Although herbal medicines play an important role as a source of medicine, concerns have been raised about the risks posed by consumption of these plants, especially if consumed above permissible levels. This study was undertaken to assess the level of exposure, toxicity and health risk associated with the consumption of herbal plants in Ado Ekiti urban market, Nigeria. Ten commonly consumed herbal plants sold in Ado Ekiti urban market were subjected to heavy metal analysis. Health risk assessment was carried out to determine the estimated daily intake (EDI) of heavy metals, health risk index (HRI), target hazard quotient for non-carcinogenic risk and estimation of cancer risk (ECR). The EDIs for lead (Pb), nickel (Ni), chromium (Cr), copper (Cu) and magnesium (Mn) were above the upper tolerable daily intake reference for all studied plant species in both children and adults, an indication that herbal use poses a short-term to long-term health risk to consumers of these herbal products. The EDI for children was significantly lower compared to that of adults, indicating higher risks for adult consumers of these herbal products. The HRI in children for Pb (Alstonia congensis, Terminalia avicennioides, Aframomum melegueta, Cymbopogon citratus and Napoleona vogelii) were greater than 1; HRI in Cu and Mn also showed an unusually high concentration, an indication that long term exposure to the consumption of these herbal plants poses a serious health risk. The HRI in children and adults follows the order Mn > Cu > Ni > Pb > Cr; cadmium (Cd) was not detected in any of the herbal plants. The ECR for Pb, Ni and Cr present in the herbal plants for children ranged between 10⁻⁶ (low) to 10⁻³ (high), while the ECR for Pb, Ni and Cr for herbal plants for adults ranged between 10⁻⁵ (acceptable) to 10⁻² (unacceptable). For both children and adults, there is a call for concern due to ECRs above the acceptable range; the consumption of these herbal plants poses a long-term cancer risk. In both children and adults, ECRs for some of the herbal plants in the present study above the acceptable range present a risk to human health. The consumption of such herbal plants poses a long-term cancer risk. The authors declare no competing financial interests.

The Coronavirus disease (COVID-19) has been transmitted worldwide over a very short time after it originated in China in December 2019. In an attempt to control its spread and reduce its health impacts, several countries including those in the African continent imposed restrictive measures that was termed “lockdown”. The outcomes of this lockdown have been reported to be beneficial to air quality worldwide. The main objective of this study is to assess the impact of lockdown due to COVID-19 on nitrogen dioxide (NO₂) levels over six major cities in Nigeria. Maps extracted from satellite (Sentinel-5P) were used to indicate the significant reduction in the level of NO₂ in the selected cities in Nigeria during two time-intervals, pre-lockdown (December, 2019) and during lockdown (April, 2020). The results show a significant reduction in NO₂ levels during the lockdown period compared with its levels during the pre-lockdown period in 2019. The reduction in NO₂ concentration levels during lockdown is likely due to less traffic, social distancing and restrictions on business and human activities. There could be an element of uncertainty in the results due to seasonality, as the comparison is done with a different season. However, the magnitude of change due to lockdown is probably much higher than the seasonal variability. Although COVID-19 has negatively impacted the health and economic status of all regions worldwide, it has benefited some aspects of air quality in most countries including Nigeria. This indicates that anthropogenic activities may be managed to reduce air pollution and positively impact the health of human beings.

Heavy metal contamination in drinking water remains a pervasive global challenge with significant consequences for environmental quality and human health. This review synthesizes findings from recent studies examining heavy metal concentrations in different sources of drinking water, including municipal tap water, groundwater, surface water, and bottled/sachet water across various geographical regions. The study used a systematic review of studies published from 2015 to 2024. The result showed a variation in the concentrations of heavy metals from all the sources, with tap water generally exhibiting lower heavy metal levels. Pb, Fe, Mn, and other metals persist in different sources and from many regions with levels above the permissible limits recommended by the World Health Organization (WHO) in some instances, which were sometimes linked to aging distribution systems and other pollution sources. Bottled and sachet water, commonly regarded as safer alternatives, also showed some levels of heavy metals such as Pb, Cd, and Cr, reflecting inconsistent packaging or production oversight. Surface waters display variability with heavy metals pollution, driven by industrial discharge, mining activities, agricultural runoff, and urban wastewater inputs. Groundwater sources, although naturally shielded, frequently contained elevated concentrations of As, Hg, and Ni due to both geological and anthropogenic factors. Pb concentrations were below detection limit in some of the published papers; however, the values reported in this study ranged from ND to 260.0 µg/L (tap water), ND to 0.259 mg/L (surface water), ND to 0.791 mg/L (groundwater), and ND to 123.15 µg/L (bottled water). Arsenic (As) concentrations ranged from ND to 692 µg/L from different sources, with the highest concentration from groundwater. Collectively, these patterns underscore the need for strengthened monitoring frameworks, improved water treatment technologies, and integrated pollution-prevention strategies. Addressing heavy metal contamination in drinking water requires coordinated policy approach and continuous monitoring to reduce human exposure and safeguard global public health.