Trace Metal Accumulation and Phytoremediation Potential of Four Crop Plants Cultivated on Pure Sewage Sludge

Phytoremediation is a viable strategy to remove trace metal contaminants from sewage sludge but still is poorly investigated. The aim of this study was to quantify the trace metal removal of B. napus, B. juncea, H. annuus, Z. mays grown on pure sewage sludge. Each species was grown on six different sewage sludge for 8 weeks and sludge were analysed for trace metal content and physico-chemical characteristics. Our results confirmed that all the tested sludge supported plant growth. The tested sludge showed a plant vigorousness lower (46% of sludge) or similar/increased (54% of sludge) compared to control treatment. B. juncea and B. napus were the most efficient species in the bioaccumulation, of trace metals. The average percentage of metals removed by the selected species was 0.2% for As, 0.85% for Cd, 0.09% for Cr, 0.36% for Cu, 0.36% for Ni, 4.2% for Se, 1.2% for Zn. In conclusion, our results showed that phytoremediation can be applied to sewage sludge, despite the chosen species have low efficiency in trace element removal. Further studies using hyperaccumulator species are needed which may lead to a higher efficiency of the process opening up new possibilities for the management strategies of this waste.

Study of Microplastics and Inorganic Contaminants in Mussels from the Montenegrin Coast, Adriatic Sea

Mussels (Mytilus galloprovincialis) collected at three locations in Boka Kotorska Bay, on the Montenegrin Adriatic coast, were analyzed for the first time by optical and Raman microscopy to detect microplastics (MPs) and other emerging contaminants in their soft tissues. Concentrations of six trace metals (Cu, Zn, Mn, Fe, Cd, and Hg) were also measured in the same samples by atomic absorption spectroscopy. Mussels from a location near the urban area of Kotor were found to exhibit the highest content of MPs and other pollutants originating from anthropogenic sources, while farmed mussels showed higher carotenoid as well as nylon content. The hypothesis of MPs acting as a possible secondary route of trace metals ingress in mussels, a thus far scarcely studied topic, was evaluated based on a comparative analysis of the obtained results. In this context, it was noticed that nylon filaments originating from mussel farming equipment might contribute to higher trace metal content. The results showed that the simultaneous analysis of different contaminants in mussels can be a significant step forward in marine environment pollution monitoring and the assessment of human health risks associated with the consumption of contaminated seafood.

The Impact of Coastal Geodynamic Processes on the Distribution of Trace Metal Content in Sandy Beach Sediments, South-Eastern Baltic Sea Coast (Lithuania)

Sandy coasts are one of the most dynamic spheres; continuously changing due to natural processes (severe weather and rising water levels) and human activities (coastal protection or port construction). Coastal geodynamic processes lead to beach sediment erosion or accumulation. The coast’s dynamic tendencies determine the changes in the volume of beach sediments; grain size; mineralogical; and geochemical composition of sediments. In addition to lithological and mineralogical analysis of sediments, geochemical analysis can provide valuable information about the local and regional patterns of sediment transport, distribution, provenance, and coasts’ conditions. The study aims to assess trace metals’ temporal and spatial distribution determined in the sandy beach sediments along the south-eastern Baltic Sea coast (Lithuania) during 2011–2018. The Lithuanian seacoast is divided into two parts: mainland and spit coast. Our results revealed that the dominant group of elements on the mainland includes Ca–Mg–Mn–Ti and on the Curonian Spit Fe–Pb–As–Co–Cr–Ni–Al, which remain unchanged during the years. The analysis included additional parameters such as beach volume, grain size and sorting, and heavy mineral concentration on the beach. The spatial analysis of trace elements indicated that the trace metal content depends on the coastal processes, but it differs in the mainland and spit sea coast. We identified a higher concentration of trace metals in the erosion-dominated areas in all analysed years on the mainland coast. On the spit coast, the trace metal concentration increased in areas associated with relict coarse sand and where the loading of sediments was active on the beach due to the northward along-shore transport.

Granulometric Discrimination of Marine Sediments Based on Trace Metal Content Measured by the Technique LIBS (Laser Induced Breakdown Spectroscopy)-=SUP=-*-=/SUP=-

The accumulation of sediment in the harbors hinders the easy movement of boats. To avoid this, dredging operations are carried out regularly to restore correct functioning but also to present water quality managing the huge amount of dredged sediments and recycling them into building materials is a major challenge for the treatment of these sediments. It is within this framework that we propose to use the Laser Induced Breakdown Spectroscopy (LIBS) as a promising new technique for measuring trace metal concentrations of marine sediment samples. Our work has focused on the effect of granulometry on the relative concentration of inorganic compounds. The Principal Component Analysis (PCA) discriminated between different sediment clustering them into three groups: G1 (1.25mm-75 μm), G2 (75 μm-50 μm) and G3 (< 50 μm). Significant differences between element concentrations in the three groups, corroborating published works, were observed and concentrations in each group are reported in this study. Keywords: heavy metals, grain size, LIBS, chemometrics, marine pollution.