Sand Extraction Site Research Articles

Early ecosystem establishment using forest floor and peat cover soils in oil sands reclamation

ABSTRACT Early trends of plant community development provide the basis of ecosystem function and reclamation success of oil sand extraction sites. However, few studies have explicitly investigated species-level interactions with different cover soil types, placement depths, and time since reclamation during early plant community development in boreal forests. We investigated effectiveness of forest floor mineral mix (FMM) and peat mineral mix (PMM) cover soils and placement depths (10 and 20 cm) at four research sites 4 to 13 years after reclamation. Outcomes of this study indicate FMM had a more positive influence on woody plant densities, vegetation cover, and species richness than PMM. Species assemblage, composition, dominance, and types (successional stages, habitat types, competitive-stress tolerant-ruderal strategies) also showed FMM cover soil performed better than PMM. Greater vegetation cover and richness on deeper (20 cm) cover soil placements were evident. However, this effect of cover soil depth would likely decrease with time. Dominant and subdominant species on FMM were native and early to late successional, thus trajectory community development on FMM followed typical early succession of boreal forests (from ruderal and annual to perennial communities), while PMM was dominated by non-native and annual forbs which could slow succession and ecosystem recovery.

Do tidal sand waves always regenerate after dredging?

Tidal sand waves are rhythmic bedforms found on sandy continental shelves that pose a threat to offshore activities. While emphasis is placed on studying their natural morphodynamic evolution, little is known about if and how fast sand waves recover after dredging. This work presents an analysis of multibeam echosounder data collected at three former sand extraction sites on the Belgian continental shelf. At one of the sites, sand waves seemed to reappear approximately 5 years after dredging had stopped, which did not happen at the other two sites during the measurement period (5 and 9 years). The lack of recovery in those sites is likely the result of larger depths and smaller local sediment availability compared with the site where recovery occurred. Furthermore, these data reveal that in the latter site sand wave recovery was established mainly through local sediment redistribution.•Tidal sand waves are isolated from bathymetric data of the Belgian continental shelf.•At only one of the three sites, sand waves seemed to regenerate after dredging.•Possible explanations are differences in water depth and local sediment availability.•The regenerating tidal sand waves do so as a result of local redistribution of sand.

Economic viability of implementing an infrastructure for recycling bedding sand from a free-stall facility for dairy cows

This study proposes to examine the economic viability of implementing the necessary infrastructure for the recycling of bedding sand from a free-stall facility in a milk production system in southern Minas Gerais, Brazil. In specific terms, the total production cost (TC), total operating cost (TOC) and effective operating cost (EOC) of a cubic meter of recycled sand were estimated in order to estimate the total sand consumption for the free-stall system and per bed year-1 as well as the equilibrium point of the amount of recycled sand, in cubic meters. The experiment was carried out on a farm located in the south of Minas Gerais from January 2016 to December 2017. Three scenarios were analyzed by the tree-point estimation method (MOP - most likely, optimistic, and pessimistic). Utilization of 85%, 95% and 75% of the recycled sand was considered for scenarios 1, 2 and 3, respectively. In all of them, the value charged per cubic meter of sand by a supplier close to the farm was considered. Monte Carlo simulation was also carried out with hurdle rates (HR) of up to 90%. Under the studied conditions, sand recycling showed to be economically viable in all scenarios, with positive net present values (NPV), internal rates of return above the HR, simple and discounted payback below the 10-year horizon, and satisfactory cost benefit-1 ratios (greater than 1). The EOC of one cubic meter of recycled sand was estimated at R$5.04, R$4.51 and R$5.72 for scenarios 1, 2 and 3, respectively, whereas the average TC, considering all scenarios, was R$6.84 (+0.81), which is less than the acquisition price of R$28.57 at the sand extraction site. The TC was R$37,219.51 and R$34,637.74 for the scenarios with HR of 8.50 and 6.99%, respectively, whereas TOC was R$22,572.08 in all analyzed scenarios. The estimated total annual sand consumption by the free-stall system was 526.44 m³, with an estimated average of 1.23 m³ (+0.28) bed-1 year-1. All Monte Carlo simulation models showed positive NPV as well as HR of up to 90%, which reflect a high probability of positive NPV.

An account of a first record of the Common Goldeneye Bucephala clangula Linnaeus, 1758 (Aves: Anseriformes: Anatidae) in Bhutan

PunatsangChhu in Wangduephodrang 27.486°N 89.899°E (1,273m) is one of the largest rivers and an important zone in Bhutan for resident and migrant water birds. It is the expanse where the diverse birds are seen on a stretch between 27.462°N 89.901°E and 27.579°N 89.867°E (Tobgay 2017). Large numbers of winter migratory water birds in Bhutan have been found in this location (Spierenburg 2005). Common Goldeneye Bucephala clangula was first sighted on Saturday, 5th of January, 2019 along PunatsangChhu 27.512657’N 89.887610’E at the elevation of 1142meter above sea level in the morning but couldn’t capture photo and more over mistreated it to be some other common water birds. However, until on 8th of January, 2019, it was a success to have photographed while it was foraging alone at the sand extraction sites at around 12:30 hours in the evening. The duck was observed diving simultaneously under water foraging at the time of sighting. It was then photographed with the help of DSLR camera and kit lens 55–300 mm until it flew away to other side of the river.

Ecosystem-based design rules for marine sand extraction sites

The demand for marine sand in the Netherlands as well as globally is increasing. Over the last decades, only shallow sand extraction of 2m below the seabed was allowed on the Dutch Continental Shelf (DCS). To guarantee sufficient supply and to decrease the surface area of direct impact, the Dutch authorities started to promote sand extraction depths over 2m for sand volumes over 10 millionm3. The ecological effects of deep sand extraction, however, are still largely unknown. Therefore, we investigated short-term effects (0–2.5y) of deep sand extraction (20–24m) and compared these with other case studies such as, regular shallow sand extraction on the DCS (2m) and an 8m deepened shipping lane. For intercomparison between case studies we used tide-averaged bed shear stress as a generic proxy for environmental and related ecological effects. Bed shear stress can be estimated with a two-dimensional quadratic friction law and showed a decrease from 0.50 to 0.04Nm−2 in a borrow pit in 20m deep water and extraction depths up to 24m. Macrozoobenthos in a borrow pit with a tide-averaged bed shear stress of around 0.41Nm–2 is expected to return back to pre-extraction conditions within 4–6 year. When tide-averaged bed shear stress decreases below 0.17Nm−2 enhanced macrozoobenthic species richness and biomass can occur. Below a tide-averaged bed shear stress of 0.08Nm−2, increasing abundance and biomass of brittle stars, white furrow shell (Abra alba) and plaice (platessa platessa) can be expected. Below 0.04Nm−2, an overdominance and high biomass of brittle stars can be expected whereas demersal fish biomass and species composition may return to reference conditions. Next to changes in faunal composition, a high sedimentation rate can be expected.Ecological data and bed shear stress values were transformed into ecosystem-based design (EBD) rules. At higher flow velocities and larger water depths, larger extraction depths can be applied to achieve desired tide-averaged bed shear stresses for related ecological effects. The EBD rules can be used in the early-design phases of future borrow pits in order to simultaneously maximise sand yields and decrease the surface area of direct impact. The EBD rules and ecological landscaping can also help in implementing the European Union's Marine Strategy Framework Directive (MSFD) guidelines and moving to or maintaining Good Environmental Status (GES).

Impact on demersal fish of a large-scale and deep sand extraction site with ecosystem-based landscaped sandbars

For the seaward harbour extension of the Port of Rotterdam in the Netherlands, approximately 220 million m3 sand was extracted between 2009 and 2013. In order to decrease the surface area of direct impact, the authorities permitted deep sand extraction, down to 20 m below the seabed. Biological and physical impacts of large-scale and deep sand extraction are still being investigated and largely unknown. For this reason, we investigated the colonization of demersal fish in a deep sand extraction site. Two sandbars were artificially created by selective dredging, copying naturally occurring meso-scale bedforms to increase habitat heterogeneity and increasing post-dredging benthic and demersal fish species richness and biomass. Significant differences in demersal fish species assemblages in the sand extraction site were associated with variables such as water depth, median grain size, fraction of very fine sand, biomass of white furrow shell (Abra alba) and time after the cessation of sand extraction. Large quantities of undigested crushed white furrow shell fragments were found in all stomachs and intestines of plaice (Pleuronectes platessa), indicating that it is an important prey item. One and two years after cessation, a significant 20-fold increase in demersal fish biomass was observed in deep parts of the extraction site. In the troughs of a landscaped sandbar however, a significant drop in biomass down to reference levels and a significant change in species assemblage was observed two years after cessation. The fish assemblage at the crests of the sandbars differed significantly from the troughs with tub gurnard (Chelidonichthys lucerna) being a Dufrêne-Legendre indicator species of the crests. This is a first indication of the applicability of landscaping techniques to induce heterogeneity of the seabed although it remains difficult to draw a strong conclusion due the lack of replication in the experiment. A new ecological equilibrium is not reached after 2 years since biotic and abiotic variables are still adapting. To understand the final impact of deep and large-scale sand extraction on demersal fish, we recommend monitoring for a longer period, at least for a period of six years or even longer.

Estimation of radon and thoron caused dose at exraction and processing sites of mineral sand mining area in Vietnam (HA TINH province)

Mineral sands are mined in several countries to supply to the titanium and zircon producing industries. Coastal black mineral sands usually contain, besides ilmenite (FeTiO3) and rutile (TiO2), radioactive minerals such as zircon (ZrSiO4) and monazite (RePO4). Radon and thoron activity concentration originated from natural radioactive contents of the black mineral sand was monitored at the extraction and processing for black minerals in the coastal areas of Ha Tinh Province, one of the around 40 coastal mineral sand deposits in Vietnam. The survey was carried out with the Raduet chambers made by Radosys Ltd—Hungary. The obtained results for 25 investigated points show that the measured values are not high in the residential houses and in case of the sand extraction site as well. At the titanium processing plant the measured values were higher than outside the facility (Radon: 18–55 Bq/m3 with average of 34 Bq/3 and Thoron 33–118 Bq/m3 with average of 58 Bq/m3) but still comparable to the average concentration of the world published by UNSCEAR. The typical outdoor levels of radon and thoron gas are each of the order of 10 Bq/m3. Although the radon concentrations were low in the zircon and titanium processing plants, the thoron concentrations in the houses for separating rutile and zircon were very high. At zircon processing factory, the thoron concentration could reach 2,931 Bq/m3 and the estimated annual effective dose would be 21.4 mSv/a. Intervention has to be taken in order to reduce the thoron level in this factory since the level of thoron and its progenies corresponding to an annual occupational effective dose is beyond the action level of 6 mSv/a.

An examination of the toxic properties of water extracts in the vicinity of an oil sand extraction site

The industrial extraction of oil sands (OS) in northern Alberta, Canada, has raised concerns about the quality of the Athabasca River. The purpose of this study was to examine the toxic properties of various water extracts on Oncorhynchus mykiss trout hepatocytes. The water samples were fractionated on a reverse-phase C(18) cartridge and the levels of light-, medium- and heavy-weight polycyclic aromatic hydrocarbons (PAHs) were determined by fluorescence spectroscopy. Primary cultures of trout hepatocytes were exposed for 48 h at 15 °C to increasing concentrations of the C(18) extract corresponding to 0.02, 0.1, 0.5 and 2.5X concentrations from upstream/downstream sites in the Athabasca River, lake and groundwater samples, OS tailings and interceptor well-water samples. Changes in cell viability, phase I and phase II biotransformation enzymes (cytochrome P4501A and glutathione S-transferase activities), oxidative damage (lipid peroxidation LPO) and genotoxicity (single and double DNA strand breaks) were monitored in post-exposure cells. The water samples decreased cell viability and increased all the above endpoints at thresholds of between 0.02 and 0.1X the water concentration. The most responsive biomarker was DNA damage but it also offered the least discrimination among sites. LPO was higher at sites downstream of the industrial operations compared to upstream sites. A decision tree analysis was performed to formulate a set of rules by which to identify the distinctive properties of each type of water samples. The analysis revealed that OS tailings and interceptor waters were characterized by an increased concentration in light PAHs (>42 μg L(-1)) and this fraction represented more than 85% of the total PAHs. These samples also inhibited GST activity, which could compromise the elimination of genotoxic PAHs present in the system. An analysis of groundwater samples revealed a contamination pattern similar to that for OS tailings. There is a need for more research into specific biomarkers of toxicity from OS tailings compounds such as naphthenic acids, light PAHs among others, which are a characteristic fingerprint of OS extraction activities.

Short-term changes in nematode communities from an abandoned intense sand extraction site on the Kwintebank (Belgian Continental Shelf) two years post-cessation

We investigated short-term changes (two years) in nematode communities (density, diversity, biomass and community composition) in an area on the Kwintebank (Belgian Continental Shelf) that was closed for sand extraction activities and compared these patterns to nematode community characteristics from another area on the Kwintebank were sand extraction was still ongoing. Six stations were sampled in 2003 and 2004 and nematode community composition and univariate measures of diversity were compared with values obtained during the extraction period and with a “pre-impact situation” sampled in 1978. Although nematode density, diversity and biomass did not change two years after cessation of the exploitation, nematode community composition did and was more stable than in the extracted site. This is attributed to the absence of continuous disturbances associated with the extraction activities such as the creation and filling up of dredge furrows. As a consequence of the typical life history traits of nematodes, recovery seems to follow different pathways when compared to macrobenthic recovery from the same impact.

Changes in nematode communities at the long-term sand extraction site of the Kwintebank (Southern Bight of the North Sea)

We investigated the long-term effects of sand extraction activities on the nematode communities from the Kwintebank. Although changes in nematode community composition cannot be completely uncoupled from natural processes, we suggest that the morphological changes in the sandbank and physical disturbance associated with the dredging activities indeed affected nematode community composition. Nematode diversity did not change since the start of the extraction activities but nematode community composition changed significantly. The SIMPER routine identified predatory nematodes to be important for the within group similarity at the start of the exploitation, while similarity in 1997 and 2001 was determined by the contribution of deposit feeding nematodes. In addition, long nematodes, vulnerable to physical disturbance became less important. These changes are attributed to long term changes in sediment characteristics in combination with additional short-term disturbances by the creation and filling of dredge furrows which are related to the extraction activities.

Morphological evolution of gravel and sand extraction pits, Tromper Wiek, Baltic Sea

The growing demand for marine mineral resources introduces anthropogenic impacts in the coastal zone, among others also through aggregate dredging. Pits created by anchor hopper dredging may affect local sediment budgets, local hydrodynamics and biological habitats. In this study we investigate the processes and time-scales of pits refilling at two extraction sites over 6 years following cessation of dredging. We focused on the evolution of a single pit at a gravel extraction site and the development of a group of three pits located at a sand extraction site. In the case of the gravel pit, a series of six sonograph and two multibeam surveys were evaluated. We observed a spatial expansion of the edge of the pit, decreasing availability of screened sand in the neighbourhood of the pit (a possible source of refilling), and a slowing down of the refilling process with time. At the sandy pit site a series of seven sonographs and two multibeam surveys were available. We observed a smoothing of the edges and larger mean refilling rates than in the gravel pit case. We conclude that the most effective method for monitoring of pit evolution is to make measurements every six months by simultaneously deploying sidescan sonar and multibeam devices.