Ghana has implemented regulation on the registration, distribution and usage of pesticides in order to evaluate their environmental and human health effects. However, environmental monitoring and certified laboratories for pesticide analysis are lacking. Pesticide misuse, misapplication, contamination of the environment and human exposure still continue, and little is known to what extent pesticide registration, distribution and use is properly implemented in Ghana. This study aimed at investigating how the pesticide policy operates in Ghana, how state (policy; national/local) and non-state (importers, dealers' and farmers) stakeholders function, what their challenges are, and to which extend the policy objectives are achieved. A conceptual framework based on the contextual interaction theory (CIT) was developed, and a review of Ghana's pesticide policy implementation with two empirical field studies on state policy and non-state policy actors was conducted, supplemented with secondary data, and a number of interviews conducted with stakeholders and informants were used. Results indicate that pesticides are registered in compliance with the law. Non-state actors scored low with respect to their mandate which likely results in environmental and human health risks. Significant association existed between Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s1066 8-018-0154-7) contains supplementary material, which is available to authorized users. 3educational level attained and knowledge (χ 2 = 3.614; P ≤ 0.05). Work experience or duration of farming also significantly influenced the knowledge of respondents (P < 0.001), as well as attitude (χ 2 = 15.328; P < 0.05). Work experience/duration of farming also significantly influenced attitude at 95% confidence level (P < 0.001), and duration of farming was significantly associated with farm management practices at 5% level of significance (P ≤ 0.05), while state actors are not motivated and resourced. It is recommended to perform preliminary risk assessment to the aquatic environment, to derive threshold levels which are protective of communities, to screen farmers for pesticide exposure and poisoning, to develop well-targeted training programmes for pesticide retailers and farmers on pesticide use, personal protective device use, as well as pesticide management and law. Additionally, pesticide policy implementers have to be motivated and resourced to carry out their mandate, being to execute the pesticide legislation.

The health of the lower basin of the Volta River in Ghana was evaluated in January–February and May–June 2016 using physicochemical parameters and benthic macroinvertebrates sampled at 10 locations. Selected environmental variables were compared to accepted environmental water quality standard values where applicable. Principal component analysis (PCA) and redundancy analysis (RDA) were used to analyse the association between the benthic macroinvertebrates distribution and physicochemical variables. Pesticide concentrations were generally below the limit of detection 0.01 and 0.005 µg/L for organophosphate/synthetic pyrethroid and organochlorines respectively. Nutrient levels were also generally low; however, significant differences existed between the values of physicochemical parameters at the different sampling sites and seasons (Monte Carlo permutation test; p = 0.002), as well as between the abundance of macroinvertebrates at the different sites and seasons (p = 0.002). The environmental variables dissolved oxygen (DO), phosphate, pH, substratum (p < 0.05), turbidity, conductivity, total dissolved solids, total solids and nitrate (0.05 < p < 0.10) significantly explained the variation in macroinvertebrate composition between sampling stations in the Volta River. Polypedilum fuscipenne, was positively correlated with turbidity and DO concentrations; Physa sp., Centroptilum sp., Centroptiloides sp., Phaon iridipennis and juvenile fish were positively correlated with nitrate concentration and pH and negatively correlated with turbidity and DO. Polluted sites were dominated by the snail Lymnaea glabra. This demonstrates that physicochemical parameters and macroinvertebrates could be applied to describe the water quality and improve the biomonitoring for water resources management and the environmental protection in the Lower Volta River.