Page 25: of Marine Technology Magazine (June 2016)

Sampling Results at the Mouth of the Doce River

Summary of results from sampling at the Doce River mouth and in shallow coastal waters in front of the river mouth. The main negative effects to the river and ocean environments are the high concentrations of particu- late matter in suspension and the toxic potential of the metals found in waters.

• Particulate material in suspension silicon (65.58µM) e ammonia nitrogen • Before the arrival of the toxic mud to inside the river mouth, on November (2.32µM) near to the River mouth, and the river mouth, between 50 and 70 phy- 22 showed a concentration of 300mg/l usually on the surface. toplankton species were present in sam- on the surface and shallow coastal wa- ples. After the arrival of the mud, only ter concentrations on the surface of 200 • Quality and quantity analysis of the between 12 and 39 species were present mg/l reaching 8,700 mg/l on the sea- phytoplankton showed high chlorophyll in the samples.

bed. All sampling stations showed high values near the river mouth, with the concentrations on the seabed, decreasing highest values at 5.3 µg/l, which are • Concentration of metals found at the in concentration towards deeper waters. considered very high for coastal regions Doce River mouth and in shallow ocean even when near estuaries. waters: • Nutrient concentrations were also • Aluminum: River-surface (10mg/l); determined along the river and sea • Although no results have been at- Ocean-seabed (30mg/l) sampling stations. In the river high con- tained about the benthic community, the • Iron: River-surface (20 mg/l); centrations of nitrate (50.69 µM), am- high rates of sedimentation and high Ocean-seabed (50mg/l) monia nitrogen (9.07µM) and silicon concentration of metal on the seabed, • Chrome: River-surface (5mg/l); (175.47 µM) were observed. The analy- have the potential to signi? cantly impact Ocean-seabed (2mg/l) sis of ocean samples also points to high these communities. • Manganese: River-surface (5mg/l); concentrations of nitrate (26.48µM), Ocean-seabed (0.5mg/l) www.marinetechnologynews.com

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