Health risk assessment of metals in food crops and related soils amended with biogas slurry in Taihu Basin: perspective from field experiment

Abstract

A health risk assessment of food crops contaminated with heavy metals (Cu, Zn, Pb, As, Cd, and Cr) through the intake of cereals and vegetables grown from biogas slurry irrigated sites was conducted. In the vegetable soils and cereal soils, the concentrations of Zn, Pb, and Cd were far higher than Chinese agricultural standards. The pollution conditions of the aforementioned heavy metals varied with the seasons. Typically, the pollution was more serious in summer than in autumn. Furthermore, the accumulative properties of the heavy metals were different in the cereals and vegetables. In particular, Cu, Zn, and Pb tended to accumulate in rice with concentrations of 6.70, 36.58, and 4.14 mg kg(-1), respectively. Pb and Cd in cereals and vegetables exceeded the maximum permissible concentrations in China. The health risk assessment revealed that the daily intake (DI) and target hazard quotients (THQs) of Pb, As, and Cd in cereals and vegetables also exceeded the FAO/WHO limit. The results indicated that heavy metal contamination posed a severe health risk to local humans.

Effects of Pig Slurry as Basal and Panicle Fertilizer on Trace Element Content and Grain Quality in Direct-Seeding Rice

“…Additionally, organic fertilization, especially farmyard manure and straw, significantly reduced the cadmium content in selected vegetables [36]. However, when soils were amended with biogas slurry, Bian et al [37] measured mean concentrations of Cr of 0.43 and 0.46 mg¨kg´1 in rice and wheat, respectively, which are close to the standard limit (0.5 mg¨kg´1), and mean concentrations of Zn, Pb, and Cd exceeded the maximum permissible levels by 1.8-, 20.7-, and 2.6-fold, respectively. The reason for the apparent contradiction may be due to differences in heavy metal contents in the PS and biogas slurries applied, or differences in soil characteristics between experiments.…”

Heavy Metals in Unprocessed or Minimally Processed Foods Consumed by Humans Worldwide: A Scoping Review

“…For the maize and wheat subgroups, there are only established ML values for Pb and Cd; the Cd concentrations that exceeded the MLs in maize were in the range of 0.23 ppm to 1.5 ppm, with Iran being the country with the highest Pb concentration [ 164 ]. Regarding Cd, the range was from 0.1 to 16.17, and the highest concentration was reported by Peng et al in China; it is important to highlight that the study samples were collected from a major agricultural area located near an important industrial base [ 172 ]. We also found values that exceeded the limits in the wheat subgroup for Pb (mean = 1.85 ppm) and Cd (mean = 0.41 ppm) in Iran [ 164 ], and for Pb (mean = 3.61 ppm) and Cd (mean = 0.2) in China, where study samples were taken from amended soils with biogas slurry [ 172 ].…”

“…There were many countries where HM concentration exceed the MLs for Pb and Cd in the vegetables group; China [ 76 , 126 , 157 , 172 ], Iran [ 110 , 146 ], Bangladesh [ 105 ], Brazil [ 147 , 154 ], Spain [ 106 ], Croatia [ 127 ], Portugal [ 44 ] Germany [ 46 ], Serbia [ 150 ], South Africa [ 37 ] and Turkey [ 135 ] were found exceeding MLs in at least one vegetables subgroup. In the leafy vegetables subgroup, exceeding MLs means values ranged, for Pb, from 0.3 ppm to 12.8 ppm, and for Cd from 0.2 ppm to 21.9 ppm; in the stalk and stem vegetables subgroup, Cd mean concentrations ranged from 0.19 ppm to 9.18 ppm, while in the Brassica subgroup, Pb concentration mean values ranged from 1.0 ppm to 15.6 ppm and for Cd from 0.05 ppm to 18.6 ppm; for the bulb vegetables subgroup, Pb exceeded values ranging from 1.0 ppm to 10.4 ppm and for Cd from 0.05 ppm to 4.47 ppm; for fruiting vegetables, Pb exceeding MLs varied from 0.056 ppm to 10.2 ppm, and for Cd from 0.05 ppm to 15.3 ppm; and finally for legume vegetables, the exceeding MLs for Pb varied from 1.3 ppm to 10.9 ppm, and for Cd from 0.17 ppm to 0.23 ppm.…”

The Future Agricultural Biogas Plant in Germany: A Vision

“…Usually, biological degradation during anaerobic digestion reduces hazardous components to various extents [203,[212][213][214][215][216][217]. However, in some cases persistent pathogens, increased heavy metal concentrations or eco-toxic effects were observed [213,216,218,219]. Elimination rates depend on the type of elements/compounds/pathogens, on feedstocks, digester operating conditions and digestate treatment.…”