The concentrations of Cu, Co, Zn, Ni, V, and Cr in topsoils at six sites located along the lower slopes of Mt. Cameroon were assessed for their potential toxicity to humans and the ecosystem. Soils were collected from horizons down to a depth of 70？cm and analysed for trace element concentration by ICP-MS technique. The Dutch soil quality standards which use %clay/silt and organic matter content to derive target values were used to assess the contamination levels of the soils. The content of these soils was also compared to the United Kingdom ICRCL “soil trigger” values. Zinc and Cu values were persistently below the normal value (A) and occurred in the lower elevation, the region of extreme weathering, while Cr and V values were above the intervention (C) values. The high content of Cr in common fertilisers poses a potential risk in toxicity in the higher elevations experiencing lower weathering rates, where soil Cr levels are elevated. 1. Introduction Many trace elements are essential macro- and micronutrients for humans, plant growth, and the maintenance of healthy ecosystems. Micronutrients like Cu, Mn, Se, and Zn can be toxic at high concentrations in the soil. Trace elements unknown to be essential to plant growth, such as barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), and nickel (Ni), are toxic at high concentrations or under certain environmental conditions in soils. One of the major factors controlling soil trace element content is the parent rock material. Soils vary across landscapes and rock weathering and other soil-forming processes may result in the addition or removal of these elements from the soil. High background concentrations of trace elements, whether from natural or anthropogenic sources, could result in mobilization and release into surface and subsurface waters and subsequently incorporation into the food chain. Soil factors such as organic matter, type and amount of clay, pH, and cation exchange capacity (CEC) influence the quantity of trace elements available for mobilization and release or sorption in a soil [1]. Regulations to protect humans and the environment from toxicities and deficiencies related to trace elements are primarily based on soil quality reference values which are being developed in many countries. Many countries that have not developed their own formal guidelines follow the “Dutch standard” to support decision-making in assessing and monitoring soil quality. The Dutch are improving their soil quality in light of new scientific work particularly with regard to the impact of listed substances on living
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