A/HRC/31/24 12. The special procedure mandate holders also presented a report on communications sent by all mandate holders. The Special Rapporteurs on the rights to freedom of peaceful assembly and of association, on the promotion and protection of the right to freedom of opinion and expression and on extrajudicial, summary or arbitrary executions presented reports containing observations on communications transmitted to Governments and replies received. III. Thirtieth session of the Human Rights Council 13. At the thirtieth session of the Human Rights Council, the following 16 special procedure mandate holders, including 12 thematic and 4 country mandate holders, presented their reports: • Working Group of Experts on People of African Descent • Working Group on Arbitrary Detention • Working Group on Enforced or Involuntary Disappearances • Special Rapporteur on the implications for human rights of the environmentally sound management and disposal of hazardous substances and wastes • Special Rapporteur on the rights of indigenous peoples • Independent Expert on the promotion of a democratic and equitable international order • Working Group on the use of mercenaries as a means of violating human rights and impeding the exercise of the right of peoples to self-determination • Independent Expert on the enjoyment of all human rights by older persons • Special Rapporteur on contemporary forms of slavery, including its causes and consequences • Special Rapporteur on the promotion of truth, justice, reparation and guarantees of non-recurrence • Special Rapporteur on the negative impact of unilateral coercive measures on the enjoyment of human rights • Special Rapporteur on the human right to safe drinking water and sanitation • Special Rapporteur on the situation of human rights in Cambodia • Independent Expert on the situation of human rights in the Central African Republic • Independent Expert on the situation of human rights in Somalia • Independent Expert on the situation of human rights in the Sudan. 14. The special procedure mandate holders presented reports on their visits to 18 countries. The Working Group on Enforced or Involuntary Disappearances presented a follow-up report to its missions to Mexico and Timor-Leste. 15. The special procedure mandate holders also presented a report on communications sent by all mandate holders. 4