The Fate of Copper Added to Surface Water: Field, Laboratory, and Modeling Studies

International audienceThe fate and effects of copper in the environment are governed by a complex set of environmental processes that include binding to inorganic and organic ligands in water, soil, and sediments. In natural waters, these interactions can limit copper bioavailability and result in copper transport from the water column to the sediment. In the present study, data on the fate of copper added to lakes, microcosms, and mesocosms were compiled and analyzed to determine copper removal rates from the water column. Studies on copper behavior in sediment were also reviewed to assess the potential for remobilization. A previously developed, screening-level fate and transport model (tableau input coupled kinetic equilibrium transport-unit world model [TICKET-UWM]) was parameterized and applied to quantify copper removal rates and remobilization in a standardized lake setting. Field and modeling results were reconciled within a framework that links copper removal rates to lake depths and solids fluxes. The results of these analyses provide converging evidence that, on a large scale, copper is removed relatively quickly from natural waters. For the majority of studies examined, more than 70% of the added copper was removed from the water column within 16 d of dosing. This information may be useful in the context of environmental hazard and risk assessment of copper. Environ Toxicol Chem 2019;38:1386-1399. (c) 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETA

Appraisal of salinity and fluoride in a semi-arid region of India using statistical and multivariate techniques

“The original publication is available at www.springerlink.com”. Copyright Springer. DOI: 10.1007/s10653-008-9222-5Various physico-chemical parameters, including fluoride (F−), were analyzed to understand the hydro-geochemistry of an aquifer in a semi-arid region of India. Furthermore, the quality of the shallow and deep aquifer (using tube well and hand pumps) was also investigated for their best ecological use including drinking, domestic, agricultural and other activities. Different multivariate techniques were applied to understand the groundwater chemistry of the aquifer. Findings of the correlation matrix were strengthened by the factor analysis, and this shows that salinity is mainly caused by magnesium salts as compared to calcium salts in the aquifer. The problem of salinization seems mainly compounded by the contamination of the shallow aquifers by the recharging water. High factor loading of total alkalinity and bicarbonates indicates that total alkalinity was mainly due to carbonates and bicarbonates of sodium. The concentration of F− was found more in the deep aquifer than the shallow aquifer. Further, only a few groundwater samples lie below the permissible limit of F−, and this indicates a risk of dental caries in the populace of the study area. The present study indicates that regular monitoring of groundwater is an important step to avoid human health risks and to assess its quality for various ecological purposes.Peer reviewe

Evaluation of hydrochemical characteristics and flow directions of groundwater quality in Udi Local Government Area Enugu State, Nigeria

A hydrogeological study was conducted at the Udi Local Government Area in south-eastern region of Nigeria to examine the hydrochemical constituent of groundwater and determine the quality for drinking and agricultural purposes. Results show that groundwater in the area is slightly acidic to slightly basic, soft and potable, when compared with the World Health Organisation standards for drinking water, and is suitable for agricultural purposes. The groundwater flow direction was determined to establish the implications of pollution from any water contamination. Twenty-one groundwater samples from existing boreholes were collected and analysed for various physicochemical parameters using standard field and laboratory techniques. Distribution of major ions was plotted on a Trilinear Piper diagram. Ajali Sandstone, known as major aquiferous layer in the area, outcrops predominately in sandy bed with medium to coarse-grained sediments. The aquifers are unconfined, semi-confined and with hydraulic conductivity values ranging from 9.0 x 10(-2) to 8.5 x 10(-2) m/day indicating medium transmissivity of groundwater in some areas and a flow net south to northward groundwater flow towards the coast. This explains why the aquifer does not appear to be very permeable and only provides a medium yield of good quality water in some regions of the study area