Biochemical Pathways of Heavy Metal Poisoning

(Campbell, 2016). Two giants in childhood lead poisoning research and advocacy, Dr. Philip Landrigan and Dr. David Bellinger, summarize the adverse effects of lead very completely, yet succinctly: “Lead is a devastating poison. It damages children’s brains, erodes intelligence, diminishes creativity and the ability to weigh consequences and make good decisions, impairs language skills, shortens attention span, and predisposes to hyperactive and aggressive behavior. Lead exposure in early childhood is linked to later increased risk for dyslexia and school failure.”(p. 3).

What are some of the effects of the crisis? For any adult, lead poisoning can cause kidney problems, fatigue, lethargy, depression, and slower reaction time. However, adults require a higher level of lead in the blood to produce those effects. For pregnant women lead poisoning can can cause miscarriages and future health problems in a developing fetus. What about children? For children, lead poisoning affects the development of children's brains and nervous systems.

Everyone is susceptible to the dangers of lead contamination; but children are especially at risk. High levels of lead in children can lead to brain and kidney damage and damage to red blood cells. Low levels of lead can also cause problems that are less life-threatening but can be just as devastating, like low IQ, hearing and language impairment, reduced attention span and poor school performance. In adults, exposure to lead can lead to an increased risk for high blood pressure. Pregnant women and their fetuses are extremely vulnerable to lead. In women, lead increases the risk of infertility and miscarriages; in fetuses, lead can cause low birth weight, premature birth and impaired mental and physical development.

Children under six years old are very easily affected to the effects of lead. Even low levels of lead in the blood of children can result in: behavior and learning problems, lower IQ and hyperactivity, slowed growth, hearing Problems and anemia; lead can accumulate in our bodies over time, where it is stored in bones along with calcium. For pregnant women, during pregnancy, lead is released from bones as maternal calcium and is used to help form the bones of the fetus. This is particularly true if a woman does not have enough dietary calcium. Lead can also cross the placental barrier exposing the fetus the lead. So lead can cause serious effects to the mother and her developing fetus, including: reduced growth of the fetus and premature birth. And for other adults, lead can also be harmful, it can cause cardiovascular effects, increased blood pressure and incidence of hypertension, decreased kidney function, and reproductive problems in both men and

The improved screening and treatment of lead poisoning decreased the severity of symptoms usually seen. However, the level of lead in the blood does not establish what symptoms are seen, since lead in blood only establishes current exposure. Recently, studies have shown that a long exposure to low amounts of lead may have severe neurobehavioral effects that are not diagnosed until the child enters school (Singhal et. al., 1980).

The effects of prolonged exposure to lead will result in lead poisoning. It causes behavior problems, hearing problems, kidney damage, and slowed body growth (Heller).

Acute lead poisoning may cause irritability, decreased attentiveness, and acute encephalopathy. Cerebral edema develops over 1 to 5 days, causing persistent and forceful vomiting, ataxic gait, seizures, altered consciousness, and, finally, intractable seizures and coma. Encephalopathy may be preceded by several weeks of irritability and decreased play activity.

The recent tragedy in Flint, Michigan has resurfaced the subtle, yet ongoing issue of lead toxicity in our society today. With the age of the internet, word quickly spread about the danger of lead contamination in drinking water to homes all over the country. But while the media focuses on lead exposure with its respect to water, it is important to remember that the use of lead has many applications and is exposed to children through a number of different sources.

In our work, the studied population has been environmental exposed to lead since childhood or/and adolescence and some of them for more than 9 year and few of them have been followed since their delivery. These facts, importantly strengths our study because most of the studies reported associating lead exposure and peripheral neurotoxicity have been carried out in adults who may have a high prevalence of comorbid conditions and risk factors, such as, smoking, drinking alcoholic beverages, eating vegetables for dinner, urban residence, exposure from lead-using industries and others. Whereas, our work was carried out in children and adolescents who are generally free from these comorbidities and from several risk factors. Therefore, and according with the design of our study, the influence of comorbidities and risk factors on peripheral neurotoxicity have been reduced significantly, and so, the direct side effects of lead on peripheral neurotoxicity could be closely ascertained. In addition, we evaluated six sensory and five motor nerves and the statistical analyses were evaluated by the gender, by age

The prenatal affects of lead poisoning greatly influence the child’s early life from mental disorders to poor health. According to one of my sources, high Blood Lead Levels (BLLs) around 350 micro grams in infants during pregnancy can result in various birth defects such as reduced gestational age, weight at birth, and facial deformities. As well as other various mental affects ranging from, anaemia, impaired visual and motor functions, hearing loss, mild mental developmental delay, attention spans, and reading and learning disabilities (Ronchetti, Van Den Hazel, Schoeters, Hanke, Rennezova, Barreto, & Villa, M. P. 2006). Lead poisoning in prenatal development is an unexpected and unfavorable outcome. While children can’t grasp the dire consequences

Humans are primarily exposed to mercury through the consumption of freshwater and marine animals that have accumulated methylmercury in their fatty tissues 4. Mercury is absorbed in gastrointestinal (GI) tissues through dietary consumption. From the GI tract, mercury enters surrounding tissues and the blood stream where it can be transported throughout the body 8. The health consequences of mercury are resultant of the intracellular binding of organelles essential for cellular function 3. Thus, mercury exposure at a cellular level can cause cellular degradation and eventual

Lead poisoning is one of the global burden and need to be focused a lot on preventive strategies.

Mixed contamination of benzo[a]pyrene (B[a]P), arsenic (As), cadmium (Cd), and lead (Pb) is a major environmental and human health concern. The mixture toxicity data on these co-contaminants are important for their risk assessment. In this study, we have determined the mixture toxicity of As, Cd and Pb and B[a]P with As, Cd or Pb in HepG2 cells. The binary mixtures of Cd + As, Cd + Pb and As + Pb and B[a]P + metals (B[a]P + As, B[a]P + Cd and B[a]P + Pb) were evaluated for their interaction on the cytotoxicity using the MTS assay. A full factorial design (4 × 5) was used to determine the interaction toxicity and all the six mixtures showed significant interaction on the cytotoxicity. We further investigated the role of oxidative stress (reactive

There is no dispute the effects that lead has on people, especially children and pregnant women. It is a cumulative toxin and the effects can be found in multiple body systems, such as the brain, liver, kidneys, and bones. In young children, large doses can lead to coma or death, and, more commonly, smaller amounts will cause learning disabilities and lowered IQ, along with other ailments such as hypertension and immunotoxicity (World Health Organization). Because of these devastating health effects, lead is no longer allowed to be used in paint, which was very common in homes and toys until the late 70’s (EPA). Lead is a natural occurring element found in the Earth’s crust, but has become a major environmental contaminant because of its widespread

Zinc is known to prevent and treat the intoxication of lead which often proves more effective along with the combination of methionine or thiamine (Flora et al., 1989; 1991). Supplementation of zinc simultaneously with methionine or thiamine helps effectively reduce urinary excretion of ALA and the lead induced ALAD activity in the blood. This suggests that the combination therapy including the essential nutrient elements and vitamins concurrently with exposure to lead could be more effective than treating the lead toxicity after exposure. This helps to reduce the absorption of lead in the gastrointestinal track. Thus it can be attributed that zinc help to reduce the lead absorption in the body, thus it is depicted from the study that lead levels and zinc levels in among both the healthy controls and workers occupationally exposed to lead can be highly correlated. Earlier it was shown that the depletion of zinc levels among individuals due to lead exposure can be restored due to supplementation of zinc. Thus zinc has been known to be an important antioxidant which was shown from the literature reviewed by Bray and Bettger (Bray and Bettger, 1990). There are two mechanisms which are been elucidated as to how zinc prevents the lead poisoning, besides being as an antioxidant. These two mechanisms are protection of sulfhydryl groups and prevention by ROS. There are several studies which indicate that zinc has a beneficial effect on treating lead poisoning (Flora et al., 1989;