Instituto de Física

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Browsing Instituto de Física by Author "Ramón Delanoy"

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    Effect of extreme weather events on the sedimentation of the Bay of Samana, Dominican Republic
    (2019) Ramón Delanoy
    The Bay of Samaná, formed by tectonism and sedimentation, is delimited to the north by the peninsula of the same name, to the south by the north slope of the Eastern Mountain Range and Los Haitises National Park, to the east by the Atlantic Ocean, and to the west by the ancient Gran Estero, today the Lower Yuna. There follows a process of continuous degradation by the existing tectonic forces and the sediment contributions by the Yuna, Yabón, and La Yeguada rivers to the south as well as by the landslides of the mountainous area of the Samaná Peninsula, during periods of storms and hurricanes. The coastal area of Samaná Bay has altered by 2.17 km2 at the mouth of the Yuna River from 2003–2015. The high turbidity level has affected coral reefs and marine species.  The  mangroves  are  lost  faster  than  they  are  regenerated  by  the  coastline’s change. Variations in the elemental compositions of calcium and iron show the terrigenous influence on the dynamics of the bay during Extreme Weather Events (EWP) in the river basins that flow into it. Abrupt changes in the rainfall regime produced an equal change in the estuary sedimentation regime, according to the 210Pb. In the 2007–2016 period, a column of sediment that reached 38 cm and a 12 cm to 8.4 km column were deposited 4 km southeast of the municipality of Sánchez and east of the mouth of the Yuna River. The Sedimentary Accumulation Rate is very high, and the content of heavy metals exceeds the threshold values of Table SQuirt.
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    Heavy metal pollution assessment in the agricultural soils of Bonao, Dominican Republic
    (2023-12-02) Natividad Miledy; Ramón Delanoy
    Heavy metal content in agricultural soils potentially impacts the food chain and human health. The present study assessed the levels of heavy metals in topsoil samples collected within an agricultural region situated in Bonao, Dominican Republic. The Energy-Dispersive X-ray Fluorescence (EDXRF) technique was utilized to measure the concentrations of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), and arsenic (As) in the samples. The assessment of soil pollution status and potential ecological risk (RI) involved the utilization of various soil pollution indices, such as the single pollution index (PI), integrated pollution index (IPI), and enrichment factor (EF). The average total concentrations of Fe, Mn, Cr, Cu, Ni, Zn, Pb, and As were 103,000, 2000, 347, 36, 92, 32, 9.6, and 4.2 mg·kg−1, respectively. The results showed that the Mn, Ni, Cu, and As levels exceeded the Food and Agriculture Organization (FAO)’s recommended levels for healthy agricultural soils. The distribution pattern of each individual metal was different, indicating they had different sources of origin. The average pollution indices indicated low-to-moderate pollution, and the potential ecological risk obtained was low. This study emphasizes the need for soil management practices to mitigate heavy metal contamination for food safety and environmental health.
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    Heavy Metal Pollution Assessment in the Agricultural Soils of Bonao, Dominican Republic
    (2023-12-02) Natividad Miledy; Ramón Delanoy
    Heavy metal content in agricultural soils potentially impacts the food chain and human health. The present study assessed the levels of heavy metals in topsoil samples collected within an agricultural region situated in Bonao, Dominican Republic. The Energy-Dispersive X-ray Fluorescence (EDXRF) technique was utilized to measure the concentrations of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), and arsenic (As) in the samples. The assessment of soil pollution status and potential ecological risk (RI) involved the utilization of various soil pollution indices, such as the single pollution index (PI), integrated pollution index (IPI), and enrichment factor (EF). The average total concentrations of Fe, Mn, Cr, Cu, Ni, Zn, Pb, and As were 103,000, 2000, 347, 36, 92, 32, 9.6, and 4.2 mg·kg−1, respectively. The results showed that the Mn, Ni, Cu, and As levels exceeded the Food and Agriculture Organization (FAO)’s recommended levels for healthy agricultural soils. The distribution pattern of each individual metal was different, indicating they had different sources of origin. The average pollution indices indicated low-to-moderate pollution, and the potential ecological risk obtained was low. This study emphasizes the need for soil management practices to mitigate heavy metal contamination for food safety and environmental health.
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    Heavy metals in agricultural soils of Constanza, Jarabacoa, San José de Ocoa, Azua, Barahona and San Juan de la Maguana, Dominican Republic, 2022
    (2024-01-01) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    The objective of this study was to establish a baseline for future studies that aim to determine possible contamination from human, agricultural and industrial activities. As well as the determination of the indices of environmental or geological contamination and enrichment factors of heavy metals Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in agricultural soils of Constanza, Jarabacoa, Rancho Arriba and San José de Ocoa (SJO), municipalities located in the valleys of the Central mountain range of the Dominican Republic. The determination of the concentrations of heavy metals was carried out using the X-ray Fluorescence technique. Just like in Azua, San Juan de la Maguana (SJM) y Barahona in the southwest. Producer municipalities of vegetables, rice, beans, corn, melon, watermelon, tomato, banana, avocado, sugar cane and fodder for cattle. The concentration of 160 mg·kg-1 Probable Effect Level (PEL) of Cr according to the SQuiRTs table (USEPA-NOAA) for agricultural soils, were exceeded in 50% of the samples in SJM, SJO, Jarabacoa and Constanza; in Barahona and Azua by 20%. The PEL of 42.8 mg·kg-1 of the Ni was higher in more than 50% of the samples from SJM, Azua, Barahona and Jarabacoa; in SJO and Constanza at 35%. In the case of Cu with a PEL of 108 mg·kg-1 in SJO and Constanza, 5% of the samples exceeded its, in the other areas the concentrations were lower. Zn, As and Pb did not manage to exceed their respective PEL.
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    Heavy metals in Agricultural Soils of Constanza, Jarabacoa, San José de Ocoa, Azua, Barahona and San Juan de la Maguana, Dominican Republic, 2022
    (2024) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    The objective of this study was to establish a baseline for future studies that aim to determine possible contamination from human, agricultural and industrial activities. As well as the determination of the indices of environmental or geological contamination and enrichment factors of heavy metals Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in agricultural soils of Constanza, Jarabacoa, Rancho Arriba and San José de Ocoa (SJO), municipalities located in the valleys of the Central mountain range of the Dominican Republic. The determination of the concentrations of heavy metals was carried out using the X-ray Fluorescence technique. Just like in Azua, San Juan de la Maguana (SJM) y Barahona in the southwest. Producer municipalities of vegetables, rice, beans, corn, melon, watermelon, tomato, banana, avocado, sugar cane and fodder for cattle. The concentration of 160 mg·kg-1 Probable Effect Level (PEL) of Cr according to the SQuiRTs table (USEPA-NOAA) for agricultural soils, were exceeded in 50% of the samples in SJM, SJO, Jarabacoa and Constanza; in Barahona and Azua by 20%. The PEL of 42.8 mg·kg-1 of the Ni was higher in more than 50% of the samples from SJM, Azua, Barahona and Jarabacoa; in SJO and Constanza at 35%. In the case of Cu with a PEL of 108 mg·kg-1 in SJO and Constanza, 5% of the samples exceeded its, in the other areas the concentrations were lower. Zn, As and Pb did not manage to exceed their respective PEL.
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    Heavy metals in agricultural soils of San Francisco de Macorís and La Vega, Dominican Republic
    (2022-10-10) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    In Dominican Republic exists cultive larges fields of various agricultural rubles. The largest extensions are rice, banana and cocoa; these are located in the Cibao Valley. In the eastern, southwestern, and a small area in the north of the country, sugar cane is cultivated. Heavy metals are found in many of these soils that could be affecting the quality of agricultural products or production. The levels of Cr, Ni, Zn, Cu, Cd, As, Hg and Pb, determined by X-ray fluorescence spectroscopy, in soils collected in two cultivation areas of Rice de La Vega and San Francisco de Macoris (SFM) have been compared with the NOAA-USEPA Canadian Agricultural Soil and Sediment Guide (CEQGs) (SQuiRTs Table). The levels of Cr and Ni in La Vega exceeded the threshold effects levels (TEL), and the probable effects levels (PEL). Pb levels in the La Vega area were higher than in SFM. In general, these metals are found in the La Vega area in higher concentrations than in SFM, exceeding PEL and TEL.
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    Heavy Metals in Agricultural Soils of San Francisco de Macorís and La Vega, Dominican Republic
    (2022-10-10) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    In Dominican Republic exists cultive larges fields of various agricultural rubles. The largest extensions are rice, banana and cocoa; these are located in the Cibao Valley. In the eastern, southwestern, and a small area in the north of the country, sugar cane is cultivated. Heavy metals are found in many of these soils that could be affecting the quality of agricultural products or production. The levels of Cr, Ni, Zn, Cu, Cd, As, Hg and Pb, determined by X-ray fluorescence spectroscopy, in soils collected in two cultivation areas of Rice de La Vega and San Francisco de Macoris (SFM) have been compared with the NOAA-USEPA Canadian Agricultural Soil and Sediment Guide (CEQGs) (SQuiRTs Table). The levels of Cr and Ni in La Vega exceeded the threshold effects levels (TEL), and the probable effects levels (PEL). Pb levels in the La Vega area were higher than in SFM. In general, these metals are found in the La Vega area in higher concentrations than in SFM, exceeding PEL and TEL.
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    Heavy metals in the northwest agricultural region Dominican Republic
    (2022-05-05) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    Heavy metals currently represent a very important source of contamination, since their intake by humans and animals in many cases is the cause of serious damage to health. Soil, air, water and food are the most common pathways for heavy metals to reach organisms. Since soil is their origin, in this study we focus on soil analysis to determine the concentration of Cr, Ni, Cu, Zn, As, Hg, Cd and Pb, which are the most toxic metals. The study site is the agricultural soils of the northwestern region of the Dominican Republic where bananas and rice are the main crops grown. Chromium levels in most samples exceeded the NOAA-USEPA Probable Effects Level (PEL). Other heavy metals were within the acceptable ranges for healthy soil, according to the Food and Agriculture Organization (FAO).
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    Heavy Metals in the Northwest Agricultural Region Dominican Republic
    (2022-05) Ramón Delanoy; Carime Matos; Yamilesa Herrera
    Heavy metals currently represent a very important source of contamination, since their intake by humans and animals in many cases is the cause of serious damage to health. Soil, air, water and food are the most common pathways for heavy metals to reach organisms. Since soil is their origin, in this study we focus on soil analysis to determine the concentration of Cr, Ni, Cu, Zn, As, Hg, Cd and Pb, which are the most toxic metals. The study site is the agricultural soils of the northwestern region of the Dominican Republic where bananas and rice are the main crops grown. Chromium levels in most samples exceeded the NOAA-USEPA Probable Effects Level (PEL). Other heavy metals were within the acceptable ranges for healthy soil, according to the Food and Agriculture Organization (FAO).
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    Hydrodynamic Stydy of Lake Enriquillo in Dominican Republic
    (2017) Ramón Delanoy
    This study presents an analysis of the hydrochemical characteristics of Lake Enriquillo in the southwestern region of the Dominican Republic. This lake is hypersaline and endorheic. The climatology of the region is influenced by the Caribbean Regulator Climate Centers (CRCCs). Due to the endorheic nature of the basin, evaporation plays an extremely important role in its dynamics [1]. During the study period, in November 2002, the water level of Lake Enriquillo was 42 m below sea level (BLS), and the salinity level was 104.2‰. By 2014, the water level of the lake rose to 29 m below sea level, and the salinity decreased to 23.4‰, as a result of the high cyclonic activity in the Caribbean region.
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    Regional assessment of the historical trends of mercury in sediment cores from Wider Caribbean coastal environments
    (2024) Ramón Delanoy
    Spatial and temporal variations of mercury (Hg) concentrations, enrichment, and potential ecological risks were studied in a suite of lead-210 (210Pb) dated sediment cores from 13 Wider Caribbean Region coastal environments. Broad variability of Hg concentrations (19–18761 ng g−1) was observed, encompassing even background levels (38–100 ng g−1). Most Hg concentration profiles exhibited a characteristic upward trend, reaching their peak values in the past two decades. Most of the sediment sections, showing from moderately to very severe Hg enrichment, were found in cores from Havana Bay and Sagua River Estuary (Cuba), Port-au-Prince Bay (Haiti), and Cartagena Bay (Colombia). These were also the most seriously contaminated sites, which can be considered regional Hg ‘hotspots’. Both Havana Bay and Port-au-Prince Bay reportedly receive waste from large cities with populations exceeding 2 million inhabitants, and watersheds affected by high erosion rates. The records from the Sagua River Estuary and Cartagena Bay reflected historical Hg contamination associated with chloralkali plants, and these sites are of very high ecological risk. These results constitute a major contribution to the scarce regional data on contaminants in the Wider Caribbean Region and provide reference information to support the evaluation of the effectiveness of the Minamata Convention
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    Sedimentation in the Bay of Samaná, Dominican Republic (1900-2016.
    (2020-08-20) Ramón Delanoy
    The purpose of this article is to provide an analysis of the geochemistry of sediments deposited in the Bay of Samaná (Dominican Republic) after 1900, emphasizing in the recent changes (last 20 years). This bay was formed by tectonism and sedimentation that joined the Samaná peninsula with the northern mountain range. From 2003 to 2016, Dominican Republic was impacted by several cyclonic systems (storms and hurricanes), which caused an increase in the runoff of all rivers and streams that flow into the coastal area by depositing large amount of sediments in the basins of the rivers and tributaries. The Sedimentary Accumulation Rate (SAR) found in the cores indicates an increase in runoff which resulted in a decrease in the area and depth of the bay where sediment was deposited by rivers and streams. When analyzing data from the period 2003 to 2019, it was observed that the Yuna River has made an intrusion of sediment displacing 2.38 km2 to the bay, its average SAR was 1.78 cm per year (cm y-1). The main cause of this increase in sediment deposition was mining, followed by deforestation, agriculture, and urban planning over the years, all activities that have the common denominator of being anthropic.