Organic and inorganic contaminants in marine sediments off northern Mozambique: Results from the R/V Dr Fridtjof Nansen environmental surveyFood & Agriculture Org., 16 nov 2020 - 80 pagine The report presents the results of the measurements of grain size, total organic carbon (TOC), hydrocarbons and metals in surface sediments (>100 samples) collected from 40 locations off the coast of northern Mozambique during an environmental survey in March–April 2018. The survey was carried out from the R/V Dr Fridtjof Nansen in the following areas: (i) Pemba – planned gas industry logistic base, (ii) Ibo Island (Quirimbas National Protected Area) to St. Lazarus Bank – the reference area, and (iii) Palma - gas exploration area. The contents of fine-grained fraction (<63 ?m) of the sediment varied strongly in all areas from coarse sediment to high mud contents, whereas TOC levels were generally low and correlated poorly with fine-grained fraction. Background levels of hydrocarbons and metals were found in most of the samples. Anthropogenic contamination was found at one site in Pemba harbour. No oil-related contamination was demonstrated, including the Palma area where gas exploration is concentrated. Elevated concentrations of barium and total hydrocarbon content at some locations in the Palma area are attributed to drilling activities but are not considered to be of environmental concern. Based on the measured concentrations of chemicals, background concentrations for the studied areas are proposed. |
Parole e frasi comuni
24 stations 25 Iron acenaphthene anthropogenic area Source Average concentrations barium baseline concentrations baseline metal concentrations baseline model upper cadmium Class I Background Class I limit collected at Station collected in northern concentrations in sediment concentrations of metals Dr Fridtjof Nansen EAF-Nansen Programme Eduardo Mondlane University eight stations exceeds the baseline grain iron concentrations Iron mg.g LAZ 9 Lazarus area manganese Maputo metals in surface mg.g¹ mg/kg dry weight model upper prediction models and baseline mud fraction contents naphthalene NEA classification NEA condition classes northern Mozambique organic carbon TOC Palma area Pemba area Pemba harbour percent perylene phenanthrene polycyclic aromatic hydrocarbons R/V Dr Fridtjof reflects contamination samples from 24 samples from eight Santo Espirito estuary sediment characteristics sediment samples collected sediment sampling stations Station LAZ Station PEM Summary statistics surface sediment samples survey three sediment samples total organic carbon upper prediction limit wellheads µg/kg dry