Changes in organic carbon and nitrogen in soil with metal pollution by Cd, Cu, Pb and Zn: a meta‐analysis

Abstract

Summary Organic carbon (OC) and nitrogen (N) storage in soil plays an important role in global climate change and in maintaining food security. Pollution of soil with heavy metals has occurred in many parts of the world, but their effects on soil OC and N have not been well addressed. Relevant data were extracted from peer‐reviewed journal papers and analysed by a meta‐analysis to determine how long‐term heavy metal pollution affected soil OC and N status. Plant biomass decreased significantly because heavy metals in soil decreased soil OC and N concentrations by 5.0 and 17.9%, respectively, but increased the C/N ratio by 5.1%. The largest reductions in soil OC and N concentrations were in soil more strongly polluted by metals. The changes in soil OC and N with metal pollution varied with climatic conditions. More substantial decreases in OC and N concentrations were likely to occur in polluted soil with large background contents of OC and low pH. Overall, heavy metals were linked to greater reductions in soil OC and N concentrations in natural ecosystems than in agro‐ecosystems. These results provided a quantitative evaluation of the effects of heavy metal pollution on the decrease in soil C and N concentrations and, therefore, on global climate change. Further consideration should be given to changes in the cycling of C and N in soil polluted with metals in natural and agro‐ecosystems.

Effects of organic matter fraction and compositional changes on distribution of cadmium and zinc in long-term polluted paddy soils

“…Consequently, metal pollution decreased the amounts of available C and N released from the decomposition of large POM size fractions and then decreased C and N adsorption by clay minerals, resulting in smaller relative increases in OC and TN concentrations of organic-mineral compounds in polluted soils than control soils. In a meta-analysis study, Zhou et al (2016) reported that C/N ratios in bulk soils were higher after long-term metal pollution than controls. According to the results of Zhou et al (2016), higher C/N ratios in 2000e250 mm POM size fractions might be explained not only by the inhibitory effects of metals on OM decomposition taking the large POM size fractions closer to the original OM inputs with high C/N ratios but also by decreased plant N utilization efficiency, resulting in larger mineral N losses from polluted soils.…”

“…The quantity and quality of SOM are important in the management of soil fertility, nutrient supply and carbon dynamics (Paul, 2016), and SOM quantity and quality can change in long-term metal polluted soils (Viventsova et al, 2005;Zhou et al, 2016). Particulate organic matter (POM) is the part of SOM that can be physically size-fractionated into different labile pools in water and used as an index of labile SOM status (Balesdent, 1996;Benbi et al, 2014).…”

Longitudinal Effects of Supplemental Forage on the Honey Bee (Apis mellifera) Microbiota and Inter- and Intra-Colony Variability

“…As the succession of the gut community has been shown to vary with age and stress, this could account for the decreased abundance of G. apicola in the foragers during almond pollination, which may be contributing to a dysbiotic gut community [63]. Within a colony, foragers interact with different plant species and individuals and may contact different floral chemicals that likely affect their gut microbiome [64]. Given the degree of variation in microbiome structure within a colony, we do not recommend that researchers pool honey bee guts for microbial analyses and instead separately sequence and analyze multiple individual bees from colony replicates.…”

Toxicokinetics of Zn and Cd in the earthworm Eisenia andrei exposed to metal-contaminated soils under different combinations of air temperature and soil moisture content

“…mining, smelting, agriculture, waste disposal) is an environmental problem worldwide (COM, 2006;FAO and ITPS, 2015;He et al, 2015). Metals exert toxic effects on soil living organisms (van Straalen, 2004;Stankovic et al, 2014), affecting the sustainability of terrestrial ecosystems and, in some cases, human health (Naveed et al, 2014;Zhou et al, 2016;Morgado et al, 2017). Toxicity is known to be related to the metal fraction that can be taken up by organisms and subsequently interact with biological targets (i.e.…”