Impact of elemental chemistry on water quality in Missouri reservoir

Abstract

Natural (weathering) and anthropogenic sources (e.g., sewage discharges, agricultural activities/fertilizers, mining, atmospheric deposition) contribute to the pollution of freshwater ecosystems (e.g., lakes, streams, etc.). The impact of pollution through trace elemental and sediment discharge in freshwater due to the bioaccumulation and biomagnification effects of methyl mercury (MeHg) has been reported in recent studies. Elevated Hg concentration in fish has been found in some lakes and new impoundment reservoirs. Thus, this study investigates the presence of Mercury (Hg), arsenic (As), cadmium (Cd), selenium (Se), lead (Pb), nickel (Ni), and zinc (Zn) to determine the composite of whole-body largemouth bass (LMB; Micropterus salmoides) samples across three Missouri Lakes (Port Hudson, Buffalo Bill, and Ben Branch reservoirs). Hg was measured by atomic absorption spectrometry while other elements were determined by inductively coupled plasma – optical emission spectrometry. Our results were compared with the US EPA Standard values to determine the concentration of 26 elements (Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Se, V, Zn, B, Hg, Pb, P, Tl, Be, Ba, Sb, Ag, Al, and As). The results show a strong interrelationship of some water quality variables due to similarities in the chemical characteristics. In addition, the weekly intakes of trace elements compared with regulatory thresholds (US EPA) and the non-carcinogenic and carcinogenic risks via the consumption of muscle were observed.

Influence of some abiotic parameters on the biodiversity of macroarthropods in the "lep-liye" forest stream

“…The level of the water column is high during the rainy season, so the dynamics of the hydraulic gradient oscillate according to the elements of seasonality and the rain regime (ONEMA, 2015) [12] . The relatively low average temperature in the Lepliyè stream would be linked to the presence of forest which would obstruct the sun's rays, this result is similar to that obtained by (Ngoay-Kossy et al 2018) [2] in the Nguitto forest stream in the CAR which had also obtained a low average temperature, this was justified by some authors by the presence of the canopy which limits incident solar radiation, the main source of contribution energy in hydro-systems (Ngoay-Kossy et al, 2018; Webb and Zhang, 2004 ; Vannote, 1980) [2,13,14] .…”