Distributions, sources and ecological risk assessment of arsenic and mercury in the surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea

Abstract

a b s t r a c tThe spatial distributions of As and Hg in riverine and marine surface sediments of the coastal southwestern Laizhou Bay were obtained, and multiple indices and guidelines were applied to assess their contamination and ecological risks. The As concentrations in riverine sediments were close to those in marine sediments, and on the whole the dominant proportion of As was identified to be from natural sources. The Hg concentrations in riverine sediments were much higher than those in marine sediments, so river transportation was likely the main way of Hg into the southwestern Laizhou Bay. In respect of As, the sediment quality was fine according to the risk assessment methods used; in contrast, Hg presented an extremely contaminated status with a very high ecological risk in some riverine sediments, while most of the marine sediments were relatively much less polluted by Hg and under a lower ecological risk from it.Ó 2015 Elsevier Ltd. All rights reserved.There is worldwide concern about contamination caused by heavy metals such as arsenic (As) and mercury (Hg), because of the environmental persistence, the biogeochemical recycling and the ecological risks of these elements. Untreated or not fully treated waste waters containing As and Hg from urban areas, industrial sites and agricultural areas are discharged into aquatic environments Bastami et al., 2015;Zalewska et al., 2015). As and Hg are highly toxic heavy metals, which are transported in the water column, accumulated in sediments, and biomagnified through the food chain, resulting in remarkable ecological risks to benthic organisms, fish and humans (Neff, 1997;Mason et al., 2000;Cotin et al., 2011;Nance et al., 2012). When entering the aquatic environment, only a small part of free metal ions stay dissolved in water because of the combined action of adsorption, hydrolysis and co-precipitation, and the rest of them get deposited in sediments (Gaur et al., 2005). However, when environmental conditions change, sediments may transform from the main sink of heavy metals to the sources of them for the overlying waters (Gaur et al., 2005;Prica et al., 2008). So the measurements of heavy metals only in the water and in the suspended materials are far from enough due to water discharge fluctuations and low resident time (Varol, 2011). Therefore the concentrations of heavy metals in sediments are often monitored to provide basic information for the environmental risk assessment (Long et al., 1995; SEPA, 2002).The Laizhou Bay is a semi-enclosed shallow coastal water region located in the northwest of Shandong Peninsula with $7000 km 2 in area and a $320 km long coastline, accounting for about 10% of the total area of the Bohai Sea, China. The Bohai Sea is recognized as one of the marine ecosystems in China that face with serious eco-environmental problems, and the Laizhou Bay is one of its three major bays . The topography of the Bay tilts from the southeast to the northwest, with a gradually down trend. Affected by the Yellow River, the Yellow River del...

Integration of microRNAome, proteomics and metabolomics to analyze arsenic-induced malignant cell transformation

“…The effects of arsenic exposure on skin have been documented, particular in skin cancer [ 8 , 9 ]. Arsenic-induced skin lesions are characteristic by veracious hyperkeratosis and pigmentation disorders [ 10 ].…”

Quim. Nova, Vol. XY, No. 00, 1-6, 200_ http://dx.doi.org/10.21577/0100-4042.20170489 *e-mail: wander.botero@arapiraca.ufal.br COMPLEXO ESTUARINO LAGUNAR MUNDAÚ-MANGUABA: CARACTERIZAÇÃO DA MATÉRIA ORGÂNICA NATURAL E INTERAÇÃO COM ÍONS Hg2+

“…Íons mercúrio são alvo de diversas pesquisas ambientais devido a sua elevada toxicidade, bioacumulacão e biomagnificação, podendo inclusive causar efeitos no sistema neurológico. [8][9][10][11][12][13] Uma vez no ambiente, o mercúrio pode interagir com a matéria orgânica natural (MON) que poderá influenciar na mobilização, degradação e transporte dessas espécies no ambiente. 8,9,[14][15][16][17][18][19][20] Buscando compreender os mecanismos pelos quais a MON do sistema lagunar Mundaú-Manguaba influencia o transporte e disponibilidade de contaminantes nesse ecossistema, o presente trabalho extraiu e caracterizou substâncias húmicas aquáticas do CELMM e realizou estudos de complexacão com íons Hg 2+ .…”

Kapulukaya Barajı Aşağı Havza’sı Sediment Örneklerinde Ağır Metal Kirlilik Düzeylerinin Değerlendirilmesi (Kızılırmak, Kırıkkale)

“…Doğal süreçler ve insan kaynaklı faaliyetler ile sucul siteme dahil olan ağır metaller, su, sediment ve canlı organizmalar gibi sucul ekosistemin öğeleri arasında dağılırlar. Bununla birlikte ağır metallerin sahip olduğu bazı özellikler nedeniyle, çok az miktarı suda serbest iyon halinde kalırken büyük bir kısmı sedimentte çökelir [7]. Bu nedenle sediment, ağır metallerin yerleşmesi ve taşınması için bir birikim alanı olarak rol oynar.…”