Toxicity screening of biochar-mineral composites using germination tests

Abstract

14This study assessed the properties and toxicity (water cress germination trials) of 38 15 waste-derived, novel biochar-mineral composites (BMCs) produced via slow pyrolysis 16 and hydrothermal carbonization (hydrochars). The biochars were produced from sewage 17 sludge and compost-like output (CLO) by varying the type of mineral additive (zeolite, 18 wood ash and lignite fly ash), the mineral-to-feedstock ratio and the carbonization 19 process. While pure hydrochars completely inhibited germination of water cress, this 20 effect was ameliorated by mineral additives. Seedlings grew best in pyrolysis chars and 21 while wood ash addition decreased plant growth in many cases, 1:10 addition to CLO 22 doubled germination rate. The factors responsible for the phytotoxicity can be attributed 23 to pH, salinity and organic contaminants. Importantly, while pure minerals inhibited 24 germination, conversion of minerals into BMCs reduced their inhibitory effects due to 25 buffered release of minerals. Overall, mineral wastes (e.g., combustion ashes) and waste 26 biomass can be used safely as sources of nutrients and stable organic carbon (for soil 27 carbon sequestration) when converted into specific biochar-mineral composites, 28 exploiting synergies between the constituents to deliver superior performance. 29

Investigation of biomass and agricultural plastic co-pyrolysis: Effect on biochar yield and properties

“…On the other hand, presence of PTEs at high levels could interrupt the seed germination through interrupting the seed metabolism [45]. Both promotion and inhibition of seed germination after mixing with biochar have been reported in previous studies [30,42,46]. However, there was no significant difference between the germination rate of GM biochar types and control treatment before leaching.…”

“…The phytotoxicity test method used in this study, which used sand only control, is an adapted version of the EN 16086-2 2011 method, which was developed by Mumme et al [30] to test biochars used for soil amendments and depict more realistic but worst case scenario effects on seed germination under soil environmental conditions. The procedure involved mixing 29.7g of white quartz sand which was heated treated in a muffle furnace at 550 °C for 6 hours (Sand, white quartz 50-70 mesh particle size, Sigma-Aldrich, Belgium) with 0.3g of biochar, to which 6.6g of deionized water was added.…”

Beheersing van bodempathogenen via bodemgezondheidsmaatregelen : Een overzicht van de beschikbare kennis voor een selectie van akkerbouwgewassen met hun bijbehorende bodemziekten

“…Van belang voor de kwaliteit van de biochar is zowel het uitgangsmateriaal (waarvan het is gemaakt) en de pyrolyseringstemperatuur (Bonanomi et al, 2015;Marra et al, 2018). Ook fytotoxische effecten op gewassen zijn gerapporteerd (Mumme et al, 2018) en het bodemleven wordt soms negatief beïnvloed (Liu et al, 2017), soms echter ook positief. Voor agro-ecosystemen die in dit literatuuronderzoek aan de orde zijn, zijn voor zover bekend nog geen effecten van biochar gerapporteerd* D .…”

Advances in ecological and health risks of biochar during environmental applications

“…虽然生物 炭可以降低土壤酸度, 但是在碱性土壤中施用生物炭 可能会降低Fe、Zn、Cu、Mn等营养元素的利用率 [93] . 而且当土壤pH超过植物自身的离子调节浓度和酸碱度 平衡时, 会严重影响植物生长, 甚至造成植物死亡 [94,95] .…”