Data to understand the biotransfer of heavy metals along the soil-plant-edible insect-human food chain in Africa.

Data on the biotransfer of heavy metals along the soil-plant-edible insect-human food chain collected along a 60km pollution gradient is presented here. These datasets consists of concentrations of eight heavy metals (Arsenic, Cadmium, Copper, Chromium, Iron, Nickel, Lead and Zinc) in the soils, in five host plants species, and in seven edible insect species determined using Atomic Absorption Spectrophotometry (AAS). Datasets for the daily intake of metals and target hazard quotients for each edible insect species are also given. These data demonstrate the potential biotransfer of heavy metals along the soil-plant-edible insect-human food chain, and that edible insects harvested in heavy metal-polluted environments could pose serious health risks. These datasets provide further understanding of the relationships among metal concentrations in the soils, host plants and edible insects, particularly in the mining regions. For further details, refer to the article, "Biotransfer of heavy metals along the soil-plant-edible insect-human food chain in Africa" Mwelwa et al., [1].

Biotransfer of heavy metals along the soil-plant-edible insect-human food chain in Africa.

Although mining is Zambia's major economic activity, it is implicated in environmental contamination, particularly with heavy metals. This study investigated the accumulation and transfer of heavy metals along the soil-plant-edible insect-human food chain. Our results revealed the presence of eight heavy metals (Arsenic, Cadmium, Chromium, Copper, Iron, Nickel, Lead, and Zinc) with a 28-60 % increase in soil concentrations at the proximity of the mining facilities. There was a higher accumulation of Cd, Cu, Ni, Fe, Pb, and Zn than As and Cr in plant species near the mine. Among the insect species studied, C. forda accumulated nickel significantly higher (70-81 %), I. obscura had higher cadmium (2-84 %) and lead (10-79 %), while I. rubra and M. falciger accumulated higher iron (41-96 %) and zinc (1-67 %), respectively, than other insect species. The quantity of I. obscura consumed (248 g person-1 day-1) was significantly higher (9-37 %) than other insect species. It was noted that the consumption of insects increased the daily intake of heavy metals, enhanced the target hazard quotient, and increased the associated health risks by up to 9 folds compared to the WHO permissible limits meaning that the daily intake of metals consumed depends on the daily quantity of insects consumed. Our findings suggest that the accumulation of heavy metals along the soil-plant-edible insect-human food chain could pose severe human and environmental health risks along the mining gradients. The potential consequences of heavy metal mobility in the consumer trophic levels and the ecotoxicological consequences are particularly concerning. Furthermore, physiological and biological studies are needed to investigate the abovementioned effects.

Tree-ring chronology data of non-native Pinus kesiya (Royle ex Gordon) in Zambia.

Although Pinus kesiya (Royle ex Gordon) is endemic to South Asia, where it grows naturally in pure stands, its growth trajectory in Zambia has not been evaluated. It is estimated that half of the P. kesiya plantation total area is found close to the Copper mine smelters, and the other half is in remote locations approximately 30 km away from the mining activities. Variation in tree growth of non-native P. kesiya forests between these locations in Zambia has been observed, but the causes are unknown. We tested the hypotheses that (i) P. kesiya annual tree-rings are cross-datable, (ii) the signals and noise in the growth ring patterns are modulated by variations in precipitation, temperature, solar radiation, and site conditions. We collected data from 67 trees growing close to the emission source and also in the location 30 km away. Site-specific tree ring-width data was collected and chronology built for P. kesiya. We present ring-width chronology data that may be used to infer the radial growth periodicity of P. keskya at each site. The re-use potential of the data presented includes developing carbon sequestration, yield, and growth models and assessing forest resilience to climate change. It is also intended to enhance the understanding of tree growth and productivity dynamics of non-native pine species. See the article "Assessing cross-datable distinct annual growth rings in non-native Pinus kesiya Royle ex Gordon in Zambia" for more information.

Data for modeling the height and diameter of Pinus merkusii and P. michoacana in Zambia.

Data on tree height and diameter of non-native Pinus merkusii (Jung. & de Vriese) and Pinus michoacana (Martinez) collected from Zambia's non-native forest plantations is presented here. A total of 1542 and 1883 pairs of height and diameter datasets for developing and testing the models are presented, respectively. During a five-year interval forest inventories, data collected supported the development of allometric relationships between height and diameter for the country's two species. Datasets are intended to be reused for various purposes to enhance the understanding of the tree height and diameter relationships of new and existing planted non-native species in Zambia. For detailed examples of the application of this data, see the article, "Stand characteristics and climate modulate height to diameter relationship in Pinus merkusii and P. michoacana in Zambia" Ng'andwe et al., 2021.

Data on tree height and diameter for Pinus kesiya in Zambia.

Forest inventories in plantations of non-native trees are conducted every five years in Zambia. Characteristics of data collected through these inventories are presented here. The data includes diameter at breast height (d), total tree height (h) and rotation categories for trees sampled. This data supported the development of robust h-d models for planted Pinus kesiya in the country. We have also presented graphical visualization of the composition and trends of the data by site and rotation. Datasets were filtered and cleaned and are ready to be used for other purposes in order to improve understanding of P. kesiya growth. For more insight please see "Modeling the height-diameter relationship of planted Pinus kesiya in Zambia" (Ng'andwe et al., 2019).

Variation of heavy metal contamination between mushroom species in the Copperbelt province, Zambia: are the people at risk?

BACKGROUND: Heavy metal contamination in mushrooms and the associated health risk are unknown in Zambia. We studied seven heavy metals and 23 mushroom species and interviewed 400 people. RESULTS: Mushrooms were found to contain substantial concentrations of Cu (894.4 ± 267.9 µg g-1 ) and Fe (998.4 ± 454.0 µg g-1 ). Significant differences in transfer factors of metals occurred between mushroom species (F11,66  = 5.36, P < 0.001). The most efficient were L. kabansus (for Zn and Ni), A. miomboensis (for Cu and Fe) and T. clypeatus (for Mn, Pb and Co). These species were also among the most preferred mushrooms for consumption based on the interviews conducted. Although 60% of the mushrooms observed were edible, only 20% were frequently consumed during the mushroom season. High positive correlations observed between soils and mushrooms suggest that contamination in mushrooms increases with soil pollution. The estimated daily intake of metals and the target hazard quotient through mushroom consumption were found to be significantly influenced by mushroom species (F11,66  = 38.8, P < 0.001) suggesting that the level of exposure to heavy metals depends on the species of mushroom consumed. CONCLUSIONS: The study has revealed that heavy metal concentrations in mushrooms exceed permissible limits and vary between species. Transfer efficiency also varies between mushroom species and contamination in mushrooms increases with soil pollution. The fact that concentrations of metals in soil were significantly high, the risk of exposure through mushroom consumption and possibly soil ingestion is even higher. © 2019 Society of Chemical Industry.