Determining toxins and harmful contaminants in starfish for future application as organic fertilizer and animal feed

Abstract

Starfish play a crucial role as extraordinary predators in marine ecosystems. They often prey on bivalves, which serve as primary economic resources in certain regions, making their management a top priority. As a result, cleaning operations have been conducted to remove starfish from the coasts, leading to the accumulation of significant waste. Within the context of the circular economy, there is potential for valorizing starfish, transforming them from waste products into valuable resources. However, before doing so, it is essential to analyze the contaminants that starfish can accumulate. To address this, a study was conducted to analyze pollutants in two species of starfish: Marthasterias glacialis and Asterias rubens, collected from the Galician Spanish shores. The goal was to assess their suitability for use as animal feed or fertilizer in agriculture. The study employed optimized methodologies to analyze trace elements, saponins, marine toxins and persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs). The validated protocols for determining these contaminants in starfish showed an acceptable performance in detection, showing the quality parameters of the analytical analysis (recoveries, precision, limit of detection (LOD) and quantification (LOQ)). Results indicated that concentrations of the legislated contaminants in the starfish samples from the Galician shores did not exceed the current EU legislation standards. Consequently, in terms of toxicology, starfish matrix could be considered a suitable raw material for the use in animal feed or as crop fertilizer.

Keywords: Asterias rubens; Galician coast; Marthasterias glacialis; Metals; Organic pollutants.

Fig. 1

Concentration of PCBs in starfish samples and their regulated values. ^*Values below the limit of detection. ^** Commission Regulation (EC) nº1259/2011 modified from Regulation (EC) nº1881/2006 regarding maximum levels for dioxins, dioxin-like PCBs and non-dioxin-like PCBs in food products (EU, 2011a)

Fig. 2

Concentration of OCPs in starfish samples and their regulated values. ^*Values below the limit of detection. ^**RD nº465/2003 on undesirable substances and products in animal nutrition (BOE, 2003)

Fig. 3

Concentration of PAHs in starfish samples and their regulated values. ^*Values below the limit of detection. ^**Regulation (EC) nº835/2011 modified from Regulation (EC) nº1881/2006 as regards the maximum content of polycyclic aromatic hydrocarbons in foodstuffs (EU, 2011b)