Preliminary investigation into the chemical composition of the invasive brown seaweed Sargassum along the West Coast of Ghana

Abstract

The arrival of the invasive brown seaweed Sargassum in the Western Region of Ghana was first reported in 2009. This impacted negatively on biodiversity, tourism and the livelihoods of the coastal communities. The objectives of the study among others were to identify and determine the nutritional and toxicological contents of the seaweed. Twenty four samples collected from 6 zones along the Western Region were analysed. Nutritional and toxicological analyses were carried out using an Atomic Absorption Spectrophotometer (AAS) 900T. Results of the study indicated that the Sargassum samples analyzed contained low concentrations of nitrogen. However, nitrogen utilized by plants, namely, nitrate and ammonia were very high, together with phosphates. This makes the Sargassum a good source organic fertilizer. However, the high concentrations of toxic heavy metals in the Sargassum defeat this assertion. Heavy metals have implications in both the growth and metabolic activities of plants. Most heavy metals, especially arsenic and lead are carcinogenic and are capable of causing skin, lung, liver and bladder cancers and miscarriages. Indiscriminate domestic and industrial wastes disposal, oil and gas activities, mining and high shipping traffic may have contributed to the heavy metal concentrations in the seaweeds.

Key words: Seaweed, Sargassum, nutrients, toxins, health.