#health risks

Ultraviolet, X-rays, Gamma Rays and Their Properties

Why do X-rays require careful handling in medical applications?

**X-rays in medicine** treat certain cancers because high-energy photons ionize and damage DNA of malignant cells, also imaging because bones absorb more than tissue, contrast. Gamma rays from Co-60 used for radiotherapy, energy ≈1.17 and 1.33 MeV, highly penetrating. X-rays have high energy and penetrating power, which can damage living tissues and cause cellular mutations, necessitating careful handling to avoid overexposure. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Potential tissue damage, illustrating EM wave transverse nature and Ma

Ref: NCERT > Physics Book > Electromagnetic Waves > Ultraviolet, X-rays, Gamma Rays and Their Properties

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Environmental Effects - Ozone, Greenhouse and Safety

Why are UV rays harmful in large quantities?

**Ozone layer depletion** environmental concern related to increased UV-B reaching surface, causing skin cancer, cataracts, damage to crops and marine life, due to CFCs releasing Cl that catalytically destroys O₃, O₃ absorbs UV 200-320 nm, depletion increases UV transmission. The document mentions that UV rays in large quantities have harmful effects on humans, such as damaging skin cells and inducing excessive melanin production. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields They have harmful effects on humans, illustrating EM wave transvers

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

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Teratogens

BPA exposure predisposes adults to:

Bisphenol A acts as xenoestrogen binding estrogen receptors alpha and beta with ability to activate estrogene-responsive genes promoting mammary epithelial proliferation. Prenatal BPA exposure during mammary placode development causes epigenetic changes including demethylation of promoter regions, increased number of terminal end buds which remain highly sensitive to estrogen. Upon pubertal estrogen rise, these hyperresponsive buds undergo excessive ductal branching and hyperplasia predisposing to neoplastic transformation. Epidemiologic and animal data link early BPA exposure to increased bre

Ref: NCBI, Endocrine Reviews: BPA exposure breast cancer risk via estrogen.

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Applied Ecology

Which pollutants are associated with endocrine disruption?

PCBs and environmental estrogens can disrupt endocrine function. Estrogens directly activate estrogen receptors, whereas PCB congeners or their metabolites may mimic hormones, antagonise receptors, or alter hormone synthesis, transport, and metabolism. The outcomes include changed development, reproduction, sex differentiation, and fertility. Carbon dioxide and methane primarily affect climate, while nitrate and phosphate are chiefly associated with nutrient enrichment rather than this specific toxic mechanism. Community-level consequences can emerge when physiological injury changes survival,

Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology

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Applied Ecology

Which condition is caused by nitrate contamination in water?

High nitrate in drinking water can cause infant methaemoglobinaemia, commonly called blue baby syndrome. Gut microbes reduce nitrate to nitrite, which oxidises haemoglobin iron from the ferrous to ferric state, producing methaemoglobin that cannot bind oxygen effectively. Infants are particularly susceptible because of gastrointestinal and enzymatic features. Minamata and Itai-itai diseases involve mercury and cadmium, respectively, while cholera is an infection. Sensitive developmental stages may respond at concentrations that cause little immediate adult mortality, making reproduction and re

Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology

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