Topsoil and urban dust pollution and toxicity in Taranto (southern Italy) industrial area and in a residential district

Our plain-English summary of Topsoil and urban dust pollution and toxicity in Taranto (southern Italy) industrial area and in a residential district, by M. Trifuoggi, G. Pagano, R. Oral, et al (Environmental Monitoring and Assessment, 2018).

The study

• Authors: M. Trifuoggi, G. Pagano, R. Oral, M. Gravina, M. Toscanesi, M. Mozzillo, A. Siciliano, P. Burić, D.M. Lyons, A. Palumbo, P.J. Thomas, L. D'Ambra, A. Crisci, M. Guida, F. Tommasi
• Journal: Environmental Monitoring and Assessment
• Published: 2018;191(1):43
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Adverse environmental conditions in the Taranto area (southern Italy) were investigated in studies of air, marine sediment, and human health. The present study aimed at providing unprecedented information on soil pollution and toxicity in a set of sites around recognized pollution sources in the Taranto area, since previous studies were focused on marine or air pollution, or on human health effects. The investigated area included a steel foundry and a power plant, as well as some sites located in an adjacent neighborhood. Surface soil samples and urban dust were collected and submitted to inorganic and organic analyses and tested for toxicity in two invertebrate bioassay models; a sea urchin (Sphaerechinus granularis) and an annelid (Caenorhabditis elegans). Inorganic analysis was carried out using ICP-MS for elemental composition for a total of 34 elements, whose levels were evaluated as a function of bioassay data analyzed through principal component analysis (PCA). Other analyses included asbestos search by powder X-ray diffraction (PXRD) and organic analysis for polycyclic aromatic hydrocarbons (PAHs) and aliphatic compounds (C10-C40). Toxicity bioassays were carried out on a sea urchin (Sphaerechinus granularis), and an annelid (Caenorhabditis elegans). Sea urchin bioassays evaluated effects of topsoil or street dust sample exposures (0.1 to 0.5% dry wt/vol) on developing embryos and on sperm, and scored as (a) % developmental defects, (b) inhibition of fertilization success and offspring damage, and (c) frequencies of mitotic aberrations. C. elegans mortality assay displayed significant toxicity associated with soil samples. The overall effects of samples showed very high toxicity at four out of nine sites. These effects were consistent with the highest levels measured for metals and PAHs. Further studies of health effects related to dust exposures in residential areas are warranted. Graphical abstract ᅟ.

In plain English

This was an environmental study of soil and street dust in the Taranto industrial area of southern Italy. It did not study people. The authors collected six topsoil samples from sites including a steel foundry and a power plant, and three street dust samples from the Tamburi residential neighborhood, home to about 18,000 inhabitants. They measured metals, hydrocarbons and PAHs, searched for asbestos by X-ray diffraction, and tested toxicity on sea urchin embryos and sperm and on the worm C. elegans. Sites 5 and 6 had the most metal pollution and were the most toxic in both kinds of test. All sites significantly increased worm deaths. PAH levels were low, and the authors found no link between toxicity and hydrocarbons or PAHs. Asbestos was not confirmed. Weak X-ray signals could fit chlorite or srebrodolskite, but serpentine and amphibole asbestos minerals also give signals there, and the authors said higher-resolution studies may be needed. The authors concluded that excess metal levels matched excess toxicity, warranting further investigation and remediation.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Environmental field sampling study with chemical and mineral analysis of soil and dust, plus laboratory toxicity tests on sea urchins and nematode worms
• Who was studied: Nine samples from nine sites in and near the Taranto industrial area (southern Italy). Six were topsoil samples from sites including a steel foundry, oil refinery and power plant. Three were street dust samples from the Tamburi neighborhood (sites 7 to 9), which has about 18,000 inhabitants. The toxicity tests used sea urchins (Sphaerechinus granularis) collected off Rovinj, Croatia, and the nematode Caenorhabditis elegans. The article does not give sampling dates.
• Exposure: Topsoil and street dust containing metals, rare earth elements, total hydrocarbons (C10 to C40) and PAHs. The samples were also searched for asbestos by powder X-ray diffraction. In the tests, sea urchin embryos were exposed to 0.1% suspensions of the samples and sea urchin sperm to 0.5% suspensions. Worms were placed directly in hydrated samples for 24 hours.
• Main results:
  • Sites 5 and 6 showed the highest levels of iron and of total metals other than iron. In Table 1, iron was 5840 mg/kg at site TA6, 5030 mg/kg at TA7 and 4600 mg/kg at TA5.
  • The statistical analysis of the metal data (PCA) characterized sites 5 and 6 by excess levels of Cu, Sn, Mn, Cr, Zn, Fe and Ni. Sites 2, 8 and 4 showed relatively low pollution levels.
  • Total hydrocarbons were highest at site 2, at 2820 mg/kg dry weight. They were lower at sites 3 and 6 (1205 and 1019 mg/kg) and under 700 mg/kg at the other sites.
  • PAHs were highest at site 4, at 6.86 mg/kg. All PAH levels were 7 mg/kg or less, which the authors described as below national limits.
  • X-ray diffraction found mainly calcite and quartz. Weak signals in the 11 to 13 degree range were consistent with chlorite and srebrodolskite, but the authors called that assignment equivocal. They noted that serpentine and amphibole asbestos minerals also give signals in this range. Asbestos was not definitively identified.
  • Sea urchin embryos reared in 0.1% sample suspensions showed significant increases in developmental defects. The increases were highly significant (p less than 0.01) at sites 6, 7 and 8.
  • In sea urchin embryos, reduced cell division and increased cell-division abnormalities were greatest with samples from sites 4 to 9.
  • When sea urchin sperm were exposed to 0.5% suspensions, soil from sites 5 and 6 caused the most harm, both to fertilization and to the offspring.
  • Samples from all sites caused highly significant C. elegans mortality after 24 hours (p less than 10 to the minus 4 to 10 to the minus 6). Sites 5 and 6 were the most toxic.
  • The authors found no relationship between the toxicity test results and the levels of total hydrocarbons or PAHs.
• The authors' conclusion: The authors concluded that the samples showed excess metal levels, in agreement with excess toxicity of the same materials. In their view this warrants further investigation and remediation. They singled out the Tamburi neighborhood as being of particular concern.
• Limitations the authors state:
  • The organic analysis covered only total aliphatic hydrocarbons and PAHs. Other compounds, such as alkylated and halogenated PAHs, were not measured.
  • X-ray diffraction could not definitively identify trace mineral phases, including possible asbestos minerals. The authors said higher-resolution synchrotron studies may be required.

Topics

Medical terms in this study, explained in our Lexicon: X-Ray Diffraction (XRD).

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