Resposta da macrofauna bentônica à biorremediação in situ em sedimentos contaminados por hidrocarbonetos no litoral de Pernambuco

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a constant threat to estuarine areas. Stimulation by inorganic fertilizers in contaminated sediments is used to accelerate the remediation process and generate diverse responses from the benthic communities present there. Considering the benthic macrofauna as an ally in monitoring the bioremediation process, a field experiment was developed using fertilizers composed of Nitrogen, Phosphorus and Potassium (NPK) of slow release (Osmocote) and fast release (liquid) with the aim of investigating the effect of biostimulation on the recovery of benthic fauna in sediments contaminated by hydrocarbons and possible differences in the structure of macrobenthos in relation to the two types of fertilizers. A randomized block design was set up in the Atapuz region, located in the Itapessoca river estuary – PE. 4 blocks with 3 treatments were determined: Control (C), Liquid Fertilizer (L) and Osmocote Fertilizer (O). Sediment samples were collected between March and June 2023 for macrofauna and PAH analysis, and physicochemical and sedimentological parameters were measured. PAHs were recorded in all samples (concentrations ranging from 0.30 ng/g-1 to 190.09 ng/g-1). Benzo[a]pyrene, benzo[a]anthracene and benzo[b]fluoranthene were the PAHs with the highest concentrations. Concentrations of Σ16PAHs reveal light to moderate contamination. Among the environmental variables, all presented constant values throughout the experiment, except rainfall increased considerably in the last month. The addition of NPK did not cause a reduction in PAHs, and the nutrient concentrations used did not accelerate the bioremediation process. 1503 specimens belonging to 29 taxa distributed in the phyla Annelida, Mollusca, Crustacea, Sipuncula and Nemertea were recorded. Sigambra grubii was the dominant species at the study site, followed by Oligochaeta and Anomalocardia flexuosa. No significant differences were found in the density, richness, diversity and evenness in the benthic community (p > 0.05) between the treatment areas in relation to the addition of fertilizers. PERMANOVA indicated significant differences only between sampling days (p < 0.05). The use of NPK-based fertilizers did not exert strong influences on the benthic community and no differences were observed in relation to the types of inorganic fertilizers used in the experiment.