Peculiarities of accumulating contaminants by vegetable crops

Abstract

The content of nitrates, radionuclides, salts of heavy metals in botanical sorts of garlic, aubergines, cabbages and rhubarb, which are spread and grown in Kharkiv area in the conditions of resource zones of the Institute of vegetable- and melon-growing of National Academy of Agrarian Sciences. The availability of specific and varietal specificity of the level of accumulating contaminants by vegetables is scientifically proved.
Garlic accumulates insignificant amounts of radionuclides and salts of heavy metals. The content of nitrates exceeded the MPC (Maximum Permissible Concentration) level 1.2–1.6 times in four sorts out of nine. All other contaminants are accumulated by garlic less intensively, and their amounts don’t exceed available concentrations. Cabbages, on the contrary, accumulate contaminants, primarily cadmium and nitrates.
The amount of nitrates, depending on the type of cabbages, fluctuates greatly: from 46.1 – in Brussels sprouts to 598.0 mg/kg – in Chinese cabbage. The amount of radionuclides for all types and sorts of cabbages is within the MPC limits, they are even 2–3 times less than in aubergines. All other sorts and types accumulate cadmium 1.2–2.4 times more than it is allowed. Its highest content is registered in Brussels sprouts.
The amount of other heavy metals contained is within the MPC limits. Rhubarb, like all early cultures, accumulates more contaminants. The amount of nitrates in rhubarb fluctuates a lot but does not exceed MPC norms. The limits of accumulating radionuclides are narrower, though their amount is higher in comparison with other vegetables (2–11 times) but does not exceed the allowed concentrations. The content of cadmium in rhubarb is within the MPC limits. Three sorts of rhubarb accumulate cadmium 1.5–2.5 times more than MPC, and only Monarkh sort contains it in the allowed amounts. Lead is accumulated in rhubarb in the admissible quantity, and only Krupnochereshkoyi sort exceeds level by 26 %. The same sort accumulates more copper. Other sorts accumulate copper 5–1.8 times less than MPC.
According to the level of accumulating nitrates in productive organs, the cultures under research are ranked in the following order: aubergine < garlic < cabbage < rhubarb. All samples of vegetables accumulate more caesium than strontium. Sorts of vegetables differ greatly by their ability to accumulate salts of heavy metals. The common feature for the investigated samples is that heavy metals can be ranked by the level of accumulation in the following order: zinc > copper > lead > cadmium. It is experimentally determined that the content of cadmium, one of the highly toxic metals, exceeds MPC in most investigated samples of cabbage and rhubarb. The differences between the sorts and cultures by the amount of nitrates, heavy metals and radionuclides are predetermined by their genotypic peculiarities.