The monitoring of the pollution status of the Brazilian coast is hampered by the lack of a consistent environmental indicator. We propose Hg as an environmental proxy to anthropogenic pollution of coastal regions due to its absence in the Brazilian geology, its ubiquity in anthropogenic effluents, and its toxicity. Available data suggest Hg "backgrounds" in coastal sediments of 1-10 ng g-1, in the East and 15-30 ng g-1 in the South. We suggest short sediment cores to establish these values estimating a geo-accumulation index to compare all areas. The distribution of index values showed the majority of southern coast at least moderately contaminated whereas many eastern areas are still pristine

Methylene Blue (MB) is a dye widely used in the industrial sector and in human and veterinary pharmacology. This dye, if improperly disposed of, can cause a significant environmental impact due to its low biodegradability, as it is a stable and complex substance. Additionally, it may affect human health and generate highly toxic byproducts. Hence, the purpose of this work is to assess the removal efficiency of MB from a synthetic effluent using a ionic flocculation process. Such a process consists of the dissolution of a biodegradable anionic surfactant (obtained from soybean oil used for frying food) in the synthetic effluent and the subsequent addition of calcium to the system. The addition of Ca leads to the formation of insoluble surfactant flocs with a high capacity to adsorb organic pollutants. The FTIR testing showed the presence of OH⁻ and C=O groups in the surfactant flocs, which favor the removal of MB by an adsorption process. The maximum adsorption capacity of MB was 101.38 mg g⁻¹. The process is in fact a chemisorption and has an exothermic nature. Desorption studies showed a desorption efficiency of up to 47.81% using an ethanol 1:2 solution. An MB removal efficiency of up to 93.71% was attained in just 0.5 min for an initial MB concentration of 100 mg L⁻¹, showing that ionic flocculation is a very fast and effective process for the treatment of effluents.

This paper estimates annual P emission to the Jaguaribe River estuary, NE Brazil, responsible for approximately 30% of the country's farmed shrimp production. Emissions increased three times between 2001 and 2006 and reached 43.9 t.year-1. These emissions make aquaculture the third main source of P for this estuary and are much smaller than emissions from agricultural sources and slightly lower than emissions from wastewater. Their relative contribution also increased from 10.5% to 20.5%. Temporal variability of P concentrations in estuarine bottom sediments also suggest an increase, but not as evident as the emissions. The spatial distribution and speciation of P (total P and inorganic P) in sampling stations located upstream and downstream from the main aquaculture area confirmed the importance of this source. Inorganic P was the dominant form present in sediments downstream and showed an increase from 67% to 75% of the total P present in the sediment.