Heavy metal concentrations in tree rings to prove prolonged existence and hypothesized health impacts - CKDu
Tree rings that occurred due to seasonality or drought are used to estimate the age of tropical and temperate trees . The heavy metal concentrations in tree rings are used to study the accumulation history by means of tree age . CKDu or Chronic Kidney Disease of Unknown etiology/Uncertain cause affects agricultural communities in countries like Sri Lanka, Central America. Heavy metal accumulation in drinking water due to agrochemical use is hypothesized as a cause for this disease. Therefore, heavy metal concentrations in body parts of patients and drinking water samples are examined to conclude the hypothesized causality. But these measurements have limitations to identify the history of heavy metal concentrations, history of availability in the environment/water to label it as the culprit. As practices, histories of agrochemical use, water use, and size of accumulation as a proxy of history are used to find the causality . But, heavy metal concentrations in tree rings of large old tress in the agricultural areas/near water sources can be examined to identify the historical accumulation levels and to separate the accumulations due to agrochemical use, assuming both people and trees share water, soils, environment commonly.