# Assessment of Heavy Metal Distributions in Sand Beaches in the Maltese Islands
## 1 Introduction  
Rocks on the Maltese islands are of the marine carbonate shallow water type, which match those found in some areas on the neighbouring island of Sicily [1]. Sand mostly forms by the erosion of exposed rock from valleys leading up to the beaches. As outlined by [PERSON] in 1960, the majority of exposed formations comprise a combination of Globigerina Limestone, Blue Clay, and Greensand formations [2], with Greensand being the most common occurrence. Such formations are soft materials, weather fast, and determine the sand colour [3], and mainly depend on the composition of the geological strata in the location and the number of tiny crustacean shells that these have originated from. As reported by [PERSON] et al. (2005) and [PERSON] and [PERSON] (2002), touristic endeavours taken up by the island have impeded the natural regeneration of sand, causing the loss of geomorphological activity in most sandy beaches [4, 5]. The major component of sand is calcium carbonate which constitutes approximately 20% of its biogenic source [6]. Contamination of sand beaches occurs also from surface soil from neighbouring arable land which tends to be transported down valleys leading up to the beaches during precipitation seasons. Additives added to the soil to enhance its properties, namely fertilizers and pesticides which include heavy metals, are soluble in rainwater resulting in the accumulation of heavy metal concentrations in sandy beaches. According to [PERSON] et al. sandy beaches generally have higher concentrations of heavy metals than soils as they infiltrate into the sand via multiple sources including water and silt [7]. The presence of heavy metals in surface soil are linked to human activity in the area, as proven by the study by [PERSON] et al. (2016) which determined the presence of heavy metals in the surface soil in the Thrace region in Turkey [8]. Results showedthat the majority of the heavy metals studied were present in the zones with most traffic and industrial areas of the region, thus contributing to the anthropogenic sources of such elements [8]. Similar relationships were obtained in an Algerian study by [PERSON] and [PERSON] (2013) showing that the concentrations of heavy metals are higher in areas of higher industrial and human development, owing to the anthropogenic effect of increased industrial activities, traffic emissions, leaching of polluting elements from improper waste disposal, and dwelling zones [9]. Similar results have been shown in our previous work undertaken about heavy metal content in agricultural soil in Malta. Links of heavy metal concentrations in the soil to the source of contamination were made, proving both the lithogenic and anthropogenic effects on toxicity concentrations upon their variations according to the plant growth stage [10]. Another study of local Maltese soil contamination by heavy metals proved that all heavy metals studied were present in Marsaxlokk, Qrendi, Gharghur, and Zabbar in Malta and Ghajnsielem in Gozo [11]. [PERSON] also reported that Al was the most abundant heavy metal in all districts studied, presenting 98% of the total heavy metal concentrations, followed by Mn, Pb, and Cu [11]. Heavy metal concentrations have been recorded also in silt and sand particles on riverbeds, which originate as agriculture chemicals, industrial effluent, fireworks remains, and improper drainage systems, which are slowly transported via rain and water currents to river estuaries along with other sedimentary particles. Bioaccumulation of such heavy metal deposits in natural environments may lead to excess concentrations surpassing limit values, unbalancing the natural environmental equilibrium. Ionic compounds in the form of soluble salts which separate due to their interaction with a solvent, such as sodium chloride, are among the major carriers of heavy metals, as these are more likely to be carried by water. Geologically in Malta, there is a substantial amount of limestone in the strata which hold soluble salts that are soluble in water [12].