Environmental quality in sediments of Cadiz and Algeciras Bays based on a weight of evidence approach (southern Spanish coast)

The proposed method provides a single result, the environmental degradation index (EDI). EDI defined samples as low degraded (outer areas of both bays) and moderately degraded (Inner Bay of Cadiz Bay, the surroundings of Algeciras port and the northern part of Algeciras Bay). These samples showed the highest concentration of aqua regia extractable metals, which exceeded effects range-low (ERL) for Zn (51-176 mg/l), Cu (11-54 mg/l), As (4.3-9.5 mg/l), Hg (0.17-0.28 mg/l), Ni (23-82 mg/l), and. Cr (37-134 mg/l). They also exceeded some quality criteria for total organic carbon (4.0-6.5%) and toxicity (120-240 TU/g) and showed poor results for macrobenthic community.