4.4G Water quality management (HL) Notes

Indicator Species

1. Indicator species are living organisms whose presence or absence reflects the quality of the environment they inhabit.
2. They provide biological evidence of pollution, as they respond to changes in oxygen levels, pH, or toxic substances.

Pollution-Intolerant and Pollution-Tolerant Species

1. Intolerant Species

1. These species are sensitive to pollutants and require clean, oxygen-rich environments.
2. Their presence indicates unpolluted water with high dissolved oxygen content.

2. Tolerant Species

1. These species can survive in polluted, oxygen-poor waters with high organic matter.
2. Their dominance indicates heavily polluted environments or organic waste accumulation.

Advantages

1. Provides a long-term reflection of environmental conditions.
2. Cost-effective compared to chemical analysis.
3. Offers insight into the ecological impact of pollutants, not just their concentration.

Limitations

1. Populations can fluctuate due to natural factors such as temperature, predators, or seasonal variation.
2. Indicator species provide qualitative, not quantitative, data.
3. Different regions require locally adapted indicator species lists due to ecological differences.

Biotic Indices

1. A biotic index is a numerical expression that assesses water quality based on the presence and diversity of organisms with varying pollution tolerances.
2. It gives an indirect measure of water quality and is particularly useful for evaluating organic pollution.

How Biotic Indices Work

1. Sampling: Collect aquatic macroinvertebrates using methods like kick sampling or net scooping.
2. Identification: Identify species groups (e.g., stoneflies, mayflies, caddisflies, Tubifex worms).
3. Scoring: Assign tolerance values, higher for pollution-tolerant species and lower for intolerant ones.
4. Calculation: Use species presence and abundance data to produce a numerical value representing overall water quality.

The Trent Biotic Index

1. The Trent Biotic Index (developed in the UK) is a classic system for freshwater assessment.
2. It relies on identifying certain key macroinvertebrates, such as stoneflies, mayflies, caddisflies, freshwater shrimp (Gammarus), water hoglouse (Asellus), and Tubifex worms, and scoring sites based on which species are present.

Interpretation of Scores

1. High index (8-10): Clean, oxygen-rich water (presence of stoneflies and mayflies).
2. Medium index (4-7): Moderately polluted water (presence of caddisflies and shrimps).
3. Low index (0-3): Heavily polluted water (dominance of Tubifex worms and midge larvae).

How the Trent Biotic Index is Applied

1. Collect macroinvertebrates using kick sampling or a D-net.
2. Identify the organisms and record how many different types are found.
3. Assign tolerance scores based on pollution sensitivity.
4. Determine the index value using the chart or formula.
5. Interpret the score to classify the water quality.

Water Quality Index (WQI)

1. A Water Quality Index (WQI) combines multiple chemical and physical parameters into a single score, giving an overall picture of water health.
2. It simplifies data from several tests into one easily interpretable number.

Common Parameters

1. Dissolved Oxygen (DO): Indicates biological health.
2. Biochemical Oxygen Demand (BOD): Shows organic pollution levels.
3. pH: Measures acidity or alkalinity.
4. Turbidity: Indicates suspended solids and clarity.
5. Nitrate and Phosphate levels: Show nutrient pollution.
6. Temperature: Affects oxygen solubility and aquatic metabolism.
7. Faecal Coliform: Indicates contamination by sewage or animal waste.

Vernier’s WQI

1. The Vernier Water Quality Index combines nine parameters, each assigned a weighting factor according to its environmental importance.
2. Each parameter is converted to a Q-value (0–100) using standard charts.
3. Q-values are multiplied by their weightings, then summed to give the overall WQI.

Interpretation

Drinking Water Quality Standards

1. Drinking water standards safeguard human health by setting limits on specific contaminants.
2. These are based on both scientific research and public health policies.

WHO Guidelines and National Regulations

1. The World Health Organization (WHO) issues recommended maximum levels for major contaminants such as fluoride, lead, nitrates, and selenium.
2. Governments may adopt these or create stricter national standards.
3. Developed nations often have statutory standards enforced through national laws (e.g., the Safe Drinking Water Act in the USA, the EU Drinking Water Directive).
4. These guidelines specify maximum permissible concentrations for substances such as:
   1. Fluoride: ≤1.5 mg/L - excessive levels cause dental and skeletal fluorosis.
   2. Lead: ≤0.01 mg/L - harmful to nervous and developmental systems.
   3. Nitrate: ≤50 mg/L - high levels cause methemoglobinemia in infants (“blue baby syndrome”).
   4. Selenium: ≤0.04 mg/L - toxic in excess, damaging the liver and nervous system.

Role in Environmental Assessments

1. Standards ensure new water-related projects comply with environmental safety criteria.
2. Companies constructing bottling plants or industrial facilities must meet local and international water quality regulations.
3. These standards protect both local communities and ecosystems from over-extraction and pollution.

Reducing Water Pollution - Role of Citizens

1. Individual Actions

1. Reduce water use: limits wastewater generation.
2. Proper waste disposal: avoid pouring oils, paints, and medicines down drains.
3. Use eco-friendly products: biodegradable detergents prevent chemical buildup.
4. Reduce plastics: less litter enters waterways.

2. Collective and Community Action

1. Citizen protests and awareness campaigns influence government action.
2. Community science projects collect water samples, measure pH, and monitor pollution.
3. Legal and lobbying efforts can enforce stricter water regulations.

Role of Regulations in International Business Agreements

Ensuring Compliance with International Standards

1. Companies may be required to comply with international standards, like those set by the WHO, or with local regulations in the host country.
2. This ensures that the company’s operations do not compromise public health or environmental quality.

Social and Environmental Responsibility

1. In international agreements, especially for multinational corporations, there is often an emphasis on corporate social responsibility (CSR).
2. Companies may be required to abide by global sustainability standards that aim to minimize environmental impacts and improve local communities' access to water.

Local vs Global Regulations

1. International businesses often face the challenge of navigating between local environmental laws and international standards.
2. In these cases, international business agreements can ensure the project adheres to global environmental standards and avoids potential risks to human health, such as unsafe drinking water or pollution.

Balancing Economic Growth and Sustainability

1. Water bottling plants in developing countries are often seen as a source of economic growth.
2. However, if unsustainable practices are used (such as over-extraction of water resources or inadequate treatment of water), the long-term social and environmental costs can outweigh the short-term economic benefits.
3. Regulatory frameworks and standards can help ensure that companies pursue sustainable development while mitigating environmental harm.