ◽  
Scour Protection ◽  
Damage Number ◽  
Measurement Effects

The present work introduces an analysis of the measurement and model effects that exist in monopile scour protection experiments with repeated small scale tests. The damage erosion is calculated using the three dimensional global damage number S3D and subarea damage number S3D,i. Results show that the standard deviation of the global damage number σ(S3D)=0.257 and is approximately 20% of the mean S3D, and the standard deviation of the subarea damage number σ(S3D,i)=0.42 which can be up to 33% of the mean S3D. The irreproducible maximum wave height, chaotic flow field and non-repeatable armour layer construction are regarded as the main reasons for the occurrence of strong model effects. The measurement effects are limited to σ(S3D)=0.039 and σ(S3D,i)=0.083, which are minor compared to the model effects.

scholarly journals Methodology for Developing Hydrological Models Based on an Artificial Neural Network to Establish an Early Warning System in Small Catchments

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Ivana Sušanj ◽  
Nevenka Ožanić ◽  
Ivan Marović
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Small Scale ◽  
Ann Model ◽  
Data Value ◽  
The Mean ◽  
Artificial Neural

In some situations, there is no possibility of hazard mitigation, especially if the hazard is induced by water. Thus, it is important to prevent consequences via an early warning system (EWS) to announce the possible occurrence of a hazard. The aim and objective of this paper are to investigate the possibility of implementing an EWS in a small-scale catchment and to develop a methodology for developing a hydrological prediction model based on an artificial neural network (ANN) as an essential part of the EWS. The methodology is implemented in the case study of the Slani Potok catchment, which is historically recognized as a hazard-prone area, by establishing continuous monitoring of meteorological and hydrological parameters to collect data for the training, validation, and evaluation of the prediction capabilities of the ANN model. The model is validated and evaluated by visual and common calculation approaches and a new evaluation for the assessment. This new evaluation is proposed based on the separation of the observed data into classes based on the mean data value and the percentages of classes above or below the mean data value as well as on the performance of the mean absolute error.

scholarly journals Mapping of mercury pollution in GIS-based small-scale mining (case study: Cineam Tasikmalaya District)

2019 ◽  
Vol 314 ◽  
pp. 012073
Author(s):  
Andi Nur Rachman ◽  
Indra Mahdi ◽  
Agi Nurhidayah ◽  
Anto Purwanto ◽  
SR Cecep Muhamad
Keyword(s):  
Mercury Pollution ◽  
Small Scale

Extraction Techniques and Analysis of Turbulence Quantities From In-Cylinder Velocity Data

1989 ◽  
Vol 111 (3) ◽  
pp. 466-478 ◽  
Author(s):  
A. E. Catania ◽  
A. Mittica
Keyword(s):  
Direct Injection ◽  
Detailed Comparison ◽  
Ensemble Average ◽  
Small Scale ◽  
Velocity Data ◽  
Mean Flow ◽  
Reciprocating Engine ◽  
Reduction Methods ◽  
The Mean ◽  
Correlation And Spectral Analysis

In addition to the frequently used statistical ensemble-average, non-Reynolds filtering operators have long been proposed for nonstationary turbulent quantities. Several techniques for the reduction of velocity data acquired in the cylinder of internal combustion reciprocating engines have been developed by various researchers in order to separate the “mean flow” from the “fluctuating motion,” cycle by cycle, and to analyze small-scale engine turbulence by statistical methods. Therefore a thorough examination of these techniques and a detailed comparison between them would seem to be a preliminary step in attempting a general study of unconventional averaging procedures for reciprocating engine flow application. To that end, in the present work, five different cycle-resolved data reduction methods and the conventional ensemble-average were applied to the same in-cylinder velocity data, so as to review and compare them. One of the methods was developed by the authors. The data were acquired in the cylinder of a direct-injection automotive diesel engine, during induction and compression strokes, using an advanced hot-wire anemometry technique. Correlation and spectral analysis of the engine turbulence, as determined from the data with the different procedures, were also performed.

scholarly journals Energetic Submesoscales Maintain Strong Mixed Layer Stratification during an Autumn Storm

2017 ◽  
Vol 47 (10) ◽  
pp. 2419-2427 ◽  
Author(s):  
Daniel B. Whitt ◽  
John R. Taylor
Keyword(s):  
Mixed Layer ◽  
North Atlantic ◽  
Small Scale ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
Ocean Stratification ◽  
The North ◽  
Large Eddy ◽  
The Mean ◽  
Scale Turbulence

AbstractAtmospheric storms are an important driver of changes in upper-ocean stratification and small-scale (1–100 m) turbulence. Yet, the modifying effects of submesoscale (0.1–10 km) motions in the ocean mixed layer on stratification and small-scale turbulence during a storm are not well understood. Here, large-eddy simulations are used to study the coupled response of submesoscale and small-scale turbulence to the passage of an idealized autumn storm, with a wind stress representative of a storm observed in the North Atlantic above the Porcupine Abyssal Plain. Because of a relatively shallow mixed layer and a strong downfront wind, existing scaling theory predicts that submesoscales should be unable to restratify the mixed layer during the storm. In contrast, the simulations reveal a persistent and strong mean stratification in the mixed layer both during and after the storm. In addition, the mean dissipation rate remains elevated throughout the mixed layer during the storm, despite the strong mean stratification. These results are attributed to strong spatial variability in stratification and small-scale turbulence at the submesoscale and have important implications for sampling and modeling submesoscales and their effects on stratification and turbulence in the upper ocean.

scholarly journals Evaluating the influence of anxiety and depression on academic performance in high school students

2021 ◽  
Author(s):  
Waleed Ahmed Shahzad
Keyword(s):  
High School ◽  
Academic Performance ◽  
High School Students ◽  
Anxiety And Depression ◽  
Small Scale ◽  
School Students ◽  
Cross Sectional ◽  
Grade Point ◽  
Negative Effect ◽  
The Mean

The purpose of this study was to evaluate whether anxiety and depression have a negative effect on academic performance. This small-scale study assessed the relationship between these factors. A cross-sectional questionnaire survey was carried out. A randomized sample of 52 high school students based in various schools across Lahore participated in the survey. Of the participants, 32 were males and 20 were females. As a measure of anxiety and depression 14 questions from the DASS-21 were utilized (The 7 questions pertaining to the measure of stress were not included in this study). Based on the DASS-21 score obtained by the respondents they were classified under categories of normal, mild, moderate, severe and extremely severe levels of anxiety and depression. As a measure of academic performance, the Grade Point Average (GPA) of the students was obtained via the survey. The mean average GPA was calculated for all the students falling under the aforementioned categories pertaining to anxiety and depression separately and these averages were compared. It was found that the mean average GPA was highest in students falling under the categories of normal and mild levels of anxiety and depression. Whereas, mean average GPA was lower in students suffering from severe levels of anxiety and depression. These findings suggest the need to come up with methods to combat anxiety and depression in high school students as these factors impede academic performance.

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