Using scleractinian corals as monitors of essential and potentially toxic elements pollution in the southern Red Sea, Yemen Republic

Abstract

This study presents a long-term follow-up investigation into the pollution levels of two significant harbors, Al-Luhaya and Al-Saleef, in the southern Red Sea (Hodeidah/Yemen) using inductively coupled plasma optical emission spectroscopy (ICP-OES). In Al-Luhaya harbor, the mass fractions of elements followed the sequence: S > Al > Fe > Ba >Mn > Zn > V > Cu > Ni > Cr > Cd > Pb > Co, while in Al-Saleef, the sequence was S > Al > Fe > Ba >Mn > Zn > V > Ni > Cu > Cr > Pb > Co > Cd. Sulfur was the dominant element in corals, its mass fraction changing in the range of 1188–1567 mg kg⁻¹ in Al-Luhaya and 2066–3047 mg kg⁻¹ in Al-Saleef. According to the Wilcoxon test, only the content of Zn in Al-Saleef corals was significantly higher than in Al-Luhaya ones. Correlation and principal component analyses were employed to disclose the elements’ relationship and associate them with pollution sources. The primary sources of the elements accumulated in corals are port activity, sewage discharge, and terrigenous input. The pollution load index and contamination factor were utilized to evaluate the extent of environmental pollution. The contamination factor values between 1 and 3.5 point at slight pollution with Fe in Al-Luhaya, while in Al-Saleef it was noted suspected contamination with Zn and Ni, and moderate pollution with Fe. The mass fractions of the elements in the present study were comparable or lower than values reported for corals collected in different zones of the Red Sea.