Impact of rapid urbanisation and industrialisation on river sediment metal contamination

Abstract

This study aimed at evidencing contaminant inputs from a rapidly growing population and the accompanying anthropogenic activities to river sediments. The Fez metropolitan area and its impacts on the Sebou's sediments (the main Moroccan river) were chosen as a case study. The Fez agglomeration is surrounded by the river Fez, receiving the wastewaters of this developing city and then flowing into the Sebou. The sediment cores from the Fez and Sebou Rivers were extracted and analysed for major elements, butyltins and toxic metals. Normalised enrichment factors and geoaccumulation index were calculated. Toxicity risk was assessed by two sets of sediment quality guideline (SQG) indices. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments in upstream of Fez city, whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which is a clear signature of recent inputs from the untreated wastewaters of Fez city. Consequently, the sediments of Fez and Sebou at the downstream of the confluence were found to be potentially toxic, according to the SQG levels. This finding is concerned with aquatic organisms, as well as to the riverside population, which is certainly exposed to these pollutants through the daily use of water. This study suggests that although Morocco has adopted environmental regulations aiming at restricting pollutant discharges into the natural ecosystems, such regulations are neither well respected by the main polluters nor efficiently enforced by the authorities.

Incorporation of zinc for fabrication of low-cost spinel-based composite ceramic membrane support to achieve its stabilization

“…The pollution of ground and surface water by hazardous metal ions is becoming an increasing public concern [1][2][3] in many regions of the world. Hazardous metals, such as zinc, copper, magnesium and nickel [4][5][6], are released into the natural environment, entering the food chain through drinking water and crop irrigation, which results in various human health problems such as diseases and disorders when exceeding their specific limits [7][8][9].…”

Historical levels of heavy metals reconstructed from sedimentary record in the Hejiang River, located in a typical mining region of Southern China

“…This value is lower than the average abundance of Al (6.5%) in sedimentary rocks in Guangxi, China (GEPI, 1992), which might contribute to the low amount of agricultural reclamation and aquaculture development. The fairly constant trend of Al concentrations, which had a low variability of 20% in the core C1 indicates that particles routinely settled (Hayzoun et al, 2014). Fe was well correlated with Al (Table 5a) and varied in concentration from 5.2% to 11.8%, which is higher than the average value in soils in Guangxi (3.8%).…”

Effects of Aquaculture on Lakes in the Central Yangtze River Basin, China, III: Heavy Metals

“…Furthermore, trace elements can be adsorbed to organic substances and minerals, such as clays and Mn and Fe oxides (Hayzoun et al. ).…”

“…Another factor that could affect accumulation of heavy metals in sediments is biogeochemical processes (Charriau et al 2011) as well as their relative mobility or degradation under varying redox conditions. Furthermore, trace elements can be adsorbed to organic substances and minerals, such as clays and Mn and Fe oxides (Hayzoun et al 2014).…”