Sediment Contamination Research Articles

Concentration of Trace Elements in Cryoconites of Mountain and Polar Regions of the World

The surface of mountain glaciers is a place of accumulation of various biogenic organomineral and mineral compounds. As a result of intensive mass deglaciation of glaciers due to climate change and anthropogenic activity, this material can significantly affect the transformation of the landscape in the periglacial zone. Thus, this work considers the contamination of the surface of the Arctic, Antarctic, and Caucasian glaciers by priority pollutants. Atomic absorption spectroscopy was used to analyze trace elements (Cu, Zn, Ni, Cd, Pb) from cryoconite deposits. It was revealed that the cryoconite dust on the Ray-Iz glacier (Polar Urals) has a high level of nickel contamination, which comes to the glacier from local rock materials as a result of their weathering. The lowest concentrations of trace elements are found in one of the Arctic plots located at Mushketov and Aldegonda glaciers, the Caucasus, and the Antarctic, which is due to their relatively low content in the composition of rocks and the relatively low contribution of long-range transport of matter to the polar regions. Contamination of moraine sediments in the periglacial zone can make a significant contribution to the formation of the soil cover of these territories, the pollution of water bodies near the glacier, as well as affect the quality of life of the people living in the immediate vicinity of the mountain areas.

Bioaccumulation of estuarine pollutants in leaf oysters (Isognomon ephippium) on the mid-north coast, New South Wales, Australia

Filter feeding bivalves are useful bioindicators for the detection of biologically available pollutants. We investigated trace metals, metalloids, and pesticides in leaf oyster (Isognomon ephippium) soft tissue and shells and compared them to sediment in five estuaries in northern New South Wales, Australia. Concentrations of Pb, Cr, Mn, Ni, Fe and Al were higher in sediments, whereas Zn, Cd, Ag, Hg, Se and As bioaccumulated in the soft tissue. The amount of Cu, Hg and Ni in the sediment from Tweed and Richmond River estuaries exceeded the Australian national sediment quality guideline values. Only one pesticide, atrazine, was detected in leaf oyster soft tissue. Combinations of six elements in the soft tissue were the best predictors of oyster condition index and shell size, whereas sediment contaminants showed weak relationships. Overall, the bioaccumulation of metals and metalloids increases with leaf oyster size and reduces leaf oyster condition, suggesting these large bivalves are useful bioindicators for pollution in estuarine environments.

Restoration of seagrass habitats: Effects of artificial and natural sediments on the development of transplanted eelgrass (Zostera marina)

Near-shore areas face multiple stressors, effects of climate change, coastal construction and contamination. Although capping the seabed in these areas with mineral masses can reduce the impact of legacy contaminants in sediment, it can also result in the loss of flora and sessile fauna, both of which are vital components of near-shore ecosystems. Eelgrass (Zostera marina) is essential to marine near-shore areas as it supports biodiversity and mitigates the effects of climate change. Therefore, it would be beneficial to modify the top layer of caps to facilitate the reestablishment of these ecosystems when capping near-shore areas. This study describes results from an in situ, six-month field experiment conducted to compare increase in leaf length over the growing season and survival of eelgrass transplanted in two commercially available substrates (Natural sand and Crushed stone) and indigenous sediment (i.e., indigenous control sediment) in a capping project in Horten Inner harbour, Norway. Similar leaf length increase was found in Natural sand and Indigenous control sediment, both significantly higher compared to Crushed stone substrate. Survival was highest in our case in the Indigenous control sediment (120 %), with no significant difference between Crushed stone (20 %) and Natural sand substrates (25 %). These findings emphasize the importance of selecting appropriate substrate for successful seagrass restoration.

Particle-based nutrients and metal contaminants in the habitat of Unionidae mussels in the Tisza River (Hungary)

Introduction:Unioniade is a species-rich family of freshwater mussels with an almost worldwide distribution. In Central European rivers Unio crassus, Unio tumidus and Unio pictorum have relatively high populations. In order to characterize the habitats of these suspension feeders, their nutrient supply and potential metal contaminants were investigated in near-bottom suspended (NBS) sediments and bottom sediments (BS) collected at four sampling locations along the Tisza River.Methods: The grain size distribution of sediments was determined by laser-diffraction technique. The total organic carbon (TOC) and the total Kjeldahl nitrogen (TN) were measured by a TOC analyzer and automated colorimetry, respectively. The phosphorous and metal concentrations were determined by inductively coupled plasma mass spectrometry following a microwave assisted acidic extraction of sediments with aqua regia.Results: The NBS sediments contained smaller grains than the BS samples, with roughly 85%–90% of the particles being less than 60 μm, allowing these mussels to catch them. Contrarily, only 2.47%–51.8% of BS samples were less than 60 μm. The NBS sediments contained 30, 23, and 15% more organic carbon, nitrogen, and phosphorous, respectively, than the BS samples. The rounded C:N:P molar ratios in the NBS sediments were 60:4:1, whereas they were 45:3:1 in the bottom sediments. The concentration of metals was also greater in the NBS sediments with the exception of Zn at Tokaj and Fe, Al, Mn, and Cr at Szeged, where prior contaminations transported by the tributaries Bodrog and Maros are stored in the top 10 cm of BS.Discussion: On basis of the measured C:N:P molar ratios it can be stated that soil-derived organic materials are the main sources of the nutrient elements in the habitats of suspension feeders in the Tisza River. The finer NBS sediments have higher specific surface area than the BS and thereby contain more biofilms on the grains resulting in higher proportion of organic nutrients and metal ions bounded as complexes or chelates. Comparing the measured metal concentrations of sediments with the concentration limits summarized in the Consensus-Based Sediment Quality Guidelines developed for evaluation of potential risk of metal contaminants in sediments for the benthic-dwelling organisms, it can be established that only the Hg concentration exceeded the probable effect concentration.

Limited Effectiveness of Carbonaceous Sorbents in Sequestering Aged Organic Contaminants in Sediments.

Carbonaceous materials are often proposed for use in restoring soils or sediments contaminated with hydrophobic organic contaminants (HOCs). However, the contamination of most sites is a result of historical events, where HOCs have resided in the solid compartment for many years or decades. The prolonged contact time, or aging, leads to reduced contaminant availability and likely diminished effectiveness of using sorbents. In this study, three different carbonaceous sorbents, i.e., biochars, powdered activated carbon, and granular activated carbon, were amended to a Superfund site marine sediment contaminated with DDT residues from decades ago. The amended sediments were incubated in seawater for up to 1 year, and the freely dissolved concentration (Cfree) and the biota-sediment accumulation factors (BSAFs) for a native polychaete (Neanthes arenaceodentata) were measured. Even though the bulk sediment concentrations were very high (6.4-154.9 μg/g OC), both Cfree and BSAFs were very small, ranging from nd to 1.34 ng/L and from nd to 0.024, respectively. The addition of carbonaceous sorbents, even at 2% (w/w), did not consistently lead to reduced DDT bioaccumulation. The limited effectiveness of carbonaceous sorbents was attributed to the low DDT availability due to prolonged aging, highlighting the need for considering contaminant aging when using sorbents for remediation.

Characterization of Manganese Oxide Modified Activated Carbon for Remediation of Redox-Sensitive Contaminants

Manganese oxide modified activated carbon (MOMAC) was synthesized as a novel in situ sediment and soil amendment for treatment of redox-sensitive contaminants, such as mercury (Hg), through buffering of reduction–oxidation (redox) potential and sorption. This study characterized MOMAC synthesis products at three different Mn concentrations on activated carbon (AC) surfaces and compared them with homogeneously precipitated Mn oxide (MnOx) and unmodified AC for properties influencing redox buffering and sorption capacity. Bulk spectroscopic analyses (XAS and XPS), XRD, and electron microscopy showed that homogeneous MnOx matched the local structure of vernadite (δ-Mn(IV)O2), while MOMAC formed aggregates on the AC surface composed mostly of vernadite with fractions of manganite (γ-Mn(III)OOH) (17–46%) and sorbed Mn(II) (11–21%). Higher bulk surface area and lower Mn average oxidation state were associated with MOMAC and are attributed to the reduction of Mn(IV) by Mn(II) adsorbed on AC or diffused into AC pores. Cation exchange reactions of Na+ and Ca2+ also contributed to Mn oxidation state changes by driving disproportionation of Mn(III) to Mn(II) and Mn(IV). In batch slurry experiments with and without Hg-contaminated sediment from Oak Ridge National Laboratory (TN, U.S.A.), addition of MOMAC and MnOx resulted in higher solution redox potential and lower pH compared to AC and no-amendment controls. MnOx poised solution redox at higher potential than MOMAC, but MOMAC was more effective at sorbing Hg released by the oxidation of sediment HgS(s), Hg0, and/or organic-associated Hg. By combining redox buffering with sorption, MOMAC is a promising in situ amendment that may efficiently target redox-sensitive contaminants in aquatic sediments.

Isotopic signatures unveil the lead sources and migration in surface mangrove sediments

Mangrove sediments act as both sinks and secondary sources for lead (Pb), yet the sources, migration, and transformations of Pb in mangrove environments are poorly understood. In this study, Pb concentration in three mangrove sediments adjacent to different land-use types was evaluated. The Pb sources were quantitatively identified using Pb isotopes. Our data indicated minor Pb contamination in the mangrove sediments, possibly due to the relative lack of developed industry in this region. The Pb isotopic ratios suggested, on average, natural sources, coal combustion, agricultural activities, and traffic-related emissions respectively contributed approximately 61.4 %, 18.8 %, 14.0 %, and 5.8 % of the Pb accumulation in the mangrove sediments, suggesting that coal combustion and agriculture were important anthropogenic Pb sources. Significant relationships were observed between the 206Pb/207Pb ratios and total organic content (TOC) in mangrove sediments, which implied contrasting Pb cycling in two mangrove environments. We further suggested that organic matter and sulfur content significantly reduced Pb mobility and bioavailability in mangrove sediments. Our study provides isotopic method to investigate the Pb sources and migration in the mangrove environment.

Evaluation of human health and ecological risk of heavy metals in water, sediment and shellfishes in typical artisanal oil mining areas of Nigeria.

Heavy metal contamination in water and sediment is a serious concern in nations that depend heavily on natural resources such as Nigeria. In most coastal communities around oil mining areas in Nigeria, drinking water quality, staple food, and livelihoods are primarily dependent on ecological systems and marine resources (e.g., fish). Thus, humans and other receptors are exposed to heavy metal risks through ingestion and dermal contact. This research evaluated the potential ecological risks of heavy metals including Cadmium (Cd), Chromium (Cr), Nickel (Ni), and Lead (Pb) in water, sediments, and shellfishes (Callinectes amnicola, Uca tangeri, Tympanotonus fuscatus, Peneaus monodon) along the Opuroama Creek in Niger Delta, Nigeria. The concentrations of heavy metals were measured in three stations using the Atomic Absorption Spectrophotometer and their relative ecological (geo-accumulation index and contamination factor) and human health risk (hazard index and hazard quotient) analysed. The toxicity response indices of the heavy metals indicate that the sediments pose significant ecological risk particularly with Cd. None of the three exposure pathways to heavy metals in the shellfish muscles and age groups pose a non-carcinogenic risk. Total Cancer Risk values for Cd and Cr exceeded the acceptable range (10-6 to 10-4) established by USEPA in children and adults, raising concerns of potential cancer risks following exposure to these metals in the area. This established a significant possibility of heavy metal risks to public health and marine organisms. The study recommends conducting in-depth health analysis and reducing oil spills while providing sustainable livelihoods to the local population.

Evaluation potentiality of Rhizophora mucronata plantation for pollutants remediation on the Red Sea Coast, Egypt

The planted Rhizophora mucronata was evaluated in two plant ages (one year and eight years) as a biological tool for reducing the mobility of heavy metals in sediments in Safaga and Hamata, Red Sea Coast, Egypt. It is an important region for tourism and nature reserves; however, this area suffers from various anthropogenic contaminants. The ability of mangrove plantations to reduce sediment contamination through bioaccumulation, phytostabilization, or phytoextraction must be clarified through the investigation of metal behavior in mangrove plants and sediments. All of the studied heavy metals had significantly higher concentrations in the Safaga site's sediments. Elder plants had much lower levels of heavy metals in their sediments than younger plants, also rhizosphere samples were less contaminated than non-rhizosphere ones. The order of remediation efficiency was Mo > Ni > Mn ≥ Co > Al > Cu > Zn ≥ Cr > Fe > V, where the highest % was 99.25, 58.97, 42.64, 42.48, 41.91, 39.47, 37.93, 37.01, 36.89, and 29.44, respectively. R. mucronata parts were more significantly contaminated with Co, Cr, Cu, Mo and Zn in Safaga site, while at the Hamata site, they were more significantly contaminated with Al, Fe, Mn, Ni, and V. The elder plants accumulated higher concentrations than younger ones and the contents of heavy metals in plant samples followed the order of root > aerial roots > shoot. Bioconcentration factor (BCF) values representing the accumulation efficiency of R. mucronata were Ni > Mo > Zn > Cu > Cr > Co > Mn ≥ Al > V > Fe, where their highest values were 17.74, 7.89, 3.95, 3.84, 2.66, 1.91, 1.67, 1.66, 1.6, 1.18, respectively. BCF values exceeded one for all metals and values of translocation factor (TF) were less than unity in all cases, thus Rhizophora mucronata can be considered as a good phytostabilizer of ten studied heavy metals able to reduce their mobility through accumulation by roots, thereby reducing off-site contamination.

Ecological risk characteristics of sediment-bound heavy metals in large shallow lakes for aquatic organisms: The case of Taihu Lake, China

Heavy metal contamination in the surface sediments of large shallow lakes in China is becoming increasingly serious. However, more attention has been paid to the human health risk of heavy metals in the past, while little consideration has been given to aquatic organisms. Taking Taihu Lake as an example, we explored the spatial and temporal heterogeneity of the potential ecological risks of seven heavy metals (Cd, As, Cu, Pb, Cr, Ni, and Zn) to species at different taxonomic scales using an improved species sensitivity distribution (SSD) method. The results showed that all six heavy metals, except Cr, were exceeded to some extent compared to background levels, with Cd being the most severe exceedance. Based on the hazardous concentration for 5% of the species (HC5), Cd had the lowest HC5 value, implying the highest ecological risk of toxicity. Ni and Pb had the highest HC5 values and the lowest risk. Cu, Cr, As and Zn were at a relatively moderate levels. For the different groups of aquatic organisms, the ecological risk of most heavy metals was generally lower for vertebrates than for the whole species. The risk for invertebrates and algae was higher than that for all species. Zn and Cu had the highest potentially affected fractions (PAFs) for all classification cases, with mean PAFs of 30.25% and 47.2%, respectively. Spatially, the high ecological risk of sediment heavy metals was significantly related to the spatial characteristics of the type and intensity of human activities in the catchment. Administratively, the environmental quality standards for freshwater sediments proposed by America and Canada are insufficient to protected against the ecological risks of heavy metals in Taihu Lake. In the absence of such standards, China urgently needs to establish an approptiate system of environmental quality standards for heavy metals in lake sediments.

Hot and heavy: Responses of ragworms (Hediste diversicolor) to copper-spiked sediments and elevated temperature

Sediment contamination and seawater warming are two major stressors to macrobenthos in estuaries. However, little is known about their combined effects on infaunal organisms. Here we investigated the responses of an estuarine polychaete Hediste diversicolor to metal-contaminated sediment and increased temperature. Ragworms were exposed to sediments spiked with 10 and 20 mg kg−1 of copper at 12 and 20 °C for three weeks. No considerable changes were observed in the expression of genes related to copper homeostasis and in the accumulation of oxidative stress damage. Dicarbonyl stress was attenuated by warming exposure. Whole-body energy reserves in the form of carbohydrates, lipids and proteins were little affected, but the energy consumption rate increased with copper exposure and elevated temperature, indicating higher basal maintenance costs of ragworms. The combined effects of copper and warming exposures were mostly additive, with copper being a weak stressor and warming a more potent stressor. These results were replicable, as confirmed by two independent experiments of similar settings conducted at two different months of the year. This study suggests the higher sensitivity of energy-related biomarkers and the need to search for more conserved molecular markers of metal exposure in H. diversicolor.

An Assessment of Southeast United States Headwater Tidal Creek Sediment Contamination Over a Twenty-Year Period in Relation to Coastal Development.

Headwater tidal creeks are a primary link between estuarine and upland habitats, serving as conduits for runoff. They are sentinel habitats, providing early warning of potential harm, thus ideal systems to evaluate the effects of coastal suburban and urban development on environmental quality. Estuarine sediments have concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) that are associated with human activity. High concentrations of contaminants can impair faunal communities, habitat quality, and ecosystem function. Forty-three headwater creeks were sampled between 1994 and 2006 to assess contaminants, and 18 of these were sampled again in 2014/2015. Watersheds were classified as forested, forested to suburban, suburban, or urban land. These values are based on their percent impervious cover (IC) levels and change in IC from 1994-2014. Analyses of temporal data resulted in significant relationships between IC and select metals, PAHs, pesticides, PCBs, and PBDEs. In addition, 11 of the creeks sampled in 2014/2015 have paired data from 1994/1995, allowing for change analysis over the 20 years. Results indicated increasing chemical contamination occurring with increasing levels of development, although only PAHs and total dichloro-diphenyl-trichloroethane (DDT) exhibited a statistically significant increase over time; PAHs also exhibited significantly higher concentrations in developed creeks. Additionally, several metals were deemed enriched in developed creeks based on reference conditions. These results expand our knowledge of how these systems respond to urban development and can inform managers about how human population growth along coastlines may predict altered tidal creek health.

Assessment of contamination of marine sediments and their potential toxicity in the Uglovoy Bay, Peter the Great Gulf, Sea of Japan/East Sea.

The content of harmful heavy metals in the bottom sediments of the Uglovoy Bay (Peter the Great Gulf, Sea of Japan/East Sea) was studied based on the surveys carried out in 2016-2021. The contamination of the sediments in the bay was compared to the background concentrations of elements and to common contamination indices. The degree of contamination was calculated using the contamination factor (Cf), modified overall degree of contamination (mCd), and index of geoaccumulation (Igeo). The toxicity of marine sediment samples for each metal was evaluated using the threshold effect level/probable effect level (TEL/PEL) values and the sediment quality guideline quotient (SQG-Q). The sources of pollutants entering the studied water area were analyzed. It is shown that the contamination of the Uglovoy Bay occurs continuously as a result of economic activities on its coast. The dynamics of contamination of the bay for the period 2016-2021 is presented.

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

The impact of population expansion through economic growth and development has been identified as one of the key drivers of both water and sediment contamination from potentially harmful elements (PHEs). This presents a major hazard not only to aquatic ecosystems but local riparian communities and beyond who rely heavily on this natural resource for drinking water and fish—a valuable source of dietary micronutrients and protein. The present study measured biogeochemical concentration of PHEs in water, sediment and fish from locations pooled into four zones within Winam Gulf and Lake Victoria area of Kenya. Captured fish were used as a sentinel receptor of lake health to evaluate potential risks to fisheries and aquaculture food security. In water, concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) were observed above the United States Environmental Protection Agency (US EPA) maximum contamination level drinking water guidelines (MCL), with aluminium (Al) observed above the Aquatic Life Criteria in all four zones. Similarly, sediment concentrations in all four zones exceeded the US EPA Effects range low (ERL) threshold guidelines for Cu, nickel (Ni), zinc (Zn) and Pb, with Cu, Zn and Pb classed at moderate contamination levels using the contamination factor. Fish tissue concentrations from the four zones were calculated using recommended daily intakes (RDI) and for PHEs as provisional maximum tolerable intakes (PMTIs) and indicated most macro- and micronutrients were at or below 10% RDI from aquaculture and wild fish, with Se indicating a greater RDI (16–29%) in all the zones. Contributions of PHEs to PMTIs were below threshold guidelines for both aquaculture and wild fish with only Cd, Cr and Pb levels being above the PMTI thresholds. There is a need to assess the long-term effects of persistent anthropogenic PHE input into Winam Gulf and the wider Lake Victoria basin. Continued monitoring of PHEs using both historical and more recent data will enable future management policies to be implemented through improved mitigation strategies to reduce their impact on water quality, fish health and subsequent human health.

Assessment of heavy metals contamination of sediments and surface waters of Bitter lake, Suez Canal, Egypt: Ecological risks and human health

The concentrations of heavy metals in the surface waters and sediments of Bitter Lake were investigated to assess the level, distribution, and source of pollution and the associated ecological and human health risks. The ecological indices of the lake water indicate low contamination degrees by heavy metals. A dermal exposure-based health risk evaluation revealed no carcinogenic or non-carcinogenic impact on human health. The contamination factor (CF) for Cu, Ni, Pb, Mn, Fe, and Zn (CF < 1) indicate low contamination levels, while Cd reaches very high contamination in most sediment sites (CF ranges from 6.2 to 72.4). Furthermore, the potential ecological risk factor (Eri) and modified hazard quotient (mHQ) indicate low ecological risk for all metals except Cd, revealing high to very high-level ecological risk in most sites (Eri ranges from 185 to 2173 and mHQ from 1.8 to 6.3). This emphasizes the urgency of prompt actions to improve the environment in Bitter Lake.

Sources of contamination in sediments of retention tanks and the influence of precipitation type on the size of pollution load

Densification of cities and urban population contributes to increased runoff and suspended solids and alteration of the urban water cycle. Nowadays, Blue-Green Infrastructure is promoted to increase a city’s resilience to floods; however, stormwater drainage systems, supported with retention tanks are still important in protecting urban areas against floods. Sediment accumulation in stormwater infrastructure relates to an issue of pollutants such as heavy metals, nutrients etc. Research on the origin of the pollutants associated with the suspension and ultimately sediment accumulated in sewage can bring new insights about processes in urban catchment areas. This is the first study, which is focused on the analysis of stable carbon and nitrogen isotopes in bottom sediments collected from municipal retention tanks to verify the origin of the deposited pollutants immediately after pluvial floods. The research was additionally extended with water quality analyzes immediately after three types of weather: a dry period, typical precipitation (< 30 mm) and torrential rainfalls (2 events with daily precipitation over 30 mm which caused pluvial flooding of the city area). Analyses of sediments indicated that the main source of carbon and nitrogen in the bottom of the retention tanks had been brought with stormwater runoff from the city area. Organic nitrogen fertilizers appeared to be the main source of nitrogen, while the sources of organic carbon were mixed: C3 land plants, wood, and oil. Additionally, it was found that torrential rainfall caused a 23-fold increase of N-NO3 concentration, a sevenfold increase of P-PO4 concentration, and an over fivefold increase of concentration of organic matter, in comparison to typical precipitation.

Assessment of filter subsampling and extrapolation for quantifying microplastics in environmental samples using Raman spectroscopy

A common method for characterizing microplastics (MPs) involves capturing the plastic particles on a filter after extraction and isolation from the sediment particles. Microplastics captured on the filter are then scanned with Raman spectroscopy for polymer identification and quantification. However, scanning the whole filter manually using Raman analysis is a labor-intensive and time-consuming process. This study investigates a subsampling method for Raman spectroscopic analysis of microplastics (operationally defined here as 45–1000 μm in size) present in sediments and isolated onto laboratory filters. The method was evaluated using spiked MPs in deionized water and two environmentally contaminated sediments. Based on statistical analyses, we found quantification of a sub-fraction of 12.5 % of the filter in a wedge form was optimal, efficient, and accurate for estimating the entire filter count. The extrapolation method was then used to assess microplastic contamination in sediments from different marine regions of the United States.

Elemental pollution status of different components of Ologe Lagoon, Lagos, Nigeria

Abstract This study evaluated the concentrations and distributions of nutrient and non-nutrient elements in water, sediment, mud, and vegetation of Ologe Lagoon, Lagos, Nigeria. Nutrient elements including Na, Ca, K, and Mg were found in high concentration values in the different components of the freshwater ecosystem. While the water had the least concentration of the elements, Trapa natans had the highest. Aluminium showed similar distribution patterns in the different components, except for T. natans. All the samples correlated significantly with water (p &amp;lt;0.05). Both the sediment and mud showed low potential ecological risk indexes of 5.3 and 5.92, respectively. Copper had the highest ecological risk with respect to single regulator indexes in the mud and sediment, notwithstanding its low concentration in the two components. Pollution indices suggested the low severity of non-nutrient elemental contamination of water, sediment, mud, and vegetation of Ologe Lagoon, and therefore, it is safe for human consumption, but not for agricultural irrigation. Pistia stratiotes and T. natans showed potentiality for use as photo-stabilisers and phytoremediators for some of the elements. The presence of radionuclides and rare earth elements in the components of Ologe Lagoon are instructive for specific policy initiatives to mitigate their effects on the population.

PFAS surveillance in abiotic matrices within vital aquatic habitats throughout Florida

Per- and polyfluoroalkyl substances (PFAS) are a group of manufactured chemicals that are resistant to degradation and thus persistent in the environment. The presence, uptake, and accumulation of PFAS is dependent upon the physiochemical properties of the PFAS and matrix, as well as the environmental conditions since the time of release. The objective of this study was to measure the extent of PFAS contamination in surface water and sediment from nine vulnerable aquatic systems throughout Florida. PFAS were detected at all sampling locations with sediment exhibiting greater PFAS concentrations when compared to surface water. At most locations, elevated concentrations of PFAS were identified around areas of increased human activity, such as airports, military bases, and wastewater effluents. The results from the present study highlight the ubiquitous presence of PFAS in vital Florida waterways and filled an important gap in understanding the distribution of PFAS in dynamic, yet vulnerable, aquatic environments.

Ecological and health risk assessment of heavy metals contamination in mangrove sediments, Red Sea coast

Due to the significance of mangroves for the diversity of marine and terrestrial life along the Red Sea coast, the present work aimed to evaluate the environmental and health risk of heavy metals in Wadi el-Gemal sediments. The findings of single and integrated indices demonstrated no significant pollution with Fe, Cu, Zn, Ni, Co, and Cd, while the sediments showed severe and minor enrichment with Mn and Cd, respectively, which might be attributed to the presence of some mining activities in the mountains near the study area. The possible carcinogenic and non-carcinogenic risks due to their dermal absorption from the sediments were analyzed and the findings demonstrated that the non-carcinogenic health hazards were within tolerable and safe limits. Moreover, the evaluation of chronic daily intake and the overall cancer risk (LCR) for adults and children for Pb and Cd both ruled out any current potential carcinogenic health risks.