Applicability of Fluorescence and Absorbance Spectroscopy to Estimate Organic Pollution in Rivers

This article explores the applicability of fluorescence and absorbance spectroscopy for estimating organic pollution in polluted rivers. The relationship between absorbance, fluorescence intensity, dissolved organic carbon, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and other water quality parameters were used to characterize and identify the origin and the spatial variability of the organic pollution in a highly polluted watershed. Analyses were performed for the Iguassu River, located in southern Brazil, with area about 2,700 km² and ∼3 million inhabitants. Samples were collect at six monitoring sites covering 107 km of the main river. BOD, COD, nitrogen, and phosphorus concentration indicates a high input of sewage to the river. Specific absorbance at 254 and 285 nm (SUVA₂₅₄ and A₂₈₅/COD) did not show significant variation between sites monitored, indicating the presence of both dissolved compounds found in domestic effluents and humic and fulvic compounds derived from allochthonous organic matter. Correlations between BOD and tryptophan-like fluorescence peak (peak T₂, r=0.7560, and peak T₁, r=0.6949) and tyrosine-like fluorescence peak (peak B, r=0.7321) indicated the presence of labile organic matter and thus confirmed the presence of sewage in the river. Results showed that fluorescence and absorbance spectroscopy provide useful information on pollution in rivers from critical watersheds and together are a robust method that is simpler and more rapid than traditional methods employed by regulatory agencies.

Sediment contamination and toxic effects on Violet Goby fish (Gobioides broussonnetii - Gobiidae) from a marine protected area in South Atlantic

The Estuarine-Lagoon Complex of Iguape-Cananéia (ELCIC), a Marine Protected Area (MPA) in Brazil, was the focus of this study that aimed to relate external levels of exposure to contaminants to toxic effects on Gobioides broussonnetii fish. Different anthropogenic contaminants such as metals, polycyclic aromatic hydrocarbons (PAHs) and pharmaceuticals and personal care products (PPCPs) were analyzed in the sediments; and biochemical, histopathological and genotoxicity biomarkers evaluated in fish; in two different seasons at three sites of the estuarine region. Higher contamination of the sediments was observed near the main urban center (Iguape city - IG). Metal concentrations were considered low to moderate, while PAHs concentrations were considered low. The concentrations of PPCPs increased due to the anthropogenic presence and were higher near IG and the Cananéia Island (CI). Contributions from historical mining, agriculture, nautical activities, oil, sewage and waste disposal, biomass and fossil fuels combustion were identified. Higher concentrations of metals and PPCPs were observed during the cold-dry season, suggesting influences of the lower hydrodynamics during the season of lower precipitation. Higher PAHs concentrations occurred in the hot-rainy season, indicating influences of greater human presence in summer. In fish, biological responses followed the same spatial and seasonal pattern. More pronounced changes in antioxidant, biotransformation, histopathological and genotoxic biomarkers were observed in IG and CI. The multivariate analysis and the integrated biomarkers response index (IBR) also evidenced worse environmental conditions in these sites. This result can indicate a negative influence of anthropogenic activities on the contamination of sediments and on the biological responses of fish. This study presented the first ecotoxicological data for the species and suggested that these chronic exposures can cause adverse effects on this fish population. The data contribute to the understanding of local environmental quality and can be applied in the future to the environmental and social management of marine protected areas.

Integrated assessment of sediment contaminant levels and biological responses in sentinel fish species Atherinella brasiliensis from a sub-tropical estuary in south Atlantic

This study combined data of the concentrations of metals, polycyclic aromatic hydrocarbons (PAHs) and pharmaceuticals and personal hygiene products (PPCPs) in the sediments and the biological responses of the Atherinella brasiliensis fish in two different sites and climate seasons in the Estuarine-Lagoon Complex of Iguape-Cananéia, Southeast Brazil. The presence of metals, PAHs, and PPCPs were observed in the sediments demonstrating the contamination throughout the system with contributions of sewage and residues disposal, oil and combustion of biomass and fossil fuels. Higher contaminations were identified in the point of greater human presence (C - Cananéia City), especially during the cold-dry season. The influence of anthropic activities and variations in the estuarine conditions, such as lower hydrodynamics during the lower rainfall period, were observed. In fish, spatial and seasonal changes in the parameters of oxidative stress and biotransformation, genotoxicity and histopathological alterations followed the same trend, with more pronounced responses in C in the cold-dry season. The biological responses of the fish revealed adverse effects in the local species population and indicated the presence of metals, PAHs and PPCPs as stressors. The multivariate analysis and the integrated biomarker response index (IBR) corroborated with these results, also indicating that site C had the worst environmental quality. The present study provides new information about the contamination of the sediments of Estuarine-Lagoon Complex of Iguape-Cananéia and the chronic exposure to contaminants in A. brasiliensis. Therefore, contributing to a better understanding of the local environmental quality with data that can support protective management of the area.