Evaluation of the effectiveness of EIAs in mitigating impacts of mining projects along the great dyke of Zimbabwe

摘要

The poor quality of Environmental Impact Statements (EISs), lack, or low implementation of the proposed mitigation measures and little or none monitoring of the implemented mitigation measures (if any is implemented) are the perceived barriers to the effectiveness of Environmental Impact Assessments (EIAs) in protecting the environment from project development activities.This thesis evaluates the effectiveness of EIAs in mitigating the environmental impacts of mining activities along the Great Dyke of Zimbabwe from a systems thinking perspective. The Mitigation Effectiveness Triangle (MET) which integrates the quality of EIS, mitigation implementation through project Environmental Management Plans (EMPs) and EIA follow-up in post EIA, as a system is the conceptual framework used in the study. Four specific research objectives are investigated: the quality of EISs in terms of impact identification and evaluation, and proposed mitigation measures; the extent to which the mitigation measures proposed in EISs are implemented by the project proponent; the EIA follow-up evidence on the effectiveness of implemented mitigation measures in protecting the environment from mining activities; and, the utility of the MET conceptual framework in enhancing the effectiveness of mitigation in EIA.A mixed methods research design was employed to collect and analyse the data. The research was in three phases. Phase I focused on the quality of EISs. Data from twenty-two mine EISs conducted between 2003 and 2010 were purposively sampled to provide information about the quality of EISs in terms environmental impact identification and proposed mitigation measures. The amended Lee and Colley (1992) EIS quality review package and Mitchell’s (1997) mitigation guidelines were used to gather and grade the quality of EISs in terms of the impacts and mitigation measures. Phase II focused on the practical implementation of mitigation measures proposed in the reviewed EISs. Two purposively selected case studies and their project EMPs, environmental managers, local communities surrounding them and field observations provided the required data. In phase III, the EIA follow-up evidence of environmental quality parameters after the implementation of mitigation measures was evaluated in order to assess the effectiveness of the implemented mitigation measures. The collected data was subjected to statistical analyses using STATA® version 11 (Stata-Corp, Texas, USA).The key finding of the thesis supports the MET conceptual framework. The framework is premised on systems thinking, that advocate for the integration, tieredness and interrelationship among EISs, EMPs and EIA follow-up evidence in order to enhance the effectiveness of mitigation in EIA. The quality of EISs in terms of impact identification and evaluation indicated that 15 (68 percent) out of the 22 reviewed EISs were graded as satisfactory; while 17 (77 percent) were graded as satisfactory in terms of proposed mitigation measures. Based on the quality of EISs findings, the study concluded that the EISs had the potential to influence some of the decisions during project planning. The reviewed EISs were however also fraught with some deficiencies, suggesting that some of the decisions recommended in EISs could be rejected by decision-makers during planning.Regarding the implementation of mitigation measures proposed in EISs, the research findings showed that 63 (98 percent) out of the 64 impacts identified in the EISs were included in project EMPs by the project proponent. In addition, 46 (63 percent) of the 73 mitigation measures proposed in the two EISs were also included in project EMPs. Data from the environmental managers at case study mines, field observations and the local communities living around the case study sites indicated that mitigation measures proposed in EISs were implemented.EIA follow-up evidence included water quality parameters (pH, nitrates, ammonia, arsenic, cadmium, lead, mercury, copper, and baron), air quality (fugitive dust, sulphur dioxide, and carbon dioxide), land, biodiversity, hazardous and solid waste, occupational safety and energy consumption. This evidence was confirmed by environmental managers and members of the local communities during questionnaire interviews.The authorized pollution limits, including the Standards Association of Zimbabwe (SAZ), the World Health Organization (WHO) maximum allowable limits were used as criteria for determining the effectiveness of the implemented mitigation measures. On that basis, some mitigation measures were found to be effective while others were not. The impact of mining on members of the local communities’ health and their limited involvement in monitoring of the implemented mitigation measures seemed to influence community perceptions on the effectiveness of the implemented mitigation measures.The study concludes by providing arguments in support of the MET conceptual framework as the first step towards holistically understanding the effectiveness of mitigation in EIA in practice. The study recommends the evaluation of mitigation effectiveness in EIA by not limiting to the quality of EISs alone, but also the implementation and monitoring of the mitigation measures in order to get a holistic picture of their effectiveness in practice. These findings suggest the need to strengthen the three components: quality of EIS, implementation and monitoring of mitigation in EISs.