Effects of PAHs on meiofauna from three estuaries with different levels of urbanization in the South Atlantic

PeerJ. 2022 Dec 2:10:e14407. doi: 10.7717/peerj.14407. eCollection 2022.

Abstract

Estuarine environments are suggested to be the final receivers of human pollution and are impacted by surrounding urbanization and compounds carried by the river waters that flow from the continent. Polycyclic aromatic hydrocarbons (PAHs) are among the contaminants that can reach estuaries and can directly affect marine conservation, being considered highly deleterious to organisms living in these environments. This research investigated the meiofauna of three estuaries exposed to different levels of urbanization and consequently different levels of PAH concentrations, in order to assess how these compounds and environmental factors affect the distribution, structure and diversity of these interstitial invertebrates. A total of 15 major meiofauna groups were identified, with Nematoda being the dominant taxon (74.64%), followed by Copepoda (9.55%) and Polychaeta (8.56%). It was possible to observe significant differences in all diversity indices studied in the estuaries. With the exception of average density, the diversity indices (richness, Shannon index and evenness) were higher in the reference estuary, Goiana estuarine system (GES). On the other hand, the Timbó estuarine system (TES) had the lowest Shannon index value and richness, while the Capibaribe estuarine system (CES) had the lowest evenness value. The latter two estuaries (TES and CES) presented intermediate and high levels of urbanization, respectively. The ecological quality assessment (EcoQ) in the studied estuaries was classified from Poor to Moderate and the estuary with the lowest demographic density in its surroundings, GES, showed a better ecological quality (Moderate EcoQ). A significant distance-based multivariate linear modelling regression (DistLM) was observed between the environmental variables and the density of the meiobenthic community, where PAHs and pH were the main contributors to organism variation. The sediments were characterized by predominance of very fine sand and silt-clay in the most polluted environments, while the control site environment (GES) was dominated by medium grains. The highest concentrations of PAHs were found in the most urbanized estuaries, and directly affected the structure of the interstitial benthic community. The metrics used in the present study proved to be adequate for assessing the environmental quality of the investigated estuaries.

Keywords: EcoQ; Ecological quality status; Pollution; Sediment quality; Tropical estuary.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Environmental Monitoring
  • Estuaries
  • Geologic Sediments / chemistry
  • Humans
  • Polycyclic Aromatic Hydrocarbons* / analysis
  • Rivers / chemistry
  • Urbanization
  • Water Pollutants, Chemical* / analysis

Substances

  • Polycyclic Aromatic Hydrocarbons
  • Water Pollutants, Chemical

Grants and funding

Renan B da Silva was supported by the grant number IBPG-1244-2.05/20 from Fundação de Amparo a Ciência e Tecnologia do Estado de Pernambuco—FACEPE. Giovanni A P Dos Santos, and Jose Roberto Botelho de Souza, were supported by the PROPESQI Notiz number 09/2019 from Federal University of Pernambuco. Débora A. A. França was supported by the BIC grant number 200216516 from PROPESQI. Raianne Amorim Cavalcante was supported by the BIC grant number 200216456 from PROPESQI, and Andre M. Esteves was supported by the grant number 310249/2019-8 from CNPq, Eliete Zanardi-Lamardo was supported by the grant number 311771/2019-0 from CNPq. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.