Contamination and toxicity in a subtropical Estuarine Protected Area influenced by former mining activities

Abstract

The present paper reviews information about sources, fate, concentrations and toxicity of the metals found in the Cananéia-Iguape Estuarine Complex (CIEC), which is within a Ramsar site, the Cananéia-Iguape-Peruíbe Environmental Protected Area (CIP-PA). The main sources of metals to CIEC are the former mining sites located upstream, on the Ribeira de Iguape River basin. Pb is reported as the element of primary concern, but Cu, Zn, Cr and As have been detected in sediments and biota. In general, higher levels of metals are associated with muddy sediments, in depositional portions of the estuary. Metals appear to be bioavailable, as sediment toxicity has been reported, together with bioaccumulation and sub-chronic effects in fish and invertebrates. Areas with higher concentrations of metals and more severe sediment toxicity are not necessarily the closest to the sources. The worse conditions occur in depositional sites, which depend on rainfall in catchment basin and hydrological processes in the estuary. In fact, during the flooding season the deposition of particles seems to move southward, carrying metals to the southern portion of the CIEC. The results suggest that the protection objectives are not being fully achieved, demanding actions to ensure control of both internal and external sources of contaminants for the CIEC. Additionally, new enforcements and actions are required to control the contamination sources of mining residues located upstream. The current review highlights that estuarine and marine protected areas may be impacted by contaminants released from distant sources, and this situation should be properly addressed in management plans.

Benthic aerobic respiration and nutrient fluxes in Cananéia-Iguape Estuarine-Lagoon complex along a salinity gradient

“…Trapandé Bay, in the southern part of the CIELC, was chosen as the saline site, ranging from 20 to 30 of salinity, in spring and winter, respectively. Despite evidence indicating the relative seasonal persistence of saltwater within the southern estuary and Trapandé Bay (Miyao Moraes et al et al, 1986), short-term episodes of intense continental runoff may move the saltwater wedge toward the southern area (Conti et al, 2012) mainly in wet seasons, and the average salinity in the region is 22.5, classifying it as a polyhaline water body (Perina and Abessa, 2020). The salinity in Pedrinhas station ranged from 2 to 12, in summer and winter, respectively, and is characterized as a mesohaline site.…”

Qualidade de sedimentos na Baía Babitonga e sua implicação na reabertura do Canal do Linguado (SC), Brasil

“…No Brasil, os estuários são historicamente atingidos pela introdução de metais provenientes de fontes antrópicas (PERINA & ABESSA, 2020), especialmente aqueles que se localizam próximos a centros de alta densidade populacional, com portos e indústrias (CLARK, 2001;PERINA & ABESSA, 2020). A introdução, direta ou indireta, tanto de elementos orgânicos quanto inorgânicos pode apresentar efeitos deletérios à saúde humana, em virtude dos efeitos nocivos aos recursos vivos (BURTON & MACPHERSON, 1995;HO & BURGESS, 2013), da diminuição da qualidade da água e redução dos atrativos naturais, causando consequentemente danos no âmbito econômico e social (AMIARD- TRIQUET & RAINBOW, 2009;MOFIJUR et al, 2021;BENNETT et al, 2023).…”

Soils of the Ribeira Valley (Brazil) as Environmental Protection Barriers: Characterization and Adsorption of Lead and Cadmium

“…Soil, water, and sediment contamination by potentially toxic metals is a global problem that can be caused by the inadequate disposal of waste from several anthropic activities. High concentrations of metals and metalloids such as arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), and zinc (Zn) are reported in several regions [1][2][3][4][5][6][7]. For instance, As concentrations of 350 mg L −1 and 860 mg kg −1 were found in water and sediments, respectively, in the Iron Quadrangle (Minas Gerais, Brazil), which is related to the release from mining tailings into the water bodies [1].…”

“…In Adrianópolis (southeastern Brazil), concentrations up to 28,585 mg kg −1 of Pb, 99,568 mg kg −1 of Zn, and 30 mg kg −1 of Cd were found in a mining waste disposal area [4]. This improper disposal caused contamination, and concentrations of up to 33.4 of Pb [5] and 15.8 of As [6] were found in sediments of the Cananéia-Iguape estuarine complex. Health authorities throughout the world are concerned with the effects of these contaminants on human health and the environment [8].…”