Nickel, vanadium, and lead as indicators of sediment contamination of marina, refinery, and shipyard areas.

Metallic elements found in the aquatic environment may originate in areas where petroleum is refined and vessels are maintained and repaired. This study aims to assess contamination caused by nickel (Ni), lead (Pb), and vanadium (V) in sediment of the Lagoa dos Patos estuary (RS, Brazil) and to evaluate them as indicators of areas under the influence of petroleum products and antifouling paints. Surface sediments were collected in summer and in winter in areas of marinas, shipyards, refinery, and a control station.

2,2'-Dihydroxy-N,N'-(ethane-1,2-di-yl)di-benzamide.

The asymmetric unit of the title compound, C(16)H(16)N(2)O(4), contains one half-mol-ecule, the whole mol-ecule being generated by an inversion center located at the mid-point of the C-C bond of the central ethane group. An intra-molecular O-H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, mol-ecules are connected via N-H⋯O hydrogen bonds, generating infinite chains along [1-10].