Cadmium and the welfare of animals

Cadmium is a toxic agent that affects human health, and in this article its impacts on animal health and welfare are examined. There is evidence that some farm animals can detect and actively avoid it when presented with feedstuffs with a range of cadmium concentrations. Concentrations in soil are usually greater than those in feedstuffs because most plants do not transport cadmium effectively into stem and leaf material. Hence, herbivores that consume some soil while grazing are particularly at risk, especially wild herbivores that are relatively long-lived, such as deer, as cadmium accumulates in their organs over time. Deer and other wild species have been found to show evidence of nephrotoxicosis as a result of cadmium consumption, even in relatively unpolluted regions. Concomitant stresses such as inadequate food supplies may exacerbate cadmium toxicity in these animals. The chemical form of cadmium is of major significance in determining the toxicity, and pigs and other monogastric animals are believed to be at risk because they cannot produce the enzyme phytase in their gastrointestinal tract. Synergistic effects with other toxic elements, such as lead, exacerbate the adverse effects of cadmium on pig welfare, and it has been established that cadmium has the ability to reduce the uptake of some essential elements, such as zinc. It is concluded that cadmium pollution has the potential to adversely affect the welfare of animals, especially animals in the wild

Cadmium, environmental exposure, and health outcomes O cádmio, a exposição ambiental ao cádmio e as consequências para a saúde

We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amounts of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body's acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been observed in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5% absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium.<br>Uma atualização sobre as questões relacionadas à avaliação dos riscos de saúde, oriundos da exposição a cádmio nos alimentos, é apresentada. Em um estudo de indivíduos sujeitos a uma elevada exposição dietária ao cádmio, a biodisponibilidade do cádmio ingerido foi confirmada, e os achados foram reforçados, diante da constatação de quantidades substanciais de cádmio acumulado, seja nos rins, nos olhos, assim como em outros tecidos e órgãos de pessoas ambientalmente expostas. Levantamos a hipótese de que essa acumulação seria o resultado de uma absorção eficiente do cádmio e do seu transporte sistêmico na absorção dos elementos cálcio, ferro, zinco e manganês pelo corpo humano. Os dados populacionais encontrados têm gerado uma preocupação quanto à validade do nível, atualmente aceito, de ingestão cádmica isenta de riscos, os rins constituindo o objeto único desses levantamentos de avaliação dos riscos à saúde, provenientes da ingestão de cádmio. Os dados também nos levam, na inferência do nível de ingestão cádmica isenta de riscos, a questionar a validade de se incorporar no modelo de avaliação de riscos para a determinação do limiar a taxa default de 5%, conhecida como nível tolerável de ingestão proporcionada semanalmente (PTWI)