SEGH Articles

Spatial distribution of Pb, Cd and Cr concentrations in moss transplants from urban recreational areas in Lisbon, Portugal

03 December 2012
Metal concentrations in moss were used to assess the contribution of atmospheric pollution to the geochemistry of soil and ground-level dust, and discriminate urban pollution sources.

Sofia Bartolomeu is currently a final year Master student in Meteorology and Oceanography Physics at University of Aveiro, Portugal. She was a Poster Winner at the 9th ISEG meeting in Aveiro, Portugal in July. She is currently working on the “Geochemical survey of Lisbon urban soils” project at the Geosciences Department of the University of Aveiro, supervised by Dr. Paula Marinho. The main aim of her study was to report on spatial patterns for some metal concentrations in moss transplants that were exposed to the urban ambient air in public recreational areas in Lisbon. Metal concentrations in the moss were used to assess the contribution of atmospheric pollution to the geochemistry of soil and ground-level dust, and discriminate urban pollution sources.

Owing to their ability to accumulate heavy metals, mosses are especially suitable to monitor heavy metal airborne pollution. Heavy metals are taken up very fast due to the lack of an epidermis and a cuticle, and they have a large surface-to-weight ratio.

This study presents results from a project entitled “Geochemical survey of Lisbon urban soils: a baseline for future human health studies”, and the main aims are (1) to report on spatial patterns for Pb, Cd and Cr concentrations in moss transplants from public recreational areas in Lisbon; (2) to compare such patterns with those of soil and ground-level dust. Fifty one topsoil and ground-level dust samples were collected in playgrounds, schoolyards, urban parks, public gardens, road-side and airport of Lisbon. At each site, 1 uncontaminated moss transplant was fixed to a horizontal tree limb, which remained in situ for a period of 6 months. Only 44 moss samples were recovered from site. The selected moss species was the Hypnum cupressiforme Hedw and the green part was used for analysis of Pb, Cd and Cr by ICP-MS.

 

For Pb, the results show that concentrations are high, range from 7.2-75.1 mg kg-1 and the higher values occur in the older part of the city. Lead emissions are mainly related to traffic and the physiographic characteristics of the old city explain the higher Pb concentrations in the moss. The element has a similar spatial distribution in soils and dusts, suggesting that airborne Pb-particles settle in the topsoil. For Cd, the results show that concentrations are low, range from 0.08-0.44 mg kg-1 and the spatial distribution is irregular, indicating point sources. However, the airport moss samples have the highest Cd concentrations. Also soil and dust samples form the airport have the highest Cd concentrations, which suggest that air-traffic is a source of Cd in the city. For Cr, the results show that concentrations range from 1.6-8.9 mg kg-1 and the higher values occur in the old city. Soils and dust show different distribution patterns, perhaps due to the fact that in the city Cr has an important geogenic source. 

In conclusion and despite the fact that by its location on the Atlantic coast and winds regime, high levels of pollutants are uncommon in Lisbon, the biomonitoring survey indicates that Pb emissions are probably traffic related, are still significant and have an higher environmental impact in the old city where the housing density is higher, the streets are narrow and have strong slopes, and the traffic is quite intense. Concentrations of Cd and Cr are quite lower and metal-laden airborne particles do not seem to be a significant source to the urban soils.

 

Sofia Bartolomeu

Physics Department, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal, 1. sofiabartolomeu@ua.pt

Keep up to date

SEGH Events

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

  • Biochar-based constructed wetlands to treat reverse osmosis rejected concentrates in chronic kidney disease endemic areas in Sri Lanka 2017-12-01

    Abstract

    The objectives were to investigate the potential remedial measures for reverse osmosis (RO) rejected water through constructed wetlands (CWs) with low-cost materials in the media established in chronic kidney disease of unknown etiology (CKDu) prevalent area in Sri Lanka. A pilot-scale surface and subsurface water CWs were established at the Medawachchiya community-based RO water supply unit. Locally available soil, calicut tile and biochar were used in proportions of 81, 16.5 and 2.5% (w/w), respectively, as filter materials in the subsurface. Vetiver grass and Scirpus grossus were selected for subsurface wetland while water lettuce and water hyacinth were chosen for free water surface CWs. Results showed that the CKDu sensitive parameters; total dissolved solids, hardness, total alkalinity and fluoride were reduced considerably (20–85%) and most met desirable levels of stipulated ambient standards. Biochar seemed to play a major role in removing fluoride from the system which may be due to the existing and adsorbed K+, Ca+2, Mg+2, etc. on the biochar surface via chemisorption. The least reduction was observed for alkalinity. This study indicated potential purification of aforesaid ions in water which are considerably present in RO rejection. Therefore, the invented bio-geo constructed wetland can be considered as a sustainable, economical and effective option for reducing high concentrations of CKDu sensitive parameters in RO rejected water before discharging into the inland waters.

  • Medical geology of endemic goiter in Kalutara, Sri Lanka; distribution and possible causes 2017-12-01

    Abstract

    This study assesses the distribution of goiter in the Kalutara District, Sri Lanka in order to find causative factors for the occurrence of goiter even after the salt iodization. A questionnaire survey was conducted at the household level and at the same time iodine and selenium levels of the water sources were analyzed. Questionnaire survey results indicated the highest numbers of goiter patients in the northern part where the lowest were found in the southern sector which may be due to the presence of acid sulfate soils. Females were more susceptible and it even showed a transmittance between generations. Average iodine concentrations in subsurface water of goiter endemic regions are 28.25 ± 15.47 μg/L whereas non-goiter regions show identical values at 24.74 ± 18.29 μg/L. Surface water exhibited relatively high values at 30.87 ± 16.13 μg/L. Endemic goiter was reported in some isolated patches where iodine and selenium concentrations low, latter was <10 μg/L. The formation of acid sulfate soils in the marshy lands in Kalutara district may lead to transformation of biological available iodine oxidation into volatile iodine by humic substances, at the same time organic matter rich peaty soil may have strong held of iodine and selenium which again induced by low pH and high temperature were suggested as the instrumental factors in the endemic goiter in Kalutara district. Hence, geochemical features such as soil pH, organic matter and thick lateritic cap in the Kalutara goiter endemic area play a role in controlling the available selenium and iodine for food chain through plant uptake and in water.

  • Nickel accumulation in paddy rice on serpentine soils containing high geogenic nickel contents in Taiwan 2017-12-01

    Abstract

    We investigated the extractability of nickel (Ni) in serpentine soils collected from rice paddy fields in eastern Taiwan to evaluate the bioavailability of Ni in the soils as well as for demonstrating the health risks of Ni in rice. Total Ni concentrations in the soils ranged were 70.2–2730 mg/kg (mean, 472 mg/kg), greatly exceeding the natural background content and soil control standard in Taiwan. Available Ni concentration only accounts for <10% of total soil Ni content; 0.1 N HCl-extractable Ni was the more suitable index for Ni bioavailability in the soil to rice than was diethylenetriaminepentaacetic acid (DTPA)-extractable Ni. The accumulation ability of rice roots was much higher than that of its shoots; however, compared with those reported previously, our brown and polished rice samples contained much higher Ni concentrations, within the ranges of 1.50–4.53 and 2.45–5.54 mg/kg, respectively. On the basis of the provisional tolerable Ni intake for adults recommended by the World Health Organization (WHO), daily consumption of this rice can result in an excessive Ni intake.