Heavy Metals and Nutrients Loads in Water, Soil, and Crops Irrigated with Effluent from WWTPs in Blantyre City, Malawi

Abstract

Heavy metals may cause acute and chronic toxic effects to humans and other organisms, hence the need to treat wastewater properly, as it contains these toxicants. This work aimed at assessing zinc, copper, cadmium, and chromium in water, soil, and plants that are irrigated with effluent from Manase and Soche Wastewater Treatment Plants (WWTPs) in Blantyre, Malawi. Atomic Absorption Spectrophotometry (AAS) was used to assess the heavy metals. Heavy Metal Health Risk Assessment (HMHRA) on plants (vegetables) around both WWTPs was also conducted. Average daily dose (ADD) and target hazard quotients (THQ) were used to assess HMHRA. Physicochemical parameters were determined using standard methods from American Public Health Association (APHA). The heavy metal ranges were below detection limit (BDL) to 6.94 mg/L in water, 0.0003 to 4.48 mg/kg in soil, and 3 to 32 mg/L in plants. The results revealed that plants irrigated with effluent from WWTP had high values of aforementioned metals exceeding the Malawi Standards and WHO permissible limits. Furthermore, the health risk assessment values showed that vegetables consumed for a long period of time from Manase WWTP were likely to cause adverse health effects as compared to those from Soche WWTP.

Applications of Omics in Plant-Microbiome Interactions

“…The fungal families selected only in treated tobacco rhizosphere were Saccharomycetales-incertaesedis and Trichocomaceae, belonged to phyla of Ascomycota and Basidiomycota respectively. Furthermore, Saccharomycetales-incertaesedis and Trichocomaceae are both involved in bioremediation of heavy metals, especially cadmium, lead, chromium, nickel, copper, and manganese (Malikula et al, 2022). Thus, as mentioned before, these fungal families may have protected the plants by degrading the heavy metals introduced with HTL-WW.…”

Valorisation of hydrothermal liquefaction wastewater in agriculture: effects on tobacco plants and rhizosphere microbiota

“…The fungal families selected only in treated tobacco rhizosphere were Saccharomycetales-incertae-sedis and Trichocomaceae, belonged to phyla of Ascomycota and Basidiomycota respectively. Furthermore, Saccharomycetales-incertae-sedis and Trichocomaceae are both involved in bioremediation of heavy metals, especially cadmium, lead, chromium, nickel, copper, and manganese ( Malikula et al., 2022 ). Thus, as mentioned before, these fungal families may have protected the plants by degrading the heavy metals introduced with HTL-WW.…”

Optimization and modelling of Pb (II) and Cu (II) adsorption onto red algae (Gracilaria changii)-based activated carbon by using response surface methodology

“…Heavy metals are non-biodegradable elements that have many toxicological effects on human health and are detrimental to the environment. They can accumulate in living organisms, causing diverse health effects and eventually becoming fatal to humans [3][4][5][6].…”

“…Surface physical properties of both DRA and RAAAdsorbentProperties References 1 S BET (m 2 /g) 2 S mic (m 2 /g) 3 S Lang (m 2 /g) 4 S ext (m 2 /g) 5 V total (cm 2 /g)6 V mic (m 2 /g) 7 D P (nm)…”