China
Africa
Explore chapters and articles related to this topic
Chlorinated Hydrocarbons
Published in Michael J. Kennish, Ecology of Estuaries: Anthropogenic Effects, 2019
PCB concentrations in bottom sediments vary widely from very low levels in relatively uncontaminated marine areas80,81 to elevated readings in highly polluted estuarine and coastal marine systems (Table 7).69,82-84 Seafloor sediments largely untainted by anthropogenic inputs of PCB compounds usually contain concentrations of less than 25 ng/g dry weight. It is not uncommon for heavily contaminated systems to have PCB levels >1000 ng/g dry weight in sediments (e.g., Hudson River, New York Bight, and Escambia Bay). In those systems where PCB contamination occurs concomitantly with high rates of sedimentation (e.g., the Christiaensen Basin of the New York Bight and sections of the Husdon River), the organochlorine compounds can be buried rapidly and, in effect, removed from the general PCB cycle in a rather brief interval of time. Bioturbation by benthic organisms tend to counter this burial process, but ultimately, significant quantities of the compounds will accumulate at depth. Thus, West and Hatcher84 discerned substantial amounts of PCBs at depths >35 cm in the Christiaensen Basin, and Bopp et al.85 detected PCBs at depths >40 cm in the Hudson River.
Barrier Islands
Published in Paul D. Komar, J. Robert Moore, CRC Handbook of Coastal Processes and Erosion, 1983
The capacity for onshore-offshore sediment transport increases with the tide range. Furthermore, in areas of high tide range the wave energy is distributed across a wide shorezone during the tidal cycle. The result is that situations occur where tide dominance is strong enough to completely eliminate barrier islands, apparently regardless of the level of wave energy. On a worldwide basis it is found that barrier islands generally do not exist along coasts where the tide range is more than 4 m.40,76 This corresponds to the macrotidal category of Davies15 and is generally found only in embayments where resonance, shoaling, and funneling effects amplify the tide range to many times its open oceanic value.18 The central part of the German Bight,76 the Bay of Fundy, Canada,48 and Nushagak Bay, Alaska, are examples of such macrotidal embayments. Instead of forming barrier islands, the sand in such macrotidal embayments is deposited as linear, lunate, or sigmoidal shoals with their long axes parallel to the predominant tidal currents.
A CPT-based method for estimation of undrained shear strength of sands and transitional soils
Published in Guido Gottardi, Laura Tonni, Cone Penetration Testing 2022, 2022
The sites comprise Quaternary deposits with a predominantly sandy sedimentary profile with occasional clay layers associated with internal channelling (RVO, 2019; RVO, 2020). Sands are mainly fine and medium with occasional coarse size in some of the soil units. The sites have been subject to evolution throughout the Pleistocene and the Holocene. Sediments and processes from these time periods dominate the geological framework. Geological formations present at the two sites within the top 50 m below seafloor include (from older to younger) Yarmouth Roads, Eem, Naaldwijk and Southern Bight. These geological formations show no evidence of cementation. Figure 2 illustrates a microscopic photograph of a typical sand sample from the HKW site.
Geomorphic responses of uplifted mixed sand and gravel beaches: combining short-term observations from Kaikōura, New Zealand with longer-term evidence
Published in New Zealand Journal of Geology and Geophysics, 2023
Kate E. MacDonald, Deirdre E. Hart, Sebastian J. Pitman
MSG beaches, relative to other beach types, have been typically neglected in international coastal research (Dawe 2001; Mason and Coates 2001). They are less commonly studied than sand beach types. They are plentiful at high/low latitudes, such as in New Zealand, Canada and Alaska, where there is a high wave energy, cold climate (Buscombe and Masselink 2006) and para- or fluvio-glacial source of coarse sediment (Zenkovich 1967; Kirk 1980). However, existing literature surrounding MSG beaches is highly localised to New Zealand (Jennings and Shulmeister 2002), in particular Hawke’s Bay (Single 1985; Paterson 2000; Ivamy and Kench 2006; Komar 2010; Dickson et al. 2011; Brown 2017), the Canterbury Bight (Kirk 1969; McLean and Kirk 1969; Kirk 1980; Pitman et al. 2019a, 2019b) and Kaikōura (McLean and Kirk 1969; McLean 1970; Kirk 1975; Dawe 1997, 2001).
Late Quaternary geological history of the Sydney estuary, Australia
Published in Australian Journal of Earth Sciences, 2023
Pleistocene estuarine sequences overlying bedrock, or basal residual deposits, have been reported for many east coast estuaries (Thom & Roy, 1985; Thom et al., 1992). Paleochannels eroded into bedrock in Broken Bay (20 km north of Sydney) were filled with Pleistocene estuarine sand and clayey sand deposited during the LIG (Roy, 1983; Roy & Thorn, 1981). Basal fluvial sand in Botany Bay (in south Sydney) graded into estuarine mud with increasing peat interbeds deposited during the LIG (Albani et al., 1978; Roy, 1983). In the Newcastle Bight (120 km north of Sydney) and at the Moruya River (250 km south of Sydney), a Pleistocene basal estuarine clay was overlain by fluvial/deltaic deposits (Roy et al., 1980), and at Tuggerah Lake (65 km north of Sydney), bedrock channels were filled with at least two sequences of Pleistocene estuarine and fluvial/deltaic sands (Roy & Peat, 1973). At Lake Macquarie and Lake Illawarra (∼100 km north and south of Sydney, respectively), at least two estuarine cycles were evident (Sloss, 2005). A basal Pleistocene sequence appears to be widespread in central NSW estuaries and, where dated, is related to the LIG event.
Occurrence, Origin and Risk Assessment of Trace Metals Measured in Petroleum Tank-farm Impacted Soils
Published in Soil and Sediment Contamination: An International Journal, 2021
Onoriode O. Emoyan, Beatrice O. Peretiemo-Clarke, Godswill O Tesi, Wilson Adjerese, Efe Ohwo
The study area is located in Oghara town situated at 5° 35ʹ N, 6° 06ʹ E, with an average human population of 150,000 (, 2020). Oghara is host to many petroleum product tank farms storing about 300 million liters of petroleum products. The tank farms are situated beside the River Ethiope that flows through the Koko River to meet the sea at the Bight of Benin. Timber logging and fishing is the major occupation of the residents along the Ethiope and Koko River Basin, the navigation channel for petroleum product vessels. Forty-five samples obtained from 15 sites were collected at the top (0–15 cm), sub (15–30 cm), and bottom (30–45 cm) soil around the tank farms (TF) in September 2019. Using standard quality control and assurance measures, a composite soil sample was extrapolated from a quadruplet sample for the determination of the metals. Upon the removal of the topsoil debris, soil samples were collected with a stainless steel auger of 2.5 cm diameter probe. All materials used were thoroughly washed with 10% HNO3 and deionized water and then dried in a drying oven. The glassware used was soaked in 10% HNO3 for 12 hrs and washed twice with deionized water.