Evaluating the responses of taxa in the orders Ephemeroptera, Plecoptera and Trichoptera (EPT) to sediment stress in the Tsitsa River and its tributaries, Eastern Cape, South Africa.
Akamagwuna FC1, Mensah PK2, Nnadozie CF2, Odume ON3.
Author information
1
Unilever Centre for Environmental Water Quality, Institute for Water Research, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa. akamagwunafrank@yahoo.com.
2
Unilever Centre for Environmental Water Quality, Institute for Water Research, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa.
3
Unilever Centre for Environmental Water Quality, Institute for Water Research, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa. nelskaro@yahoo.com.
Abstract
Excessive delivery of fine sediment has been implicated as the main water quality stressor in the Tsitsa River catchment. This study evaluates the responses of the taxa Ephemeroptera, Plecoptera and Trichoptera (EPT) to suspended sediment and grain size distribution in eight selected study sites in the Tsitsa River catchment. The sampling of macroinvertebrates took place seasonally from August 2016 to April 2017 and EPT identified to either genus or species level. To avoid site redundancy, the sites were clustered into four groups, with groups 1 and 2 being more impacted when compared to groups 3 and 4. The results of the sediment grain size analysis revealed that sediment grain size distribution ranged from 0.121 to 5.61 μm; percent clay and percent silt were the most dominant sediment fractions across all groups. Among the EPT metrics examined, Shannon index, Simpson's index, evenness, Ephemeroptera abundance, EPT abundance and Trichoptera abundance were sensitive, differentiating between sediment groups 3 and 4 (less impacted groups) from 1 and 2 (highly impacted groups). Site groups 3 and 4 supported more EPT species, in terms of the number of individuals and diversity. Species such as Caenis sp., Pseudocloeon glaucum, Oligoneuropsis lawrencei and Baetis sp. were considered sediment-tolerant, displaying strong positive association with influenced groups. Taxa such as Hydropsyche sp., Pseudocloeon sp., Cheumatopsyche sp. and Afronurus sp. were considered sediment-sensitive. Overall, the present study revealed that genera/species within the order EPT were differentially sensitive to fine sediment stress and grain sizes, proving to be useful bioindicators.

KEYWORDS:
EPT metrics; Fine sediment grain sizes; Macroinvertebrates; Sediment-tolerant; South Africa; Tsitsa River

PMID: 31650234 DOI: 10.1007/s10661-019-7846-9
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22.
Environ Monit Assess. 2019 Oct 23;191(11):660. doi: 10.1007/s10661-019-7819-z.
A study of the radiological baseline conditions around the planned Sinop (Turkey) nuclear power plant using the mapping method.
Baltas H1, Yesilkanat CM2, Kiris E3, Sirin M3.
Author information
1
Department of Physics, Faculty of Arts and Science, Recep Tayyip Erdoğan University, 53100, Rize, Turkey. hasan.baltas@erdogan.edu.tr.
2
Science Teaching Department, Faculty of Education, Artvin Çoruh University, 08000, Artvin, Turkey.
3
Department of Physics, Faculty of Arts and Science, Recep Tayyip Erdoğan University, 53100, Rize, Turkey.
Abstract
This study makes a first attempt at a detailed estimation of the background radioactivity level and its distribution at the Sinop nuclear power plant site. The activity concentration levels of 226Ra, 232Th, 40K and 137Cs radionuclides in soil samples collected from 88 locations around Sinop Province, Turkey, in November 2016, were measured using gamma spectrometry. The distributions of radionuclide levels obtained from the results were evaluated using a geostatistical method, and the estimated radiation levels were determined using the ordinary kriging (OK) method, which is the best linear unbiased estimator (BLUE) for unmeasured points. Estimates of distribution results were evaluated using cross-validation diagrams, and it was shown that the OK method could predict radiological distributions for appropriate criteria. Finally, using the kriging parameters, distributions of radiation levels for the entire work area were mapped at a spatial resolution of 100 × 100 m2. These maps show that the natural radionuclides (226Ra, 232Th and 40K) are distributed at higher levels to the southeast of Sinop than in the other regions, and the activity of an artificial radionuclide (137Cs) is high in the interior and northern sections.

KEYWORDS:
Baseline data; Nuclear power plant; Radiological map; Sinop Province; Soil

PMID: 31646407 DOI: 10.1007/s10661-019-7819-z
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