Harmful Elements in Estuarine and Coastal Systems

Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities

The biouptake and toxicity of arsenic species on the green microalga Chlorella salina in seawater

The present study focuses on the biouptake, biotransformations, and toxicity of arsenic species on the marine green alga Chlorella salina in seawater from the Bulgarian Black Sea coast. Exposure to equal concentrations of As(III) or As(V) led to equivalent levels of toxicity and total intracellular arsenic content. Biouptake and toxicity of methylated arsenic species, monomethylarsonate (MMA) and dimethylarsinate (DMA), were approximately three orders of magnitude lower than those for inorganic arsenic species. Seawater enrichment with phosphate (up to 1.3mg P L−1) resulted in a significant reduction of both intracellular As content and toxicity due to As(III) and As(V). In contrast, the toxicity and intracellular content ofMMAandDMAwere unaffected by the presence of phosphate.We measured the distribution and excretion of intracellular arsenic species, and demonstrated that the release of As(V) and/or As(III), together with the bio-reduction of As(V) and the subsequent methylation of As(III) may be a detoxification mechanism for these algae. The implications of the results with respect to arsenic species bioavailability and toxicity in marine water are further discussed

Vitality and detoxification ability of yeasts in naturally As-rich musts

Considering the carcinogenic risk to human health, it is necessary to carry out research into arsenic (As) content in agro-food products and the impact of food processing on the final content. Yeast fermentation may represent a strategy for detoxifying some widespread beverages such as wine, beer and rice wine. A preliminary study of some commercial yeast species showed different viability responses to the presence of As. Yeasts had a noteworthy detoxification capability during fermentation, reducing the initial As content by about 75 % on average (minimum–maximum: 45–92 %), making it possible to produce wines with a considerably reduced content as compared to the corresponding grape juices from naturally As-rich soils. Nevertheless, significant differences between strains were observed in relation to resistance to arsenic toxicity and As removal capability. The choice of yeast strain can determine a difference of 40 % on the As content remaining in the wine after fermentation. Arsenic content of up to 1000 µg/L did not significantly worsen the fermentation of some wine yeasts, suggesting that the use of specific yeasts may represent an effective tool for reducing As in fermented beverage