A Comparative Assessment of Trace Element Accumulation in Native and Improved Rice (Oryza sativa L.) Varieties Grown Under Different Conditions of Fertilizer Application

An approach for evaluating the bioavailability and risk assessment of potentially toxic elements using edible and inedible plants-the Remance (Panama) mining area as a model

Mining affects the environment, particularly through the persistence of accumulation of tailings materials; this is aggravated under tropical climatic conditions, which favours the release of potentially toxic elements (PTEs) bioavailable to the local flora and fauna and supposing a risk to human health. The Remance gold mine (Panamá), exploited intermittently for more than 100 years, and has remained derelict for over 20 years. Within the area live farmers who carry out subsistence agriculture and livestock activities. The objective of this study has been to study the transference of PTEs in the local agricultural soil-plants system, with the goal of identifying their bioavailability to perform a human risk assessment. The results obtained of the Bioaccumulation coefficient in local plants show very weak to strong absorption of As (< 0.001-1.50), Hg (< 0.001-2.38), Sb (0.01-7.83), Cu (0.02-2.89), and Zn (0.06-5.32). In the case of Cu in grass (18.3 mg kg^-1) and plants (16.9 mg kg^-1) the concentrations exceed the maximum authorised value in animal nutrition for ruminants (10 mg kg^-1). The risk to human health for edible plants exceeds the non-carcinogenic risk for rice, corn, cassava, and tea leaves for Sb (HQ 19.450, 18.304, 6.075, 1.830, respectively), the carcinogenic risk for Cu (CR = 2.3 × 10^-3, 7.7 × 10 ^-4, 1.1 × 10^-3, 1.0 × 10^-3, respectively), and the carcinogenic risk for As in rice, corn and tea leaves (CR = 8 × 10^-5, 3 × 10^-5, 3 × 10^-5, respectively). Urgent measures are needed to alleviate these effects.

Could Consumption of Trace Element-Contaminated Rice Be a Risk Factor for Acute Interstitial Nephritis with Uncertain Etiology in the Dry Zone of Sri Lanka?

Ingestion of toxic trace elements in the human body has been considered one of the major reasons for renal dysfunction. Chronic kidney disease with uncertain etiological factors (CKDu) is a recently described clinical entity in which the disease is found in geographically isolated pockets in the dry zone of Sri Lanka. In CKDu regions, an increasing number of cases are reported with acute interstitial nephritis without any known reason (AINu). However, recent exposure to certain risk behaviors or nephrotoxins, or both, is suspected for the AINu. Consumption of foods that are contaminated with trace elements is one of the main pathways of human exposure to environmental toxins. The current study was carried out to assess the possibility of trace element-contaminated rice consumption on the etiopathogenesis of AINu. Samples of rice consumed by 32 clinically diagnosed AINu cases were collected and analyzed for possible nephrotoxic trace elements. Out of 32 patients, 26 were histologically confirmed with tubulointerstitial disease. The results revealed that the mean values of Cd, As, and Pb were 0.18, 0.055, and 0.135 mg/kg, with ranges of 0.020-1.06, 0.012-0.222, and 0.003-0.744 mg/kg (on dry weight basis), respectively. This study indicated that the investigated toxic trace element levels of rice consumed by AINu were reasonably below the recommended levels of the Codex Alimentarius Commission of FAO and WHO. Hence, it is less likely that rice consumption is to be a risk factor for the etiology of AINu.