# Assessment of Heavy Metal Distributions in Sand Beaches in the Maltese Islands
## 3 Results and Discussion
### Chemical Analysis
#### 3.1.1 Descriptive Statistics
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Mean**} & \multicolumn{2}{c}{**Study from Baja**} & \multicolumn{2}{c}{**Study from Malaga**} & \multicolumn{2}{c}{**Study from Abu**} & \multicolumn{2}{c}{**Study from Abu**} & \multicolumn{2}{c}{**Carbonate Rock**} \\  & **Concentrations in** & **Domitia, Italy** & **Bay, Spain** & **Khashaba Beach,** & **Sabratha Coast,** & **Background Values** \\  & **This Study (ug/g)** & **(ppm)** [33] & **(mg/kg)** [34] & **Egypt (ug/g)** [35] & **Libya (ug/g)** [36] & **(ppm)** [31] \\ \hline Cu & 2.549 & - & - & 50-99 & 17.300 & 4 \\ Fe & 93.766 & - & - & 49.900-198,100 & 2084 & 3800 \\ Mn & 10.503 & - & - & 450-640 & 36.210 & 1100 \\ Pb & 5.082 & 23.5 & 46.7-218 & 214-476 & 11.690 & 9 \\ Sr & 186.953 & - & - & 53-388 & 6.550 & 20 \\ Zn & 4.474 & 52.5 & - &Libya, especially in the case of Pb, where samples were also analysed using AAS technology. Concentrations for sand in Maltese bays was notably lower than those recorded in all studies referenced in Table 7. Unfortunately, Sr content was not reviewed in any of these studies so comparison lacks, but the concentration obtained is much less than background value for Sr stated by [PERSON] and [PERSON] [31]. The distributions of Fe and Mn proved symmetrical since the skewness coefficients are almost equal to zero and the mean and median values are very close. This means that their distributions are homogenous and are derived from non-point sources which may be of predominant lithogenic origin, namely bedrock erosion due to wave dominant coastal location [33] or predominant anthropogenic sources which may include industrial pollution, vehicle emissions from nearby roads, tourist resorts, stormwater runoff [35], and contamination from sea vessel fuel hydrocarbon derivatives from marine traffic [36]. Skewness coefficients for Cu, Pb, Sr, and Zn are higher showing that data might be affected by point sources found on the specific beaches analysed. This is further studied by principal component analysis and cluster analysis. Upon carrying out the Kolmogorov-Smirnov normality test on the concentrations for the heavy metals assessed, only the data for Mn are normal with a \(p=0.200>0.050\). This result links directly to the homogeneity of the Mn distribution shown by the skewness coefficient, and hints to the possibly prevalent lithogenic origin of Mn. The Mann-Whitney U-test and the Kruskal-Wallis test, shown in Table 8, were performed to check relationships among the concentrations across the different islands of Malta and Gozo; across the coordinates where these lie, including the north, south, west or east region of Malta and Gozo; and across each of the bays reviewed. It is important to note that the Pb distribution resulted in the same in Malta and Gozo, with Mean Rank for Malta = 67.010; Mean Rank for Gozo = 70.280; N = 134; U = 1195.500; \(p=0.729\). The distribution of Zn concentrations was also similar over the two islands studied, with Mean Rank for Malta = 67.100; Mean Rank for Gozo = 69.780; N = 134; U = 1185.500; z = 0.284; \(p=0.776\). The hypotheses defining similarity across Malta and Gozo for all other elemental concentrations were rejected since the obtained values of \(p<0.05\). None of the heavy metal concentrations were the same in different regions located around the coast, thus this hypothesis was rejected. Cu and Sr were highest in the south of Malta and Gozo, Zn and Fe had higher concentrations along the west coast, while Mn and Fe proved more abundant along the east coast. Upon performing a Kruskal-Wallis test, Pb concentrations were marginally equal in all regions (\(H(3)=13.984\); N = 134; \(p=0.003\)), although a considerable number of outliers resulted from samples located in southern bays. None of the elemental concentrations studied have been proven similar across the different bays chosen for this study.