A study reveals the presence of toxic pesticides in urban effluents and warns about the ecological risk in Latin America – Noticias Ambientales

Report on Pesticide Contamination in Urban Wastewater and Implications for Sustainable Development Goals

A recent study in Costa Rica’s Central Valley has identified significant contamination of urban wastewater with pesticides, posing a direct challenge to the achievement of several Sustainable Development Goals (SDGs). The research reveals that conventional wastewater treatment plants are ineffective at removing these chemical compounds, thereby threatening public health, water quality, and ecosystem integrity.

Key Findings: A Threat to SDG 6 and SDG 14

The investigation detected 29 distinct chemical compounds from household, commercial, and industrial products in both influent and effluent from four treatment systems. This continuous release of pollutants directly undermines SDG 6 (Clean Water and Sanitation), particularly Target 6.3, which aims to improve water quality by reducing pollution and halving the proportion of untreated wastewater.

• High-Risk Compounds: Five pesticides were identified as particularly concerning due to their concentration levels exceeding safe limits for aquatic life, creating a persistent threat to freshwater ecosystems as outlined in SDG 14 (Life Below Water) and SDG 15 (Life on Land). These include:
  1. Cypermethrin
  2. Diazinon
  3. Cinerin II
  4. Diuron
  5. Terbutryn
• Newly Detected Pesticides: The study recorded five pesticides in urban wastewater for the first time, highlighting an emerging pollution challenge for SDG 11 (Sustainable Cities and Communities). These compounds, originating from domestic insecticides and food preservatives, include flubendiamide, dichloran, biphenyl, and 1,4-dimethylnaphthalene.
• Health Implications: Many of the identified chemicals are associated with adverse effects on the nervous and endocrine systems, posing a risk to human health and contradicting the objectives of SDG 3 (Good Health and Well-being).

Toxicological Impact and Environmental Risk Assessment

Methodology

Researchers employed a hazard coefficient to compare pesticide concentrations against established safety thresholds for aquatic fauna. Further toxicity tests were conducted using sentinel organisms, including a freshwater crustacean, a luminescent bacterium, and lettuce seeds, to provide a comprehensive risk profile.

Synergistic Effects on Ecosystems

The results confirmed that 17 of the substances present a high environmental risk individually. However, the study’s most critical finding was the cumulative toxicity of the chemical mixture. The combined presence of multiple compounds in both raw and treated water amplified the overall environmental risk, demonstrating that the impact is greater than the sum of its parts. This synergistic effect presents a complex challenge for environmental protection efforts aligned with SDG 14 and SDG 15.

Infrastructural and Regulatory Deficiencies

Limitations in Water Treatment Infrastructure

The report underscores a systemic failure in regional water management, a critical barrier to achieving SDG 6. Most Latin American treatment facilities are designed to remove organic matter and are not equipped to filter or degrade persistent chemical pollutants like pesticides. In some cases, pesticide concentrations were observed to increase post-treatment, likely due to their detachment from solid waste during the process. With less than 15% of Costa Rica’s population connected to wastewater treatment systems, the vast majority of urban effluent enters rivers untreated, magnifying the environmental damage.

Regulatory Gaps and Unsustainable Production

The study highlights a significant regulatory lag that impedes progress toward SDG 12 (Responsible Consumption and Production). The chemical industry introduces new compounds faster than regulatory bodies can assess and control them. This allows substances banned in other regions to remain in use, leading to a continuous flow of pollutants from urban centers into natural water systems. The lack of updated regulations and technological investment leaves cities vulnerable to persistent, invisible pollution, directly conflicting with the goals of SDG 11.

Advancing Regional Environmental Management

Opportunities for Policy and Technological Advancement

This research provides a scientific foundation for transforming urban environmental management in Latin America and advancing multiple SDGs.

• Informing Policy: The data enables the development of effective, evidence-based policies to update regulations, ban highly toxic substances, and improve safety standards for consumer products, contributing to SDG 12.
• Improving Infrastructure: The findings offer critical insights for redesigning wastewater treatment plants with technologies capable of removing persistent pollutants, a necessary step toward fulfilling SDG 6 and SDG 11.
• Fostering Collaboration: The initiative encourages cooperation between universities, governments, and civil society, embodying the principles of SDG 17 (Partnerships for the Goals) to create integrated solutions for pollution control, citizen education, and long-term environmental monitoring.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

   The article on pesticide contamination in urban wastewater in Costa Rica addresses several interconnected Sustainable Development Goals (SDGs). The core issues of water pollution, chemical waste management, public health risks, and ecosystem degradation directly link to the following SDGs:

   • SDG 3: Good Health and Well-being: The article highlights the presence of pesticides associated with “harmful effects on the nervous system and hormonal disruptions,” which poses a direct threat to human health through contaminated water sources.
   • SDG 6: Clean Water and Sanitation: This is the most central SDG discussed. The article focuses on the failure of wastewater treatment plants to remove pesticides, the low percentage of the population connected to treatment systems (less than 15% in Costa Rica), and the resulting pollution of rivers and streams.
   • SDG 11: Sustainable Cities and Communities: The problem is framed as an urban issue, where pesticides from “household, commercial, and industrial products” and use in “gardens, buildings, businesses, and public spaces” accumulate in urban wastewater, highlighting a failure in urban environmental management.
   • SDG 12: Responsible Consumption and Production: The article discusses the “rapid incorporation of new molecules into the market” and the continuous flow of pollutants from consumer and commercial products, pointing to unsustainable patterns of chemical production and use.
   • SDG 15: Life on Land: The direct impact on freshwater ecosystems is a key concern. The article states that pesticide levels “exceeded safe limits for aquatic organisms, implying a constant risk for rivers and streams,” which directly relates to the protection of terrestrial and freshwater ecosystems.

2. What specific targets under those SDGs can be identified based on the article’s content?

   Based on the specific problems detailed in the article, the following SDG targets can be identified:

   • Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination. The article’s focus on pesticides like cypermethrin and diazinon, which have known harmful effects, directly relates to this target of reducing illness from water pollution.
   • Target 6.3: By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally. The article’s core theme is the release of hazardous chemicals (pesticides) into rivers due to both untreated wastewater and ineffective treatment plants. The statistic that “less than 15% of the population is connected to wastewater treatment systems” directly addresses the issue of untreated wastewater.
   • Target 11.6: By 2030, reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality and municipal and other waste management. The study’s focus on “urban wastewater” and how cities “contribute invisible pollutants to ecosystems” aligns perfectly with reducing the environmental impact of urban centers, specifically concerning water pollution and waste management.
   • Target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle, in accordance with agreed international frameworks, and significantly reduce their release to air, water and soil to minimize their adverse impacts on human health and the environment. The article discusses the “regulatory lag” in controlling dangerous substances and the need to “ban highly toxic substances,” which is central to the sound management of chemicals described in this target.
   • Target 15.1: By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains and drylands, in line with obligations under international agreements. The finding that pesticide levels create a “constant risk for rivers and streams” and represent a “high environmental risk” for aquatic fauna directly concerns the conservation of inland freshwater ecosystems.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

   The article mentions or implies several specific indicators that can be used to measure progress:

   • For Target 6.3:
     • Indicator 6.3.1 (Proportion of wastewater safely treated): The article provides a direct data point for this indicator by stating, “In Costa Rica, less than 15% of the population is connected to wastewater treatment systems.” Progress would be measured by an increase in this percentage.
     • Indicator 6.3.2 (Proportion of bodies of water with good ambient water quality): The study’s methodology of detecting and measuring the “concentrations” of 29 different pesticide compounds in river-bound effluents serves as a direct measure of water quality. A reduction in these concentrations would indicate progress.
   • For Target 12.4:
     • An implied indicator is the number of hazardous chemicals and pesticides regulated or banned. The article points to a “regulatory lag” and the need to “ban dangerous substances,” suggesting that tracking the implementation of such bans would be a key measure of progress. The detection of “five pesticides that had never been recorded before” also highlights gaps in monitoring that need to be addressed.
   • For Target 15.1:
     • The article describes a specific methodology that functions as an indicator of ecosystem health: the use of a hazard coefficient that “compares pesticide concentrations with safe levels for aquatic fauna.” Measuring this coefficient over time would indicate whether the risk to ecosystems is increasing or decreasing.
     • Another indicator is the result of ecotoxicity tests conducted with “sentinel organisms: a freshwater crustacean, a luminescent bacterium, and lettuce seeds.” The survival and health of these organisms when exposed to the water samples provide a direct measure of the water’s toxicity and its impact on freshwater life.

SDGs, Targets, and Indicators Summary

Source: noticiasambientales.com