NEI indicates the contribution of heavy metals with a concentration not exceeding the highest desirable limit (I i) in the water sample, while vice versa regarding the PEI. Water quality increases with the decrease of PEI and NEI values. The water worthiness is assessed based on a pair of indices, NEI and PEI.
As per the new indexing approach, heavy metal contamination in water samples is evaluated by two types of indices: the negative evaluation index (NEI) and positive evaluation index (PEI). It is created in order to avoid the weaknesses of the current indexing systems. The new approach is developed based on the most frequently used methods for indexing heavy metals pollution in water. The present study proposes a new approach for indexing heavy metals ions to examine groundwater quality in North Kurdufan Province, Sudan.
