The attenuation of concentrations model: a new method for assessing mercury mobility in sediments

Abstract

Recebido em 14/10/02; aceito em 22/8/03 In this work we propose a new approach for the determination of the mobility of mercury in sediments based on spatial distribution of concentrations. We chose the Tainheiros Cove, located in the Todos os Santos Bay, Brazil, as the study area, for it has a history of mercury contamination due to a chloro-alkali plant that was active during 12 years. Twenty-six surface sediment samples were collected from the area and mercury concentrations were measured by cold vapour atomic absorption spectrophotometry. A contour map was constructed from the results, indicating that mercury accumulated in a "hot spot" where concentrations reach more than 1 µg g -1 . The model is able to estimate mobility of mercury in the sediments based on the distances between isoconcentration contours that determines an attenuation of concentrations factor. Values of attenuation ranged between 0.0729 (East of the hot spot, indicating higher mobility) to 0.7727 (North of the hot spot, indicating lower mobility).

Mercury distribution in sediments of a shallow tropical reservoir in Brazil

“…Starting from this distribution map, the model of attenuation of concentrations was constructed (Wasserman & Queiroz 2004, Ribeiro et al 2013. The attenuation of concentrations is based on the distance between contours.…”

“…In the present study, our objective was to evaluate the mercury distribution in superficial sediments of the Juturnaíba reservoir, using the model of attenuation of the concentration proposed by Wasserman and Queiroz (2004) and Ribeiro et al (2013), which consists of an evaluation of the mobility of the metal based on its spatial distribution in surface sediments. Furthermore, the behavior of this metal was evaluated in the light of total carbon, total nitrogen concentrations and granulometry of the sediments.…”

Baía de todos os santos: aspectos oceanográficos

“…michelini, M. decactis, A. agaricites, S. stellata, S. radians, P. astreoides, P. branneri, F. gravida, M. cavernosa, M. harttii, M. hispida, S. wellsi (Laborel, 1969 Santos et al, 2000). Como consequência deste crescimento urbano e do desenvolvimento industrial ocorreram vários eventos de poluição quer crônica por efluentes industriais e esgotos domésticos, derramados durante décadas, ou durante grandes acidentes pontuais, a exemplo do grande derramamento de 48.000 l de petróleo bruto, em 1992 e o derramamento de 900 kg de mercúrio na Enseada dos Tainheiros (Wasserman e Queiroz, 2004). A perda da qualidade da água da baía pode ter causado uma extinção local na maioria dos seus recifes internos.…”

Human Disturbance, Natural Resilience and Management Futures: The Coral Reefs of Todos Os Santos Bay, Bahia, Brazil

“…The landscape changed from predominantly agricultural to industrial in Zone A (Herold, 2004). Around 200 industries were established in the region, including metallurgic, textile, and chemical plants (Wasserman, & Queiroz, 2004). Paredes et al (1995) argue that environmental quality at TSB was aggravated during the decade between 1982-1992, particularly on the estuarine waters of Subaé River on Zone B, where all concentrations of heavy metals sharply increased in sediment.…”

“…Population growth (Table 2), associated with industrial development, added to the degradation of the bay (Wasserman, & Queiroz, 2004). More sediment and sewage were discharged into runoff entering the bay waters.…”