Soil Contamination and Bioaccumulation of Heavy Metals by a Tropical Earthworm Species (<i>Alma nilotica</i>) at Informal E‐Waste Recycling Sites in Douala, Cameroon

Nfor, Brian; Fai, Patricia Bi Asanga; Tamungang, Simon Awafor; Basu, Niladri

doi:10.1002/etc.5264

Cited by 11 publications

(6 citation statements)

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“…Lanno et al ( 2019) also reported over 10-fold difference in Pb BAFs in earthworms across 6 soil treatments. Although Pb and Cr showed up as the more bioaccumulative metals, Alma nilotica is capable of quickly eliminating them when taken out of the contaminated medium unlike Cu and Zn which are only slowly eliminated (Nfor et al, 2022b). No correlation was found between the BAFs and the metal concentrations in either the soil or earthworms.…”

Section: Resultsmentioning

confidence: 89%

“…In Cameroon, for example, increased environmental contamination with heavy metals continues to be a subject of major concern. Studies conducted in various localities of the country (Defo et al, 2015;Mofor et al, 2017;Blanchard et al, 2018;Nfor et al, 2022a;Nfor et al, 2022b) have revealed soils contaminated with heavy metals at non-negligible levels from various anthropogenic activities including mining, industrial activities, addition of chemical fertilizers and pesticides, as well as transportation, dumping and discharge of waste electrical and electronic equipment.…”

Section: Introductionmentioning

confidence: 99%

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Association between heavy metal uptake and growth and reproduction in the anecic earthworm, Alma nilotica (Grube 1855)

Fai,

Ngogang,

Kouemo

et al. 2023

Ecotoxicology

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Elevated heavy metal concentrations in soils is a cause for concern as they are hazardous to soil organisms including earthworms which are considered as ecosystem engineers. Current ecotoxicity tests predominantly use temperate earthworm species, and thus there is the need to include a broader genera of native species to improve ecological risk assessment. Alma nilotica, is a tropical anecic earthworm species that survives well under laboratory conditions and has potential for use in ecotoxicology testing but lacks published toxicity data for important pollutants. Growth and reproduction bioassays were carried out with Alma nilotica to determine the relationship between the concentrations of Cu, Zn, Pb and Cr in spiked soils and their bioaccumulation and toxic effects. Positive linear relationships were found between soil-metal and internal earthworm-metal concentrations. Cu did not inhibit growth up to 35 days of exposure but became toxic with longer exposure duration. Zn was not regulated by Alma nilotica although it is an essential metal that is well regulated by Eisenia sp. commonly used in standard ecotoxicity tests, showing differences in metal regulation by earthworms of different ecological functional groups. Based on bioaccumulation factors (BAFs), growth inhibition and reproduction effects the metals were ranked in decreasing toxicity as Pb > Cr > Zn > Cu. The mean 20% Internal Effects Concentrations (IEC20s) for reproduction were 1.03. 1.77, 10.2 and 218 mg metal/kg earthworm for Pb, Cr, Zn and Cu respectively. These data can contribute to the improvement of metal risk assessment particularly in tropical contexts.

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Section: Resultsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Association between heavy metal uptake and growth and reproduction in the anecic earthworm, Alma nilotica (Grube 1855)

Fai,

Ngogang,

Kouemo

et al. 2023

Ecotoxicology

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“…Earthworms bioaccumulate toxic substances from the soil substrate in their body tissues [84,85]. This process is pertinent to food safety because human industrial activities have released a number of toxic chemicals into the soil which pose a risk to human health should they enter the food chain [86].…”

Section: Foraged Earthworms May Be Harmful For Humansmentioning

confidence: 99%

Can foraging for earthworms significantly reduce global famine in a catastrophe?

Miller,

Mulhall,

Pfau

et al. 2024

Preprint

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Earthworms are a resilient group of species that thrive in a variety of habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, such as a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine following a reduction in sunlight with or without global catastrophic loss of infrastructure was considered. Methods for extracting worms were analysed, along with scalability, climate-related barriers to foraging, and pre-consumption processing requirements. Estimations of the global earthworm resource suggest it could provide three years of the protein needs of the current world population, at a median cost of 353 USD·kg−1 dry carbohydrate equivalent or a mean cost of 1200 (90% confidence interval: 32–8500) USD·kg−1 dry carbohydrate equivalent. This is more expensive than other resilient food options and, moreover, earthworms may bioaccumulate heavy metals and other contaminants, presenting a health risk. While costs appear high, there are a number of uncertainties that remain to be addressed. In particular, earthworm biomass distribution may be higher in specific locations. Real-world news reports of earthworm foraging in China and Vietnam detail high yields, suggesting a targeted approach to foraging in the most abundant regions could provide a more feasible application of earthworms as a resilient food source.

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“…The average daily intakes (ADI mg/kg/day) were determined by the following Equation according to Nfor et al 12 :…”

Section: Exposure Assessmentmentioning

confidence: 99%

Health Risk Assessment of Heavy Metals in Groundwater Around Some E-Waste Dumpsites from Three States in Southwestern Nigeria

Odunaike,

Alausa,

Adejumobi

et al. 2023

Asian J. Biol. Sci

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Background and Objective:The e-waste dumpsites, among others, are eye sore in many developing countries, with damaging effects on public health and the environment. Although e-waste dumpsites are sparse, the few ones that exist may contain high levels of heavy metals released into the environment. Therefore, carcinogenic and non-carcinogenic health risks posed by heavy metals are used to determine the quality of groundwater in the study area. Materials and Methods: Thirty samples of groundwater from the hand-dug wells were collected, with five samples from each of the six stations. The elemental analysis of some toxic heavy metals was performed using an atomic absorption spectrophotometer. The data preparation and arrangement were carried out using Microsoft Excel. Results: None of the heavy metals were detected in samples of groundwater from Karakata Market, Akure. The results of the carcinogenic and non-carcinogenic tests for adults and children showed that hazard quotient and hazard index values were below one in all the pathways like inhalation, ingestion and dermal. This implies that the heavy metals posed no carcinogenic or non-carcinogenic threat to the inhabitants of the study area. The total cancer risks due to ingestion and inhalation revealed that ingestion was the principal exposure pathway. The total cancer risk for children and adults was within the acceptable limits of the United States Environmental Protection Agency and the World Health Organization. Conclusion: The study indicated that all the results were below the limit recommended. Therefore, no environmental or health risk is expected in the study areas. However, no matter how small the environmental and health risks may be, long-term exposure to heavy metals may be detrimental to human health.

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Soil Contamination and Bioaccumulation of Heavy Metals by a Tropical Earthworm Species (Alma nilotica) at Informal E‐Waste Recycling Sites in Douala, Cameroon

Cited by 11 publications

References 50 publications

Association between heavy metal uptake and growth and reproduction in the anecic earthworm, Alma nilotica (Grube 1855)

Association between heavy metal uptake and growth and reproduction in the anecic earthworm, Alma nilotica (Grube 1855)

Can foraging for earthworms significantly reduce global famine in a catastrophe?

Health Risk Assessment of Heavy Metals in Groundwater Around Some E-Waste Dumpsites from Three States in Southwestern Nigeria

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