This study was done to investigate the effects of common food additives such as sodium benzoate (SB) and ascorbic acid (AA) on haematological parameters of male Wistar rats. Forty-eight (48) male albino rats with an average weight of 105 g were grouped into twelve (n = 4) of Basal Control and other 11 groups orally administered 1 mg of SB, 10 mg of SB, 10 mg of AA, 0.2 mg of AA + 0.5 mg of SB, 0.2 mg of AA + 1 mg of SB, 0.2 mg of AA + 10 mg of SB, 0.2 mg of SB + 0.1 mg of AA, 0.2 mg of SB + 0.5 mg of AA, carbonated soft drinks (CSD)+ 0.1 mg of AA, CSD + 1 mg of AA and CSD + 10 mg of AA, respectively for 21 non-consecutive days. At the end of the experiment, blood samples were collected in EDTA anticoagulant tubes, haematological parameters were evaluated, and data were analyzed. There was a dose-dependent increase (p < 0.05) in White Blood Cell counts of SB treated rats compared with the control group. The lymphocyte exhibited significant reduction (p < 0.05) in the groups treated with 1mg SB and 10mg SB/kg bodyweight of 67 ± 2.96 and 58 ± 4.18%, respectively. The mean corpuscular haemoglobin showed no significant difference at 95% confidence interval. However, mean corpuscular haemoglobin concentration, haematocrit and platelet were affected by an increase in the concentrations of SB. High SB concentrations increased the destruction of erythrocytes, which directly increased the catabolism of haemoglobin. However, AA administration mitigated the adverse effects of SB on the haematological parameters of the animal.

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Mhlathuze Estuary constitutes one of the ecological most important estuaries in southern Africa and is regarded as an estuary of high conservation importance. The ongoing expansion of the adjacent industrialized Richards Bay Harbour increases the risk of metal pollution to the estuary. This study provides insight into the extent and sources of trace metal contamination using pollution indices and sediment quality guidelines and the effect on macrobenthic habitat quality. Sediment samples for sediment metal and macrobenthic analysis were collected quarterly during 2016-2017 at five sites in the estuary using a marine-grade Zabalocki grab. Metal concentrations were determined using an ICP-OES. Sediment metal concentrations were consistently highest in the subtidal mudflats and lowest in marine sand at the mouth of the estuary. Concentrations of all metals displayed significant differences between sites (P < 0.05). Pollution indices indicated moderate enrichment of Cr at all sites, although the mean pollution load index showed the estuary to be unpolluted. Comparison with sediment quality guidelines revealed that concentrations of Ni and Cr were potentially toxic to biota. Using multivariate analysis, metal concentrations appeared not to significantly affect the macrobenthic community. The multi-metric biotic index M-AMBI proved to be a robust tool in the habitat quality assessment of the estuary. The continuing use of M-AMBI as a biomonitoring tool for ecological management of the estuary is advocated.

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