SEGH Articles

The relationship between heavy metals and sedimentary organic matter in the Oxford Clay (Jurassic) of the southern UK

03 December 2012
Pin Ru is studying for a PhD in sedimentary organic matter and its interaction with waste in landfill sites

Pin Ru is studying for a PhD studies (2009-present) in sedimentary organic matter and its interaction with waste in landfill sites at the University of Southampton in the UK. This is supervised by Prof. John Marshall and Dr. Clive Trueman of the School of Ocean and Earth Sciences and Prof. William Powrie, Dr David Smallman and Dr Anne Stringfellow from the School of Civil Engineering and the Environment. She was a poster winner at the 9th ISEGH meeting in Aveiro, Portugal, July 2012.

The Oxford Clay is an organic rich sediment widely distributed across the southern UK. It has been widely used for brick making and this has led to the many former pits being used as landfill sites. Some of the more modern sites are now specifically excavated for landfill. Although it has excellent retention properties for landfill it occurs above the minor aquifer of the Kellaways Sand. This must not become contaminated. Heavy metals are relatively abundant in the Oxford Clay and the waste water that drains from the landfill sites. It is very important to understand the source of these metals as to their source from either the Oxford Clay or the landfill. It is also important to understand how these metals might interact with the organic matter in the Oxford Clay.

 

This investigation has determined the distribution of organic matter through a cored section of Oxford Clay from a landfill site. Analyses include TOC%(Total organic carbon contain), visual kerogens in transmitted light and the phytoclast component in reflected light. TOC% enables us to determine the boundary between the Oxford Clay and Kellaways Sand. Changes in quartz size and the percentage of clay and quartz confirm this determination. The organic matter found in rock is mainly phytoclasts (vitrinite and semifusinite), pollen and AOM (amorphous organic matter). Point counts shows that AOM dominates all samples. Heavy metals including V, Cr, Co, Cu, Ni, As, Zn were analysed to compare with the organic matter data. Phytoclasts have been regarded as particularly important on account of their presumed interaction with metals from groundwater. In addition to organic petrology the distribution of selected heavy metals through parts of the core and within different organic and mineral fractions of single samples has also been investigated. This variation of different metal ions concentration implies a link between TOC% and AOM percentage.

For clarifying the relationship between heavy metals and various factors, iron content,TOC%, AOM%, Clay% and Pyrite% are measured in order to compare with heavy metals abundance. In the Oxford Clay, copper is richer in the AOM, while Arsenic appears richer in pyrite. Cobalt, Nickel and Chromium have higher contents in the AOM than in pyrite. The zinc concentration fluctuates between pyrite and AOM and may be linked with sphalerite occurrence. More samples are being analyzed to confirm the correlation of heavy metals in the Kellayways Sand.

Pin Ru

University of Southampton, UK

Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Exposure to respirable and fine dust particle over North-Central India: chemical characterization, source interpretation, and health risk analysis 2019-12-10

    Abstract

    This study enhances the understanding of the particulate matters (PM2.5 and PM10) and their physical and chemical behavior over the Taj Mahal, Agra, in North-Central India. The mass concentration was determined, and the shape and size of the particles and chemical characterizations have been carried out using SEM–EDX. The high level and significant variation of PM10 (162.2 µg m−3) and PM2.5 (83.9 µg m−3) were observed. The exceedance factor of the present study region is in critical and moderate condition. Morphological characterization reveals the particles of different shapes and sizes, while elemental analysis shows the presence of Si, Al, Fe, Ca, K, Cl, Mg, Na, Cu, and Zn. The dominance of Si indicated the contribution of natural sources, i.e., soil over this region. Three significant sources, viz. soil/road paved dust/vegetative emissions, vehicular/industrial emissions, and intermingling of dust and combustion particles, have been identified using principal component analysis over North-Central India. Health risk analysis of particulate matter identified carcinogenic and non-carcinogenic metals in the present study, which comes in contact with human beings during inhalation. The non-carcinogenic risk was much higher than the acceptable level. The high carcinogenic risks were found in Zn in PM10 and Cu in PM2.5 for both children and adults.

  • Integration of remote sensing data and in situ measurements to monitor the water quality of the Ismailia Canal, Nile Delta, Egypt 2019-12-10

    Abstract

    The Ismailia Canal is one of the most important tributaries of the River Nile in Egypt. It is threatened by extinction from several sources of pollution, in addition to the intersection and nearness of the canal path with the Bilbayes drain and the effluent from the two largest conventional wastewater treatment plants in Greater Cairo. In this study, the integration of remote sensing and geospatial information system techniques is carried out to enhance the contribution of satellite data in water quality management in the Ismailia Canal. A Landsat-8 operational land imager image dated 2018 was used to detect the land use and land cover changes in the area of study, in addition to retrieving various spectral band ratios. Statistical correlations were applied among the extracted band ratios and the measured in situ water quality parameters. The most appropriate spectral band ratios were extracted from the NIR band (near infrared/blue), which showed a significant correlation with eight water quality metrics (CO3, BOD5, COD, TSS, TDS, Cl, NH4, and fecal coliform bacteria). A linear regression model was then established to predict information about these important water quality parameters along Ismailia Canal. The developed models, using linear regression equations for this study, give a set of powerful decision support frameworks with statistical tools to provide comprehensive, integrated views of surface water quality information under similar circumstances.

  • Geophagy among East African Chimpanzees: consumed soils provide protection from plant secondary compounds and bioavailable iron 2019-12-01

    Abstract

    Geophagy, the intentional consumption of earth materials, has been recorded in humans and other animals. It has been hypothesized that geophagy is an adaptive behavior, and that clay minerals commonly found in eaten soil can provide protection from toxins and/or supplement micronutrients. To test these hypotheses, we monitored chimpanzee geophagy using camera traps in four permanent sites at the Budongo Forest Reserve, Uganda, from October 2015–October 2016. We also collected plants, and soil chimpanzees were observed eating. We analyzed 10 plant and 45 soil samples to characterize geophagic behavior and geophagic soil and determine (1) whether micronutrients are available from the soil under physiological conditions and if iron is bioavailable, (2) the concentration of phenolic compounds in plants, and (3) if consumed soils are able to adsorb these phenolics. Chimpanzees ate soil and drank clay-infused water containing 1:1 and 2:1 clay minerals and > 30% sand. Under physiological conditions, the soils released calcium, iron, and magnesium. In vitro Caco-2 experiments found that five times more iron was bioavailable from three of four soil samples found at the base of trees. Plant samples contained approximately 60 μg/mg gallic acid equivalent. Soil from one site contained 10 times more 2:1 clay minerals, which were better at removing phenolics present in their diet. We suggest that geophagy may provide bioavailable iron and protection from phenolics, which have increased in plants over the last 20 years. In summary, geophagy within the Sonso community is multifunctional and may be an important self-medicative behavior.