Metal concentrations in sediments and clams in four Moroccan estuaries

Cheggour, Mohamed; Chafik, A.; Fisher, Nicholas S.; Benbrahim, Samir

doi:10.1016/j.marenvres.2004.04.002

Cited by 97 publications

(52 citation statements)

References 33 publications

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“…Scrobicularia plana is a commonly used bioindicator for metal associated environmental monitoring (Byrne and O'Halloran, 2001;García-Luque et al, 2004;Pérez et al, 2004;Riba et al, 2004;Cheggour et al, 2005), but some background is needed to integrate the different and fragmentary literature available, since not always the same size classes are used and therefore intercomparison becomes very complex.…”

Section: Discussionmentioning

confidence: 99%

“…Scrobicularia plana, a long-lived deposit feeding bivalve species present in muddy to sandy sediments (Verdelhos et al, 2005), has a wide geographical distribution and has been previously used both in biomonitoring programs (Cheggour et al, 2005) and toxicity tests (Byrne and O'Halloran, 2001;García-Luque et al, 2004;Pérez et al, 2004;Riba et al, 2004). Its life cycle in southern Europe is well studied, where it has a lifespan of 5 years, with one annual recruitment period and growth rates of roughly 1 cm yr À1 (Verdelhos et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Pattern and annual rates of Scrobicularia plana mercury bioaccumulation in a human induced mercury gradient (Ria de Aveiro, Portugal)

Coelho

Rosa

Pereira

et al. 2006

Estuarine, Coastal and Shelf Science

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Due to the lack of knowledge regarding annual bioaccumulation rates in estuarine and marine fauna, the main aim of this work was to study the annual mercury bioaccumulation in the well-documented bivalve species Scrobicularia plana along a human induced mercury gradient in the Ria de Aveiro coastal lagoon (Portugal) and in a nearby, non-polluted system (Mondego estuary), parallel to the risks associated with its consumption by humans.Minimum total mercury concentration was as low as 0.019 mg kg À1 (wwt) in 4þ year old organisms in the reference site, where a significant negative correlation ( p < 0.05) was found between total mercury concentrations and size, resulting in negative bioaccumulation rates (detoxification). On the other hand, values reached 1.8 mg kg À1 (wwt) in 3þ year old bivalves from the most contaminated area, where a strong positive correlation with size was found ( p < 0.01) and annual bioaccumulation rates were as high as 0.25 mg kg À1 yr À1 . Annual bioaccumulation rates were highly correlated with suspended particulate matter mercury concentrations. Even though the levels of organic mercury contents increased parallel to the contamination gradient, at each sampling station, no increment was found with age, which corresponded to a decrease in organic mercury percentage with age.In terms of ecological management and public health, the ratio of 0.01 consistently found between Scrobicularia plana annual mercury accumulation rates and SPM mercury levels for most sites may permit to roughly estimate S. plana contamination of commercial sized individuals (>2.5 cm) and, if verified and confirmed in other systems, be used as a simple management tool.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pattern and annual rates of Scrobicularia plana mercury bioaccumulation in a human induced mercury gradient (Ria de Aveiro, Portugal)

Coelho

Rosa

Pereira

et al. 2006

Estuarine, Coastal and Shelf Science

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“…1), concentrations of Pb and Cd of up to 297.0 and 4.0 mg/kg, respectively, were recorded in Nador Lagoon sediment [8]. Along the Atlantic Coast of Morocco, the contribution of agricultural (phosphate fertilizers and pesticides) and industrial waste to coastal pollution was noted by Cheggour et al [10], who reported contamination (mg/kg) of Sebou Estuary sediments by Cd (2.3  0.7), Ni (101  24), Zn (179  24) and Cu (51.5  12).…”

Section: North Africamentioning

confidence: 91%

“…1, heavy metal pollution of water, sediment and/or soil has been reported in many African countries (marked [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Notable heavy metals that have been reported include lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu), cobalt (Co), zinc (Zn), chromium (Cr), nickel (Ni), manganese (Mn), iron (Fe), arsenic (As) and vanadium (V).…”

Section: Current Status and Extent Of Heavy Metal Pollution In Africamentioning

confidence: 99%

Current Levels of Heavy Metal Pollution in Africa

2010

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ABSTRACT. Studies of environmental pollution in Africa indicate that toxic metal pollution has reached unprecedented levels over the past decade. Human exposure to toxic metals has become a major health risk on the continent and is the subject of increasing attention from national and international environmentalists. This paper reviews data from the past decade on environmental pollution in Africa and highlights countries where most heavy metal pollutions have been reported. Characteristics of heavy metal pollution in North, West, East and Southern regions of Africa have been described, as have major sources of pollution in the different regions. This review summarizes the sites where most of the heavy metal pollution has been reported in Africa and, where applicable, presents reported levels of pollution in different environmental compartments in the context of internationally acceptable limits. Contaminations in fish and food animals as well as impacts of heavy metal pollution on humans are also described.KEY WORDS: Africa, environment, heavy metals, pollution.J. Vet. Med. Sci. 72(10): 1257-1263, 2010 For many years, Africa was considered safe from heavy metal pollution [6]. However, rapid population growth and high urbanization rates have resulted in a recent expansion of cities in the absence of proper planning and without adequate waste disposal facilities [25]. Consequently, solid waste management has become a major challenge in many African countries, as waste production exceeds capacities for collection and disposal by local authorities [49]. As observed by the United Nations Centre for Human Settlements (UNCHS) [56], only one-third of the solid waste generated in urban areas across Africa is collected, and of that, only 2% is recovered and recycled. Furthermore, use of leaded gasoline [36], fugitive dusts [13], indiscriminate dumping and burning of toxic waste, including nickel/cadmium-based batteries, due to weak pollution legislation has worsened heavy metal pollution on the continent [22].Recently, the United Nations Environment Program (UNEP) Global Environment Outlook (GEO) 4 [58] noted that Africa continues to be at risk from hazardous and electronic waste dumping due to inadequate monitoring capabilities and institutional mechanisms for managing such waste. There are limited resources for environmental management in most African countries, as most developmental programs are focused on economic growth and industrialization [52]. As a result, industrial expansion and increased extraction of natural resources have resulted in widespread heavy metal pollution [3,59].According to a comprehensive study on the environmental burden of disease by the World Health Organization (WHO) [62], environmental risk factors account for a quarter of the total burden of disease and 2.97 million human deaths every year in Africa. Since toxic metals constitute serious health hazards, the extent of toxic metal contamination of the African environment has been the subject of considerable interest. Although improvements i...

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“…In this study, we focused on metallic contamination of two intertidal bivalves molluscs from the Souss estuary, S. plana and C. edule, that are ubiquitous in Moroccan Atlantic estuaries (Bergayou and Moukrim 2005). These clams, as other bivalves, possess the main attributes that make them suitable as sentinels of chemical contamination in Moroccan environment (Cheggour et al 2000(Cheggour et al , 2001(Cheggour et al , 2005. Moreover, they can be found on the European and African Atlantic coasts as well as in the Mediterranean, allowing comparative surveys.…”

mentioning

confidence: 99%

Monitoring of Trace Metal Contamination in the Souss Estuary (South Morocco) Using the Clams Cerastoderma edule and Scrobicularia plana

Anajjar

Chiffoleau

Bergayou

et al. 2008

Bull Environ Contam Toxicol

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Concentrations of seven metals (Cd, Cu, Cr, Pb, Ni, Zn, Hg) were monitored monthly during 2 years in two bivalves, Cerastoderma edule and Scrobicularia plana collected from the Souss Estuary (South Morocco) before and after the commissioning of a sewage treatment plant in November 2002. According to trace metals, changes in concentrations were observed mainly in S. plana, characterised by a decrease of Cu, Hg and Pb when Cd was clearly increasing. Conversely, no clear changes were observed in C. edule during the same periods. This study suggests the use of S. plana in the monitoring of trace metal contamination of such coastal marine environments.

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Metal concentrations in sediments and clams in four Moroccan estuaries

Cited by 97 publications

References 33 publications

Pattern and annual rates of Scrobicularia plana mercury bioaccumulation in a human induced mercury gradient (Ria de Aveiro, Portugal)

Pattern and annual rates of Scrobicularia plana mercury bioaccumulation in a human induced mercury gradient (Ria de Aveiro, Portugal)

Current Levels of Heavy Metal Pollution in Africa

Monitoring of Trace Metal Contamination in the Souss Estuary (South Morocco) Using the Clams Cerastoderma edule and Scrobicularia plana

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